    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[] clone(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    /**
    073     * Constructs a new instance.
    074     */
    075    public ConfigurationPropertiesFactoryBean() {
    076    }
    077
    078    /**
    079     * Constructs a new instance.
    080     *
    081     * @param configuration The configuration to compose.
    082     */
    083    public ConfigurationPropertiesFactoryBean(final Configuration configuration) {
    084        Assert.notNull(configuration, "configuration");
    085        this.compositeConfiguration = new CompositeConfiguration(configuration);
    086    }
    087
    088    /**
    089     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
    090     */
    091    @Override
    092    public void afterPropertiesSet() throws Exception {
    093        if (compositeConfiguration == null && ArrayUtils.isEmpty(configurations) && ArrayUtils.isEmpty(locations)) {
    094            throw new IllegalArgumentException("no configuration object or location specified");
    095        }
    096
    097        if (compositeConfiguration == null) {
    098            compositeConfiguration = new CompositeConfiguration();
    099        }
    100
    101        compositeConfiguration.setThrowExceptionOnMissing(throwExceptionOnMissing);
    102
    103        if (configurations != null) {
    104            Stream.of(configurations).forEach(compositeConfiguration::addConfiguration);
    105        }
    106
    107        if (locations != null) {
    108            for (final Resource location : locations) {
    109                compositeConfiguration.addConfiguration(new Configurations().properties(location.getURL()));
    110            }
    111        }
    112    }
    113
    114    /**
    115     * Gets the composite configuration.
    116     *
    117     * @return the composite configuration.
    118     */
    119    public CompositeConfiguration getConfiguration() {
    120        return compositeConfiguration;
    121    }
    122
    123    /**
    124     * Gets a copy of the configurations.
    125     *
    126     * @return a copy of the configurations.
    127     */
    128    public Configuration[] getConfigurations() {
    129        return clone(configurations);
    130    }
    131
    132    /**
    133     * Gets a copy of the resource locations.
    134     *
    135     * @return a copy of the resource locations.
    136     */
    137    public Resource[] getLocations() {
    138        return clone(locations);
    139    }
    140
    141    /**
    142     * @see org.springframework.beans.factory.FactoryBean#getObject()
    143     */
    144    @Override
    145    public Properties getObject() throws Exception {
    146        return compositeConfiguration != null ? ConfigurationConverter.getProperties(compositeConfiguration) : null;
    147    }
    148
    149    /**
    150     * @see org.springframework.beans.factory.FactoryBean#getObjectType()
    151     */
    152    @Override
    153    public Class<?> getObjectType() {
    154        return Properties.class;
    155    }
    156
    157    /**
    158     * @see org.springframework.beans.factory.FactoryBean#isSingleton()
    159     */
    160    @Override
    161    public boolean isSingleton() {
    162        return true;
    163    }
    164
    165    /**
    166     * Tests the underlying CompositeConfiguration throwExceptionOnMissing flag.
    167     *
    168     * @return the underlying CompositeConfiguration throwExceptionOnMissing flag.
    169     */
    170    public boolean isThrowExceptionOnMissing() {
    171        return throwExceptionOnMissing;
    172    }
    173
    174    /**
    175     * Sets the commons configurations objects which will be used as properties.
    176     *
    177     * @param configurations commons configurations objects which will be used as properties.
    178     */
    179    public void setConfigurations(final Configuration... configurations) {
    180        this.configurations = clone(configurations);
    181    }
    182
    183    /**
    184     * Shortcut for loading compositeConfiguration from Spring resources. It will internally create a
    185     * PropertiesConfiguration object based on the URL retrieved from the given Resources.
    186     *
    187     * @param locations resources of configuration files
    188     */
    189    public void setLocations(final Resource... locations) {
    190        this.locations = clone(locations);
    191    }
    192
    193    /**
    194     * Sets the underlying CompositeConfiguration throwExceptionOnMissing flag.
    195     *
    196     * @see org.apache.commons.configuration2.AbstractConfiguration#setThrowExceptionOnMissing(boolean)
    197     * @param throwExceptionOnMissing The new value for the property
    198     */
    199    public void setThrowExceptionOnMissing(final boolean throwExceptionOnMissing) {
    200        this.throwExceptionOnMissing = throwExceptionOnMissing;
    201    }
    202}