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'databene commons' is an open source Java library by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * Licensed 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.databene.commons.condition;

import org.databene.commons.ComparableComparator;
import org.databene.commons.Condition;

import java.util.Comparator;

/**
 * Condition implementation that compares an arbitrary number of arguments 
 * with one of different available operators.
 * Created: 06.03.2006 17:49:06
 * @param  the type of argument to evaluate
 * @since 0.1
 * @author Volker Bergmann
 */
public class ComparationCondition implements Condition {

    public static final int EQUAL = 0;
    public static final int NOT_EQUAL = 1;
    public static final int GREATER_OR_EQUAL = 2;
    public static final int GREATER = 3;
    public static final int LESS_OR_EQUAL = 4;
    public static final int LESS = 5;

    private int operator;
    private Comparator comparator;

    public ComparationCondition() {
        this(EQUAL);
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public ComparationCondition(int operator) {
        this(operator, new ComparableComparator());
    }

    public ComparationCondition(int operator, Comparator comparator) {
        this.operator = operator;
        this.comparator = comparator;
    }

    public int getOperator() {
        return operator;
    }

    public void setOperator(int operator) {
        this.operator = operator;
    }

    public Comparator getComparator() {
        return comparator;
    }

    public void setComparator(Comparator comparator) {
        this.comparator = comparator;
    }

    @Override
	public boolean evaluate(E[] arguments) {
        if (arguments.length != 2)
            throw new IllegalArgumentException("Comparation only supported for two arguments, found: "
                    + arguments.length);
        int comparation = comparator.compare(arguments[0], arguments[1]);
        switch (operator) {
            case EQUAL            : return comparation == 0;
            case NOT_EQUAL        : return comparation != 0;
            case GREATER_OR_EQUAL : return comparation >= 0;
            case GREATER          : return comparation == 1;
            case LESS_OR_EQUAL    : return comparation <= 0;
            case LESS             : return comparation == -1;
            default               : throw new IllegalStateException("Operator no supported: " + operator);
        }
    }
}