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/**
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* '$RCSfile$'
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* Purpose: A Class that implements replication for metacat
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* Copyright: 2000 Regents of the University of California and the
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* National Center for Ecological Analysis and Synthesis
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* Authors: Chad Berkley
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* Release: @release@
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*
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* '$Author: berkley $'
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* '$Date: 2001-12-20 12:13:11 -0800 (Thu, 20 Dec 2001) $'
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* '$Revision: 887 $'
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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package edu.ucsb.nceas.metacat;
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import java.util.*;
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import java.io.*;
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import java.sql.*;
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import java.net.*;
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import java.lang.*;
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import java.text.*;
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import javax.servlet.*;
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import javax.servlet.http.*;
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import org.xml.sax.*;
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public class MetacatReplication extends HttpServlet implements Runnable
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{
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private String deltaT;
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Timer replicationDaemon;
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private static MetaCatUtil util = new MetaCatUtil();
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private Vector fileLocks = new Vector();
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private Thread lockThread = null;
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/**
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* Initialize the servlet by creating appropriate database connections
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*/
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public void init(ServletConfig config) throws ServletException
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{
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//initialize db connections to handle any update requests
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MetaCatUtil util = new MetaCatUtil();
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deltaT = util.getOption("deltaT");
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//the default deltaT can be set from metacat.properties
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//create a thread to do the delta-T check but don't execute it yet
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replicationDaemon = new Timer(true);
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}
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public void destroy()
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{
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replicationDaemon.cancel();
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// System.out.println("Replication daemon cancelled.");
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}
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public void doGet (HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException
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{
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// Process the data and send back the response
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handleGetOrPost(request, response);
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}
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public void doPost(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException
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{
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// Process the data and send back the response
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handleGetOrPost(request, response);
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}
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private void handleGetOrPost(HttpServletRequest request,
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HttpServletResponse response)
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throws ServletException, IOException
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{
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PrintWriter out = response.getWriter();
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Hashtable params = new Hashtable();
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Enumeration paramlist = request.getParameterNames();
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// NOT NEEDED - doesn't provide enough security because of possible IP spoofing
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// REPLACED with running replication comminications over HTTPS
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// String requestingServerIP = request.getRemoteAddr();
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// InetAddress iaddr = InetAddress.getByName(requestingServerIP);
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// String requestingServer = iaddr.getHostName();
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while (paramlist.hasMoreElements()) {
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String name = (String)paramlist.nextElement();
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String[] value = request.getParameterValues(name);
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params.put(name, value);
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}
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String action = ((String[])params.get("action"))[0];
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String server = null;
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try {
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// check if the server is included in the list of replicated servers
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if ( !action.equals("servercontrol") &&
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!action.equals("stop") &&
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!action.equals("start") &&
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!action.equals("getall") ) {
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server = ((String[])params.get("server"))[0];
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if ( getServerCode(server) == 0 ) {
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System.out.println("Action \"" + action +
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"\" rejected for server: " + server);
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return;
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} else {
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System.out.println("Action \"" + action +
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"\" accepted for server: " + server);
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}
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}
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} catch (Exception e) {
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System.out.println("Error in MetacatReplication.handleGetOrPost: " +
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e.getMessage() );
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return;
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}
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if ( action.equals("stop") ) {
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//stop the replication server
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replicationDaemon.cancel();
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replicationDaemon = new Timer(true);
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out.println("Replication Handler Stopped");
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MetacatReplication.replLog("deltaT handler stopped");
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} else if ( action.equals("start") ) {
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//start the replication server
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int rate;
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if ( params.containsKey("rate") ) {
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rate = new Integer(
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new String(((String[])params.get("rate"))[0])).intValue();
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if(rate < 30) {
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out.println("Replication deltaT rate cannot be less than 30!");
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//deltaT<30 is a timing mess!
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rate = 1000;
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}
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} else {
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rate = 1000;
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}
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out.println("New rate is: " + rate + " seconds.");
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replicationDaemon.cancel();
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replicationDaemon = new Timer(true);
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replicationDaemon.scheduleAtFixedRate(new ReplicationHandler(out), 0,
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rate * 1000);
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out.println("Replication Handler Started");
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MetacatReplication.replLog("deltaT handler started with rate=" +
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rate + " seconds");
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} else if ( action.equals("getall") ) {
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//updates this server exactly once
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replicationDaemon.schedule(new ReplicationHandler(out), 0);
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response.setContentType("text/html");
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out.println("<html><body>\"Get All\" Done</body></html>");
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} else if ( action.equals("forcereplicate") ) {
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handleForceReplicateRequest(out, params, response);
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} else if ( action.equals("update") ) {
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//request an update list from the server
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handleUpdateRequest(out, params, response);
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} else if ( action.equals("read") ) {
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//request a specific document from the server
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//note that this could be replaced by a call to metacatServlet
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//handleGetDocumentAction().
