    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.mail.resolver;
    018
    019import java.io.IOException;
    020
    021import javax.activation.DataSource;
    022
    023import org.apache.commons.mail.DataSourceResolver;
    024
    025/**
    026 * A composite data source resolver. It allows to resolve data sources coming from multiple locations such as the classpath, the file system or an URL.
    027 *
    028 * @since 1.3
    029 */
    030public class DataSourceCompositeResolver extends DataSourceBaseResolver {
    031
    032    /** The list of resolvers */
    033    private final DataSourceResolver[] dataSourceResolvers;
    034
    035    /**
    036     * Constructs a new instance.
    037     *
    038     * @param dataSourceResolvers a list of resolvers being used
    039     */
    040    public DataSourceCompositeResolver(final DataSourceResolver[] dataSourceResolvers) {
    041        this.dataSourceResolvers = dataSourceResolvers.clone();
    042    }
    043
    044    /**
    045     * Constructs a new instance.
    046     *
    047     * @param dataSourceResolvers a list of resolvers being used
    048     * @param isLenient           shall we ignore resources not found or throw an exception?
    049     */
    050    public DataSourceCompositeResolver(final DataSourceResolver[] dataSourceResolvers, final boolean isLenient) {
    051        super(isLenient);
    052        this.dataSourceResolvers = dataSourceResolvers.clone();
    053    }
    054
    055    /**
    056     * Gets the underlying data source resolvers.
    057     *
    058     * @return underlying data source resolvers
    059     */
    060    public DataSourceResolver[] getDataSourceResolvers() {
    061        // clone the internal array to prevent external modification (see EMAIL-116)
    062        return dataSourceResolvers.clone();
    063    }
    064
    065    /** {@inheritDoc} */
    066    @Override
    067    public DataSource resolve(final String resourceLocation) throws IOException {
    068        final DataSource result = resolve(resourceLocation, true);
    069        if (isLenient() || result != null) {
    070            return result;
    071        }
    072        throw new IOException("The following resource was not found : " + resourceLocation);
    073
    074    }
    075
    076    /** {@inheritDoc} */
    077    @Override
    078    public DataSource resolve(final String resourceLocation, final boolean isLenient) throws IOException {
    079        for (int i = 0; i < dataSourceResolvers.length; i++) {
    080            final DataSourceResolver dataSourceResolver = dataSourceResolvers[i];
    081            final DataSource dataSource = dataSourceResolver.resolve(resourceLocation, isLenient);
    082            if (dataSource != null) {
    083                return dataSource;
    084            }
    085        }
    086        if (isLenient) {
    087            return null;
    088        }
    089        throw new IOException("The following resource was not found : " + resourceLocation);
    090    }
    091}