org.mule.keygenerator.ExpressionMuleEventKeyGenerator.java Source code

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Here is the source code for org.mule.keygenerator.ExpressionMuleEventKeyGenerator.java

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/*
 * $Id$
 * --------------------------------------------------------------------------------------
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 *
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.keygenerator;

import org.mule.api.MuleEvent;
import org.mule.api.MuleEventKeyGenerator;

import java.io.NotSerializableException;
import java.io.Serializable;

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

/**
 * Implements {@link org.mule.api.MuleEventKeyGenerator} using the Mule expression language to
 * generate the cache keys.
 */
public class ExpressionMuleEventKeyGenerator implements MuleEventKeyGenerator {

    protected Log logger = LogFactory.getLog(getClass());

    private String expression;

    public Serializable generateKey(MuleEvent event) throws NotSerializableException {
        Object key = event.getMuleContext().getExpressionManager().evaluate(expression, event);

        if (logger.isDebugEnabled()) {
            logger.debug("Generated key for event: " + event + " key: " + key);
        }

        if (key instanceof Serializable) {
            return (Serializable) key;
        } else {
            throw new NotSerializableException("Generated key must a serializable object but was "
                    + (key != null ? key.getClass().getName() : "null"));
        }
    }

    public String getExpression() {
        return expression;
    }

    public void setExpression(String expression) {
        this.expression = expression;
    }
}