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handleGetDocumentRequest(out, params, response);
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} else if ( action.equals("getlock") ) {
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handleGetLockRequest(out, params, response);
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} else if ( action.equals("getdocumentinfo") ) {
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handleGetDocumentInfoRequest(out, params, response);
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} else if ( action.equals("gettime") ) {
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handleGetTimeRequest(out, params, response);
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} else if ( action.equals("getcatalog") ) {
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handleGetCatalogRequest(out, params, response, true);
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} else if ( action.equals("servercontrol") ) {
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handleServerControlRequest(out, params, response);
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}
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out.close();
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}
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/**
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* This method can add, delete and list the servers currently included in
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* xml_replication.
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* action subaction other needed params
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* ---------------------------------------------------------
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* servercontrol add server
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* servercontrol delete server
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* servercontrol list
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*/
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private void handleServerControlRequest(PrintWriter out, Hashtable params,
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HttpServletResponse response)
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{
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String subaction = ((String[])params.get("subaction"))[0];
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Connection conn = null;
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try {
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conn = util.openDBConnection();
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PreparedStatement pstmt = null;
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// add server to server list
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if ( subaction.equals("add") ) {
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String replicate = ((String[])params.get("replicate"))[0];
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String server = ((String[])params.get("server"))[0];
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pstmt = conn.prepareStatement("INSERT INTO xml_replication " +
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"(server, last_checked, replicate) " +
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"VALUES ('" + server + "', to_date(" +
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"'01/01/00', 'MM/DD/YY'), '" +
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replicate + "')");
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pstmt.execute();
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pstmt.close();
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conn.commit();
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out.println("Server " + server + " added");
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response.setContentType("text/html");
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out.println("<html><body><table border=\"1\">");
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out.println("<tr><td><b>server</b></td><td><b>last_checked</b></td><td>");
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out.println("<b>replicate</b></td></tr>");
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pstmt = conn.prepareStatement("SELECT * FROM xml_replication");
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pstmt.execute();
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ResultSet rs = pstmt.getResultSet();
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boolean tablehasrows = rs.next();
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while(tablehasrows) {
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out.println("<tr><td>" + rs.getString(2) + "</td><td>");
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out.println(rs.getString(3) + "</td><td>");
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out.println(rs.getString(4) + "</td></tr>");
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tablehasrows = rs.next();
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}
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out.println("</table></body></html>");
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// download certificate with the public key on this server
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// and import it as a trusted certificate
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String certURL = ((String[])params.get("certificate"))[0];
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downloadCertificate(certURL);
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// delete server from server list
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} else if ( subaction.equals("delete") ) {
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String server = ((String[])params.get("server"))[0];
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pstmt = conn.prepareStatement("DELETE FROM xml_replication " +
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"WHERE server LIKE '" + server + "'");
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pstmt.execute();
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pstmt.close();
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conn.commit();
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out.println("Server " + server + " deleted");
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response.setContentType("text/html");
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out.println("<html><body><table border=\"1\">");
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out.println("<tr><td><b>server</b></td><td><b>last_checked</b></td><td>");
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out.println("<b>replicate</b></td></tr>");
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pstmt = conn.prepareStatement("SELECT * FROM xml_replication");
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pstmt.execute();
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ResultSet rs = pstmt.getResultSet();
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boolean tablehasrows = rs.next();
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while(tablehasrows)
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{
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out.println("<tr><td>" + rs.getString(2) + "</td><td>");
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out.println(rs.getString(3) + "</td><td>");
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out.println(rs.getString(4) + "</td></tr>");
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tablehasrows = rs.next();
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}
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out.println("</table></body></html>");
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// list servers in server list
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} else if ( subaction.equals("list") ) {
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response.setContentType("text/html");
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out.println("<html><body><table border=\"1\">");
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out.println("<tr><td><b>server</b></td><td><b>last_checked</b></td><td>");
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out.println("<b>replicate</b></td></tr>");
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pstmt = conn.prepareStatement("SELECT * FROM xml_replication");
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pstmt.execute();
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ResultSet rs = pstmt.getResultSet();
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boolean tablehasrows = rs.next();
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while(tablehasrows) {
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out.println("<tr><td>" + rs.getString(2) + "</td><td>");
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out.println(rs.getString(3) + "</td><td>");
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out.println(rs.getString(4) + "</td></tr>");
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tablehasrows = rs.next();
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}
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out.println("</table></body></html>");
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}
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pstmt.close();
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conn.close();
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} catch(Exception e) {
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System.out.println("Error in " +
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"MetacatReplication.handleServerControlRequest " +
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e.getMessage());
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e.printStackTrace(System.out);
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}
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}
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// download certificate with the public key from certURL and
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// upload it onto this server; it then must be imported as a
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// trusted certificate
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private void downloadCertificate (String certURL)
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throws FileNotFoundException, IOException, MalformedURLException
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{
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MetaCatUtil util = new MetaCatUtil();
