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Tomcat example source code file (

This example Tomcat source code file ( is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

class, class, elcontextimpl, elexception, elexception, expressionevaluator, expressionevaluatorimpl, expressionevaluatorimpl, expressionfactory, functionmapper, functionmapper, functionmapperimpl, jsp, object, servlet, variableresolver

The Tomcat source code

 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.
package org.apache.jasper.el;

import javax.el.ELContext;
import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import javax.servlet.jsp.el.ELException;
import javax.servlet.jsp.el.ELParseException;
import javax.servlet.jsp.el.Expression;
import javax.servlet.jsp.el.ExpressionEvaluator;
import javax.servlet.jsp.el.FunctionMapper;
import javax.servlet.jsp.el.VariableResolver;

public final class ExpressionEvaluatorImpl extends ExpressionEvaluator {

	private final ExpressionFactory factory;
	public ExpressionEvaluatorImpl(ExpressionFactory factory) {
		this.factory = factory;

	public Expression parseExpression(String expression, Class expectedType,
			FunctionMapper fMapper) throws ELException {
		try {
			ELContextImpl ctx = new ELContextImpl(ELResolverImpl.DefaultResolver);
            if (fMapper != null) {
                ctx.setFunctionMapper(new FunctionMapperImpl(fMapper));
			ValueExpression ve = this.factory.createValueExpression(ctx, expression, expectedType);
			return new ExpressionImpl(ve);
		} catch (javax.el.ELException e) {
			throw new ELParseException(e.getMessage());

	public Object evaluate(String expression, Class expectedType,
			VariableResolver vResolver, FunctionMapper fMapper)
			throws ELException {
		return this.parseExpression(expression, expectedType, fMapper).evaluate(vResolver);


Other Tomcat examples (source code examples)

Here is a short list of links related to this Tomcat source code file:

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