evaluator.java

jboss规则引擎

package org.drools.spi;

/*
 * Copyright 2005 JBoss Inc
 * 
 * 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.
 */

import java.io.Serializable;

public interface Evaluator
    extends
    Serializable {
    // Operators
    public static final int EQUAL            = 1;
    public static final int NOT_EQUAL        = 10;
    public static final int LESS             = 20;
    public static final int LESS_OR_EQUAL    = 30;
    public static final int GREATER          = 40;
    public static final int GREATER_OR_EQUAL = 50;
    public static final int CONTAINS         = 60;
    public static final int MATCHES          = 70;
    public static final int EXCLUDES         = 80;

    // Types
    public static final int CHAR_TYPE        = 100;
    public static final int BYTE_TYPE        = 110;
    public static final int SHORT_TYPE       = 120;
    public static final int INTEGER_TYPE     = 130;
    public static final int LONG_TYPE        = 140;
    public static final int FLOAT_TYPE       = 150;
    public static final int DOUBLE_TYPE      = 160;
    public static final int BOOLEAN_TYPE     = 170;
    public static final int STRING_TYPE      = 180;
    public static final int DATE_TYPE        = 190;
    public static final int ARRAY_TYPE       = 200;
    public static final int OBJECT_TYPE      = 210;
    public static final int NULL_TYPE        = 300;

    public int getType();

    public int getOperator();

    /**
     * This method will apply the evaluator on the objects.
     * 
     * Typically, they follow this form:
     * Fact(object1 operator object2)
     * 
     * Where operator selects the appropraite concrete evaluator, and object1, and object2
     * are parameters to this method.
     * 
     * So Person(age < 42) will have object1==age field (of the Person fact object)
     * and "42" will be the object2 value.
     */
    public boolean evaluate(Object object1,
                            Object object2);

}