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String certPath = util.getOption("certPath"); //the path to be uploaded to
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// get filename from the URL of the certificate
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String filename = certURL;
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int slash = Math.max(filename.lastIndexOf('/'), filename.lastIndexOf('\\'));
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if ( slash > -1 ) {
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filename = filename.substring(slash + 1);
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}
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// open file output strem to write the input into it
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File f = new File(certPath, filename);
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synchronized (f) {
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try {
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if ( f.exists() ) {
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throw new IOException("File already exist: " + f.getCanonicalFile());
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//if ( f.exists() && !f.canWrite() ) {
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// throw new IOException("Not writable: " + f.getCanonicalFile());
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}
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} catch (SecurityException se) {
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// if a security manager exists,
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// its checkRead method is called for f.exist()
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// or checkWrite method is called for f.canWrite()
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throw se;
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}
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// create a buffered byte output stream
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// that uses a default-sized output buffer
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FileOutputStream fos = new FileOutputStream(f);
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BufferedOutputStream out = new BufferedOutputStream(fos);
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// this should be http url
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URL url = new URL(certURL);
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BufferedInputStream bis = null;
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try {
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bis = new BufferedInputStream(url.openStream());
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byte[] buf = new byte[4 * 1024]; // 4K buffer
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int b = bis.read(buf);
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while (b != -1) {
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out.write(buf, 0, b);
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b = bis.read(buf);
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}
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} finally {
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if (bis != null) bis.close();
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}
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// the input and the output streams must be closed
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bis.close();
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357
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out.flush();
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out.close();
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359
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fos.close();
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360
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} // end of synchronized(f)
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361
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}
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362
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|
363
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/**
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364
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* when a forcereplication request comes in, this method sends a read request
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* to the requesting server for the specified docid.
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366
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*/
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367
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private void handleForceReplicateRequest(PrintWriter out, Hashtable params,
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368
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HttpServletResponse response)
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369
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{
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370
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String server = ((String[])params.get("server"))[0]; // the server that
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String docid = ((String[])params.get("docid"))[0]; // sent the document
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372
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String dbaction = "UPDATE"; // the default action is UPDATE
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boolean override = false;
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int serverCode = 1;
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375
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376
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try {
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377
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//if the url contains a dbaction then the default action is overridden
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378
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if(params.containsKey("dbaction")) {
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379
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dbaction = ((String[])params.get("dbaction"))[0];
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380
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serverCode = MetacatReplication.getServerCode(server);
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override = true; //we are now overriding the default action
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382
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}
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MetacatReplication.replLog("force replication request from " + server);
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384
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|
385
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// sending back read request to server
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386
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URL u = new URL("https://" + server + "?action=read&docid=" + docid);
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387
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String xmldoc = MetacatReplication.getURLContent(u);
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388
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389
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// get the document info from server
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390
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URL docinfourl = new URL("https://" + server +
|
391
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"?action=getdocumentinfo&docid=" + docid);
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392
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String docInfoStr = MetacatReplication.getURLContent(docinfourl);
|
393
|
|
394
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//dih is the parser for the docinfo xml format
|
395
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DocInfoHandler dih = new DocInfoHandler();
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396
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XMLReader docinfoParser = ReplicationHandler.initParser(dih);
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docinfoParser.parse(new InputSource(new StringReader(docInfoStr)));
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398
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Hashtable docinfoHash = dih.getDocInfo();
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399
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String user = (String)docinfoHash.get("user_owner");
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400
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|
401
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// write the document here
|
402
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System.out.println("Open db connection");
|
403
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Connection conn = util.openDBConnection();
|
404
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System.out.println("DB connection opened");
|
405
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DocumentImpl.write(conn, new StringReader(xmldoc), null, dbaction, docid,
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user, null, serverCode, override);
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407
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conn.close();
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408
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409
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MetacatReplication.replLog("document " + docid + " added to DB with " +
|
410
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"action " + dbaction);
|
411
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} catch(Exception e) {
|
412
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System.out.println("ERROR in MetacatReplication.handleForceReplicate" +
|
413
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"Request(): " + e.getMessage());
|
414
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}
|
415
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}
|
416
|
|
417
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/**
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418
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* Grants or denies a lock to a requesting host.
