All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.apache.commons.io.comparator.CompositeFileComparator Maven / Gradle / Ivy

There is a newer version: 2024.11.18751.20241128T090041Z-241100
Show newest version
/*
 * 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.Comparator;
import java.util.function.IntFunction;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

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

* This comparator can be used to sort lists or arrays of files by combining a number of other comparators. *

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

 *       CompositeFileComparator comparator = new CompositeFileComparator(
 *           DirectoryFileComparator.DIRECTORY_COMPARATOR,
 *           NameFileComparator.NAME_COMPARATOR);
 *       List<File> list = ...
 *       comparator.sort(list);
 * 
*

Deprecating Serialization

*

* Serialization is deprecated and will be removed in 3.0. *

* * @since 2.0 */ public class CompositeFileComparator extends AbstractFileComparator implements Serializable { private static final Comparator[] EMPTY_COMPARATOR_ARRAY = {}; private static final long serialVersionUID = -2224170307287243428L; /** * Delegates. */ private final Comparator[] delegates; /** * Constructs a composite comparator for the set of delegate comparators. * * @param delegates The delegate file comparators */ public CompositeFileComparator(@SuppressWarnings("unchecked") final Comparator... delegates) { this.delegates = delegates == null ? emptyArray() : delegates.clone(); } /** * Constructs a composite comparator for the set of delegate comparators. * * @param delegates The delegate file comparators */ public CompositeFileComparator(final Iterable> delegates) { this.delegates = delegates == null ? emptyArray() : StreamSupport.stream(delegates.spliterator(), false).toArray((IntFunction[]>) Comparator[]::new); } /** * Compares 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) { return Stream.of(delegates).map(delegate -> delegate.compare(file1, file2)).filter(r -> r != 0).findFirst().orElse(0); } @SuppressWarnings("unchecked") // types are already correct private Comparator[] emptyArray() { return (Comparator[]) EMPTY_COMPARATOR_ARRAY; } /** * 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(); } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy