StringPatternSetUtil.java

/**************************************************************************************
 * Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 * http://esper.codehaus.org                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.type;

import com.espertech.esper.collection.Pair;

import java.util.List;

/**
 * Pattern matching utility.
 */
public class StringPatternSetUtil
{
    /**
     * Executes a seriers of include/exclude patterns against a match string,
     * returning the last pattern match result as boolean in/out.
     * @param defaultValue the default value if there are no patterns or no matches change the value
     * @param patterns to match against, true in the pair for include, false for exclude
     * @param literal to match
     * @return true for included, false for excluded
     */
    public static Boolean evaluate(boolean defaultValue, List<Pair<StringPatternSet, Boolean>> patterns, String literal)
    {
        boolean result = defaultValue;

        for (Pair<StringPatternSet, Boolean> item : patterns)
        {
            if (result)
            {
                if (!item.getSecond())
                {
                    boolean testResult = item.getFirst().match(literal);
                    if (testResult)
                    {
                        result = false;
                    }
                }
            }
            else
            {
                if (item.getSecond())
                {
                    boolean testResult = item.getFirst().match(literal);
                    if (testResult)
                    {
                        result = true;
                    }
                }
            }
        }

        return result;
    }
}