/*
 * 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.vfs2.filter;

import java.io.Serializable;
import java.util.Date;

import org.apache.commons.vfs2.FileContent;
import org.apache.commons.vfs2.FileFilter;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSelectInfo;
import org.apache.commons.vfs2.FileSystemException;

Filters files based on a cutoff time, can filter either newer files or files
equal to or older.

For example, to print all files and directories in the current directory
older than one day:

FileSystemManager fsManager = VFS.getManager();
FileObject dir = fsManager.toFileObject(new File("."));
// We are interested in files older than one day
long cutoff = System.currentTimeMillis() - (24 * 60 * 60 * 1000);
AgeFileFilter filter = new AgeFileFilter(cutoff);
FileObject[] files = dir.findFiles(new FileFilterSelector(filter));
for (int i = 0; i < files.length; i++) {
    System.out.println(files[i]);
}

Author:
This code was originally ported from Apache Commons IO File Filter
See Also:
http://commons.apache.org/proper/commons-io/
Since:
2.4/**
 * Filters files based on a cutoff time, can filter either newer files or files
 * equal to or older.
 * <p>
 * For example, to print all files and directories in the current directory
 * older than one day:
 * </p>
 *
 * <pre>
 * FileSystemManager fsManager = VFS.getManager();
 * FileObject dir = fsManager.toFileObject(new File(&quot;.&quot;));
 * // We are interested in files older than one day
 * long cutoff = System.currentTimeMillis() - (24 * 60 * 60 * 1000);
 * AgeFileFilter filter = new AgeFileFilter(cutoff);
 * FileObject[] files = dir.findFiles(new FileFilterSelector(filter));
 * for (int i = 0; i &lt; files.length; i++) {
 *     System.out.println(files[i]);
 * }
 * </pre>
 *
 * @author This code was originally ported from Apache Commons IO File Filter
 * @see "http://commons.apache.org/proper/commons-io/"
 * @since 2.4
 */
public class AgeFileFilter implements FileFilter, Serializable {

    private static final long serialVersionUID = 1L;

    
Whether the files accepted will be older or newer. /** Whether the files accepted will be older or newer. */
    private final boolean acceptOlder;

    
The cutoff time threshold. /** The cutoff time threshold. */
    private final long cutoff;

    
Tests if the specified File is newer than the specified time
reference.
Params:
fileObject – the File of which the modification date must be compared, must not be null
timeMillis – the time reference measured in milliseconds since the epoch
                  (00:00:00 GMT, January 1, 1970)
Throws:
FileSystemException – Thrown for file system errors.
IllegalArgumentException – if the file is null
Returns:
true if the File exists and has been modified after the
        given time reference./**
     * Tests if the specified <code>File</code> is newer than the specified time
     * reference.
     *
     * @param fileObject the <code>File</code> of which the modification date must
     *                   be compared, must not be {@code null}
     * @param timeMillis the time reference measured in milliseconds since the epoch
     *                   (00:00:00 GMT, January 1, 1970)
     * @return true if the <code>File</code> exists and has been modified after the
     *         given time reference.
     * @throws FileSystemException Thrown for file system errors.
     * @throws IllegalArgumentException if the file is {@code null}
     */
    private static boolean isFileNewer(final FileObject fileObject, final long timeMillis) throws FileSystemException {
        if (fileObject == null) {
            throw new IllegalArgumentException("No specified file");
        }
        if (!fileObject.exists()) {
            return false;
        }
        try (final FileContent content = fileObject.getContent()) {
            final long lastModified = content.getLastModifiedTime();
            return lastModified > timeMillis;
        }
    }

    
Constructs a new age file filter for files older than (at or before) a
certain cutoff date.
Params:
cutoffDate – the threshold age of the files/**
     * Constructs a new age file filter for files older than (at or before) a
     * certain cutoff date.
     *
     * @param cutoffDate the threshold age of the files
     */
    public AgeFileFilter(final Date cutoffDate) {
        this(cutoffDate, true);
    }

    
Constructs a new age file filter for files on any one side of a certain
cutoff date.
Params:
cutoffDate –  the threshold age of the files
acceptOlder – if true, older files (at or before the cutoff) are
                   accepted, else newer ones (after the cutoff)./**
     * Constructs a new age file filter for files on any one side of a certain
     * cutoff date.
     *
     * @param cutoffDate  the threshold age of the files
     * @param acceptOlder if true, older files (at or before the cutoff) are
     *                    accepted, else newer ones (after the cutoff).
     */
    public AgeFileFilter(final Date cutoffDate, final boolean acceptOlder) {
        this(cutoffDate.getTime(), acceptOlder);
    }

