/*
* Copyright 2002-2012 the original author or authors.
*
* 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.springframework.expression.spel.support;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.expression.BeanResolver;
import org.springframework.expression.ConstructorResolver;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.MethodFilter;
import org.springframework.expression.MethodResolver;
import org.springframework.expression.OperatorOverloader;
import org.springframework.expression.PropertyAccessor;
import org.springframework.expression.TypeComparator;
import org.springframework.expression.TypeConverter;
import org.springframework.expression.TypeLocator;
import org.springframework.expression.TypedValue;
import org.springframework.util.Assert;
/**
* Provides a default EvaluationContext implementation.
*
* <p>To resolve properties/methods/fields this context uses a reflection mechanism.
*
* @author Andy Clement
* @author Juergen Hoeller
* @author Sam Brannen
* @since 3.0
*/
public class StandardEvaluationContext implements EvaluationContext {
private TypedValue rootObject;
private List<ConstructorResolver> constructorResolvers;
private List<MethodResolver> methodResolvers;
private ReflectiveMethodResolver reflectiveMethodResolver;
private List<PropertyAccessor> propertyAccessors;
private TypeLocator typeLocator;
private TypeConverter typeConverter;
private TypeComparator typeComparator = new StandardTypeComparator();
private OperatorOverloader operatorOverloader = new StandardOperatorOverloader();
private final Map<String, Object> variables = new HashMap<String, Object>();
private BeanResolver beanResolver;
public StandardEvaluationContext() {
setRootObject(null);
}
public StandardEvaluationContext(Object rootObject) {
this();
setRootObject(rootObject);
}
public void setRootObject(Object rootObject, TypeDescriptor typeDescriptor) {
this.rootObject = new TypedValue(rootObject, typeDescriptor);
}
public void setRootObject(Object rootObject) {
this.rootObject = (rootObject != null ? new TypedValue(rootObject) : TypedValue.NULL);
}
public TypedValue getRootObject() {
return this.rootObject;
}
public void addConstructorResolver(ConstructorResolver resolver) {
ensureConstructorResolversInitialized();
this.constructorResolvers.add(this.constructorResolvers.size() - 1, resolver);
}
public boolean removeConstructorResolver(ConstructorResolver resolver) {
ensureConstructorResolversInitialized();
return this.constructorResolvers.remove(resolver);
}
public List<ConstructorResolver> getConstructorResolvers() {
ensureConstructorResolversInitialized();
return this.constructorResolvers;
}
public void setConstructorResolvers(List<ConstructorResolver> constructorResolvers) {
this.constructorResolvers = constructorResolvers;
}
public void addMethodResolver(MethodResolver resolver) {
ensureMethodResolversInitialized();
this.methodResolvers.add(this.methodResolvers.size() - 1, resolver);
}
public boolean removeMethodResolver(MethodResolver methodResolver) {
ensureMethodResolversInitialized();
return this.methodResolvers.remove(methodResolver);
}
public List<MethodResolver> getMethodResolvers() {
ensureMethodResolversInitialized();
return this.methodResolvers;
}
public void setBeanResolver(BeanResolver beanResolver) {
this.beanResolver = beanResolver;
}
public BeanResolver getBeanResolver() {
return this.beanResolver;
}
public void setMethodResolvers(List<MethodResolver> methodResolvers) {
this.methodResolvers = methodResolvers;
}
public void addPropertyAccessor(PropertyAccessor accessor) {
ensurePropertyAccessorsInitialized();
this.propertyAccessors.add(this.propertyAccessors.size() - 1, accessor);
}
public boolean removePropertyAccessor(PropertyAccessor accessor) {
return this.propertyAccessors.remove(accessor);
}
public List<PropertyAccessor> getPropertyAccessors() {
ensurePropertyAccessorsInitialized();
return this.propertyAccessors;
}
public void setPropertyAccessors(List<PropertyAccessor> propertyAccessors) {
this.propertyAccessors = propertyAccessors;
}
public void setTypeLocator(TypeLocator typeLocator) {
Assert.notNull(typeLocator, "TypeLocator must not be null");
this.typeLocator = typeLocator;
}
public TypeLocator getTypeLocator() {
if (this.typeLocator == null) {
this.typeLocator = new StandardTypeLocator();
}
return this.typeLocator;
}
public void setTypeConverter(TypeConverter typeConverter) {
Assert.notNull(typeConverter, "TypeConverter must not be null");
this.typeConverter = typeConverter;
}
public TypeConverter getTypeConverter() {
if (this.typeConverter == null) {
this.typeConverter = new StandardTypeConverter();
}
return this.typeConverter;
}
public void setTypeComparator(TypeComparator typeComparator) {
Assert.notNull(typeComparator, "TypeComparator must not be null");
this.typeComparator = typeComparator;
}
public TypeComparator getTypeComparator() {
return this.typeComparator;
}
public void setOperatorOverloader(OperatorOverloader operatorOverloader) {
Assert.notNull(operatorOverloader, "OperatorOverloader must not be null");
this.operatorOverloader = operatorOverloader;
}
public OperatorOverloader getOperatorOverloader() {
return this.operatorOverloader;
}
public void setVariable(String name, Object value) {
this.variables.put(name, value);
}
public void setVariables(Map<String,Object> variables) {
this.variables.putAll(variables);
}
public void registerFunction(String name, Method method) {
this.variables.put(name, method);
}
public Object lookupVariable(String name) {
return this.variables.get(name);
}
/**
* Register a {@code MethodFilter} which will be called during method resolution
* for the specified type.
*
* <p>The {@code MethodFilter} may remove methods and/or sort the methods which
* will then be used by SpEL as the candidates to look through for a match.
*
* @param type the type for which the filter should be called
* @param filter a {@code MethodFilter}, or {@code null} to unregister a filter for the type
* @throws IllegalStateException if the {@link ReflectiveMethodResolver} is not in use
*/
public void registerMethodFilter(Class<?> type, MethodFilter filter) throws IllegalStateException {
ensureMethodResolversInitialized();
if (reflectiveMethodResolver != null) {
reflectiveMethodResolver.registerMethodFilter(type, filter);
} else {
throw new IllegalStateException("Method filter cannot be set as the reflective method resolver is not in use");
}
}
private void ensurePropertyAccessorsInitialized() {
if (this.propertyAccessors == null) {
initializePropertyAccessors();
}
}
private synchronized void initializePropertyAccessors() {
if (this.propertyAccessors == null) {
List<PropertyAccessor> defaultAccessors = new ArrayList<PropertyAccessor>();
defaultAccessors.add(new ReflectivePropertyAccessor());
this.propertyAccessors = defaultAccessors;
}
}
private void ensureMethodResolversInitialized() {
if (this.methodResolvers == null) {
initializeMethodResolvers();
}
}
private synchronized void initializeMethodResolvers() {
if (this.methodResolvers == null) {
List<MethodResolver> defaultResolvers = new ArrayList<MethodResolver>();
defaultResolvers.add(reflectiveMethodResolver = new ReflectiveMethodResolver());
this.methodResolvers = defaultResolvers;
}
}
private void ensureConstructorResolversInitialized() {
if (this.constructorResolvers == null) {
initializeConstructorResolvers();
}
}
private synchronized void initializeConstructorResolvers() {
if (this.constructorResolvers == null) {
List<ConstructorResolver> defaultResolvers = new ArrayList<ConstructorResolver>();
defaultResolvers.add(new ReflectiveConstructorResolver());
this.constructorResolvers = defaultResolvers;
}
}
}