|
419
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* The servlet parameters of interrest are:
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420
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* docid: the docid of the file the lock is being requested for
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421
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* currentdate: the timestamp of the document on the remote server
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422
|
*
|
423
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*/
|
424
|
private void handleGetLockRequest(PrintWriter out, Hashtable params,
|
425
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HttpServletResponse response)
|
426
|
{
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427
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Connection conn = null;
|
428
|
try
|
429
|
{
|
430
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
431
|
"handleGetLockRequest");
|
432
|
String docid = ((String[])params.get("docid"))[0];
|
433
|
String remoteRev = ((String[])params.get("updaterev"))[0];
|
434
|
DocumentImpl requestDoc = new DocumentImpl(conn, docid);
|
435
|
MetacatReplication.replLog("lock request for " + docid);
|
436
|
int localRevInt = requestDoc.getRev();
|
437
|
int remoteRevInt = Integer.parseInt(remoteRev);
|
438
|
|
439
|
if(remoteRevInt >= localRevInt)
|
440
|
{
|
441
|
if(!fileLocks.contains(docid))
|
442
|
{ //grant the lock if it is not already locked
|
443
|
fileLocks.add(0, docid); //insert at the beginning of the queue Vector
|
444
|
//send a message back to the the remote host authorizing the insert
|
445
|
out.println("<lockgranted><docid>" +docid+ "</docid></lockgranted>");
|
446
|
lockThread = new Thread(this);
|
447
|
lockThread.setPriority(Thread.MIN_PRIORITY);
|
448
|
lockThread.start();
|
449
|
System.out.println("lock granted for " + docid);
|
450
|
MetacatReplication.replLog("lock granted for " + docid);
|
451
|
}
|
452
|
else
|
453
|
{ //deny the lock
|
454
|
out.println("<filelocked><docid>" + docid + "</docid></filelocked>");
|
455
|
MetacatReplication.replLog("lock denied for " + docid +
|
456
|
"reason: file already locked");
|
457
|
}
|
458
|
}
|
459
|
else
|
460
|
{//deny the lock.
|
461
|
out.println("<outdatedfile><docid>" + docid + "</docid></filelocked>");
|
462
|
MetacatReplication.replLog("lock denied for " + docid +
|
463
|
"reason: client has outdated file");
|
464
|
}
|
465
|
conn.close();
|
466
|
}
|
467
|
catch(Exception e)
|
468
|
{
|
469
|
System.out.println("error requesting file lock from MetacatReplication." +
|
470
|
"handleGetLockRequest: " + e.getMessage());
|
471
|
e.printStackTrace(System.out);
|
472
|
}
|
473
|
}
|
474
|
|
475
|
/**
|
476
|
* Sends all of the xml_documents information encoded in xml to a requestor
|
477
|
* the format is:
|
478
|
* <!ELEMENT documentinfo (docid, docname, doctype, doctitle, user_owner,
|
479
|
* user_updated, public_access, rev)
|
480
|
* all of the subelements of document info are #PCDATA
|
481
|
*/
|
482
|
private void handleGetDocumentInfoRequest(PrintWriter out, Hashtable params,
|
483
|
HttpServletResponse response)
|
484
|
{
|
485
|
String docid = ((String[])(params.get("docid")))[0];
|
486
|
StringBuffer sb = new StringBuffer();
|
487
|
Connection conn = null;
|
488
|
try
|
489
|
{
|
490
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
491
|
"handleGetDocumentInfoRequest");
|
492
|
DocumentImpl doc = new DocumentImpl(conn, docid);
|
493
|
sb.append("<documentinfo><docid>").append(docid);
|
494
|
sb.append("</docid><docname>").append(doc.getDocname());
|
495
|
sb.append("</docname><doctype>").append(doc.getDoctype());
|
496
|
sb.append("</doctype>");
|
497
|
// DOCTITLE attr cleared from the db
|
498
|
// sb.append("</doctype><doctitle>").append(doc.getDocTitle());
|
499
|
sb.append("<user_owner>").append(doc.getUserowner());
|
500
|
sb.append("</user_owner><user_updated>").append(doc.getUserupdated());
|
501
|
sb.append("</user_updated><public_access>").append(doc.getPublicaccess());
|
502
|
sb.append("</public_access><rev>").append(doc.getRev());
|
503
|
sb.append("</rev></documentinfo>");
|
504
|
response.setContentType("text/xml");
|
505
|
out.println(sb.toString());
|
506
|
conn.close();
|
507
|
}
|
508
|
catch (Exception e)
|
509
|
{
|
510
|
System.out.println("error in " +
|
511
|
"metacatReplication.handlegetdocumentinforequest: " +
|
512
|
e.getMessage());
|
513
|
}
|
514
|
|
515
|
}
|
516
|
|
517
|
/**
|
518
|
* Sends a document to a remote host
|
519
|
*/
|
520
|
private void handleGetDocumentRequest(PrintWriter out, Hashtable params,
|
521
|
HttpServletResponse response)
|
522
|
{
|
523
|
Connection conn = null;
|
524
|
try
|
525
|
{
|
526
|
String docid = ((String[])(params.get("docid")))[0];
|
527
|
System.out.println("incoming get request for document: " + docid);
|
528
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
529
|
"handleGetDocumentRequest");
|
530
|
DocumentImpl di = new DocumentImpl(conn, docid);
|
531
|
response.setContentType("text/xml");
|
532
|
out.print(di.toString());
|
533
|
conn.close();
|
534
|
MetacatReplication.replLog("document " + docid + " sent");
|
535
|
System.out.println("document " + docid + " sent");
|
536
|
}
|
537
|
catch(Exception e)
|
538
|
{
|
539
|
System.out.println("error getting document from MetacatReplication." +
|
540
|
"handlGetDocumentRequest " + e.getMessage());
|
541
|
e.printStackTrace(System.out);
|
542
|
}
|
543
|
|
544
|
}
|
545
|
|
546
|
/**
|
547
|
* Sends a list of all of the documents on this sever along with their
|
548
|
* revision numbers.
