| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.configuration2.io; |
| |
| import java.net.URL; |
| |
| /** |
| * <p> |
| * An interface allowing applications to customize the process of locating a file. |
| * </p> |
| * <p> |
| * {@link FileHandler} uses {@link FileLocator} objects for referencing files. These objects are not guaranteed to |
| * identify a file in a unique way. For instance, if only a file name is defined, this could mean a relative file name |
| * in the current directory, the name of a resource to be loaded from the class path, or something else. Before the file |
| * described by a {@code FileLocator} can be actually accessed, an unambiguous URL pointing to this file has to be |
| * obtained. This is the job of a {@code FileLocationStrategy}. |
| * </p> |
| * <p> |
| * This interface defines a method for locating a file provided as a {@code FileLocator} object. If location is |
| * successful, a URL is returned. A concrete implementation can perform arbitrary actions to search for the file in |
| * question at various places. There will also be an implementation allowing the combination of multiple |
| * {@code FileLocationStrategy} implementations; so a file can be searched using multiple strategies until one of them |
| * is successful. |
| * </p> |
| * |
| * @since 2.0 |
| */ |
| public interface FileLocationStrategy { |
| /** |
| * Tries to locate the specified file. The method also expects the {@code FileSystem} to be used. Note that the |
| * {@code FileLocator} object may also contain a {@code FileSystem}, but this is optional. The passed in |
| * {@code FileSystem} should be used, and callers must not pass a <b>null</b> reference for this argument. A concrete |
| * implementation has to evaluate the properties stored in the {@code FileLocator} object and try to match them to an |
| * existing file. If this can be done, a corresponding URL is returned. Otherwise, result is <b>null</b>. |
| * Implementations should not throw an exception (unless parameters are <b>null</b>) as there might be alternative |
| * strategies which can find the file in question. |
| * |
| * @param fileSystem the {@code FileSystem} to be used for this operation |
| * @param locator the object describing the file to be located |
| * @return a URL pointing to the referenced file if location was successful; <b>null</b> if the file could not be |
| * resolved |
| */ |
| URL locate(FileSystem fileSystem, FileLocator locator); |
| } |