com.krawler.baseline.crm.bizservice.el.ExpressionManagerImpl.java Source code

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Here is the source code for com.krawler.baseline.crm.bizservice.el.ExpressionManagerImpl.java

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/*
 * Copyright (C) 2012  Krawler Information Systems Pvt Ltd
 * All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/
package com.krawler.baseline.crm.bizservice.el;

import java.util.Map;

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

/**
 * This util file will be providing APIs for expressions parsing, validation and evaluation.
 * 
 * @author Ashutosh
 *
 */
public class ExpressionManagerImpl implements ExpressionManager {
    private static final Log LOG = LogFactory.getLog(ExpressionManagerImpl.class);

    /* (non-Javadoc)
     * @see com.krawler.baseline.crm.bizservices.el.ExpressionManager#validateExpression(java.lang.String)
     */
    public boolean validateExpression(String expression) {
        boolean result = true;
        try {
            MVEL.compileExpression(expression);
        } catch (Exception e) {
            LOG.info("Can't compile the expression:" + expression, e);
            result = false;
        }

        return result;
    }

    /* (non-Javadoc)
     * @see com.krawler.baseline.crm.bizservices.el.ExpressionManager#evaluateExpression(java.lang.String, java.util.Map)
     */
    public Object evaluateExpression(String expression, Map<String, Object> variablesMap) throws Exception {
        Object result = null;

        try {
            result = MVEL.eval(expression, variablesMap);
        } catch (Exception e) {
            LOG.info("Can't evaluate the expression:" + expression, e);
            throw e;
        }

        return result;
    }

    /* (non-Javadoc)
     * @see com.krawler.baseline.crm.bizservice.el.ExpressionManager#evaluateExpression(java.lang.String, java.util.List)
     */
    public Object evaluateExpression(String expression, String key, Map<String, ExpressionVariables> variables) {
        Object result = null;
        if (variables != null && !variables.isEmpty()) {
            Object compiledExpression = MVEL.compileExpression(expression);

            for (ExpressionVariables variable : variables.values()) {
                try {
                    result = MVEL.executeExpression(compiledExpression, variable.getVariablesMapForFormulae());
                    if (result instanceof Double) {
                        Double d = (Double) result;
                        if (d == null || d.isInfinite() || d.isNaN())
                            result = null;
                    }
                    variable.getOutputMap().put(key, result);
                } catch (Exception e) {
                    LOG.info("Can't evaluate the expression:" + expression, e);
                }
            }
        }
        return result;
    }
}