/*
 * 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;

/**
 * This filter accepts <code>File</code>s that are directories.
 * <p>
 * For example, here is how to print out a list of the
 * current directory's subdirectories:
 *
 * <pre>
 * File dir = new File(".");
 * String[] files = dir.list( DirectoryFileFilter.INSTANCE );
 * for ( int i = 0; i &lt; files.length; i++ ) {
 *     System.out.println(files[i]);
 * }
 * </pre>
 *
 * @since 1.0
 *
 *
 * @see FileFilterUtils#directoryFileFilter()
 */
public class DirectoryFileFilter extends AbstractFileFilter implements Serializable {

    /**
     * Singleton instance of directory filter.
     * @since 1.3
     */
    public static final IOFileFilter DIRECTORY = new DirectoryFileFilter();
    /**
     * Singleton instance of directory filter.
     * Please use the identical DirectoryFileFilter.DIRECTORY constant.
     * The new name is more JDK 1.5 friendly as it doesn't clash with other
     * values when using static imports.
     */
    public static final IOFileFilter INSTANCE = DIRECTORY;
    private static final long serialVersionUID = -5148237843784525732L;

    /**
     * Restrictive constructor.
     */
    protected DirectoryFileFilter() {
    }

    /**
     * Checks to see if the file is a directory.
     *
     * @param file  the File to check
     * @return true if the file is a directory
     */
    @Override
    public boolean accept(final File file) {
        return file.isDirectory();
    }

}

/*
 * 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;

/**
 * This filter accepts <code>File</code>s that are directories.
 * <p>
 * For example, here is how to print out a list of the current directory's subdirectories:
 *
 * <pre>
 * File dir = new File(".");
 * String[] files = dir.list(DirectoryFileFilter.INSTANCE);
 * for (int i = 0; i &lt; files.length; i++) {
 *     System.out.println(files[i]);
 * }
 * </pre>
 *
 * @since 1.0
 *
 *
 * @see FileFilterUtils#directoryFileFilter()
 */
public class DirectoryFileFilter extends AbstractFileFilter implements Serializable {

    /**
     * Singleton instance of directory filter.
     * 
     * @since 1.3
     */
    public static final IOFileFilter DIRECTORY = new DirectoryFileFilter();

    /**
     * Singleton instance of directory filter. Please use the identical DirectoryFileFilter.DIRECTORY constant. The new
     * name is more JDK 1.5 friendly as it doesn't clash with other values when using static imports.
     */
    public static final IOFileFilter INSTANCE = DIRECTORY;

    private static final long serialVersionUID = -5148237843784525732L;

    /**
     * Restrictive constructor.
     */
    protected DirectoryFileFilter() {
        // empty.
    }

    /**
     * Checks to see if the file is a directory.
     *
     * @param file the File to check
     * @return true if the file is a directory
     */
    @Override
    public boolean accept(final File file) {
        return file.isDirectory();
    }

}

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