[16869] | 1 | /*
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| 2 | * GDBMWrapper.java
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| 3 | * Copyright (C) 2008 New Zealand Digital Library, http://www.nzdl.org
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| 4 | *
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| 5 | * This program is free software; you can redistribute it and/or modify
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| 6 | * it under the terms of the GNU General Public License as published by
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| 7 | * the Free Software Foundation; either version 2 of the License, or
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| 8 | * (at your option) any later version.
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| 9 | *
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| 10 | * This program is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 13 | * GNU General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU General Public License
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| 16 | * along with this program; if not, write to the Free Software
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| 17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 18 | */
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[9874] | 19 | package org.greenstone.gsdl3.util;
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| 20 |
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| 21 | import au.com.pharos.gdbm.GdbmFile;
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| 22 | import au.com.pharos.packing.*;
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| 23 | import au.com.pharos.gdbm.GdbmException;
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| 24 |
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[15325] | 25 | import org.apache.log4j.Logger;
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[13124] | 26 |
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[16809] | 27 | import java.io.UnsupportedEncodingException;
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[17907] | 28 | import java.io.File;
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[16809] | 29 |
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[24393] | 30 | /**
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| 31 | * java wrapper class for gdbm - uses Java-GDBM written by Martin Pool replaces
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| 32 | * gdbmclass in the old version
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[9874] | 33 | */
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| 34 |
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[24393] | 35 | public class GDBMWrapper implements FlatDatabaseWrapper
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| 36 | {
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[9874] | 37 |
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[24393] | 38 | static Logger logger = Logger.getLogger(org.greenstone.gsdl3.util.GDBMWrapper.class.getName());
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| 39 |
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| 40 | /*
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| 41 | * GdbmFile modes: READER - read access, many readers may share the database
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| 42 | * WRITER - read/write access, exclusive access WRCREAT - read/write access,
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| 43 | * create db if doesn't exist NEWDB - read/write access, db should be
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| 44 | * replaced if exists
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| 45 | */
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| 46 |
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| 47 | protected GdbmFile db_ = null;
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| 48 |
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| 49 | /**
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| 50 | * open the database filename, with mode mode - uses the constants above, eg
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| 51 | * GdbmFile.WRITER
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| 52 | */
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| 53 | public boolean openDatabase(String filename, int mode)
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| 54 | {
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| 55 | // need to convert mode to GdbmFile mode
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| 56 | if (mode == READ)
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| 57 | {
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| 58 | mode = GdbmFile.READER;
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| 59 | }
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| 60 | else if (mode == WRITE)
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| 61 | {
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| 62 | mode = GdbmFile.WRITER;
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| 63 | }
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| 64 | else
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| 65 | {
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| 66 | logger.error("invalid mode, " + mode + ", opening db for reading only");
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| 67 | mode = GdbmFile.READER;
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| 68 | }
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| 69 | try
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| 70 | {
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| 71 | if (db_ != null)
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| 72 | {
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| 73 | db_.close();
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| 74 | }
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| 75 |
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| 76 | // The java version of the C++ code in common-src/src/lib/gdbmclass.cpp
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| 77 | if (mode == GdbmFile.READER)
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| 78 | {
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| 79 | // Looking to read in the database
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| 80 | // we now use gdb extension. Check for ldb/bdb in case of legacy collection
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| 81 | // if not (first time) then generate using txt2db
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| 82 | if (!new File(filename).exists())
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| 83 | {
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| 84 | logger.warn("Database file " + filename + " does not exist. Looking for ldb/bdb version");
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| 85 | int extension = filename.lastIndexOf('.');
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| 86 | String filename_head = filename.substring(0, extension);
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| 87 | filename = filename_head + ".ldb";
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| 88 | if (!new File(filename).exists())
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| 89 | {
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| 90 | filename = filename_head + ".bdb";
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| 91 |
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| 92 | if (!new File(filename).exists())
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| 93 | {
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| 94 | logger.warn("ldb/bdb version of database file " + filename + " does not exist. Looking for txtgz version of db file.");
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| 95 | // put the filename back to gdb
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| 96 | filename = filename_head + ".gdb";
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| 97 | // need to generate architecture native GDBM file using txt2db
