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Revision 309

Added by bojilova over 24 years ago

added Pool of Connections
DBQuery, DBReader, DBTransform, DBUtil are created on every request and use the connections from the Pool
same with DBWriter and DBValidate

      *    Purpose: A Class that implements utility methods for a metadata catalog
      *  Copyright: 2000 Regents of the University of California and the
      *             National Center for Ecological Analysis and Synthesis
      *    Authors: Matt Jones
      *    Authors: Matt Jones, Jivka Bojilova
+     *
      *   '$Author$'
      *     '$Date$'
-...
     import java.sql.DriverManager;
     import java.sql.SQLException;
     import java.util.PropertyResourceBundle;
     import java.util.Hashtable;
     import java.util.Enumeration;
     /**
      * A suite of utility classes for the metadata catalog server
-...
       private PropertyResourceBundle options = null;
       private static String propertiesFile = "edu.ucsb.nceas.metacat.metacat";
       private Hashtable connectionPool = new Hashtable();
       private static boolean debug = false;
       /**
-...
           return value;
+      }
       /* Utility method to create and return a pool of Connection objects */
       public Hashtable getConnectionPool()
                     throws SQLException, ClassNotFoundException {
         int initConn = (new Integer(getOption("initialConnections"))).intValue();
         for ( int i = 0; i < initConn; i++ ) {
             connectionPool.put( openDBConnection(), Boolean.FALSE );
+        }
         return connectionPool;
+      }
       /* Utility method to get a unused Connection object from the pool */
       public Connection getConnection()
                     throws SQLException, ClassNotFoundException {
         Connection conn = null;
         Enumeration connections = connectionPool.keys();
         synchronized (connectionPool) {
           while (connections.hasMoreElements()) {
             conn = (Connection)connections.nextElement();
             Boolean b = (Boolean)connectionPool.get(conn);
             if (b == Boolean.FALSE) {
                 // unused connection; test if it works and get it
                 try {
                     conn.setAutoCommit(true);
                 } catch (SQLException e) {
                     // problem with the connection, replace it
                     conn = openDBConnection();
+                }
                 // update the pool to show this one taken
                 connectionPool.put(conn, Boolean.TRUE);
                 return conn;
+            }
+          }
+        }
         // If we get here, there no free connections;
         // we need to make more
         int incConn = (new Integer(getOption("incrementConnections"))).intValue();
         for ( int i = 0; i < incConn; i++ ) {
             connectionPool.put( openDBConnection(), Boolean.FALSE );
+        }
         // Recurse to get one of the new connections
         return getConnection();
+      }
       /* Utility method to give the connection back to the pool */
       public void returnConnection (Connection returned) {
         Connection conn;
         Enumeration connections = connectionPool.keys();
         while (connections.hasMoreElements()) {
             conn = (Connection)connections.nextElement();
             if ( conn == returned ) {
                 connectionPool.put( conn, Boolean.FALSE );
                 break;
+            }
+        }
+      }
       /** Utility method to convert a file handle into a URL */
       public static URL fileToURL(File file)
+      {
-...
     /**
      * '$Log$
      * 'Revision 1.10  2000/06/26 10:35:05  jones
      * 'Merged in substantial changes to DBWriter and associated classes and to
      * 'the MetaCatServlet in order to accomodate the new UPDATE and DELETE
      * 'functions.  The command line tools and the parameters for the
      * 'servlet have changed substantially.
      * '
      * 'Revision 1.9.2.4  2000/06/26 00:51:06  jones
      * 'If docid passed to DBWriter.write() is not unique, classes now generate
      * 'an AccessionNumberException containing the new docid generated as a

