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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     https://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.configuration2.io;
18  
19  import java.io.File;
20  import java.net.URL;
21  
22  import org.apache.commons.lang3.StringUtils;
23  
24  /**
25   * <p>
26   * A specialized implementation of {@code FileLocationStrategy} which tries to construct a file path from the locator's
27   * base path and file name.
28   * </p>
29   * <p>
30   * This strategies ignores the URL stored in the passed in {@link FileLocator}. It generates a path by concatenating the
31   * base path (if present) and the file name. If the resulting path points to a valid file, the corresponding URL is
32   * returned.
33   * </p>
34   *
35   * @since 2.0
36   */
37  public class BasePathLocationStrategy implements FileLocationStrategy {
38  
39      /**
40       * Constructs a new instance.
41       */
42      public BasePathLocationStrategy() {
43          // empty
44      }
45  
46      /**
47       * {@inheritDoc} This implementation uses utility methods from {@code FileLocatorUtils} to generate a {@code File} from
48       * the locator's base path and file name. If this {@code File} exists, its URL is returned.
49       */
50      @Override
51      public URL locate(final FileSystem fileSystem, final FileLocator locator) {
52          if (StringUtils.isNotEmpty(locator.getFileName())) {
53              final File file = FileLocatorUtils.constructFile(locator.getBasePath(), locator.getFileName());
54              if (file.isFile()) {
55                  return FileLocatorUtils.convertFileToURL(file);
56              }
57          }
58  
59          return null;
60      }
61  }