Commons IO example source code file (DelegateFileFilter.java)

This example Commons IO source code file (DelegateFileFilter.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, delegatefilefilter, delegatefilefilter, filefilter, filenamefilter, illegalargumentexception, io, override, override, serializable, string, string, the, the

The Commons IO DelegateFileFilter.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.FileFilter;
import java.io.FilenameFilter;
import java.io.Serializable;

/**
 * This class turns a Java FileFilter or FilenameFilter into an IO FileFilter.
 * 
 * @since Commons IO 1.0
 * @version $Revision: 1005099 $ $Date: 2010-10-06 17:13:01 +0100 (Wed, 06 Oct 2010) $
 * 
 * @author Stephen Colebourne
 * @see FileFilterUtils#asFileFilter(FileFilter)
 * @see FileFilterUtils#asFileFilter(FilenameFilter)
 */
public class DelegateFileFilter extends AbstractFileFilter implements Serializable {

    /** The Filename filter */
    private final FilenameFilter filenameFilter;
    /** The File filter */
    private final FileFilter fileFilter;

    /**
     * Constructs a delegate file filter around an existing FilenameFilter.
     * 
     * @param filter  the filter to decorate
     */
    public DelegateFileFilter(FilenameFilter filter) {
        if (filter == null) {
            throw new IllegalArgumentException("The FilenameFilter must not be null");
        }
        this.filenameFilter = filter;
        this.fileFilter = null;
    }

    /**
     * Constructs a delegate file filter around an existing FileFilter.
     * 
     * @param filter  the filter to decorate
     */
    public DelegateFileFilter(FileFilter filter) {
        if (filter == null) {
            throw new IllegalArgumentException("The FileFilter must not be null");
        }
        this.fileFilter = filter;
        this.filenameFilter = null;
    }

    /**
     * Checks the filter.
     * 
     * @param file  the file to check
     * @return true if the filter matches
     */
    @Override
    public boolean accept(File file) {
        if (fileFilter != null) {
            return fileFilter.accept(file);
        } else {
            return super.accept(file);
        }
    }

    /**
     * Checks the filter.
     * 
     * @param dir  the directory
     * @param name  the filename in the directory
     * @return true if the filter matches
     */
    @Override
    public boolean accept(File dir, String name) {
        if (filenameFilter != null) {
            return filenameFilter.accept(dir, name);
        } else {
            return super.accept(dir, name);
        }
    }

    /**
     * Provide a String representaion of this file filter.
     *
     * @return a String representaion
     */
    @Override
    public String toString() {
        String delegate = (fileFilter != null ? fileFilter.toString() : filenameFilter.toString()); 
        return super.toString() + "(" + delegate + ")";
    }
    
}