Java tutorial
/* * File : $Source: /alkacon/cvs/alkacon/com.alkacon.opencms.counter/src/com/alkacon/opencms/counter/CmsCounterManager.java,v $ * Date : $Date: 2009/06/18 17:26:12 $ * Version: $Revision: 1.2 $ * * This library is part of OpenCms - * the Open Source Content Mananagement System * * Copyright (C) 2005 Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software GmbH, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package com.alkacon.opencms.counter; import com.alkacon.opencms.util.CmsDbUtil; import org.opencms.configuration.CmsConfigurationManager; import org.opencms.file.CmsObject; import org.opencms.main.CmsException; import org.opencms.main.CmsLog; import org.opencms.main.CmsRuntimeException; import org.opencms.module.A_CmsModuleAction; import org.opencms.module.CmsModule; import org.opencms.util.CmsStringUtil; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import java.util.TreeMap; import org.apache.commons.logging.Log; /** * This is a helper class that provides methods used for the table counter in the database.<p> * * @author Anja Roettgers * * @version $Revision: 1.2 $ * * @since 7.0.3 */ public class CmsCounterManager extends A_CmsModuleAction { /** Constant for the module name. */ public static final String MODULE_NAME = "com.alkacon.opencms.counter"; /** Query to check if the table exists in the database. */ private static final String C_CHECK_DB = "SELECT count(*) FROM CMS_COUNTER_MODULES"; /** the name of the table of counters in the database.*/ private static final String C_COUNTER_TABLE = "CMS_COUNTER_MODULES"; /** Query to insert a new entry in the counter table.*/ private static final String C_CREATE_COUNTER_ENTRY = "INSERT INTO " + C_COUNTER_TABLE + " (COUNTER_KEY, COUNTER_COUNT) VALUES(?,?)"; /** Query to create the counter table in the database.*/ private static final String C_CREATE_TABLE = "CREATE TABLE " + C_COUNTER_TABLE + " (" + " COUNTER_KEY varchar(255) default NULL," + " COUNTER_COUNT int default NULL" + ") "; /** Query to update a counter entry.*/ private static final String C_DELETE_COUNTER_ENTRY = "DELETE FROM " + C_COUNTER_TABLE + " WHERE COUNTER_KEY= ?"; /** Query to get a counter entry.*/ private static final String C_GET_COUNTER_ENTRY = "SELECT COUNTER_COUNT FROM " + C_COUNTER_TABLE + " WHERE COUNTER_KEY = ?"; /** Query to get all counter entries from the database.*/ private static final String C_GET_COUNTERS = "SELECT * FROM " + C_COUNTER_TABLE; /** Query to update a counter entry from the database.*/ private static final String C_UPDATE_COUNTER_ENTRY = "UPDATE " + C_COUNTER_TABLE + " SET COUNTER_COUNT=? WHERE COUNTER_KEY = ?"; /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsCounterManager.class); /** The connection pool id. */ private String m_connectionPool; /** * default constructor.<p> */ public CmsCounterManager() { // NOOP } /** * This function deletes a counter entry in the database.<p> * * @param entryKey the counter entry which should be deleted * * @return <code>true</code> if successfully deleting otherwise <code>false</code> * * @throws CmsException if an error occurred */ public boolean deleteCounter(String entryKey) throws CmsException { boolean result = false; Connection con = null; PreparedStatement statement = null; // check if the parameters are empty if (CmsStringUtil.isEmptyOrWhitespaceOnly(entryKey)) { return result; } try { // get connection and execute the delete query con = CmsDbUtil.getInstance().getConnection(m_connectionPool); statement = con.prepareStatement(C_DELETE_COUNTER_ENTRY); statement.setString(1, entryKey); result = statement.execute(); } catch (SQLException ex) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_ACCESSING_DB_1, C_COUNTER_TABLE), ex); } throw new CmsException(Messages.get().container(Messages.LOG_ERROR_DELETE_COUNTER_1, entryKey)); } finally { CmsDbUtil.getInstance().closeConnection(null, statement, con); } return result; } /** * This function returns the value of the counter entry.