Revision 320
Added by bojilova over 24 years ago
| src/edu/ucsb/nceas/metacat/MetaCatUtil.java | ||
|---|---|---|
| 100 | 100 |
|
| 101 | 101 |
/* Utility method to get a unused Connection object from the pool */ |
| 102 | 102 |
public Connection getConnection() |
| 103 |
throws SQLException, ClassNotFoundException {
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throws SQLException, ClassNotFoundException, Exception {
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|
| 104 | 104 |
|
| 105 | 105 |
Connection conn = null; |
| 106 | 106 |
Enumeration connections = connectionPool.keys(); |
| 107 | 107 |
|
| 108 | 108 |
synchronized (connectionPool) {
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| 109 | 109 |
while (connections.hasMoreElements()) {
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| 110 | 111 |
conn = (Connection)connections.nextElement(); |
| 111 | 112 |
Boolean b = (Boolean)connectionPool.get(conn); |
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if (b == Boolean.FALSE) {
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if (conn == null) {
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// closed connection; replace it |
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conn = openDBConnection(); |
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// update the pool to show this one taken |
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connectionPool.put(conn, Boolean.TRUE); |
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return conn; |
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} else if (b == Boolean.FALSE) {
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| 114 | 122 |
// unused connection; test if it works and get it |
| 115 | 123 |
try {
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| 116 | 124 |
conn.setAutoCommit(true); |
| ... | ... | |
| 120 | 128 |
} |
| 121 | 129 |
// update the pool to show this one taken |
| 122 | 130 |
connectionPool.put(conn, Boolean.TRUE); |
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| 123 | 132 |
return conn; |
| 124 | 133 |
} |
| 125 | 134 |
} |
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}
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} |
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| 127 | 136 |
|
| 128 | 137 |
// If we get here, there no free connections; |
| 129 | 138 |
// we need to make more |
| 130 | 139 |
int incConn = (new Integer(getOption("incrementConnections"))).intValue();
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int maxConn = (new Integer(getOption("maximumConnections"))).intValue();
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int k = connectionPool.size(); |
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if ( k >= maxConn ) {
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throw new Exception("The maximum of " + maxConn +
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" open db connections is reached." + |
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" New db connection to MetaCat" + |
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" cannot be established."); |
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} |
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// decide how many new connections to open; no more than the maximum |
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if ( incConn > maxConn - k ) { incConn = maxConn - k; }
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// get them |
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| 131 | 153 |
for ( int i = 0; i < incConn; i++ ) {
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| 132 | 154 |
connectionPool.put( openDBConnection(), Boolean.FALSE ); |
| 133 | 155 |
} |
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| 135 | 157 |
// Recurse to get one of the new connections |
| 136 | 158 |
return getConnection(); |
| 137 | 159 |
} |
| ... | ... | |
| 142 | 164 |
Connection conn; |
| 143 | 165 |
Enumeration connections = connectionPool.keys(); |
| 144 | 166 |
|
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while (connections.hasMoreElements()) {
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if (returned != null) {
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while (connections.hasMoreElements()) {
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| 146 | 169 |
conn = (Connection)connections.nextElement(); |
| 147 | 170 |
if ( conn == returned ) {
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| 148 | 171 |
connectionPool.put( conn, Boolean.FALSE ); |
| 149 | 172 |
break; |
| 150 | 173 |
} |
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} |
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} |
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} |
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| 152 | 176 |
} |
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/* Utility method to close all the connection from the pool */ |
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public void closeConnections() {
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Connection conn; |
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Enumeration connections = connectionPool.keys(); |
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while (connections.hasMoreElements()) {
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conn = (Connection)connections.nextElement(); |
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if ( conn != null ) {
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try {
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conn.close(); |
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} catch (SQLException e) {}
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} |
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} |
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} |
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/** Utility method to convert a file handle into a URL */ |
| ... | ... | |
| 196 | 236 |
|
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/** |
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* '$Log$ |
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* 'Revision 1.11 2000/08/01 18:26:50 bojilova |
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* 'added Pool of Connections |
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* 'DBQuery, DBReader, DBTransform, DBUtil are created on every request and use the connections from the Pool |
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* 'same with DBWriter and DBValidate |
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* ' |
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| 199 | 244 |