|
549
|
* The format is:
|
550
|
* <!ELEMENT replication (server, updates)>
|
551
|
* <!ELEMENT server (#PCDATA)>
|
552
|
* <!ELEMENT updates ((updatedDocument | deleteDocument)*)>
|
553
|
* <!ELEMENT updatedDocument (docid, rev)>
|
554
|
* <!ELEMENT deletedDocument (docid, rev)>
|
555
|
* <!ELEMENT docid (#PCDATA)>
|
556
|
* <!ELEMENT rev (#PCDATA)>
|
557
|
* note that the rev in deletedDocument is always empty. I just left
|
558
|
* it in there to make the parser implementation easier.
|
559
|
*/
|
560
|
private void handleUpdateRequest(PrintWriter out, Hashtable params,
|
561
|
HttpServletResponse response)
|
562
|
{
|
563
|
Connection conn = null;
|
564
|
try
|
565
|
{
|
566
|
System.out.println("received update request");
|
567
|
StringBuffer docsql = new StringBuffer();
|
568
|
StringBuffer doclist = new StringBuffer();
|
569
|
Vector packageFiles = new Vector();
|
570
|
|
571
|
//get all docs that reside on this server
|
572
|
doclist.append("<?xml version=\"1.0\"?><replication>");
|
573
|
doclist.append("<server>").append(util.getOption("server"));
|
574
|
doclist.append(util.getOption("replicationpath"));
|
575
|
doclist.append("</server><updates>");
|
576
|
|
577
|
docsql.append("select docid, rev, doctype from xml_documents where ");
|
578
|
docsql.append("server_location = 1");
|
579
|
|
580
|
//get any deleted documents
|
581
|
StringBuffer delsql = new StringBuffer();
|
582
|
delsql.append("select distinct docid from ");
|
583
|
delsql.append("xml_revisions where docid not in (select docid from ");
|
584
|
delsql.append("xml_documents) and server_location = 1");
|
585
|
|
586
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
587
|
"handleUpdateRequest");
|
588
|
PreparedStatement pstmt = conn.prepareStatement(docsql.toString());
|
589
|
pstmt.execute();
|
590
|
ResultSet rs = pstmt.getResultSet();
|
591
|
boolean tablehasrows = rs.next();
|
592
|
while(tablehasrows)
|
593
|
{
|
594
|
String recordDoctype = rs.getString(3);
|
595
|
if(!recordDoctype.equals("BIN"))
|
596
|
{ //don't replicate data files
|
597
|
Vector packagedoctypes = MetaCatUtil.getOptionList(
|
598
|
MetaCatUtil.getOption("packagedoctype"));
|
599
|
if(!packagedoctypes.contains(recordDoctype))
|
600
|
{ //if this is a package file, put it at the end
|
601
|
//because if a package file is read before all of the files it
|
602
|
//refers to are loaded then there is an error
|
603
|
doclist.append("<updatedDocument>");
|
604
|
doclist.append("<docid>").append(rs.getString(1));
|
605
|
doclist.append("</docid><rev>").append(rs.getInt(2));
|
606
|
doclist.append("</rev>");
|
607
|
doclist.append("</updatedDocument>");
|
608
|
}
|
609
|
else
|
610
|
{ //the package files are saved to be put into the xml later.
