1
|
/**
|
2
|
* '$RCSfile$'
|
3
|
* Purpose: A class to asyncronously do delta-T replication checking
|
4
|
* Copyright: 2000 Regents of the University of California and the
|
5
|
* National Center for Ecological Analysis and Synthesis
|
6
|
* Authors: Chad Berkley
|
7
|
* Release: @release@
|
8
|
*
|
9
|
* '$Author: berkley $'
|
10
|
* '$Date: 2000-11-09 13:21:43 -0800 (Thu, 09 Nov 2000) $'
|
11
|
* '$Revision: 520 $'
|
12
|
*/
|
13
|
|
14
|
package edu.ucsb.nceas.metacat;
|
15
|
|
16
|
import java.sql.*;
|
17
|
import java.util.*;
|
18
|
import java.lang.Thread;
|
19
|
import java.io.*;
|
20
|
import java.net.*;
|
21
|
import org.xml.sax.AttributeList;
|
22
|
import org.xml.sax.ContentHandler;
|
23
|
import org.xml.sax.DTDHandler;
|
24
|
import org.xml.sax.EntityResolver;
|
25
|
import org.xml.sax.ErrorHandler;
|
26
|
import org.xml.sax.InputSource;
|
27
|
import org.xml.sax.XMLReader;
|
28
|
import org.xml.sax.SAXException;
|
29
|
import org.xml.sax.SAXParseException;
|
30
|
import org.xml.sax.helpers.XMLReaderFactory;
|
31
|
|
32
|
/**
|
33
|
* This class handles deltaT replication checking. Whenever this TimerTask
|
34
|
* is fired it checks each server in xml_replication for updates and updates
|
35
|
* the local db as needed.
|
36
|
*/
|
37
|
public class replicationHandler extends TimerTask
|
38
|
{
|
39
|
MetaCatUtil util = new MetaCatUtil();
|
40
|
Hashtable serverList = new Hashtable();
|
41
|
Connection conn;
|
42
|
PrintWriter out;
|
43
|
|
44
|
public replicationHandler(PrintWriter o)
|
45
|
{
|
46
|
this.out = o;
|
47
|
}
|
48
|
|
49
|
/**
|
50
|
* Method that implements TimerTask.run(). It runs whenever the timer is
|
51
|
* fired.
|
52
|
*/
|
53
|
public void run()
|
54
|
{
|
55
|
System.out.println("replicationHandler is running");
|
56
|
//find out the last_checked time of each server in the server list and
|
57
|
//send a query to each server to see if there are any documents in
|
58
|
//xml_documents with an update_date > last_checked
|
59
|
try
|
60
|
{
|
61
|
conn = util.openDBConnection();
|
62
|
serverList = buildServerList(conn);
|
63
|
System.out.println("Server list: " + serverList.toString());
|
64
|
update(serverList, conn);
|
65
|
}
|
66
|
catch (Exception e)
|
67
|
{
|
68
|
System.out.println("Error in replicationHandler.run(): " + e.getMessage());
|
69
|
}
|
70
|
}
|
71
|
|
72
|
private void update(Hashtable serverList, Connection conn)
|
73
|
{
|
74
|
PreparedStatement pstmt;
|
75
|
Enumeration keys;
|
76
|
int istreamInt;
|
77
|
char istreamChar;
|
78
|
StringBuffer serverResponse = new StringBuffer();
|
79
|
String server;
|
80
|
String update;
|
81
|
Vector responses = new Vector();
|
82
|
replMessageHandler message = new replMessageHandler();
|
83
|
|
84
|
try
|
85
|
{
|
86
|
//build a list of servers with updated documents. Choose the newest
|
87
|
//one out of the list, update this server, update last_checked
|
88
|
|
89
|
keys = serverList.keys();
|
90
|
while(keys.hasMoreElements())
|
91
|
{ //update from one server at a time
|
92
|
server = (String)(keys.nextElement());
|
93
|
update = (String)(serverList.get(server));
|
94
|
//send the server a date and it will send back any docid that has
|
95
|
//been modified after that date
|
96
|
|
97
|
update = update.replace(' ', '+');
|
98
|
|
99
|
