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Commons IO example source code file (RegexFileFilter.java)

This example Commons IO source code file (RegexFileFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons IO tags/keywords

abstractfilefilter, abstractfilefilter, illegalargumentexception, illegalargumentexception, io, iocase, override, pattern, pattern, regex, regexfilefilter, regexfilefilter, serializable, string

The Commons IO RegexFileFilter.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.io.filefilter;

import java.io.File;
import java.io.Serializable;
import java.util.regex.Pattern;

import org.apache.commons.io.IOCase;

/**
 * Filters files using supplied regular expression(s).
 * <p/>
 * See java.util.regex.Pattern for regex matching rules
 * <p/>
 *
 * <p/>
 * e.g.
 * <pre>
 * File dir = new File(".");
 * FileFilter fileFilter = new RegexFileFilter("^.*[tT]est(-\\d+)?\\.java$");
 * File[] files = dir.listFiles(fileFilter);
 * for (int i = 0; i < files.length; i++) {
 *   System.out.println(files[i]);
 * }
 * </pre>
 *
 * @author Oliver Siegmar
 * @version $Revision: 659817 $
 * @since Commons IO 1.4
 */
public class RegexFileFilter extends AbstractFileFilter implements Serializable {

    /** The regular expression pattern that will be used to match filenames */
    private final Pattern pattern;

    /**
     * Construct a new regular expression filter.
     *
     * @param pattern regular string expression to match
     * @throws IllegalArgumentException if the pattern is null
     */
    public RegexFileFilter(String pattern) {
        if (pattern == null) {
            throw new IllegalArgumentException("Pattern is missing");
        }

        this.pattern = Pattern.compile(pattern);
    }

    /**
     * Construct a new regular expression filter with the specified flags case sensitivity.
     *
     * @param pattern regular string expression to match
     * @param caseSensitivity  how to handle case sensitivity, null means case-sensitive
     * @throws IllegalArgumentException if the pattern is null
     */
    public RegexFileFilter(String pattern, IOCase caseSensitivity) {
        if (pattern == null) {
            throw new IllegalArgumentException("Pattern is missing");
        }
        int flags = 0;
        if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
            flags = Pattern.CASE_INSENSITIVE;
        }
        this.pattern = Pattern.compile(pattern, flags);
    }

    /**
     * Construct a new regular expression filter with the specified flags.
     *
     * @param pattern regular string expression to match
     * @param flags pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
     * @throws IllegalArgumentException if the pattern is null
     */
    public RegexFileFilter(String pattern, int flags) {
        if (pattern == null) {
            throw new IllegalArgumentException("Pattern is missing");
        }
        this.pattern = Pattern.compile(pattern, flags);
    }

    /**
     * Construct a new regular expression filter for a compiled regular expression
     *
     * @param pattern regular expression to match
     * @throws IllegalArgumentException if the pattern is null
     */
    public RegexFileFilter(Pattern pattern) {
        if (pattern == null) {
            throw new IllegalArgumentException("Pattern is missing");
        }

        this.pattern = pattern;
    }

    /**
     * Checks to see if the filename matches one of the regular expressions.
     *
     * @param dir   the file directory
     * @param name  the filename
     * @return true if the filename matches one of the regular expressions
     */
    @Override
    public boolean accept(File dir, String name) {
        return (pattern.matcher(name).matches());
    }

}

Other Commons IO examples (source code examples)

Here is a short list of links related to this Commons IO RegexFileFilter.java source code file:



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