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Tomcat example source code file (ELNode.java)

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

Java - Tomcat tags/keywords

elnode, elnode, eltext, function, functioninfo, iterator, iterator, jasperexception, jasperexception, jsp, nodes, root, servlet, string, string, text, util

The Tomcat ELNode.java 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
 * 
 *      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.compiler;

import java.util.*;
import javax.servlet.jsp.tagext.FunctionInfo;
import org.apache.jasper.JasperException;

/**
 * This class defines internal representation for an EL Expression
 *
 * It currently only defines functions.  It can be expanded to define
 * all the components of an EL expression, if need to.
 *
 * @author Kin-man Chung
 */

abstract class ELNode {

    abstract public void accept(Visitor v) throws JasperException;

    /**
     * Child classes
     */


    /**
     * Represents an EL expression: anything in ${ and }.
     */
    public static class Root extends ELNode {

	private ELNode.Nodes expr;
    private char type;

	Root(ELNode.Nodes expr, char type) {
	    this.expr = expr;
        this.type = type;
	}

	public void accept(Visitor v) throws JasperException {
	    v.visit(this);
	}

	public ELNode.Nodes getExpression() {
	    return expr;
	}

    public char getType() {
        return type;
    }
    }

    /**
     * Represents text outside of EL expression.
     */
    public static class Text extends ELNode {

	private String text;

	Text(String text) {
	    this.text = text;
	}

	public void accept(Visitor v) throws JasperException {
	    v.visit(this);
	}

	public String getText() {
	    return text;
	}
    }

    /**
     * Represents anything in EL expression, other than functions, including
     * function arguments etc
     */
    public static class ELText extends ELNode {

	private String text;

	ELText(String text) {
	    this.text = text;
	}

	public void accept(Visitor v) throws JasperException {
	    v.visit(this);
	}

	public String getText() {
	    return text;
	}
    }

    /**
     * Represents a function
     * Currently only include the prefix and function name, but not its
     * arguments.
     */
    public static class Function extends ELNode {

	private String prefix;
	private String name;
	private String uri;
	private FunctionInfo functionInfo;
	private String methodName;
	private String[] parameters;

	Function(String prefix, String name) {
	    this.prefix = prefix;
	    this.name = name;
	}

	public void accept(Visitor v) throws JasperException {
	    v.visit(this);
	}

	public String getPrefix() {
	    return prefix;
	}

	public String getName() {
	    return name;
	}

	public void setUri(String uri) {
	    this.uri = uri;
	}

	public String getUri() {
	    return uri;
	}

	public void setFunctionInfo(FunctionInfo f) {
	    this.functionInfo = f;
	}

	public FunctionInfo getFunctionInfo() {
	    return functionInfo;
	}

	public void setMethodName(String methodName) {
	    this.methodName = methodName;
	}

	public String getMethodName() {
	    return methodName;
	}

	public void setParameters(String[] parameters) {
	    this.parameters = parameters;
	}

	public String[] getParameters() {
	    return parameters;
	}
    }

    /**
     * An ordered list of ELNode.
     */
    public static class Nodes {

	/* Name used for creating a map for the functions in this
	   EL expression, for communication to Generator.
	 */
	String mapName = null;	// The function map associated this EL
	private List<ELNode> list;

	public Nodes() {
	    list = new ArrayList<ELNode>();
	}

	public void add(ELNode en) {
	    list.add(en);
	}

	/**
	 * Visit the nodes in the list with the supplied visitor
	 * @param v The visitor used
	 */
	public void visit(Visitor v) throws JasperException {
	    Iterator<ELNode> iter = list.iterator();
	    while (iter.hasNext()) {
	        ELNode n = iter.next();
	        n.accept(v);
	    }
	}

	public Iterator<ELNode> iterator() {
	    return list.iterator();
	}

	public boolean isEmpty() {
	    return list.size() == 0;
	}

	/**
	 * @return true if the expression contains a ${...}
	 */
	public boolean containsEL() {
	    Iterator<ELNode> iter = list.iterator();
	    while (iter.hasNext()) {
	        ELNode n = iter.next();
	        if (n instanceof Root) {
	            return true;
	        }
	    }
	    return false;
	}

	public void setMapName(String name) {
	    this.mapName = name;
	}

	public String getMapName() {
	    return mapName;
	}
    
    }

    /*
     * A visitor class for traversing ELNodes
     */
    public static class Visitor {

	public void visit(Root n) throws JasperException {
	    n.getExpression().visit(this);
	}

	public void visit(Function n) throws JasperException {
	}

	public void visit(Text n) throws JasperException {
	}

	public void visit(ELText n) throws JasperException {
	}
    }
}

Other Tomcat examples (source code examples)

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

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