/*
* Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors.
*
* Licensed 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 org.switchyard.component.common.knowledge.expression;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import org.mvel2.MVEL;
import org.mvel2.ParserContext;
import org.mvel2.integration.VariableResolver;
import org.mvel2.integration.VariableResolverFactory;
import org.mvel2.integration.impl.ImmutableDefaultFactory;
import org.mvel2.integration.impl.MapVariableResolverFactory;
import org.mvel2.integration.impl.SimpleValueResolver;
import org.switchyard.common.property.PropertyResolver;
/**
* MVELExpression.
*
* @author David Ward <<a href="mailto:dward@jboss.org">dward@jboss.org</a>> © 2012 Red Hat Inc.
*/
public class MVELExpression implements Expression {
private final String _expression;
private final PropertyResolverFactory _propertyResolverFactory;
private Serializable _compiled;
/**
* Creates a new MVELExpression with the specified expression and {@link PropertyResolver}.
* @param expression the specified expression
* @param propertyResolver the specified {@link PropertyResolver}
*/
public MVELExpression(String expression, PropertyResolver propertyResolver) {
_expression = expression;
_propertyResolverFactory = new PropertyResolverFactory(propertyResolver);
compile();
}
/**
* {@inheritDoc}
*/
@Override
public String getExpression() {
return _expression;
}
/**
* {@inheritDoc}
*/
@Override
public ExpressionType getType() {
return ExpressionType.MVEL;
}
private void compile() {
ParserContext pc = new ParserContext();
pc.addPackageImport("java.util");
pc.addPackageImport("org.switchyard");
_compiled = MVEL.compileExpression(_expression, pc);
}
/**
* {@inheritDoc}
*/
@Override
public boolean isCompiled() {
return _compiled != null;
}
/**
* {@inheritDoc}
*/
@Override
public Object run() {
return run(null);
}
/**
* {@inheritDoc}
*/
@Override
public Object run(Map<String, Object> variables) {
if (variables == null) {
variables = new HashMap<String, Object>();
}
VariableResolverFactory factory = new MapVariableResolverFactory(variables, _propertyResolverFactory);
return isCompiled() ? MVEL.executeExpression(_compiled, factory) : MVEL.eval(_expression, factory);
}
@SuppressWarnings("serial")
private static final class PropertyResolverFactory extends ImmutableDefaultFactory {
private final PropertyResolver _propertyResolver;
private PropertyResolverFactory(PropertyResolver propertyResolver) {
_propertyResolver = propertyResolver;
}
/**
* {@inheritDoc}
*/
@Override
public boolean isResolveable(String name) {
return name != null && _propertyResolver.resolveProperty(name) != null;
}
/**
* {@inheritDoc}
*/
@Override
public VariableResolver getVariableResolver(String name) {
Object value = name != null ? _propertyResolver.resolveProperty(name) : null;
return new SimpleValueResolver(value);
}
}
}