com.glaf.core.el.Mvel2ExpressionEvaluator.java Source code

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Here is the source code for com.glaf.core.el.Mvel2ExpressionEvaluator.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.glaf.core.el;

import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.mvel2.MVEL;

import com.glaf.core.util.LogUtils;
import com.glaf.core.util.StringTools;

public class Mvel2ExpressionEvaluator {
    protected final static Log logger = LogFactory.getLog(Mvel2ExpressionEvaluator.class);

    public static Object evaluate(String expression, Map<String, Object> context) {
        Object result = null;
        try {
            if (expression != null && context != null) {
                expression = translateExpression(expression);
                result = MVEL.eval(expression, context);
                if (result != null) {
                    if (result instanceof Map<?, ?>) {
                        return ((Map<?, ?>) result).keySet().iterator().next();
                    }
                }
            }
        } catch (Exception ex) {
            logger.debug("error expression:" + expression);
            if (LogUtils.isDebug()) {
                logger.debug(ex);
            }
            throw new RuntimeException(ex);
        }
        return result;
    }

    private static String translateExpression(String expression) {
        if (expression == null) {
            return null;
        }
        expression = StringTools.replaceIgnoreCase(expression, "#{", "");
        expression = StringTools.replaceIgnoreCase(expression, "${", "");
        expression = StringTools.replaceIgnoreCase(expression, "}", "");
        return expression;
    }

    public static void main(String[] args) throws Exception {
        String expression = null;
        Object obj = null;
        Map<String, Object> context = new java.util.HashMap<String, Object>();
        context.put("roleId", "admin");
        context.put("roleType", "-5");

        expression = "#{roleType > 0}";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        context.put("roleType", "2345");
        expression = "#{roleType > 0}";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        context.put("a", 123);
        context.put("b", 789);
        expression = "#{ a + b }";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        context.put("a", "123");
        context.put("b", "789");
        expression = "#{ a*1.0 + b*1.0 }";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        context.put("c", 123D);
        context.put("d", 789D);
        expression = "#{ c / d }";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        context.put("a", "123");
        context.put("b", "789");
        expression = "#{ a*1.0 / b*1.0 }";

        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        expression = "#{ c >= 0 and d >0 }";
        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        expression = "#{ c >= 0 and d > 0 and c/d > 0.16 }";
        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

        expression = "#{ c >= 0 and d >0 and c/d > 0.15 }";
        obj = Mvel2ExpressionEvaluator.evaluate(expression, context);
        if (obj != null) {
            System.out.println("[type]=" + obj.getClass().getName() + "\t[value]=" + obj);
        }

    }

}