org.mule.module.spel.EvaluationContextFactory.java Source code

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Here is the source code for org.mule.module.spel.EvaluationContextFactory.java

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/*
 * Copyright (c) 2011, Victor Romero. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
package org.mule.module.spel;

import org.mule.api.MuleContext;
import org.mule.api.MuleMessage;
import org.mule.api.registry.MuleRegistry;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.Assert;

public class EvaluationContextFactory {

    protected static final String CONTEXT_VAR_NAME = "context";

    protected static final String REGISTRY_VAR_NAME = "registry";

    protected static final String MESSAGE_VAR_NAME = "message";

    protected static final String ORIGINAL_PAYLOAD_VAR_NAME = "originalPayload";

    protected static final String PAYLOAD_VAR_NAME = "payload";

    protected static final String SYSTEM_PROPERTIES_VAR_NAME = "systemProperties";

    protected static final String ENVIRONMENT_VAR_NAME = "systemEnvironment";

    protected static final String ID_VAR_NAME = "id";

    protected MuleContext muleContext;

    protected MuleRegistry muleRegistry;

    protected MuleRegistryBeanResolver beanResolver;

    public EvaluationContextFactory(MuleContext muleContext) {
        this.muleContext = muleContext;
        muleRegistry = muleContext.getRegistry();
        beanResolver = new MuleRegistryBeanResolver(muleContext);
    }

    public EvaluationContext create(MuleMessage message) {
        Assert.notNull(message, "Message cannot be null");

        StandardEvaluationContext simpleContext = new StandardEvaluationContext();

        simpleContext.setVariable(CONTEXT_VAR_NAME, muleContext);
        simpleContext.setVariable(REGISTRY_VAR_NAME, muleRegistry);
        simpleContext.setVariable(MESSAGE_VAR_NAME, message);
        simpleContext.setVariable(ORIGINAL_PAYLOAD_VAR_NAME, message.getOriginalPayload());
        simpleContext.setVariable(PAYLOAD_VAR_NAME, message.getPayload());
        simpleContext.setVariable(ID_VAR_NAME, message.getUniqueId());

        /* systemProperties and systemEnvironment are spring beans already registered
           in the mule registry, and thus available as @systemEnvironment and @systemProperties.
           But this is collateral, so to properly to mimic Spring framework behavior both beans will
           be added as variables. 
        */

        if (muleRegistry != null) {
            simpleContext.setVariable(SYSTEM_PROPERTIES_VAR_NAME,
                    muleRegistry.get(ConfigurableApplicationContext.SYSTEM_PROPERTIES_BEAN_NAME));
            simpleContext.setVariable(ENVIRONMENT_VAR_NAME,
                    muleRegistry.get(ConfigurableApplicationContext.SYSTEM_ENVIRONMENT_BEAN_NAME));
        }

        simpleContext.setRootObject(message.getPayload());

        simpleContext.setBeanResolver(beanResolver);
        return simpleContext;
    }

}