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 */
018
019package org.apache.oozie.util;
020
021import java.util.regex.Matcher;
022import java.util.regex.Pattern;
023
024/**
025 * Class for rule mapping
026 */
027public class MappingRule {
028
029    private static Pattern variableNamePattern = Pattern.compile("\\$\\{[0-9]\\}");
030    private Pattern fromPattern;
031    private String fromString;
032    private String toString;
033    private boolean patternMatch;
034
035    /**
036     * Maps from source rule to destination rule
037     * @param fromRule - Rule for which input needs to be matched
038     * @param toRule - Rule for value to be returned
039     */
040    public MappingRule(String fromRule, String toRule) {
041        if (fromRule.contains("$")) {
042            patternMatch = true;
043            fromRule = fromRule.replaceAll("\\.", "\\\\.");
044            Matcher match = variableNamePattern.matcher(fromRule);
045            fromRule = match.replaceAll("(.*)");
046            fromPattern = Pattern.compile(fromRule);
047        }
048        else {
049            fromString = fromRule;
050        }
051        toString = toRule;
052    }
053
054    /**
055     * Gets the from rule
056     * @return fromString Gets the from rule
057     */
058    public String getFromRule() {
059        return fromString;
060    }
061
062    /**
063     * Gets the to rule
064     * @return toString Gets the to rule
065     */
066    public String getToRule() {
067        return toString;
068    }
069
070    /**
071     * Applies rules based on the input
072     * @param input input to apply the rule to
073     * @return result Applies rules based on the input
074     */
075    public String applyRule(String input) {
076        if (patternMatch) {
077            Matcher match = fromPattern.matcher(input);
078            if (match.matches()) {
079                String result = toString;
080                int count = match.groupCount();
081                for (int i = 1; i <= count; i++) {
082                    result = result.replace("${" + (i) + "}", match.group(i));
083                }
084                return result;
085            }
086        }
087        else if (input.equals(fromString)) {
088            return toString;
089        }
090        return null;
091    }
092}