001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.fs;
020    
021    import java.util.regex.PatternSyntaxException;
022    import java.io.IOException;
023    
024    import org.apache.hadoop.classification.InterfaceAudience;
025    import org.apache.hadoop.classification.InterfaceStability;
026    
027    /**
028     * A filter for POSIX glob pattern with brace expansions.
029     */
030    @InterfaceAudience.Public
031    @InterfaceStability.Evolving
032    public class GlobFilter implements PathFilter {
033      private final static PathFilter DEFAULT_FILTER = new PathFilter() {
034          @Override
035          public boolean accept(Path file) {
036            return true;
037          }
038        };
039    
040      private PathFilter userFilter = DEFAULT_FILTER;
041      private GlobPattern pattern;
042    
043      /**
044       * Creates a glob filter with the specified file pattern.
045       *
046       * @param filePattern the file pattern.
047       * @throws IOException thrown if the file pattern is incorrect.
048       */
049      public GlobFilter(String filePattern) throws IOException {
050        init(filePattern, DEFAULT_FILTER);
051      }
052    
053      /**
054       * Creates a glob filter with the specified file pattern and an user filter.
055       *
056       * @param filePattern the file pattern.
057       * @param filter user filter in addition to the glob pattern.
058       * @throws IOException thrown if the file pattern is incorrect.
059       */
060      public GlobFilter(String filePattern, PathFilter filter) throws IOException {
061        init(filePattern, filter);
062      }
063    
064      void init(String filePattern, PathFilter filter) throws IOException {
065        try {
066          userFilter = filter;
067          pattern = new GlobPattern(filePattern);
068        }
069        catch (PatternSyntaxException e) {
070          // Existing code expects IOException startWith("Illegal file pattern")
071          throw new IOException("Illegal file pattern: "+ e.getMessage(), e);
072        }
073      }
074    
075      boolean hasPattern() {
076        return pattern.hasWildcard();
077      }
078    
079      @Override
080      public boolean accept(Path path) {
081        return pattern.matches(path.getName()) && userFilter.accept(path);
082      }
083    }