/*
 * 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.regex.Pattern;

import org.apache.commons.vfs2.FileFilter;
import org.apache.commons.vfs2.FileSelectInfo;

Filters files using supplied regular expression(s).

See java.util.regex.Pattern for regex matching rules.


For example, to retrieve and print all java files where the name matched the
regular expression in the current directory:

FileSystemManager fsManager = VFS.getManager();
FileObject dir = fsManager.toFileObject(new File("."));
FileObject[] files = dir.findFiles(new FileFilterSelector(new RegexFileFilter("ˆ.*[tT]est(-\\d+)?\\.java$")));
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 using supplied regular expression(s).
 * <p>
 * See java.util.regex.Pattern for regex matching rules.
 * </p>
 *
 * <p>
 * For example, to retrieve and print all java files where the name matched the
 * regular expression in the current directory:
 * </p>
 *
 * <pre>
 * FileSystemManager fsManager = VFS.getManager();
 * FileObject dir = fsManager.toFileObject(new File(&quot;.&quot;));
 * FileObject[] files = dir.findFiles(new FileFilterSelector(new RegexFileFilter(&quot;ˆ.*[tT]est(-\\d+)?\\.java$&quot;)));
 * 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 RegexFileFilter implements FileFilter, Serializable {

    private static final long serialVersionUID = 1L;

    
Exception message when no pattern is given in the constructor. /** Exception message when no pattern is given in the constructor. */
    public static final String PATTERN_IS_MISSING = "Pattern is missing";

    
The regular expression pattern that will be used to match file names. /** The regular expression pattern that will be used to match file names. */
    private final Pattern pattern;

    
Construct a new regular expression filter for a compiled regular expression.
Params:
pattern – regular expression to match - Cannot be null/**
     * Construct a new regular expression filter for a compiled regular expression.
     *
     * @param pattern regular expression to match - Cannot be null
     */
    public RegexFileFilter(final Pattern pattern) {
        if (pattern == null) {
            throw new IllegalArgumentException(PATTERN_IS_MISSING);
        }

        this.pattern = pattern;
    }

    
Construct a new regular expression filter.
Params:
pattern – regular string expression to match - Cannot be null/**
     * Construct a new regular expression filter.
     *
     * @param pattern regular string expression to match - Cannot be null
     */
    public RegexFileFilter(final String pattern) {
        if (pattern == null) {
            throw new IllegalArgumentException(PATTERN_IS_MISSING);
        }

        this.pattern = Pattern.compile(pattern);
    }

    
Construct a new regular expression filter with the specified flags.
Params:
pattern – regular string expression to match
flags –  pattern flags - e.g. Pattern.CASE_INSENSITIVE/**
     * Construct a new regular expression filter with the specified flags.
     *
     * @param pattern regular string expression to match
     * @param flags   pattern flags - e.g. {@link Pattern#CASE_INSENSITIVE}
     */
    public RegexFileFilter(final String pattern, final int flags) {
        if (pattern == null) {
            throw new IllegalArgumentException(PATTERN_IS_MISSING);
        }
        this.pattern = Pattern.compile(pattern, flags);
    }

    
Construct a new regular expression filter with the specified flags case
sensitivity.
Params:
pattern –         regular string expression to match - Cannot be null
caseSensitivity – how to handle case sensitivity, null means
                       case-sensitive/**
     * Construct a new regular expression filter with the specified flags case
     * sensitivity.
     *
     * @param pattern         regular string expression to match - Cannot be null
     * @param caseSensitivity how to handle case sensitivity, null means
     *                        case-sensitive
     */
    public RegexFileFilter(final String pattern, final IOCase caseSensitivity) {
        if (pattern == null) {
            throw new IllegalArgumentException(PATTERN_IS_MISSING);
        }
        int flags = 0;
        if (caseSensitivity != null && !caseSensitivity.isCaseSensitive()) {
            flags = Pattern.CASE_INSENSITIVE;
        }
        this.pattern = Pattern.compile(pattern, flags);
    }

    
Checks to see if the file name matches one of the regular expressions.
Params:
fileInfo – the File to check
Returns:
true if the file matches one of the regular expressions/**
     * Checks to see if the file name matches one of the regular expressions.
     *
     * @param fileInfo the File to check
     *
     * @return true if the file matches one of the regular expressions
     */
    @Override
    public boolean accept(final FileSelectInfo fileInfo) {
        final String name = fileInfo.getFile().getName().getBaseName();
        return pattern.matcher(name).matches();
    }

}