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| 98 |
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| 99 | // replace sought after gdbm filename ext with ".txt.gz"
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| 100 |
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| 101 | String txtgzFilename = filename_head + ".txt.gz";
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| 102 | if (new File(txtgzFilename).exists())
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| 103 | {
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| 104 | // Test to make sure Perl is on the path
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| 105 | // On Linux, the output of the test goes to STDOUT so redirect it to STDERR
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| 106 | String cmdTest = "perl -v 2>&1";
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| 107 | //String cmdTest = "echo %PATH%";
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| 108 | int returnValue = Processing.runProcess(cmdTest);
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| 109 | if (returnValue != 0)
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| 110 | {
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| 111 | logger.error("Tried to find Perl. Return exit value of running " + cmdTest + ": " + returnValue + ", (expected this to be 0)");
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| 112 | logger.error("Check that Perl is set in your PATH environment variable.");
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| 113 | //log.error("At present, PATH=" + System.getenv("PATH"));
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| 114 | }
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| 115 |
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| 116 | String cmd = "perl -S txtgz-to-gdbm.pl \"" + txtgzFilename + "\" \"" + filename + "\"";
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| 117 | returnValue = Processing.runProcess(cmd);
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| 118 | // For some reason, launching this command with gsdl_system() still returns 1
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| 119 | // even when it returns 0 when run from the command-line. We can check whether
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| 120 | // we succeeded by looking at whether the output database file was created.
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| 121 | if (returnValue != 0)
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| 122 | {
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| 123 | logger.warn("Warning, non-zero return value on running command \"" + cmd + "\": " + returnValue);
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| 124 | if (!new File(filename).exists())
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| 125 | {
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| 126 | logger.error("Tried to run command \"" + cmd + "\", but it failed");
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| 127 | }
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| 128 | }
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| 129 | }
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| 130 | }
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| 131 | }
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| 132 |
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| 133 | }
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| 134 | }
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| 135 |
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| 136 | db_ = new GdbmFile(filename, mode);
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| 137 | }
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| 138 | catch (GdbmException e)
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| 139 | { // the database wasn't opened or created
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| 140 | logger.error("couldn't open database " + filename);
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| 141 | return false;
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| 142 | }
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| 143 | db_.setKeyPacking(new StringPacking());
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| 144 | db_.setValuePacking(new StringPacking());
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| 145 | return true;
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[17907] | 146 | }
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| 147 |
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[24393] | 148 | /** close the database associated with this wrapper */
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| 149 | public void closeDatabase()
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| 150 | {
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| 151 | try
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| 152 | {
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| 153 | if (db_ != null)
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| 154 | {
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| 155 | db_.close();
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| 156 | db_ = null;
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| 157 | if (System.getProperty("os.name").startsWith("Windows"))
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| 158 | {
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| 159 | //Hack: force Windows to let go of the gdb file
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| 160 | System.gc();
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| 161 | }
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[17907] | 162 | }
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| 163 | }
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[24393] | 164 | catch (GdbmException e)
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| 165 | {
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| 166 | // should never get here - close never actually throws an exception
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| 167 | logger.error("error on close()");
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[18663] | 168 | }
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[17907] | 169 | }
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| 170 |
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[24393] | 171 | public String getValue(String key)
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| 172 | {
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| 173 | if (db_ == null)
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| 174 | {
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| 175 | return null;
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| 176 | }
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| 177 | String s_info;
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| 178 | try
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| 179 | {
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| 180 | try
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| 181 | {
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| 182 | // The key is UTF8: do db lookup using the UTF8 version of key
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| 183 | s_info = (String) db_.fetch(key.getBytes("UTF-8"));
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| 184 | }
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| 185 | catch (UnsupportedEncodingException e)
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| 186 | {
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| 187 | logger.warn("utf8 key for " + key + " unrecognised. Retrying with default encoding.");
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| 188 | // retry db lookup using default encoding of key instead of UTF8
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| 189 | s_info = (String) db_.fetch(key);
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| 190 | }
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| 191 | }
