001 /* 002 * Copyright (C) 2006 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017 package com.google.common.io; 018 019 import com.google.common.annotations.Beta; 020 import com.google.common.base.Preconditions; 021 022 import java.io.File; 023 import java.io.FilenameFilter; 024 import java.util.regex.Pattern; 025 import java.util.regex.PatternSyntaxException; 026 027 /** 028 * File name filter that only accepts files matching a regular expression. 029 * 030 * @author Apple Chow 031 * @since 1 032 */ 033 @Beta 034 public final class PatternFilenameFilter implements FilenameFilter { 035 036 private final Pattern pattern; 037 038 /** 039 * Constructs a pattern file name filter object. 040 * @param patternStr the pattern string on which to filter file names 041 * 042 * @throws PatternSyntaxException if pattern compilation fails (runtime) 043 */ 044 public PatternFilenameFilter(String patternStr) { 045 this(Pattern.compile(patternStr)); 046 } 047 048 /** 049 * Constructs a pattern file name filter object. 050 * @param pattern the pattern on which to filter file names 051 */ 052 public PatternFilenameFilter(Pattern pattern) { 053 this.pattern = Preconditions.checkNotNull(pattern); 054 } 055 056 @Override public boolean accept(File dir, String fileName) { 057 return pattern.matcher(fileName).matches(); 058 } 059 }