    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     */
    017    package org.apache.commons.io.filefilter;
    018
    019    import java.io.File;
    020    import java.io.Serializable;
    021    import java.util.regex.Pattern;
    022
    023    import 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 < files.length; i++) {
    038     *   System.out.println(files[i]);
    039     * }
    040     * </pre>
    041     *
    042     * @author Oliver Siegmar
    043     * @version $Revision: 659817 $
    044     * @since Commons IO 1.4
    045     */
    046    public class RegexFileFilter extends AbstractFileFilter implements Serializable {
    047
    048        /** The regular expression pattern that will be used to match filenames */
    049        private final Pattern pattern;
    050
    051        /**
    052         * Construct a new regular expression filter.
    053         *
    054         * @param pattern regular string expression to match
    055         * @throws IllegalArgumentException if the pattern is null
    056         */
    057        public RegexFileFilter(String pattern) {
    058            if (pattern == null) {
    059                throw new IllegalArgumentException("Pattern is missing");
    060            }
    061
    062            this.pattern = Pattern.compile(pattern);
    063        }
    064
    065        /**
    066         * Construct a new regular expression filter with the specified flags case sensitivity.
    067         *
    068         * @param pattern regular string expression to match
    069         * @param caseSensitivity  how to handle case sensitivity, null means case-sensitive
    070         * @throws IllegalArgumentException if the pattern is null
    071         */
    072        public RegexFileFilter(String pattern, IOCase caseSensitivity) {
    073            if (pattern == null) {
    074                throw new IllegalArgumentException("Pattern is missing");
    075            }
    076            int flags = 0;
    077            if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
    078                flags = Pattern.CASE_INSENSITIVE;
    079            }
    080            this.pattern = Pattern.compile(pattern, flags);
    081        }
    082
    083        /**
    084         * Construct a new regular expression filter with the specified flags.
    085         *
    086         * @param pattern regular string expression to match
    087         * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
    088         * @throws IllegalArgumentException if the pattern is null
    089         */
    090        public RegexFileFilter(String pattern, int flags) {
    091            if (pattern == null) {
    092                throw new IllegalArgumentException("Pattern is missing");
    093            }
    094            this.pattern = Pattern.compile(pattern, flags);
    095        }
    096
    097        /**
    098         * Construct a new regular expression filter for a compiled regular expression
    099         *
    100         * @param pattern regular expression to match
    101         * @throws IllegalArgumentException if the pattern is null
    102         */
    103        public RegexFileFilter(Pattern pattern) {
    104            if (pattern == null) {
    105                throw new IllegalArgumentException("Pattern is missing");
    106            }
    107
    108            this.pattern = pattern;
    109        }
    110
    111        /**
    112         * Checks to see if the filename matches one of the regular expressions.
    113         *
    114         * @param dir   the file directory
    115         * @param name  the filename
    116         * @return true if the filename matches one of the regular expressions
    117         */
    118        @Override
    119        public boolean accept(File dir, String name) {
    120            return (pattern.matcher(name).matches());
    121        }
    122
    123    }