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 checks whether the provided file name is already
026 * an absolute file name.
027 * <p>
028 * This strategy ignores the URL and the base path stored in the passed in {@link FileLocator}. It is only triggered by
029 * absolute names in the locator's {@code fileName} component.
030 * </p>
031 * <p>
032 * See {@link AbstractFileLocationStrategy} learn how to grant an deny URL schemes and hosts.
033 * </p>
034 *
035 * @see AbstractFileLocationStrategy
036 * @since 2.0
037 */
038public class AbsoluteNameLocationStrategy extends AbstractFileLocationStrategy {
039
040    /**
041     * Builds new instances of {@link ProvidedURLLocationStrategy}.
042     *
043     * @return a new builder.
044     * @since 2.15.0
045     */
046    public static StrategyBuilder<AbsoluteNameLocationStrategy> builder() {
047        return new StrategyBuilder<>(AbsoluteNameLocationStrategy::new);
048    }
049
050    /**
051     * Constructs a new instance where URL resources are bound by {@link AbstractFileLocationStrategy.AbstractBuilder}.
052     */
053    public AbsoluteNameLocationStrategy() {
054        // empty
055    }
056
057    /**
058     * Constructs a new instance where URL resources are bound by {@link AbstractFileLocationStrategy.AbstractBuilder}.
059     *
060     * @param builder How to build the instance.
061     * @since 2.15.0
062     */
063    public AbsoluteNameLocationStrategy(final AbstractBuilder<?, ?> builder) {
064        super(builder);
065    }
066
067    /**
068     * {@inheritDoc}
069     * <p>
070     * This implementation constructs a {@code File} object from the locator's file name (if defined). If this
071     * results in an absolute file name pointing to an existing file, the corresponding URL is returned.
072     * </p>
073     */
074    @Override
075    public URL locate(final FileSystem fileSystem, final FileLocator locator) {
076        if (StringUtils.isNotEmpty(locator.getFileName())) {
077            final File file = new File(locator.getFileName());
078            if (file.isAbsolute() && file.exists()) {
079                return check(FileLocatorUtils.convertFileToURL(file));
080            }
081        }
082        return null;
083    }
084}