      *    Purpose: A Class that implements a metadata catalog as a java Servlet
      *  Copyright: 2000 Regents of the University of California and the
      *             National Center for Ecological Analysis and Synthesis
      *    Authors: Matt Jones, Dan Higgins
      *    Authors: Matt Jones, Dan Higgins, Jivka Bojilova
+     *
      *   '$Author$'
      *     '$Date$'
-...
       private ServletConfig		config = null;
       private ServletContext	context = null;
       private Connection 		conn = null;
       private DBQuery		queryobj = null;
       private DBReader		docreader = null;
       private DBTransform		dbt = null;
       private DBUtil        dbutil = null;
       private Hashtable 		connectionPool = new Hashtable();
       //private connection  conn = null;
       //private DBQuery		queryobj = null;
       //private DBReader    docreader = null;
       //private DBTransform dbt = null;
       //private DBUtil      dbutil = null;
       private String 		resultStyleURL = null;
       private String 		xmlcatalogfile = null;
       private String 		saxparser = null;
       private String    		defaultdatapath = null;
       private String        defaultdatapath = null;
     					// path to directory where data files
     					// that can be downloaded will be stored
       private String    		executescript  = null;
       private String        executescript  = null;
     					// script to get data file and put it
                                         	// in defaultdocpath dir
                         // in defaultdocpath dir
       private PropertyResourceBundle options = null;
       private MetaCatUtil util = null;
-...
           executescript = util.getOption("executescript");
           try {
             // Open a pool of db connections
             connectionPool = util.getConnectionPool();
           } catch (Exception e) {
             System.err.println("Error creating pool of database connections");
             System.err.println(e.getMessage());
+          }
     /*
           try {
             // Open a connection to the database
             conn = util.openDBConnection();
-...
             dbutil = new DBUtil(conn);
           } catch (Exception e) {
             System.err.println("Error opening database connection");
             System.err.println("Error creating pool of database connections");
             System.err.println(e.getMessage());
+          }
     */
         } catch ( ServletException ex ) {
           throw ex;
+        }
-...
         HttpServletResponse response)
         throws ServletException, IOException {
         if ( util == null ) {
             util = new MetaCatUtil();
+        }
         if ( connectionPool == null ) {
           try {
             // Open a pool of db connections
             connectionPool = util.getConnectionPool();
           } catch (Exception e) {
             System.err.println("Error creating pool of database connections");
             System.err.println(e.getMessage());
+          }
+        }
     /*
         if (conn == null) {
           System.err.println("Connection to database lost.  Reopening...");
           try {
-...
             System.err.println("Error opening database connection");
+          }
+        }
     */
         // Get a handle to the output stream back to the client
         PrintWriter out = response.getWriter();
         //response.setContentType("text/html");
-...
           String[] doctypeArr = null;
           String doctype = null;
           Reader xmlquery = null;
           Connection conn = null;
           // Run the query if it is a structured query
           // or, if it is a free-text, simple query,
-...
             System.err.println("Error handling query -- illegal action value");
+          }
           try {
             conn = util.getConnection();
             DBQuery queryobj = new DBQuery(conn, saxparser);
             doclist = queryobj.findDocuments(xmlquery);
           } catch (Exception e) {
             response.setContentType("text/html");
             out.println(e.getMessage());
             return;
           } finally {
             if ( conn != null ) { util.returnConnection(conn); }
+          }
     /*
           if (queryobj != null) {
               doclist = queryobj.findDocuments(xmlquery);
           } else {
             out.println("Query Object Init failed.");
             return;
+          }
     */
           // Create a buffer to hold the xml result
           StringBuffer resultset = new StringBuffer();
-...
         String docidstr = null;
         String docid = null;
         String doc = null;
         Connection conn = null;
         try {
           // Find the document id number
           docidstr = ((String[])params.get("docid"))[0];
           //docid = (new Long(docidstr)).longValue();
           docid = docidstr;
           conn = util.getConnection();
           DBReader docreader = new DBReader(conn);
           DBTransform dbt = new DBTransform(conn);
           // Get the document indicated fromthe db
           doc = docreader.readXMLDocument(docid);
         } catch (NullPointerException npe) {
           response.setContentType("text/html");
           out.println("Error getting document ID: " + docidstr +" (" + docid + ")");
+        }
           // Return the document in XML or HTML format
           String qformat = ((String[])params.get("qformat"))[0];
-...
             // Transform the document to the new doctype
             dbt.transformXMLDocument(doc, sourcetype, "-//W3C//HTML//EN", out);
+          }
         } catch (NullPointerException npe) {
           response.setContentType("text/html");
           out.println("Error getting document ID: " + docidstr +" (" + docid + ")");
         } catch (Exception e) {
           response.setContentType("text/html");
           out.println(e.getMessage());
         } finally {
           if ( conn != null ) { util.returnConnection(conn); }
+        }
+      }
       /**
-...
       private void handleInsertOrUpdateAction(PrintWriter out, Hashtable params,
