/*
* 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.expression;
import static org.mule.expression.ExpressionConstants.OPTIONAL_ARGUMENT;
import javax.activation.DataHandler;
import org.mule.api.MuleMessage;
import org.mule.api.expression.ExpressionEvaluator;
import org.mule.api.expression.RequiredValueException;
import org.mule.config.i18n.CoreMessages;
public abstract class BaseAttachmentExpressionEvaluator implements ExpressionEvaluator
{
public Object evaluate(String expression, MuleMessage message)
{
if (expression == null)
{
return null;
}
boolean required;
if (expression.endsWith(OPTIONAL_ARGUMENT))
{
expression = expression.substring(0, expression.length() - OPTIONAL_ARGUMENT.length());
required = false;
}
else
{
required = true;
}
DataHandler dh = getAttachment(message, expression);
if (dh == null && required)
{
throw new RequiredValueException(CoreMessages.expressionEvaluatorReturnedNull(getName(), expression));
}
return dh;
}
protected abstract DataHandler getAttachment(MuleMessage message, String attachmentName);
}