| /* |
| * 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> |
| * |
| * @since 2.0 |
| */ |
| public class CompositeFileComparator extends AbstractFileComparator implements Serializable { |
| |
| private static final Comparator<?>[] EMPTY_COMPARATOR_ARRAY = new Comparator<?>[0]; |
| private static final long serialVersionUID = -2224170307287243428L; |
| 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<>(); |
| for (final Comparator<File> comparator : delegates) { |
| list.add(comparator); |
| } |
| this.delegates = (Comparator<File>[]) list.toArray(EMPTY_COMPARATOR_ARRAY); //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. |
| */ |
| @Override |
| 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(); |
| } |
| } |