    
Constructs a new age file filter for files older than (at or before) a
certain File (whose last modification time will be used as reference).
Params:
cutoffReference – the file whose last modification time is usesd as the
                       threshold age of the files
Throws:
FileSystemException – Error reading the last modification time from the
                            reference file object./**
     * Constructs a new age file filter for files older than (at or before) a
     * certain File (whose last modification time will be used as reference).
     *
     * @param cutoffReference the file whose last modification time is usesd as the
     *                        threshold age of the files
     *
     * @throws FileSystemException Error reading the last modification time from the
     *                             reference file object.
     */
    public AgeFileFilter(final FileObject cutoffReference) throws FileSystemException {
        this(cutoffReference, true);
    }

    
Constructs a new age file filter for files on any one side of a certain File
(whose last modification time will be used as reference).
Params:
cutoffReference – the file whose last modification time is usesd as the
                       threshold age of the files
acceptOlder –     if true, older files (at or before the cutoff) are
                       accepted, else newer ones (after the cutoff).
Throws:
FileSystemException – Error reading the last modification time from the
                            reference file object./**
     * Constructs a new age file filter for files on any one side of a certain File
     * (whose last modification time will be used as reference).
     *
     * @param cutoffReference the file whose last modification time is usesd as the
     *                        threshold age of the files
     * @param acceptOlder     if true, older files (at or before the cutoff) are
     *                        accepted, else newer ones (after the cutoff).
     *
     * @throws FileSystemException Error reading the last modification time from the
     *                             reference file object.
     */
    public AgeFileFilter(final FileObject cutoffReference, final boolean acceptOlder) throws FileSystemException {
        this(cutoffReference.getContent().getLastModifiedTime(), acceptOlder);
    }

    
Constructs a new age file filter for files equal to or older than a certain
cutoff.
Params:
cutoff – the threshold age of the files/**
     * Constructs a new age file filter for files equal to or older than a certain
     * cutoff.
     *
     * @param cutoff the threshold age of the files
     */
    public AgeFileFilter(final long cutoff) {
        this(cutoff, true);
    }

    
Constructs a new age file filter for files on any one side of a certain
cutoff.
Params:
cutoff –      the threshold age of the files
acceptOlder – if true, older files (at or before the cutoff) are
                   accepted, else newer ones (after the cutoff)./**
     * Constructs a new age file filter for files on any one side of a certain
     * cutoff.
     *
     * @param cutoff      the threshold age of the files
     * @param acceptOlder if true, older files (at or before the cutoff) are
     *                    accepted, else newer ones (after the cutoff).
     */
    public AgeFileFilter(final long cutoff, final boolean acceptOlder) {
        this.acceptOlder = acceptOlder;
        this.cutoff = cutoff;
    }

    
Checks to see if the last modification of the file matches cutoff favorably.

If last modification time equals cutoff and newer files are required, file
IS NOT selected. If last modification time equals cutoff and older
files are required, file IS selected.

Params:
fileInfo – the File to check
Throws:
FileSystemException – Thrown for file system errors.
Returns:
true if the file name matches/**
     * Checks to see if the last modification of the file matches cutoff favorably.
     * <p>
     * If last modification time equals cutoff and newer files are required, file
     * <b>IS NOT</b> selected. If last modification time equals cutoff and older
     * files are required, file <b>IS</b> selected.
     * </p>
     *
     * @param fileInfo the File to check
     *
     * @return true if the file name matches
     * @throws FileSystemException Thrown for file system errors.
     */
    @Override
    public boolean accept(final FileSelectInfo fileInfo) throws FileSystemException {
        final boolean newer = isFileNewer(fileInfo.getFile(), cutoff);
        return acceptOlder ? !newer : newer;
    }

    
Provide a String representaion of this file filter.
Returns:
a String representaion/**
     * Provide a String representaion of this file filter.
     *
     * @return a String representaion
     */
    @Override
    public String toString() {
        final String condition = acceptOlder ? "<=" : ">";
        return super.toString() + "(" + condition + cutoff + ")";
    }
}