                    HttpServletResponse response) {
         Connection conn = null;
         try {
           // Get the document indicated
           String[] doctext = (String[])params.get("doctext");
-...
               doAction = "UPDATE";
+            }
             // write the document to the database
             DBWriter dbw = new DBWriter(conn, saxparser);
             try {
               String accNumber = docid[0];
               if (accNumber.equals("")) {
                 accNumber = null;
+              }
               newdocid = dbw.write(xml, doAction, accNumber);
             } catch (NullPointerException npe) {
               newdocid = dbw.write(xml, doAction, null);
+            }
                 // get a connection from the pool
                 conn = util.getConnection();
                 // write the document to the database
                 DBWriter dbw = new DBWriter(conn, saxparser);
                 try {
                     String accNumber = docid[0];
                     if (accNumber.equals("")) {
                         accNumber = null;
+                    }
                     newdocid = dbw.write(xml, doAction, accNumber);
                 } catch (NullPointerException npe) {
                   newdocid = dbw.write(xml, doAction, null);
+                }
             } catch (Exception e) {
               response.setContentType("text/html");
               out.println(e.getMessage());
             } finally {
               if ( conn != null ) { util.returnConnection(conn); }
+            }
             // set content type and other response header fields first
             response.setContentType("text/xml");
             out.println("<?xml version=\"1.0\"?>");
-...
                    HttpServletResponse response) {
         String[] docid = (String[])params.get("docid");
         Connection conn = null;
         // delete the document from the database
         try {
           // get a connection from the pool
           conn = util.getConnection();
           DBWriter dbw = new DBWriter(conn, saxparser);
                                           // NOTE -- NEED TO TEST HERE
                                           // FOR EXISTENCE OF PARAM
-...
           out.println("<error>");
           out.println(e.getMessage());
           out.println("</error>");
+        }
         } finally {
           if ( conn != null ) { util.returnConnection(conn); }
+        }
+      }
       /**
-...
         // Get the document indicated
         String valtext = null;
         try {
           valtext = ((String[])params.get("valtext"))[0];
         } catch (Exception nullpe) {
           Connection conn = null;
           String docid = null;
           try {
             // Find the document id number
             docid = ((String[])params.get("docid"))[0];
             // Get the document indicated fromthe db
             // get a connection from the pool
             conn = util.getConnection();
             DBReader docreader = new DBReader(conn);
             // Get the document indicated from the db
             valtext = docreader.readXMLDocument(docid);
           } catch (NullPointerException npe) {
             response.setContentType("text/xml");
             out.println("<error>Error getting document ID: " + docid + "</error>");
+          }
             return; // Jivka added
           } catch (Exception e) {
             response.setContentType("text/html");
             out.println(e.getMessage());
           } finally {
             if ( conn != null ) { util.returnConnection(conn); }
+          }
+        }
         Connection conn = null;
         try {
           // get a connection from the pool
           conn = util.getConnection();
           DBValidate valobj = new DBValidate(saxparser,conn);
           boolean valid = valobj.validateString(valtext);
-...
           // set content type and other response header fields first
           response.setContentType("text/xml");
           out.println("<error>Error validating document.</error>");
+        }
         } catch (Exception e) {
           response.setContentType("text/html");
           out.println(e.getMessage());
         } finally {
           if ( conn != null ) { util.returnConnection(conn); }
+        }
+      }
       /**
-...
       private void handleGetDoctypesAction(PrintWriter out, Hashtable params,
                                            HttpServletResponse response) {
         Connection conn = null;
         try {
             // get connection from the pool
             conn = util.getConnection();
             DBUtil dbutil = new DBUtil(conn);
             String doctypes = dbutil.readDoctypes();
             out.println(doctypes);
-...
           out.println("<error>");
           out.println(e.getMessage());
           out.println("</error>");
+        }
         } finally {
           if ( conn != null ) { util.returnConnection(conn); }
+        }
+      }
-...
       private void handleGetDataGuideAction(PrintWriter out, Hashtable params,
                                             HttpServletResponse response) {
         Connection conn = null;
         try {
             // get connection from the pool
             conn = util.getConnection();
             DBUtil dbutil = new DBUtil(conn);
             String dataguide = dbutil.readDataGuide("");
             out.println(dataguide);
-...
           out.println("<error>");
           out.println(e.getMessage());
           out.println("</error>");
+        }
         } finally {
           if ( conn != null ) { util.returnConnection(conn); }
+        }
+      }
-...
     /**
      * '$Log$
      * 'Revision 1.54  2000/07/27 23:12:21  bojilova
      * 'Added "getdoctypes" and "getdataguide" action handlers
      * '
      * 'Revision 1.53  2000/07/26 20:48:29  bojilova
      * 'Added "Login Client" action for login from the Desktop Client
      * '

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Revision 309

Added by bojilova over 24 years ago