org.tinygroup.jspengine.runtime.ExpressionEvaluatorImpl Maven / Gradle / Ivy
/**
* Copyright (c) 1997-2013, www.tinygroup.org ([email protected]).
*
* Licensed under the GPL, Version 3.0 (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.gnu.org/licenses/gpl.html
*
* 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.tinygroup.jspengine.runtime;
import org.tinygroup.jspengine.el.ExpressionFactoryImpl;
import javax.el.ELContext;
import javax.el.ELResolver;
import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.el.*;
import java.util.Iterator;
/**
* This is the implementation of ExpreesioEvaluator
* using implementation of JSP2.1.
*
* @author Kin-man Chung
* @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: jluehe $
**/
public class ExpressionEvaluatorImpl extends ExpressionEvaluator
{
private PageContext pageContext;
//-------------------------------------
/**
* Constructor
**/
public ExpressionEvaluatorImpl (PageContext pageContext) {
this.pageContext = pageContext;
}
//-------------------------------------
public Expression parseExpression(String expression,
Class expectedType,
FunctionMapper fMapper )
throws ELException {
ExpressionFactory fac = new ExpressionFactoryImpl();
javax.el.ValueExpression expr;
ELContextImpl elContext = new ELContextImpl(null);
javax.el.FunctionMapper fm = new FunctionMapperWrapper(fMapper);
elContext.setFunctionMapper(fm);
try {
expr = fac.createValueExpression(
elContext,
expression, expectedType);
} catch (javax.el.ELException ex) {
throw new ELException(ex);
}
return new ExpressionImpl(expr, pageContext);
}
public Object evaluate(String expression,
Class expectedType,
VariableResolver vResolver,
FunctionMapper fMapper )
throws ELException {
ELContextImpl elContext;
if (vResolver instanceof VariableResolverImpl) {
elContext = (ELContextImpl) pageContext.getELContext();
}
else {
// The provided variable Resolver is a custom resolver,
// wrap it with a ELResolver
elContext = new ELContextImpl(new ELResolverWrapper(vResolver));
}
javax.el.FunctionMapper fm = new FunctionMapperWrapper(fMapper);
elContext.setFunctionMapper(fm);
ExpressionFactory fac = new ExpressionFactoryImpl();
Object value;
try {
ValueExpression expr = fac.createValueExpression(
elContext,
expression,
expectedType);
value = expr.getValue(elContext);
} catch (javax.el.ELException ex) {
throw new ELException(ex);
}
return value;
}
static private class ExpressionImpl extends Expression {
private ValueExpression valueExpr;
private PageContext pageContext;
ExpressionImpl(ValueExpression valueExpr,
PageContext pageContext) {
this.valueExpr = valueExpr;
this.pageContext = pageContext;
}
public Object evaluate(VariableResolver vResolver) throws ELException {
ELContext elContext;
if (vResolver instanceof VariableResolverImpl) {
elContext = pageContext.getELContext();
}
else {
// The provided variable Resolver is a custom resolver,
// wrap it with a ELResolver
elContext = new ELContextImpl(new ELResolverWrapper(vResolver));
}
try {
return valueExpr.getValue(elContext);
} catch (javax.el.ELException ex) {
throw new ELException(ex);
}
}
}
private static class FunctionMapperWrapper
extends javax.el.FunctionMapper {
private FunctionMapper mapper;
FunctionMapperWrapper(FunctionMapper mapper) {
this.mapper = mapper;
}
public java.lang.reflect.Method resolveFunction(String prefix,
String localName) {
return mapper.resolveFunction(prefix, localName);
}
}
private static class ELResolverWrapper extends ELResolver {
private VariableResolver vResolver;
ELResolverWrapper(VariableResolver vResolver) {
this.vResolver = vResolver;
}
public Object getValue(ELContext context,
Object base,
Object property)
throws javax.el.ELException {
if (base == null) {
context.setPropertyResolved(true);
try {
return vResolver.resolveVariable(property.toString());
} catch (ELException ex) {
throw new javax.el.ELException(ex);
}
}
return null;
}
public Class getType(ELContext context,
Object base,
Object property)
throws javax.el.ELException {
return null;
}
public void setValue(ELContext context,
Object base,
Object property,
Object value)
throws javax.el.ELException {
}
public boolean isReadOnly(ELContext context,
Object base,
Object property)
throws javax.el.ELException {
return false;
}
public Iterator getFeatureDescriptors(ELContext context,
Object base) {
return null;
}
public Class getCommonPropertyType(ELContext context,
Object base) {
return null;
}
}
}