Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.configuration.beanutils; import java.lang.reflect.Array; import java.util.Collection; import java.util.Iterator; import java.util.List; import org.apache.commons.beanutils.DynaBean; import org.apache.commons.beanutils.DynaClass; import org.apache.commons.configuration.Configuration; import org.apache.commons.configuration.ConfigurationMap; import org.apache.commons.configuration.ConversionException; import org.apache.commons.configuration.SubsetConfiguration; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * The <tt>ConfigurationDynaBean</tt> dynamically reads and writes * configurations properties from a wrapped configuration-collection * {@link org.apache.commons.configuration.Configuration} instance. It also * implements a {@link java.util.Map} interface so that it can be used in * JSP 2.0 Expression Language expressions. * * <p>The <code>ConfigurationDynaBean</code> maps nested and mapped properties * to the appropriate <code>Configuration</code> subset using the * {@link org.apache.commons.configuration.Configuration#subset} * method. Similarly, indexed properties reference lists of configuration * properties using the * {@link org.apache.commons.configuration.Configuration#getList(String)} * method. Setting an indexed property always throws an exception.</p> * * <p>Note: Some of the methods expect that a dot (".") is used as * property delimitor for the wrapped configuration. This is true for most of * the default configurations. Hierarchical configurations, for which a specific * expression engine is set, may cause problems.</p> * * @author <a href="mailto:ricardo.gladwell@btinternet.com">Ricardo Gladwell</a> * @version $Revision: 681804 $, $Date: 2008-08-01 21:58:59 +0200 (Fr, 01 Aug 2008) $ * @since 1.0-rc1 */ public class ConfigurationDynaBean extends ConfigurationMap implements DynaBean { /** Constant for the property delimiter.*/ private static final String PROPERTY_DELIMITER = "."; /** The logger.*/ private static Log log = LogFactory.getLog(ConfigurationDynaBean.class); /** * Creates a new instance of <code>ConfigurationDynaBean</code> and sets * the configuration this bean is associated with. * * @param configuration the configuration */ public ConfigurationDynaBean(Configuration configuration) { super(configuration); if (log.isTraceEnabled()) { log.trace("ConfigurationDynaBean(" + configuration + ")"); } } public void set(String name, Object value) { if (log.isTraceEnabled()) { log.trace("set(" + name + "," + value + ")"); } if (value == null) { throw new NullPointerException("Error trying to set property to null."); } if (value instanceof Collection) { Collection collection = (Collection) value; Iterator iterator = collection.iterator(); while (iterator.hasNext()) { getConfiguration().addProperty(name, iterator.next()); } } else if (value.getClass().isArray()) { int length = Array.getLength(value); for (int i = 0; i < length; i++) { getConfiguration().addProperty(name, Array.get(value, i)); } } else { getConfiguration().setProperty(name, value); } } public Object get(String name) { if (log.isTraceEnabled()) { log.trace("get(" + name + ")"); } // get configuration property Object result = getConfiguration().getProperty(name); if (result == null) { // otherwise attempt to create bean from configuration subset Configuration subset = new SubsetConfiguration(getConfiguration(), name, PROPERTY_DELIMITER); if (!subset.isEmpty()) { result = new ConfigurationDynaBean(subset); } } if (log.isDebugEnabled()) { log.debug(name + "=[" + result + "]"); } if (result == null) { throw new IllegalArgumentException("Property '" + name + "' does not exist."); } return result; } public boolean contains(String name, String key) { Configuration subset = getConfiguration().subset(name); if (subset == null) { throw new IllegalArgumentException("Mapped property '" + name + "' does not exist."); } return subset.containsKey(key); } public Object get(String name, int index) { try { List list = getConfiguration().getList(name); if (list.isEmpty()) { throw new IllegalArgumentException("Indexed property '" + name + "' does not exist."); } return list.get(index); } catch (ConversionException e) { throw new IllegalArgumentException("Property '" + name + "' is not indexed."); } } public Object get(String name, String key) { Configuration subset = getConfiguration().subset(name); if (subset == null) { throw new IllegalArgumentException("Mapped property '" + name + "' does not exist."); } return subset.getProperty(key); } public DynaClass getDynaClass() { return new ConfigurationDynaClass(getConfiguration()); } public void remove(String name, String key) { Configuration subset = new SubsetConfiguration(getConfiguration(), name, PROPERTY_DELIMITER); subset.setProperty(key, null); } public void set(String name, int index, Object value) { try { Object property = getConfiguration().getProperty(name); if (property == null) { throw new IllegalArgumentException("Property '" + name + "' does not exist."); } else if (property instanceof List) { List list = (List) property; list.set(index, value); getConfiguration().setProperty(name, list); } else if (property.getClass().isArray()) { Array.set(property, index, value); } else if (index == 0) { getConfiguration().setProperty(name, value); } else { throw new IllegalArgumentException("Property '" + name + "' is not indexed."); } } catch (ConversionException e) { throw new IllegalArgumentException("Property '" + name + "' is not indexed."); } } public void set(String name, String key, Object value) { getConfiguration().setProperty(name + "." + key, value); } }