Java tutorial
/* * RHQ Management Platform * Copyright (C) 2005-2008 Red Hat, Inc. * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation version 2 of the License. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ package org.rhq.plugins.database; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.Collections; import java.util.HashSet; import java.util.Set; import java.util.regex.Matcher; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.rhq.core.domain.configuration.Configuration; import org.rhq.core.domain.configuration.PropertySimple; import org.rhq.core.pluginapi.inventory.DiscoveredResourceDetails; import org.rhq.core.pluginapi.inventory.InvalidPluginConfigurationException; import org.rhq.core.pluginapi.inventory.ResourceDiscoveryComponent; import org.rhq.core.pluginapi.inventory.ResourceDiscoveryContext; import org.rhq.core.util.jdbc.JDBCUtil; /** * Discovery for a generic component that can read data out of a table for monitoring purposes. Neccessary configuration * properties table - the name of the table to search for during inventory metricQuery - the query run to load metric * data name - the name of the resource description - the description of the resource * * @author Greg Hinkle */ public class CustomTableRowDiscoveryComponent implements ResourceDiscoveryComponent<DatabaseComponent<?>> { private final Log log = LogFactory.getLog(getClass()); public Set<DiscoveredResourceDetails> discoverResources( ResourceDiscoveryContext<DatabaseComponent<?>> resourceDiscoveryContext) throws InvalidPluginConfigurationException, Exception { Statement statement = null; ResultSet resultSet = null; Configuration config = resourceDiscoveryContext.getDefaultPluginConfiguration(); String table = config.getSimpleValue("table", null); String keyColumn = config.getSimpleValue("keyColumn", null); try { Connection conn = resourceDiscoveryContext.getParentResourceComponent().getConnection(); String resourceName = config.getSimpleValue("name", null); String resourceDescription = config.getSimpleValue("description", ""); if (resourceName == null) { throw new InvalidPluginConfigurationException( "The 'name' connection property has to be specified."); } statement = conn.createStatement(); resultSet = statement.executeQuery("SELECT * FROM " + table); Set<DiscoveredResourceDetails> found = new HashSet<DiscoveredResourceDetails>(); while (resultSet.next()) { config = resourceDiscoveryContext.getDefaultPluginConfiguration(); String key = resultSet.getString(keyColumn); config.put(new PropertySimple("key", key)); DiscoveredResourceDetails details = new DiscoveredResourceDetails( resourceDiscoveryContext.getResourceType(), key, formatMessage(resourceName, key), null, formatMessage(resourceDescription, key), config, null); found.add(details); } return found; } catch (SQLException e) { log.debug("table " + table + " column " + keyColumn, e); } finally { JDBCUtil.safeClose(resultSet); JDBCUtil.safeClose(statement); } return Collections.emptySet(); } /** * Format a message with {<key>} formatted replacement keys. * * @param message the message to format * @param key to replace; if null returns the message as-is * * @return the formatted text with variables replaced */ public static String formatMessage(String message, String key) { if (key == null) return message; key = Matcher.quoteReplacement(key); message = message.replaceAll("\\{key\\}", key); return message; } }