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 *     https://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.io;
018
019import java.io.File;
020import java.net.URL;
021
022import org.apache.commons.lang3.StringUtils;
023
024/**
025 * A specialized implementation of {@code FileLocationStrategy} which tries to construct a file path from the locator's
026 * base path and file name.
027 * <p>
028 * This strategies ignores the URL stored in the passed in {@link FileLocator}. It generates a path by concatenating the
029 * base path (if present) and the file name. If the resulting path points to a valid file, the corresponding URL is
030 * returned.
031 * </p>
032 * <p>
033 * See {@link AbstractFileLocationStrategy} learn how to grant an deny URL schemes and hosts.
034 * </p>
035 *
036 * @see AbstractFileLocationStrategy
037 * @since 2.0
038 */
039public class BasePathLocationStrategy extends AbstractFileLocationStrategy {
040
041    /**
042     * Builds new instances of {@link ProvidedURLLocationStrategy}.
043     *
044     * @return a new builder.
045     * @since 2.15.0
046     */
047    public static StrategyBuilder<BasePathLocationStrategy> builder() {
048        return new StrategyBuilder<>(BasePathLocationStrategy::new);
049    }
050
051    /**
052     * Constructs a new instance where URL resources are bound by {@link AbstractFileLocationStrategy.AbstractBuilder}.
053     */
054    public BasePathLocationStrategy() {
055        // empty
056    }
057
058    /**
059     * Constructs a new instance where URL resources are bound by {@link AbstractFileLocationStrategy.AbstractBuilder}.
060     *
061     * @param builder How to build the instance.
062     * @since 2.15.0
063     */
064    public BasePathLocationStrategy(final AbstractBuilder<?, ?> builder) {
065        super(builder);
066    }
067
068    /**
069     * {@inheritDoc} This implementation uses utility methods from {@code FileLocatorUtils} to generate a {@code File} from
070     * the locator's base path and file name. If this {@code File} exists, its URL is returned.
071     */
072    @Override
073    public URL locate(final FileSystem fileSystem, final FileLocator locator) {
074        if (StringUtils.isNotEmpty(locator.getFileName())) {
075            final File file = FileLocatorUtils.constructFile(locator.getBasePath(), locator.getFileName());
076            if (file.isFile()) {
077                return check(FileLocatorUtils.convertFileToURL(file));
078            }
079        }
080        return null;
081    }
082}