org.apache.commons.io.comparator.NameFileComparator Maven / Gradle / Ivy
/*
* 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 org.apache.commons.io.IOCase;
/**
* Compare the names of two files for order (see {@link File#getName()}).
*
* This comparator can be used to sort lists or arrays of files
* by their name either in a case-sensitive, case-insensitive or
* system dependent case sensitive way. A number of singleton instances
* are provided for the various case sensitivity options (using {@link IOCase})
* and the reverse of those options.
*
* Example of a case-sensitive file name sort using the
* {@link #NAME_COMPARATOR} singleton instance:
*
* List<File> list = ...
* ((AbstractFileComparator) NameFileComparator.NAME_COMPARATOR).sort(list);
*
*
* Example of a reverse case-insensitive file name sort using the
* {@link #NAME_INSENSITIVE_REVERSE} singleton instance:
*
* File[] array = ...
* ((AbstractFileComparator) NameFileComparator.NAME_INSENSITIVE_REVERSE).sort(array);
*
*
*
* @since 1.4
*/
public class NameFileComparator extends AbstractFileComparator implements Serializable {
private static final long serialVersionUID = 8397947749814525798L;
/** Case-sensitive name comparator instance (see {@link IOCase#SENSITIVE}) */
public static final Comparator NAME_COMPARATOR = new NameFileComparator();
/** Reverse case-sensitive name comparator instance (see {@link IOCase#SENSITIVE}) */
public static final Comparator NAME_REVERSE = new ReverseComparator(NAME_COMPARATOR);
/** Case-insensitive name comparator instance (see {@link IOCase#INSENSITIVE}) */
public static final Comparator NAME_INSENSITIVE_COMPARATOR = new NameFileComparator(IOCase.INSENSITIVE);
/** Reverse case-insensitive name comparator instance (see {@link IOCase#INSENSITIVE}) */
public static final Comparator NAME_INSENSITIVE_REVERSE = new ReverseComparator(NAME_INSENSITIVE_COMPARATOR);
/** System sensitive name comparator instance (see {@link IOCase#SYSTEM}) */
public static final Comparator NAME_SYSTEM_COMPARATOR = new NameFileComparator(IOCase.SYSTEM);
/** Reverse system sensitive name comparator instance (see {@link IOCase#SYSTEM}) */
public static final Comparator NAME_SYSTEM_REVERSE = new ReverseComparator(NAME_SYSTEM_COMPARATOR);
/** Whether the comparison is case sensitive. */
private final IOCase caseSensitivity;
/**
* Construct a case sensitive file name comparator instance.
*/
public NameFileComparator() {
this.caseSensitivity = IOCase.SENSITIVE;
}
/**
* Construct a file name comparator instance with the specified case-sensitivity.
*
* @param caseSensitivity how to handle case sensitivity, null means case-sensitive
*/
public NameFileComparator(final IOCase caseSensitivity) {
this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity;
}
/**
* Compare the names of two files with the specified case sensitivity.
*
* @param file1 The first file to compare
* @param file2 The second file to compare
* @return a negative value if the first file's name
* is less than the second, zero if the names are the
* same and a positive value if the first files name
* is greater than the second file.
*/
@Override
public int compare(final File file1, final File file2) {
return caseSensitivity.checkCompareTo(file1.getName(), file2.getName());
}
/**
* String representation of this file comparator.
*
* @return String representation of this file comparator
*/
@Override
public String toString() {
return super.toString() + "[caseSensitivity=" + caseSensitivity + "]";
}
}