* 'Revision 1.10 2000/06/26 10:35:05 jones |
| 200 | 245 |
* 'Merged in substantial changes to DBWriter and associated classes and to |
| 201 | 246 |
* 'the MetaCatServlet in order to accomodate the new UPDATE and DELETE |
| src/edu/ucsb/nceas/metacat/MetaCatServlet.java | ||
|---|---|---|
| 124 | 124 |
} |
| 125 | 125 |
} |
| 126 | 126 |
|
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/** |
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* Close all db connections from the pool |
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*/ |
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public void destroy() {
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if (util != null) {
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util.closeConnections(); |
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} |
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} |
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/** Handle "GET" method requests from HTTP clients */ |
| 128 | 138 |
public void doGet (HttpServletRequest request, HttpServletResponse response) |
| 129 | 139 |
throws ServletException, IOException {
|
| ... | ... | |
| 395 | 405 |
} |
| 396 | 406 |
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try {
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conn = util.getConnection(); |
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DBQuery queryobj = new DBQuery(conn, saxparser); |
| 400 | 411 |
doclist = queryobj.findDocuments(xmlquery); |
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util.returnConnection(conn); |
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} catch (Exception e) {
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if ( conn != null ) { util.returnConnection(conn); }
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response.setContentType("text/html");
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out.println(e.getMessage()); |
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return; |
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} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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} |
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/* |
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if (queryobj != null) {
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doclist = queryobj.findDocuments(xmlquery); |
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} else {
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out.println("Query Object Init failed.");
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return; |
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} |
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*/ |
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// Create a buffer to hold the xml result |
| 417 | 422 |
StringBuffer resultset = new StringBuffer(); |
| 418 | 423 |
|
| ... | ... | |
| 503 | 508 |
response.setContentType("text/html");
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| 504 | 509 |
out.println(e.getMessage()); |
| 505 | 510 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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| 507 | 512 |
} |
| 508 | 513 |
|
| 509 | 514 |
} |
| ... | ... | |
| 554 | 559 |
response.setContentType("text/html");
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| 555 | 560 |
out.println(e.getMessage()); |
| 556 | 561 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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| 558 | 563 |
} |
| 559 | 564 |
|
| 560 | 565 |
// set content type and other response header fields first |
| ... | ... | |
| 627 | 632 |
out.println(e.getMessage()); |
| 628 | 633 |
out.println("</error>");
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| 629 | 634 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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| 631 | 636 |
} |
| 632 | 637 |
} |
| 633 | 638 |
|
| ... | ... | |
| 659 | 664 |
} catch (NullPointerException npe) {
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response.setContentType("text/xml");
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| 661 | 666 |
out.println("<error>Error getting document ID: " + docid + "</error>");
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if ( conn != null ) { util.returnConnection(conn); }
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| 662 | 668 |
return; // Jivka added |
| 663 | 669 |
} catch (Exception e) {
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| 664 | 670 |
response.setContentType("text/html");
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| 665 | 671 |
out.println(e.getMessage()); |
| 666 | 672 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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| 668 | 674 |
} |
| 669 | 675 |
} |
| 670 | 676 |
|
| ... | ... | |
| 687 | 693 |
response.setContentType("text/html");
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| 688 | 694 |
out.println(e.getMessage()); |
| 689 | 695 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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} |
| 692 | 698 |
} |
| 693 | 699 |
|
| ... | ... | |
| 770 | 776 |
out.println(e.getMessage()); |
| 771 | 777 |
out.println("</error>");
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| 772 | 778 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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util.returnConnection(conn);
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| 774 | 780 |
} |
| 775 | 781 |
|
| 776 | 782 |
} |
| ... | ... | |
| 807 | 813 |
out.println(e.getMessage()); |
| 808 | 814 |
out.println("</error>");
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| 809 | 815 |
} finally {
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if ( conn != null ) { util.returnConnection(conn); }
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| 816 |
util.returnConnection(conn);
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| 811 | 817 |
} |
| 812 | 818 |
|
| 813 | 819 |
} |
| ... | ... | |
| 816 | 822 |
|
| 817 | 823 |
/** |
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* '$Log$ |
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* 'Revision 1.57 2000/08/03 23:20:31 bojilova |
|
| 826 |
* 'Changes related to "getdataguide" action |
|
| 827 |
* ' |
|
| 819 | 828 |
* 'Revision 1.55 2000/08/01 18:26:50 bojilova |
| 820 | 829 |
* 'added Pool of Connections |
| 821 | 830 |
* 'DBQuery, DBReader, DBTransform, DBUtil are created on every request and use the connections from the Pool |
Also available in: Unified diff
more precise handling of the Connection Pool