|
611
|
Vector v = new Vector();
|
612
|
v.add(new String(rs.getString(1)));
|
613
|
v.add(new Integer(rs.getInt(2)));
|
614
|
packageFiles.add(new Vector(v));
|
615
|
}
|
616
|
}
|
617
|
tablehasrows = rs.next();
|
618
|
}
|
619
|
|
620
|
pstmt = conn.prepareStatement(delsql.toString());
|
621
|
pstmt.execute();
|
622
|
rs = pstmt.getResultSet();
|
623
|
tablehasrows = rs.next();
|
624
|
while(tablehasrows)
|
625
|
{ //handle the deleted documents
|
626
|
doclist.append("<deletedDocument><docid>").append(rs.getString(1));
|
627
|
doclist.append("</docid><rev></rev></deletedDocument>");
|
628
|
//note that rev is always empty for deleted docs
|
629
|
tablehasrows = rs.next();
|
630
|
}
|
631
|
|
632
|
//now we can put the package files into the xml results
|
633
|
for(int i=0; i<packageFiles.size(); i++)
|
634
|
{
|
635
|
Vector v = (Vector)packageFiles.elementAt(i);
|
636
|
doclist.append("<updatedDocument>");
|
637
|
doclist.append("<docid>").append((String)v.elementAt(0));
|
638
|
doclist.append("</docid><rev>");
|
639
|
doclist.append(((Integer)v.elementAt(1)).intValue());
|
640
|
doclist.append("</rev>");
|
641
|
doclist.append("</updatedDocument>");
|
642
|
}
|
643
|
|
644
|
doclist.append("</updates></replication>");
|
645
|
MetaCatUtil.debugMessage("doclist: " + doclist.toString());
|
646
|
pstmt.close();
|
647
|
conn.close();
|
648
|
response.setContentType("text/xml");
|
649
|
out.println(doclist.toString());
|
650
|
System.out.println("doclist: " + doclist.toString());
|
651
|
System.out.println("update request handled");
|
652
|
}
|
653
|
catch(Exception e)
|
654
|
{
|
655
|
System.out.println("error in MetacatReplication.handleupdaterequest: " +
|
656
|
e.getMessage());
|
657
|
e.printStackTrace(System.out);
|
658
|
}
|
659
|
|
660
|
}
|
661
|
|
662
|
/**
|
663
|
* Returns the xml_catalog table encoded in xml
|
664
|
*/
|
665
|
public static String getCatalogXML()
|
666
|
{
|
667
|
return handleGetCatalogRequest(null, null, null, false);
|
668
|
}
|
669
|
|
670
|
/**
|
671
|
* Sends the contents of the xml_catalog table encoded in xml
|
672
|
* The xml format is:
|
673
|
* <!ELEMENT xml_catalog (row*)>
|
674
|
* <!ELEMENT row (entry_type, source_doctype, target_doctype, public_id,
|
675
|
* system_id)>
|
676
|
* All of the sub elements of row are #PCDATA
|
677
|
|
678
|
* If printFlag == false then do not print to out.
|
679
|
*/
|
680
|
private static String handleGetCatalogRequest(PrintWriter out,
|
681
|
Hashtable params,
|
682
|
HttpServletResponse response,
|
683
|
boolean printFlag)
|
684
|
{
|
685
|
Connection conn = null;
|
686
|
PreparedStatement pstmt = null;
|
687
|
try
|
688
|
{
|
689
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
690
|
"handleGetCatalogRequest");
|
691
|
pstmt = conn.prepareStatement("select entry_type, " +
|
692
|
"source_doctype, target_doctype, public_id, " +
|
693
|
"system_id from xml_catalog");
|
694
|
pstmt.execute();
|
695
|
ResultSet rs = pstmt.getResultSet();
|
696
|
boolean tablehasrows = rs.next();
|
697
|
StringBuffer sb = new StringBuffer();
|
698
|
sb.append("<?xml version=\"1.0\"?><xml_catalog>");
|
699
|
while(tablehasrows)
|
700
|
{
|
701
|
sb.append("<row><entry_type>").append(rs.getString(1));
|
702
|
sb.append("</entry_type><source_doctype>").append(rs.getString(2));
|
703
|
sb.append("</source_doctype><target_doctype>").append(rs.getString(3));
|
704
|
sb.append("</target_doctype><public_id>").append(rs.getString(4));
|
705
|
sb.append("</public_id><system_id>").append(rs.getString(5));
|
706
|
sb.append("</system_id></row>");
|
707
|
|
708
|
tablehasrows = rs.next();
|
709
|
}
|
710
|
sb.append("</xml_catalog>");
|
711
|
conn.close();
|
712
|
if(printFlag)
|
713
|
{
|
714
|
response.setContentType("text/xml");
|
715
|
out.println(sb.toString());
|
716
|
}
|
717
|
pstmt.close();
|
718
|
return sb.toString();
|
719
|
}
|
720
|
catch(Exception e)
|
721
|
{
|
722
|
try
|
723
|
{
|
724
|
pstmt.close();
|
725
|
conn.close();
|
726
|
}
|
727
|
catch(Exception ee)
|
728
|
{}
|
729
|
System.out.println("error in MetacatReplication.handleGetCatalogRequest:"+
|
730
|
e.getMessage());
|
731
|
e.printStackTrace(System.out);
|
732
|
}
|
733
|
return null;
|
734
|
}
|
735
|
|
736
|
/**
|
737
|
* Sends the current system date to the remote server. Using this action
|
738
|
* for replication gets rid of any problems with syncronizing clocks
|
739
|
* because a time specific to a document is always kept on its home server.
|
740
|
*/
|
741
|
private void handleGetTimeRequest(PrintWriter out, Hashtable params,
|
742
|
HttpServletResponse response)
|
743
|
{
|
744
|
SimpleDateFormat formatter = new SimpleDateFormat ("yy-MM-dd HH:mm:ss");
|
745
|
java.util.Date localtime = new java.util.Date();
|
746
|
String dateString = formatter.format(localtime);
|
747
|
response.setContentType("text/xml");
|
748
|
|
749
|
out.println("<timestamp>" + dateString + "</timestamp>");
|
750
|
}
|
751
|
|
752
|
/**
|
753
|
* this method handles the timeout for a file lock. when a lock is
|
754
|
* granted it is granted for 30 seconds. When this thread runs out
|
755
|
* it deletes the docid from the queue, thus eliminating the lock.
