org.jeasy.rules.mvel.MVELCondition Maven / Gradle / Ivy
/**
* The MIT License
*
* Copyright (c) 2018, Mahmoud Ben Hassine ([email protected])
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.jeasy.rules.mvel;
import org.jeasy.rules.api.Condition;
import org.jeasy.rules.api.Facts;
import org.mvel2.MVEL;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.Serializable;
/**
* This class is an implementation of {@link Condition} that uses MVEL to evaluate the condition.
*
* @author Mahmoud Ben Hassine ([email protected])
*/
public class MVELCondition implements Condition {
private static Logger LOGGER = LoggerFactory.getLogger(MVELCondition.class);
private String expression;
private Serializable compiledExpression;
/**
* Create a new {@link MVELCondition}.
*
* @param expression the condition written in expression language
*/
public MVELCondition(String expression) {
this.expression = expression;
compiledExpression = MVEL.compileExpression(expression);
}
@Override
public boolean evaluate(Facts facts) {
try {
return (boolean) MVEL.executeExpression(compiledExpression, facts.asMap());
} catch (Exception e) {
LOGGER.debug("Unable to evaluate expression: '" + expression + "' on facts: " + facts, e);
return false;
}
}
}