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| 192 | catch (GdbmException e)
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| 193 | {
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| 194 | logger.error("couldn't get record");
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| 195 | return null;
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| 196 | }
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| 197 | if (s_info == null)
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| 198 | {
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| 199 | // record not present
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| 200 | logger.error("key " + key + " not present in db");
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| 201 | return null;
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| 202 | }
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| 203 | return s_info;
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| 204 | }
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[9874] | 205 |
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[24393] | 206 | /**
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| 207 | * sets the given key to the given value in the database
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| 208 | */
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| 209 | public boolean setValue(String key, String value)
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| 210 | {
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| 211 | if (db_ == null || !db_.isWritable())
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| 212 | {
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| 213 | logger.error("GDBM database is either null or not writable");
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| 214 | return false;
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| 215 | }
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| 216 |
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| 217 | try
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| 218 | {
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| 219 | db_.store(key, value);
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| 220 | }
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| 221 | catch (GdbmException ex)
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| 222 | {
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| 223 | logger.error("Error storing " + key + " = " + value + " in GDBM database");
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| 224 | logger.error("Error message is: " + ex.getMessage());
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| 225 | return false;
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| 226 | }
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| 227 | return true;
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[16809] | 228 | }
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[9874] | 229 |
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[24393] | 230 | /**
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| 231 | * deletes the entry for given key
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| 232 | */
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| 233 | public boolean deleteKey(String key)
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| 234 | {
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| 235 | if (db_ == null)
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| 236 | {
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| 237 | logger.error("GDBM database is null");
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| 238 | return false;
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| 239 | }
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| 240 |
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| 241 | try
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| 242 | {
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| 243 | db_.delete(key);
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| 244 | }
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| 245 | catch (GdbmException ex)
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| 246 | {
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| 247 | logger.error("Error deleting key " + key + " from the database");
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| 248 | logger.error("Error message is: " + ex.getMessage());
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| 249 | return false;
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| 250 | }
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| 251 |
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| 252 | return true;
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| 253 | }
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[9874] | 254 |
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[24393] | 255 | /**
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| 256 | * returns a string of key-value entries that can be printed for debugging
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| 257 | * purposes.
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| 258 | */
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| 259 | public String displayAllEntries()
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| 260 | {
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| 261 | StringBuffer output = new StringBuffer();
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| 262 | try
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| 263 | {
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| 264 | java.util.Enumeration e = db_.keys();
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| 265 | while (e.hasMoreElements())
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| 266 | {
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| 267 | Object key = e.nextElement();
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| 268 | Object value = db_.fetch(key);
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[16797] | 269 |
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[24393] | 270 | output.append("key href: ");
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| 271 | output.append((String) key);
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| 272 | output.append("\tvalue ID: ");
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| 273 | output.append((String) value);
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| 274 | output.append("\n");
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| 275 | //logger.warn("key: " + key + "\tvalue: " + value);
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[16809] | 276 |
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[24393] | 277 | String urlkey = java.net.URLEncoder.encode((String) key, "UTF8");
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| 278 | output.append("URL encoded key: " + urlkey);
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| 279 | //logger.warn("URL encoded key: " + urlkey);
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| 280 | }
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| 281 | }
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| 282 | catch (UnsupportedEncodingException e)
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| 283 | {
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| 284 | logger.warn("Trouble converting key to UTF-8.");
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| 285 | }
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| 286 | catch (Exception e)
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| 287 | {
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| 288 | logger.warn("Exception encountered when trying to displayAllEntries():" + e);
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| 289 | }
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| 290 | return output.toString();
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[16797] | 291 | }
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[9874] | 292 | }
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