001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.oozie.util;
019
020import java.util.regex.Matcher;
021import java.util.regex.Pattern;
022
023/**
024 * Class for rule mapping
025 */
026public class MappingRule {
027
028    private static Pattern variableNamePattern = Pattern.compile("\\$\\{[0-9]\\}");
029    private Pattern fromPattern;
030    private String fromString;
031    private String toString;
032    private boolean patternMatch;
033
034    /**
035     * Maps from source rule to destination rule
036     * @param fromRule - Rule for which input needs to be matched
037     * @param toRule - Rule for value to be returned
038     */
039    public MappingRule(String fromRule, String toRule) {
040        if (fromRule.contains("$")) {
041            patternMatch = true;
042            fromRule = fromRule.replaceAll("\\.", "\\\\.");
043            Matcher match = variableNamePattern.matcher(fromRule);
044            fromRule = match.replaceAll("(.*)");
045            fromPattern = Pattern.compile(fromRule);
046        }
047        else {
048            fromString = fromRule;
049        }
050        toString = toRule;
051    }
052
053    /**
054     * Gets the from rule
055     * @return
056     */
057    public String getFromRule() {
058        return fromString;
059    }
060
061    /**
062     * Gets the to rule
063     * @return
064     */
065    public String getToRule() {
066        return toString;
067    }
068
069    /**
070     * Applies rules based on the input
071     * @param input
072     * @return
073     */
074    public String applyRule(String input) {
075        if (patternMatch) {
076            Matcher match = fromPattern.matcher(input);
077            if (match.matches()) {
078                String result = toString;
079                int count = match.groupCount();
080                for (int i = 1; i <= count; i++) {
081                    result = result.replace("${" + (i) + "}", match.group(i));
082                }
083                return result;
084            }
085        }
086        else if (input.equals(fromString)) {
087            return toString;
088        }
089        return null;
090    }
091}