    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;
    020import java.io.InputStream;
    021import java.net.MalformedURLException;
    022import java.net.URL;
    023
    024import javax.activation.DataSource;
    025import javax.activation.URLDataSource;
    026
    027/**
    028 * Creates a {@code DataSource} based on an URL.
    029 *
    030 * @since 1.3
    031 */
    032public class DataSourceUrlResolver extends DataSourceBaseResolver {
    033
    034    /** The base url of the resource when resolving relative paths */
    035    private final URL baseUrl;
    036
    037    /**
    038     * Constructs a new instance.
    039     *
    040     * @param baseUrl the base URL used for resolving relative resource locations
    041     */
    042    public DataSourceUrlResolver(final URL baseUrl) {
    043        this.baseUrl = baseUrl;
    044    }
    045
    046    /**
    047     * Constructs a new instance.
    048     *
    049     * @param baseUrl the base URL used for resolving relative resource locations
    050     * @param lenient shall we ignore resources not found or complain with an exception
    051     */
    052    public DataSourceUrlResolver(final URL baseUrl, final boolean lenient) {
    053        super(lenient);
    054        this.baseUrl = baseUrl;
    055    }
    056
    057    /**
    058     * Create an URL based on a base URL and a resource location suitable for loading the resource.
    059     *
    060     * @param resourceLocation a resource location
    061     * @return the corresponding URL
    062     * @throws java.net.MalformedURLException creating the URL failed
    063     */
    064    protected URL createUrl(final String resourceLocation) throws MalformedURLException {
    065        // if we get an non-existing base url than the resource can
    066        // be directly used to create an URL
    067        if (baseUrl == null) {
    068            return new URL(resourceLocation);
    069        }
    070        // if we get an non-existing location what we shall do?
    071        if (resourceLocation == null || resourceLocation.isEmpty()) {
    072            throw new IllegalArgumentException("No resource defined");
    073        }
    074        // if we get a stand-alone resource than ignore the base url
    075        if (isFileUrl(resourceLocation) || isHttpUrl(resourceLocation)) {
    076            return new URL(resourceLocation);
    077        }
    078        return new URL(getBaseUrl(), resourceLocation.replace("&amp;", "&"));
    079    }
    080
    081    /**
    082     * Gets the base URL used for resolving relative resource locations.
    083     *
    084     * @return the baseUrl
    085     */
    086    public URL getBaseUrl() {
    087        return baseUrl;
    088    }
    089
    090    /** {@inheritDoc} */
    091    @Override
    092    public DataSource resolve(final String resourceLocation) throws IOException {
    093        return resolve(resourceLocation, isLenient());
    094    }
    095
    096    /** {@inheritDoc} */
    097    @Override
    098    public DataSource resolve(final String resourceLocation, final boolean isLenient) throws IOException {
    099        DataSource result = null;
    100        try {
    101            if (!isCid(resourceLocation)) {
    102                result = new URLDataSource(createUrl(resourceLocation));
    103                // validate we can read.
    104                try (InputStream inputStream = result.getInputStream()) {
    105                    inputStream.read();
    106                }
    107            }
    108            return result;
    109        } catch (final IOException e) {
    110            if (isLenient) {
    111                return null;
    112            }
    113            throw e;
    114        }
    115    }
    116}