    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.configuration2.builder;
    018
    019import org.apache.commons.configuration2.beanutils.BeanHelper;
    020import org.apache.commons.configuration2.ex.ConfigurationRuntimeException;
    021
    022/**
    023 * <p>
    024 * A specialized implementation of {@code DefaultParametersHandler} that copies
    025 * the properties of a {@link BuilderParameters} object (passed at construction
    026 * time) onto the object to be initialized.
    027 * </p>
    028 * <p>
    029 * Using this handler implementation makes specifying default values pretty
    030 * straight-forward: Just create a corresponding parameters object, initialize
    031 * it as desired, and pass it to this class. When invoked the handler uses
    032 * functionality from <em>Commons BeanUtils</em> to copy all properties defined
    033 * in the associated parameters object onto the target object. This is based on
    034 * reflection. Properties not available for the target object are silently
    035 * ignored. If an exception occurs during the copy operation, it is re-thrown as
    036 * a runtime exception.
    037 * </p>
    038 * <p>
    039 * Note that there is no default way to create a defensive copy of the passed in
    040 * parameters object; therefore, the reference is stored. This makes it possible
    041 * to change the parameters object later on, and the changes will be effective
    042 * when initializing objects afterwards. Client code should not rely on this
    043 * feature.
    044 * </p>
    045 *
    046 * @since 2.0
    047 */
    048public class CopyObjectDefaultHandler implements
    049        DefaultParametersHandler<Object>
    050{
    051    /** The source object with the properties to be initialized. */
    052    private final BuilderParameters source;
    053
    054    /**
    055     * Creates a new instance of {@code CopyObjectDefaultHandler} and
    056     * initializes it with the specified source object. The properties defined
    057     * by the source object are copied onto the objects to be initialized.
    058     *
    059     * @param src the source object (must not be <b>null</b>)
    060     * @throws IllegalArgumentException if the source object is <b>null</b>
    061     */
    062    public CopyObjectDefaultHandler(final BuilderParameters src)
    063    {
    064        if (src == null)
    065        {
    066            throw new IllegalArgumentException(
    067                    "Source object must not be null!");
    068        }
    069        source = src;
    070    }
    071
    072    /**
    073     * Returns the source object of this handler. This is the object whose
    074     * properties are copied on the objects to be initialized.
    075     *
    076     * @return the source object of this {@code CopyObjectDefaultHandler}
    077     */
    078    public BuilderParameters getSource()
    079    {
    080        return source;
    081    }
    082
    083    /**
    084     * {@inheritDoc} This implementation uses
    085     * {@code PropertyUtils.copyProperties()} to copy all defined properties
    086     * from the source object onto the passed in parameters object. Both the map
    087     * with properties (obtained via the {@code getParameters()} method of the
    088     * source parameters object) and other properties of the source object are
    089     * copied.
    090     *
    091     * @throws ConfigurationRuntimeException if an exception occurs
    092     * @see BuilderParameters#getParameters()
    093     */
    094    @Override
    095    public void initializeDefaults(final Object parameters)
    096    {
    097        try
    098        {
    099            BeanHelper.copyProperties(parameters, getSource()
    100                    .getParameters());
    101            BeanHelper.copyProperties(parameters, getSource());
    102        }
    103        catch (final Exception e)
    104        {
    105            // Handle all reflection-related exceptions the same way
    106            throw new ConfigurationRuntimeException(e);
    107        }
    108    }
    109}