<p> * * @param entryKey the id of the counter entry * * @return return the value of the counter entry otherwise <code>null</code> if nothing is found or an exception occurred */ public Integer getCounter(String entryKey) { Integer result = null; Connection con = null; PreparedStatement statement = null; ResultSet res = null; // check if the parameters are empty if (CmsStringUtil.isEmptyOrWhitespaceOnly(entryKey)) { return result; } try { // get the connection and create the statement con = CmsDbUtil.getInstance().getConnection(m_connectionPool); statement = con.prepareStatement(C_GET_COUNTER_ENTRY); statement.setString(1, entryKey); // execute the query and return the value of the entry res = statement.executeQuery(); if (res.next()) { result = new Integer(res.getInt(1)); } // make a log entry if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_DEBUG_GET_COUNTER_2, entryKey, result)); } } catch (Exception ex) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_ACCESSING_DB_1, C_COUNTER_TABLE), ex); } } finally { CmsDbUtil.getInstance().closeConnection(res, statement, con); } return result; } /** * This functions returns all counter entries from the database.<p> * * @return a Map of all counter entries with id as key and {@link Integer} as value */ public TreeMap getCounters() { TreeMap result = new TreeMap(); PreparedStatement statement = null; Connection con = null; ResultSet res = null; try { // get connection and set the statements con = CmsDbUtil.getInstance().getConnection(m_connectionPool); statement = con.prepareStatement(C_GET_COUNTERS); res = statement.executeQuery(); // the query result is parsing into key and value String key; int value; while (res.next()) { key = res.getString(1); value = res.getInt(2); result.put(key, new Integer(value)); } } catch (Exception ex) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_ACCESSING_DB_1, C_COUNTER_TABLE), ex); } } finally { CmsDbUtil.getInstance().closeConnection(res, statement, con); } return result; } /** * Returns the count value of the counter entry incremented. <p> * * Important: the incremented value is saved in the database.<p> * * @param entryKey the id of the counter entry * * @return return the incremented value of the counter entry otherwise it returns <code>1</code> * * @throws CmsException if an exception occurred */ public int incrementCounter(String entryKey) throws CmsException { int result = 0; Integer value = getCounter(entryKey); if (value != null) { result = value.intValue(); } result++; setCounter(entryKey, result); return result; } /** * @see org.opencms.module.I_CmsModuleAction#initialize(org.opencms.file.CmsObject, CmsConfigurationManager, CmsModule) */ public void initialize(CmsObject adminCms, CmsConfigurationManager configurationManager, CmsModule module) { super.initialize(adminCms, configurationManager, module); try { m_connectionPool = CmsDbUtil.getInstance().getConnectionPoolParameter(module.getName()); } catch (CmsRuntimeException ex) { if (LOG.isInfoEnabled()) { LOG.info(ex); } m_connectionPool = "default"; } // check if the required database tables exists and create its try { List createScript = new ArrayList(); createScript.add(C_CREATE_TABLE); CmsDbUtil.getInstance().ensureDBTablesExistance(m_connectionPool, C_CHECK_DB, createScript); } catch (Exception e) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_CREATING_TABLE_1, C_COUNTER_TABLE), e); } } } /** * This functions adds a new counter entry to the database table or if its exists then * the value is updated. <p> * * @param entryKey the id of the counter entry * @param newValue the value of the counter entry * * @throws CmsException if an exception occurred */ public void setCounter(String entryKey, int newValue) throws CmsException { Connection con = null; PreparedStatement statement = null; // check if the values are empty if (CmsStringUtil.isEmptyOrWhitespaceOnly(entryKey) || newValue < 0) { throw new CmsRuntimeException(Messages.get().container(Messages.LOG_ERROR_MISSING_VALUES_1, "update")); } try { // gets the connection and check if the Counter-Entry exists con = CmsDbUtil.getInstance().getConnection(m_connectionPool); Integer count = getCounter(entryKey); // create the statement to create or update if (count == null) { statement = con.prepareStatement(C_CREATE_COUNTER_ENTRY); statement.setString(1, entryKey); statement.setInt(2, newValue); } else { statement = con.prepareStatement(C_UPDATE_COUNTER_ENTRY); statement.setInt(1, newValue); statement.setString(2, entryKey); } // execute the statement statement.executeUpdate(); } catch (SQLException ex) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_ACCESSING_DB_1, C_COUNTER_TABLE), ex); } throw new CmsException( Messages.get().container(Messages.LOG_ERROR_SET_COUNTER_2, String.valueOf(newValue), entryKey)); } finally { CmsDbUtil.getInstance().closeConnection(null, statement, con); } } }