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/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 * Copyright 2004 The Apache Software Foundation
 *
 * 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.apache.jasper.runtime;

import java.util.Iterator;

import jakarta.el.ELContext;
import jakarta.el.ELResolver;
import jakarta.el.ValueExpression;
import jakarta.el.ExpressionFactory;

import jakarta.servlet.jsp.PageContext;
import jakarta.servlet.jsp.el.Expression;
import jakarta.servlet.jsp.el.ELException;
import jakarta.servlet.jsp.el.FunctionMapper;
import jakarta.servlet.jsp.el.ExpressionEvaluator;
import jakarta.servlet.jsp.el.VariableResolver;

/**
 * 

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: kchung $ */ 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 = ExpressionFactory.newInstance(); jakarta.el.ValueExpression expr; ELContextImpl elContext = new ELContextImpl(null); jakarta.el.FunctionMapper fm = new FunctionMapperWrapper(fMapper); elContext.setFunctionMapper(fm); try { expr = fac.createValueExpression( elContext, expression, expectedType); } catch (jakarta.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)); } jakarta.el.FunctionMapper fm = new FunctionMapperWrapper(fMapper); elContext.setFunctionMapper(fm); ExpressionFactory fac = ExpressionFactory.newInstance(); Object value; try { ValueExpression expr = fac.createValueExpression( elContext, expression, expectedType); value = expr.getValue(elContext); } catch (jakarta.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 (jakarta.el.ELException ex) { throw new ELException(ex); } } } private static class FunctionMapperWrapper extends jakarta.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 jakarta.el.ELException { if (base == null) { context.setPropertyResolved(true); try { return vResolver.resolveVariable(property.toString()); } catch (ELException ex) { throw new jakarta.el.ELException(ex); } } return null; } public Class getType(ELContext context, Object base, Object property) throws jakarta.el.ELException { return null; } public void setValue(ELContext context, Object base, Object property, Object value) throws jakarta.el.ELException { } public boolean isReadOnly(ELContext context, Object base, Object property) throws jakarta.el.ELException { return false; } public Iterator getFeatureDescriptors(ELContext context, Object base) { return null; } public Class getCommonPropertyType(ELContext context, Object base) { return null; } } }





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