/*

  * 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.comparator;

 import java.io.File;

 import java.io.Serializable;

 import java.util.ArrayList;

 import java.util.Comparator;

 import java.util.List;

 /**

  * Compare two files using a set of delegate file {@link Comparator}.

  * <p>

  * This comparator can be used to sort lists or arrays of files

  * by combining a number other comparators.

  * <p>

  * Example of sorting a list of files by type (i.e. directory or file)

  * and then by name:

  * <pre>

  *       CompositeFileComparator comparator =

  *                       new CompositeFileComparator(

  *                                 (AbstractFileComparator) DirectoryFileComparator.DIRECTORY_COMPARATOR,

  *                                 (AbstractFileComparator) NameFileComparator.NAME_COMPARATOR);

  *       List<File> list = ...

  *       comparator.sort(list);

  * </pre>

  *

  * @version $Id: CompositeFileComparator.java 1469107 2013-04-17 23:45:53Z sebb $

  * @since 2.0

  */

 public class CompositeFileComparator extends AbstractFileComparator implements Serializable {

     private static final Comparator<?>[] NO_COMPARATORS = {};

     private final Comparator<File>[] delegates;

     /**

      * Create a composite comparator for the set of delegate comparators.

      *

      * @param delegates The delegate file comparators

      */

     @SuppressWarnings("unchecked") // casts 1 & 2 must be OK because types are already correct

     public CompositeFileComparator(final Comparator<File>... delegates) {

         if (delegates == null) {

             this.delegates = (Comparator<File>[]) NO_COMPARATORS;//1

         } else {

             this.delegates = (Comparator<File>[]) new Comparator<?>[delegates.length];//2

             System.arraycopy(delegates, 0, this.delegates, 0, delegates.length);

         }

     }

     /**

      * Create a composite comparator for the set of delegate comparators.

      *

      * @param delegates The delegate file comparators

      */

     @SuppressWarnings("unchecked") // casts 1 & 2 must be OK because types are already correct

     public CompositeFileComparator(final Iterable<Comparator<File>> delegates) {

         if (delegates == null) {

             this.delegates = (Comparator<File>[]) NO_COMPARATORS; //1

         } else {

             final List<Comparator<File>> list = new ArrayList<Comparator<File>>();

             for (final Comparator<File> comparator : delegates) {

                 list.add(comparator);

             }

             this.delegates = (Comparator<File>[]) list.toArray(new Comparator<?>[list.size()]); //2

         }

     }

     /**

      * Compare the two files using delegate comparators.

      * 

      * @param file1 The first file to compare

      * @param file2 The second file to compare

      * @return the first non-zero result returned from

      * the delegate comparators or zero.

      */

     public int compare(final File file1, final File file2) {

         int result = 0;

         for (final Comparator<File> delegate : delegates) {

             result = delegate.compare(file1, file2);

             if (result != 0) {

                 break;

             }

         }

         return result;

     }

     /**

      * String representation of this file comparator.

      *

      * @return String representation of this file comparator

      */

     @Override

     public String toString() {

         final StringBuilder builder = new StringBuilder();

         builder.append(super.toString());

         builder.append('{');

         for (int i = 0; i < delegates.length; i++) {

             if (i > 0) {

                 builder.append(',');

             }

             builder.append(delegates[i]);

         }

         builder.append('}');

         return builder.toString();

     }

 }