URL u = new URL("http://" + server + "?update=" + update);
|
100
|
InputStreamReader istream = new InputStreamReader(u.openStream());
|
101
|
while((istreamInt = istream.read()) != -1)
|
102
|
{
|
103
|
istreamChar = (char)istreamInt;
|
104
|
serverResponse.append(istreamChar);
|
105
|
}
|
106
|
responses.add(serverResponse.toString()); //list of updates
|
107
|
}
|
108
|
//System.out.println("responses: " + responses.toString());
|
109
|
|
110
|
//initialize the parser
|
111
|
XMLReader parser = initParser(message);
|
112
|
for(int i=0; i<responses.size(); i++)
|
113
|
{ //parse the xml and get the result
|
114
|
parser.parse(new InputSource(
|
115
|
new StringReader(
|
116
|
(String)(responses.elementAt(i)))));
|
117
|
Vector v = new Vector(message.getResultVect());
|
118
|
for(int j=0; j<v.size(); j++)
|
119
|
{
|
120
|
Vector w = new Vector((Vector)(v.elementAt(j)));
|
121
|
System.out.print("param " + j + ": " + w.toString());
|
122
|
//so now we have a list of the documents that need to be updated, so
|
123
|
//now we need to request them. from the server and update them here
|
124
|
}
|
125
|
System.out.println("");
|
126
|
}
|
127
|
|
128
|
|
129
|
}
|
130
|
catch(Exception e)
|
131
|
{
|
132
|
System.out.println("Error in replicationHandler.update(): " +
|
133
|
e.getMessage());
|
134
|
}
|
135
|
}
|
136
|
|
137
|
/**
|
138
|
* Method to initialize the message parser
|
139
|
*/
|
140
|
private static XMLReader initParser(replMessageHandler rmh)
|
141
|
throws Exception
|
142
|
{
|
143
|
XMLReader parser = null;
|
144
|
|
145
|
try {
|
146
|
ContentHandler chandler = rmh;
|
147
|
|
148
|
// Get an instance of the parser
|
149
|
MetaCatUtil util = new MetaCatUtil();
|
150
|
String parserName = util.getOption("saxparser");
|
151
|
parser = XMLReaderFactory.createXMLReader(parserName);
|
152
|
|
153
|
// Turn off validation
|
154
|
parser.setFeature("http://xml.org/sax/features/validation", false);
|
155
|
|
156
|
// Set Handlers in the parser
|
157
|
/*
|
158
|
parser.setProperty("http://xml.org/sax/properties/declaration-handler",
|
159
|
chandler);
|
160
|
parser.setProperty("http://xml.org/sax/properties/lexical-handler",
|
161
|
chandler);
|
162
|
*/
|
163
|
parser.setContentHandler((ContentHandler)chandler);
|
164
|
parser.setErrorHandler((ErrorHandler)chandler);
|
165
|
|
166
|
} catch (Exception e) {
|
167
|
throw e;
|
168
|
}
|
169
|
|
170
|
return parser;
|
171
|
}
|
172
|
|
173
|
/**
|
174
|
* Method to query xml_replication and build a hashtable of each server
|
175
|
* and it's last update time.
|
176
|
* @param conn a connection to the database
|
177
|
*/
|
178
|
private Hashtable buildServerList(Connection conn)
|
179
|
{
|
180
|
Hashtable sl = new Hashtable();
|
181
|
PreparedStatement pstmt;
|
182
|
try
|
183
|
{
|
184
|
pstmt = conn.prepareStatement("select server, last_checked from " +
|
185
|
"xml_replication");
|
186
|
pstmt.execute();
|
187
|
ResultSet rs = pstmt.getResultSet();
|
188
|
boolean tableHasRows = rs.next();
|
189
|
while(tableHasRows)
|
190
|
{
|
191
|
sl.put(rs.getString(1), rs.getString(2));
|
192
|
tableHasRows = rs.next();
|
193
|
}
|
194
|
}
|
195
|
catch(Exception e)
|
196
|
{
|
197
|
System.out.println("error in replicationHandler.buildServerList(): " +
|
198
|
e.getMessage());
|
199
|
}
|
200
|
return sl;
|
201
|
}
|
202
|
}
|