|
756
|
*/
|
757
|
public void run()
|
758
|
{
|
759
|
try
|
760
|
{
|
761
|
MetaCatUtil.debugMessage("thread started for docid: " +
|
762
|
(String)fileLocks.elementAt(0));
|
763
|
System.out.println("thread started for docid: " +
|
764
|
(String)fileLocks.elementAt(0));
|
765
|
Thread.sleep(30000); //the lock will expire in 30 seconds
|
766
|
MetaCatUtil.debugMessage("thread for docid: " +
|
767
|
(String)fileLocks.elementAt(fileLocks.size() - 1) +
|
768
|
" exiting.");
|
769
|
System.out.println("thread for docid: " +
|
770
|
(String)fileLocks.elementAt(fileLocks.size() - 1) +
|
771
|
" exiting.");
|
772
|
fileLocks.remove(fileLocks.size() - 1);
|
773
|
//fileLocks is treated as a FIFO queue. If there are more than one lock
|
774
|
//in the vector, the first one inserted will be removed.
|
775
|
}
|
776
|
catch(Exception e)
|
777
|
{
|
778
|
System.out.println("error in file lock thread from MetacatReplication." +
|
779
|
"run: " + e.getMessage());
|
780
|
}
|
781
|
}
|
782
|
|
783
|
/**
|
784
|
* Returns the name of a server given a serverCode
|
785
|
* @param serverCode the serverid of the server
|
786
|
* @return the servername or null if the specified serverCode does not
|
787
|
* exist.
|
788
|
*/
|
789
|
public static String getServer(int serverCode)
|
790
|
{
|
791
|
//System.out.println("serverid: " + serverCode);
|
792
|
Connection conn = null;
|
793
|
try
|
794
|
{
|
795
|
conn = MetacatReplication.getDBConnection("MetacatReplication." +
|
796
|
"getServer");
|
797
|
String sql = new String("select server from " +
|
798
|
"xml_replication where serverid = " +
|
799
|
serverCode);
|
800
|
PreparedStatement pstmt = conn.prepareStatement(sql);
|
801
|
//System.out.println("getserver sql: " + sql);
|
802
|
pstmt.execute();
|
803
|
ResultSet rs = pstmt.getResultSet();
|
804
|
boolean tablehasrows = rs.next();
|
805
|
if(tablehasrows)
|
806
|
{
|
807
|
//System.out.println("server: " + rs.getString(1));
|
808
|
return rs.getString(1);
|
809
|
}
|
810
|
pstmt.close();
|
811
|
conn.close();
|
812
|
}
|
813
|
catch(Exception e)
|
814
|
{
|
815
|
System.out.println("Error in MetacatReplication.getServer: " +
|
816
|
e.getMessage());
|
817
|
}
|
818
|
return null;
|
819
|
//return null if the server does not exist
|
820
|
}
|
821
|
|
822
|
/**
|
823
|
* Returns a server code given a server name
|
824
|
* @param server the name of the server
|
825
|
* @return integer > 0 representing the code of the server, 0 if the server
|
826
|
* does not exist.
|
827
|
*/
|
828
|
public static int getServerCode(String server) throws Exception
|
829
|
{
|
830
|
Connection conn = null;
|
831
|
PreparedStatement pstmt = null;
|
832
|
int serverCode = 0;
|
833
|
|
834
|
try {
|
835
|
|
836
|
conn = util.openDBConnection();
|
837
|
pstmt = conn.prepareStatement("SELECT serverid FROM xml_replication " +
|
838
|
"WHERE server LIKE '" + server + "'");
|
839
|
pstmt.execute();
|
840
|
ResultSet rs = pstmt.getResultSet();
|
841
|
boolean tablehasrows = rs.next();
|
842
|
if ( tablehasrows ) {
|
843
|
serverCode = rs.getInt(1);
|
844
|
pstmt.close();
|
845
|
conn.close();
|
846
|
return serverCode;
|
847
|
}
|
848
|
|
849
|
} catch(Exception e) {
|
850
|
throw e;
|
851
|
|
852
|
} finally {
|
853
|
try {
|
854
|
pstmt.close();
|
855
|
conn.close();
|
856
|
} catch(Exception ee) {}
|
857
|
}
|
858
|
|
859
|
return serverCode;
|
860
|
}
|
861
|
|
862
|
/**
|
863
|
* This method returns the content of a url
|
864
|
* @param u the url to return the content from
|
865
|
* @return a string representing the content of the url
|
866
|
* @throws java.io.IOException
|
867
|
*/
|
868
|
public static String getURLContent(URL u) throws java.io.IOException
|
869
|
{
|
870
|
//System.out.println("url: " + u.toString());
|
871
|
char istreamChar;
|
872
|
int istreamInt;
|
873
|
InputStreamReader istream = new InputStreamReader(u.openStream());
