/* 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.camunda.bpm.engine.impl.el;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.camunda.bpm.engine.delegate.Expression;
import org.camunda.bpm.engine.delegate.VariableScope;
import org.camunda.bpm.engine.impl.core.variable.CoreVariableScope;
import org.camunda.bpm.engine.impl.javax.el.ArrayELResolver;
import org.camunda.bpm.engine.impl.javax.el.BeanELResolver;
import org.camunda.bpm.engine.impl.javax.el.CompositeELResolver;
import org.camunda.bpm.engine.impl.javax.el.ELContext;
import org.camunda.bpm.engine.impl.javax.el.ELResolver;
import org.camunda.bpm.engine.impl.javax.el.ExpressionFactory;
import org.camunda.bpm.engine.impl.javax.el.FunctionMapper;
import org.camunda.bpm.engine.impl.javax.el.ListELResolver;
import org.camunda.bpm.engine.impl.javax.el.MapELResolver;
import org.camunda.bpm.engine.impl.javax.el.ValueExpression;
import org.camunda.bpm.engine.impl.juel.ExpressionFactoryImpl;
/**
* <p>
* Central manager for all expressions.
* </p>
* <p>
* Process parsers will use this to build expression objects that are stored in
* the process definitions.
* </p>
* <p>
* Then also this class is used as an entry point for runtime evaluation of the
* expressions.
* </p>
*
* @author Tom Baeyens
* @author Dave Syer
* @author Frederik Heremans
*/
public class ExpressionManager {
protected List<FunctionMapper> functionMappers = new ArrayList<FunctionMapper>();
protected ExpressionFactory expressionFactory;
// Default implementation (does nothing)
protected ELContext parsingElContext = new ProcessEngineElContext(functionMappers);
protected Map<Object, Object> beans;
public ExpressionManager() {
this(null);
}
public ExpressionManager(Map<Object, Object> beans) {
// Use the ExpressionFactoryImpl built-in version of juel, with parametrised method expressions enabled
expressionFactory = new ExpressionFactoryImpl();
this.beans = beans;
}
public Expression createExpression(String expression) {
ValueExpression valueExpression = expressionFactory.createValueExpression(parsingElContext, expression, Object.class);
return new JuelExpression(valueExpression, this, expression);
}
public void setExpressionFactory(ExpressionFactory expressionFactory) {
this.expressionFactory = expressionFactory;
}
public ELContext getElContext(VariableScope<?> variableScope) {
ELContext elContext = null;
if (variableScope instanceof CoreVariableScope) {
CoreVariableScope<?> variableScopeImpl = (CoreVariableScope<?>) variableScope;
elContext = variableScopeImpl.getCachedElContext();
}
if (elContext==null) {
elContext = createElContext(variableScope);
if (variableScope instanceof CoreVariableScope) {
((CoreVariableScope<?>)variableScope).setCachedElContext(elContext);
}
}
return elContext;
}
protected ProcessEngineElContext createElContext(VariableScope<?> variableScope) {
ELResolver elResolver = createElResolver(variableScope);
return new ProcessEngineElContext(functionMappers, elResolver);
}
protected ELResolver createElResolver(VariableScope<?> variableScope) {
CompositeELResolver elResolver = new CompositeELResolver();
elResolver.add(new VariableScopeElResolver(variableScope));
if(beans != null) {
// ACT-1102: Also expose all beans in configuration when using standalone engine, not
// in spring-context
elResolver.add(new ReadOnlyMapELResolver(beans));
}
elResolver.add(new ProcessApplicationElResolverDelegate());
elResolver.add(new ArrayELResolver());
elResolver.add(new ListELResolver());
elResolver.add(new MapELResolver());
elResolver.add(new BeanELResolver());
return elResolver;
}
/**
* @param elFunctionMapper
*/
public void addFunctionMapper(FunctionMapper elFunctionMapper) {
this.functionMappers.add(elFunctionMapper);
}
}