    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 *      http://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.io.filefilter;
    018
    019import java.io.File;
    020import java.io.Serializable;
    021import java.util.regex.Pattern;
    022
    023import org.apache.commons.io.IOCase;
    024
    025/**
    026 * Filters files using supplied regular expression(s).
    027 * <p>
    028 * See java.util.regex.Pattern for regex matching rules.
    029 * </p>
    030 *
    031 * <p>
    032 * e.g.
    033 * <pre>
    034 * File dir = new File(".");
    035 * FileFilter fileFilter = new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$");
    036 * File[] files = dir.listFiles(fileFilter);
    037 * for (int i = 0; i &lt; files.length; i++) {
    038 *   System.out.println(files[i]);
    039 * }
    040 * </pre>
    041 *
    042 * @since 1.4
    043 */
    044public class RegexFileFilter extends AbstractFileFilter implements Serializable {
    045
    046    private static final long serialVersionUID = 4269646126155225062L;
    047    /** The regular expression pattern that will be used to match file names */
    048    private final Pattern pattern;
    049
    050    /**
    051     * Construct a new regular expression filter.
    052     *
    053     * @param pattern regular string expression to match
    054     * @throws IllegalArgumentException if the pattern is null
    055     */
    056    public RegexFileFilter(final String pattern) {
    057        if (pattern == null) {
    058            throw new IllegalArgumentException("Pattern is missing");
    059        }
    060
    061        this.pattern = Pattern.compile(pattern);
    062    }
    063
    064    /**
    065     * Construct a new regular expression filter with the specified flags case sensitivity.
    066     *
    067     * @param pattern regular string expression to match
    068     * @param caseSensitivity  how to handle case sensitivity, null means case-sensitive
    069     * @throws IllegalArgumentException if the pattern is null
    070     */
    071    public RegexFileFilter(final String pattern, final IOCase caseSensitivity) {
    072        if (pattern == null) {
    073            throw new IllegalArgumentException("Pattern is missing");
    074        }
    075        int flags = 0;
    076        if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
    077            flags = Pattern.CASE_INSENSITIVE;
    078        }
    079        this.pattern = Pattern.compile(pattern, flags);
    080    }
    081
    082    /**
    083     * Construct a new regular expression filter with the specified flags.
    084     *
    085     * @param pattern regular string expression to match
    086     * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
    087     * @throws IllegalArgumentException if the pattern is null
    088     */
    089    public RegexFileFilter(final String pattern, final int flags) {
    090        if (pattern == null) {
    091            throw new IllegalArgumentException("Pattern is missing");
    092        }
    093        this.pattern = Pattern.compile(pattern, flags);
    094    }
    095
    096    /**
    097     * Construct a new regular expression filter for a compiled regular expression
    098     *
    099     * @param pattern regular expression to match
    100     * @throws IllegalArgumentException if the pattern is null
    101     */
    102    public RegexFileFilter(final Pattern pattern) {
    103        if (pattern == null) {
    104            throw new IllegalArgumentException("Pattern is missing");
    105        }
    106
    107        this.pattern = pattern;
    108    }
    109
    110    /**
    111     * Checks to see if the file name matches one of the regular expressions.
    112     *
    113     * @param dir   the file directory (ignored)
    114     * @param name  the file name
    115     * @return true if the file name matches one of the regular expressions
    116     */
    117    @Override
    118    public boolean accept(final File dir, final String name) {
    119        return pattern.matcher(name).matches();
    120    }
    121
    122}