    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 */
    017
    018package org.apache.commons.configuration2.spring;
    019
    020import java.util.Properties;
    021import java.util.stream.Stream;
    022
    023import org.apache.commons.configuration2.CompositeConfiguration;
    024import org.apache.commons.configuration2.Configuration;
    025import org.apache.commons.configuration2.ConfigurationConverter;
    026import org.apache.commons.configuration2.builder.fluent.Configurations;
    027import org.apache.commons.lang3.ArrayUtils;
    028import org.springframework.beans.factory.FactoryBean;
    029import org.springframework.beans.factory.InitializingBean;
    030import org.springframework.core.io.Resource;
    031import org.springframework.util.Assert;
    032
    033/**
    034 * <p>
    035 * FactoryBean which wraps a Commons CompositeConfiguration object for usage with PropertiesLoaderSupport. This allows
    036 * the compositeConfiguration object to behave like a normal {@link Properties} object which can be passed on to
    037 * setProperties() method allowing PropertyOverrideConfigurer and PropertyPlaceholderConfigurer to take advantage of
    038 * Commons Configuration.
    039 * </p>
    040 * <p>
    041 * Internally a CompositeConfiguration object is used for merging multiple Configuration objects.
    042 * </p>
    043 *
    044 * @see java.util.Properties
    045 * @see org.springframework.core.io.support.PropertiesLoaderSupport
    046 */
    047public class ConfigurationPropertiesFactoryBean implements InitializingBean, FactoryBean<Properties> {
    048
    049    /**
    050     * Creates a defensive copy of the specified array. Handles null values correctly.
    051     *
    052     * @param src the source array
    053     * @param <T> the type of the array
    054     * @return the defensive copy of the array
    055     */
    056    private static <T> T[] defensiveCopy(final T[] src) {
    057        return src != null ? src.clone() : null;
    058    }
    059
    060    /** Internal CompositeConfiguration containing the merged configuration objects **/
    061    private CompositeConfiguration compositeConfiguration;
    062
    063    /** Supplied configurations that will be merged in compositeConfiguration **/
    064    private Configuration[] configurations;
    065
    066    /** Spring resources for loading configurations **/
    067    private Resource[] locations;
    068
    069    /** @see org.apache.commons.configuration2.AbstractConfiguration#throwExceptionOnMissing **/
    070    private boolean throwExceptionOnMissing = true;
    071
    072    public ConfigurationPropertiesFactoryBean() {
    073    }
    074
    075    public ConfigurationPropertiesFactoryBean(final Configuration configuration) {
    076        Assert.notNull(configuration, "configuration");
    077        this.compositeConfiguration = new CompositeConfiguration(configuration);
    078    }
    079
    080    /**
    081     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
    082     */
    083    @Override
    084    public void afterPropertiesSet() throws Exception {
    085        if (compositeConfiguration == null && ArrayUtils.isEmpty(configurations) && ArrayUtils.isEmpty(locations)) {
    086            throw new IllegalArgumentException("no configuration object or location specified");
    087        }
    088
    089        if (compositeConfiguration == null) {
    090            compositeConfiguration = new CompositeConfiguration();
    091        }
    092
    093        compositeConfiguration.setThrowExceptionOnMissing(throwExceptionOnMissing);
    094
    095        if (configurations != null) {
    096            Stream.of(configurations).forEach(compositeConfiguration::addConfiguration);
    097        }
    098
    099        if (locations != null) {
    100            for (final Resource location : locations) {
    101                compositeConfiguration.addConfiguration(new Configurations().properties(location.getURL()));
    102            }
    103        }
    104    }
    105
    106    public CompositeConfiguration getConfiguration() {
    107        return compositeConfiguration;
    108    }
    109
    110    public Configuration[] getConfigurations() {
    111        return defensiveCopy(configurations);
    112    }
    113
    114    public Resource[] getLocations() {
    115        return defensiveCopy(locations);
    116    }
    117
    118    /**
    119     * @see org.springframework.beans.factory.FactoryBean#getObject()
    120     */
    121    @Override
    122    public Properties getObject() throws Exception {
    123        return compositeConfiguration != null ? ConfigurationConverter.getProperties(compositeConfiguration) : null;
    124    }
    125
    126    /**
    127     * @see org.springframework.beans.factory.FactoryBean#getObjectType()
    128     */
    129    @Override
    130    public Class<?> getObjectType() {
    131        return Properties.class;
    132    }
    133
    134    /**
    135     * @see org.springframework.beans.factory.FactoryBean#isSingleton()
    136     */
    137    @Override
    138    public boolean isSingleton() {
    139        return true;
    140    }
    141
    142    public boolean isThrowExceptionOnMissing() {
    143        return throwExceptionOnMissing;
    144    }
    145
    146    /**
    147     * Sets the commons configurations objects which will be used as properties.
    148     *
    149     * @param configurations commons configurations objects which will be used as properties.
    150     */
    151    public void setConfigurations(final Configuration... configurations) {
    152        this.configurations = defensiveCopy(configurations);
    153    }
    154
    155    /**
    156     * Shortcut for loading compositeConfiguration from Spring resources. It will internally create a
    157     * PropertiesConfiguration object based on the URL retrieved from the given Resources.
    158     *
    159     * @param locations resources of configuration files
    160     */
    161    public void setLocations(final Resource... locations) {
    162        this.locations = defensiveCopy(locations);
    163    }
    164
    165    /**
    166     * Sets the underlying Commons CompositeConfiguration throwExceptionOnMissing flag.
    167     *
    168     * @see org.apache.commons.configuration2.AbstractConfiguration#setThrowExceptionOnMissing(boolean)
    169     * @param throwExceptionOnMissing The new value for the property
    170     */
    171    public void setThrowExceptionOnMissing(final boolean throwExceptionOnMissing) {
    172        this.throwExceptionOnMissing = throwExceptionOnMissing;
    173    }
    174}