|
874
|
StringBuffer serverResponse = new StringBuffer();
|
875
|
while((istreamInt = istream.read()) != -1)
|
876
|
{
|
877
|
istreamChar = (char)istreamInt;
|
878
|
serverResponse.append(istreamChar);
|
879
|
}
|
880
|
|
881
|
return serverResponse.toString();
|
882
|
}
|
883
|
|
884
|
/**
|
885
|
* Method for writing replication messages to a log file specified in
|
886
|
* metacat.properties
|
887
|
*/
|
888
|
public static void replLog(String message)
|
889
|
{
|
890
|
try
|
891
|
{
|
892
|
FileOutputStream fos = new FileOutputStream(
|
893
|
util.getOption("replicationlog"), true);
|
894
|
PrintWriter pw = new PrintWriter(fos);
|
895
|
SimpleDateFormat formatter = new SimpleDateFormat ("yy-MM-dd HH:mm:ss");
|
896
|
java.util.Date localtime = new java.util.Date();
|
897
|
String dateString = formatter.format(localtime);
|
898
|
dateString += " :: " + message;
|
899
|
//time stamp each entry
|
900
|
pw.println(dateString);
|
901
|
pw.flush();
|
902
|
}
|
903
|
catch(Exception e)
|
904
|
{
|
905
|
System.out.println("error writing to replication log from " +
|
906
|
"MetacatReplication.replLog: " + e.getMessage());
|
907
|
//e.printStackTrace(System.out);
|
908
|
}
|
909
|
}
|
910
|
|
911
|
/**
|
912
|
* Returns true if the replicate field for server in xml_replication is 1.
|
913
|
* Returns false otherwise
|
914
|
*/
|
915
|
public static boolean replToServer(String server)
|
916
|
{
|
917
|
Connection conn = null;
|
918
|
PreparedStatement pstmt = null;
|
919
|
try
|
920
|
{
|
921
|
conn = MetacatReplication.getDBConnection("MetacatReplication.replToServer");
|
922
|
pstmt = conn.prepareStatement("select replicate from " +
|
923
|
"xml_replication where server like '" +
|
924
|
server + "'");
|
925
|
pstmt.execute();
|
926
|
ResultSet rs = pstmt.getResultSet();
|
927
|
boolean tablehasrows = rs.next();
|
928
|
if(tablehasrows)
|
929
|
{
|
930
|
int i = rs.getInt(1);
|
931
|
if(i == 1)
|
932
|
{
|
933
|
pstmt.close();
|
934
|
conn.close();
|
935
|
return true;
|
936
|
}
|
937
|
else
|
938
|
{
|
939
|
pstmt.close();
|
940
|
conn.close();
|
941
|
return false;
|
942
|
}
|
943
|
}
|
944
|
}
|
945
|
catch(Exception e)
|
946
|
{
|
947
|
System.out.println("error in MetacatReplication.replToServer: " +
|
948
|
e.getMessage());
|
949
|
}
|
950
|
finally
|
951
|
{
|
952
|
try
|
953
|
{
|
954
|
pstmt.close();
|
955
|
conn.close();
|
956
|
}
|
957
|
catch(Exception ee)
|
958
|
{}
|
959
|
}
|
960
|
return false;
|
961
|
//the default if this server does not exist is to not replicate to it.
|
962
|
}
|
963
|
|
964
|
/**
|
965
|
* A method for redundantly trying to connect. this method will attempt to
|
966
|
* connect to the DB 3 times before failing.
|
967
|
* @param methodname the methodname from which this method is called.
|
968
|
*/
|
969
|
public static Connection getDBConnection(String methodname) throws Exception
|
970
|
{
|
971
|
Connection conn = null;
|
972
|
try
|
973
|
{
|
974
|
try
|
975
|
{ //this connection is prone to error for some reason so we
|
976
|
//try to connect it three times before quiting.
|
977
|
conn = util.openDBConnection();
|
978
|
return conn;
|
979
|
}
|
980
|
catch(SQLException sqle)
|
981
|
{
|
982
|
try
|
983
|
{
|
984
|
conn = util.openDBConnection();
|
985
|
return conn;
|
986
|
}
|
987
|
catch(SQLException sqlee)
|
988
|
{
|
989
|
try
|
990
|
{
|
991
|
conn = util.openDBConnection();
|
992
|
return conn;
|
993
|
}
|
994
|
catch(SQLException sqleee)
|
995
|
{
|
996
|
System.out.println("error getting db connection in " +
|
997
|
methodname + ": " +
|
998
|
sqleee.getMessage());
|
999
|
return conn;
|
1000
|
}
|
1001
|
}
|
1002
|
}
|
1003
|
}
|
1004
|
catch(Exception e)
|
1005
|
{
|
1006
|
throw new java.lang.Exception("error in " + methodname + ": " +
|
1007
|
e.getMessage());
|
1008
|
}
|
1009
|
}
|
1010
|
}
|