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/*
* =============================================================================
*
* Copyright (c) 2011-2018, The THYMELEAF team (http://www.thymeleaf.org)
*
* 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.thymeleaf.spring4.expression;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.context.expression.MapAccessor;
import org.springframework.expression.BeanResolver;
import org.springframework.expression.ConstructorResolver;
import org.springframework.expression.EvaluationContext;
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.expression.spel.support.StandardEvaluationContext;
import org.thymeleaf.expression.IExpressionObjects;
import org.thymeleaf.standard.expression.RestrictedRequestAccessUtils;
import org.thymeleaf.standard.expression.StandardExpressionObjectFactory;
import org.thymeleaf.util.Validate;
/**
*
* Implementation of Thymeleaf's {@link IThymeleafEvaluationContext} interface designed to wrap around a
* delegated implementation of {@link EvaluationContext}, adding the
* Thymeleaf-required {@link PropertyAccessor} implementations and (optionally)
* a series of variables to be accessed like {@code #variableName} during expression evaluation.
*
*
* Note a class with this name existed since 2.1.0, but it was completely reimplemented
* in Thymeleaf 3.0
*
*
* @author Daniel Fernández
*
* @since 3.0.0
*
*/
public final class ThymeleafEvaluationContextWrapper implements IThymeleafEvaluationContext {
private static final MapAccessor MAP_ACCESSOR_INSTANCE = new MapAccessor();
private final EvaluationContext delegate;
private final List propertyAccessors; // can be initialized to null if we can delegate
private IExpressionObjects expressionObjects = null;
private boolean requestParametersRestricted = false;
private Map additionalVariables = null;
public ThymeleafEvaluationContextWrapper(final EvaluationContext delegate) {
super();
Validate.notNull(delegate, "Evaluation context delegate cannot be null");
this.delegate = delegate;
if ((this.delegate instanceof ThymeleafEvaluationContext)) {
this.propertyAccessors = null; // No need to initialize our own list
} else if (this.delegate instanceof StandardEvaluationContext) {
((StandardEvaluationContext) this.delegate).addPropertyAccessor(SPELContextPropertyAccessor.INSTANCE);
((StandardEvaluationContext) this.delegate).addPropertyAccessor(MAP_ACCESSOR_INSTANCE);
this.propertyAccessors = null; // No need to initialize our own list
} else {
// We don't know the specific EvaluationContext implementation, so we need to initialize our own PA list
this.propertyAccessors = new ArrayList(5);
this.propertyAccessors.addAll(this.delegate.getPropertyAccessors());
this.propertyAccessors.add(SPELContextPropertyAccessor.INSTANCE);
this.propertyAccessors.add(MAP_ACCESSOR_INSTANCE);
}
}
public TypedValue getRootObject() {
return this.delegate.getRootObject();
}
public List getConstructorResolvers() {
return this.delegate.getConstructorResolvers();
}
public List getMethodResolvers() {
return this.delegate.getMethodResolvers();
}
public List getPropertyAccessors() {
return this.propertyAccessors == null ? this.delegate.getPropertyAccessors() : this.propertyAccessors;
}
public TypeLocator getTypeLocator() {
return this.delegate.getTypeLocator();
}
public TypeConverter getTypeConverter() {
return this.delegate.getTypeConverter();
}
public TypeComparator getTypeComparator() {
return this.delegate.getTypeComparator();
}
public OperatorOverloader getOperatorOverloader() {
return this.delegate.getOperatorOverloader();
}
public BeanResolver getBeanResolver() {
return this.delegate.getBeanResolver();
}
public void setVariable(final String name, final Object value) {
if (this.additionalVariables == null) {
this.additionalVariables = new HashMap(5, 1.0f);
}
this.additionalVariables.put(name, value);
}
public Object lookupVariable(final String name) {
if (this.expressionObjects != null && this.expressionObjects.containsObject(name)) {
final Object result = this.expressionObjects.getObject(name);
if (result != null) {
// We need to first check if we are in a restricted environment. If so, restrict access to the request.
if (this.requestParametersRestricted &&
(StandardExpressionObjectFactory.REQUEST_EXPRESSION_OBJECT_NAME.equals(name) ||
StandardExpressionObjectFactory.HTTP_SERVLET_REQUEST_EXPRESSION_OBJECT_NAME.equals(name))) {
return RestrictedRequestAccessUtils.wrapRequestObject(result);
}
return result;
}
}
if (this.additionalVariables != null && this.additionalVariables.containsKey(name)) {
final Object result = this.additionalVariables.get(name);
if (result != null) {
return result;
}
}
// fall back to delegate
return this.delegate.lookupVariable(name);
}
public boolean isVariableAccessRestricted() {
return this.requestParametersRestricted;
}
public void setVariableAccessRestricted(final boolean restricted) {
this.requestParametersRestricted = restricted;
}
public IExpressionObjects getExpressionObjects() {
return this.expressionObjects;
}
public void setExpressionObjects(final IExpressionObjects expressionObjects) {
this.expressionObjects = expressionObjects;
}
}