node.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * 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.Iterator;
import java.util.List;
import java.util.Vector;
import java.util.ArrayList;

import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import javax.servlet.jsp.tagext.BodyTag;
import javax.servlet.jsp.tagext.DynamicAttributes;
import javax.servlet.jsp.tagext.IterationTag;
import javax.servlet.jsp.tagext.JspIdConsumer;
import javax.servlet.jsp.tagext.SimpleTag;
import javax.servlet.jsp.tagext.TagAttributeInfo;
import javax.servlet.jsp.tagext.TagData;
import javax.servlet.jsp.tagext.TagFileInfo;
import javax.servlet.jsp.tagext.TagInfo;
import javax.servlet.jsp.tagext.TagVariableInfo;
import javax.servlet.jsp.tagext.TryCatchFinally;
import javax.servlet.jsp.tagext.VariableInfo;

import org.apache.jasper.JasperException;
import org.apache.jasper.compiler.tagplugin.TagPluginContext;
import org.xml.sax.Attributes;

/**
 * An internal data representation of a JSP page or a JSP docuement (XML). Also
 * included here is a visitor class for tranversing nodes.
 * 
 * @author Kin-man Chung
 * @author Jan Luehe
 * @author Shawn Bayern
 * @author Mark Roth
 */

abstract class Node implements TagConstants {

    private static final VariableInfo[] ZERO_VARIABLE_INFO = {};

    protected Attributes attrs;

    // xmlns attributes that represent tag libraries (only in XML syntax)
    protected Attributes taglibAttrs;

    /*
     * xmlns attributes that do not represent tag libraries (only in XML syntax)
     */
    protected Attributes nonTaglibXmlnsAttrs;

    protected Nodes body;

    protected String text;

    protected Mark startMark;

    protected int beginJavaLine;

    protected int endJavaLine;

    protected Node parent;

    protected Nodes namedAttributeNodes; // cached for performance

    protected String qName;

    protected String localName;

    /*
     * The name of the inner class to which the codes for this node and its body
     * are generated. For instance, for <jsp:body> in foo.jsp, this is
     * "foo_jspHelper". This is primarily used for communicating such info from
     * Generator to Smap generator.
     */
    protected String innerClassName;

    private boolean isDummy;

    /**
     * Zero-arg Constructor.
     */
    public Node() {
        this.isDummy = true;
    }

    /**
     * Constructor.
     * 
     * @param start
     *            The location of the jsp page
     * @param parent
     *            The enclosing node
     */
    public Node(Mark start, Node parent) {
        this.startMark = start;
        this.isDummy = (start == null);
        addToParent(parent);
    }

    /**
     * Constructor.
     * 
     * @param qName
     *            The action's qualified name
     * @param localName
     *            The action's local name
     * @param start
     *            The location of the jsp page
     * @param parent
     *            The enclosing node
     */
    public Node(String qName, String localName, Mark start, Node parent) {
        this.qName = qName;
        this.localName = localName;
        this.startMark = start;
        this.isDummy = (start == null);
        addToParent(parent);
    }

    /**
     * Constructor for Nodes parsed from standard syntax.
     * 
     * @param qName
     *            The action's qualified name
     * @param localName
     *            The action's local name
     * @param attrs
     *            The attributes for this node
     * @param start
     *            The location of the jsp page
     * @param parent
     *            The enclosing node
     */
    public Node(String qName, String localName, Attributes attrs, Mark start,
            Node parent) {
        this.qName = qName;
        this.localName = localName;
        this.attrs = attrs;
        this.startMark = start;
        this.isDummy = (start == null);
        addToParent(parent);
    }

    /**
     * Constructor for Nodes parsed from XML syntax.
     * 
     * @param qName
     *            The action's qualified name
     * @param localName
     *            The action's local name
     * @param attrs
     *            The action's attributes whose name does not start with xmlns
     * @param nonTaglibXmlnsAttrs
     *            The action's xmlns attributes that do not represent tag
     *            libraries
     * @param taglibAttrs
     *            The action's xmlns attributes that represent tag libraries
     * @param start
     *            The location of the jsp page
     * @param parent
     *            The enclosing node
     */
    public Node(String qName, String localName, Attributes attrs,
            Attributes nonTaglibXmlnsAttrs, Attributes taglibAttrs, Mark start,
            Node parent) {
        this.qName = qName;
        this.localName = localName;
        this.attrs = attrs;
        this.nonTaglibXmlnsAttrs = nonTaglibXmlnsAttrs;
        this.taglibAttrs = taglibAttrs;
        this.startMark = start;
        this.isDummy = (start == null);
        addToParent(parent);
    }

    /*
     * Constructor.
     * 
     * @param qName The action's qualified name @param localName The action's
     * local name @param text The text associated with this node @param start
     * The location of the jsp page @param parent The enclosing node
     */
    public Node(String qName, String localName, String text, Mark start,
            Node parent) {
        this.qName = qName;
        this.localName = localName;
        this.text = text;
        this.startMark = start;
        this.isDummy = (start == null);
        addToParent(parent);
    }

    public String getQName() {
        return this.qName;
    }

    public String getLocalName() {
        return this.localName;
    }

    /*
     * Gets this Node's attributes.
     * 
     * In the case of a Node parsed from standard syntax, this method returns
     * all the Node's attributes.
     * 
     * In the case of a Node parsed from XML syntax, this method returns only
     * those attributes whose name does not start with xmlns.
     */
    public Attributes getAttributes() {
        return this.attrs;
    }

    /*
     * Gets this Node's xmlns attributes that represent tag libraries (only
     * meaningful for Nodes parsed from XML syntax)
     */
    public Attributes getTaglibAttributes() {
        return this.taglibAttrs;
    }

    /*
     * Gets this Node's xmlns attributes that do not represent tag libraries
     * (only meaningful for Nodes parsed from XML syntax)
     */
    public Attributes getNonTaglibXmlnsAttributes() {
        return this.nonTaglibXmlnsAttrs;
    }

    public void setAttributes(Attributes attrs) {
        this.attrs = attrs;
    }

    public String getAttributeValue(String name) {
        return (attrs == null) ? null : attrs.getValue(name);
    }

    /**
     * Get the attribute that is non request time expression, either from the
     * attribute of the node, or from a jsp:attrbute
     */
    public String getTextAttribute(String name) {

        String attr = getAttributeValue(name);
        if (attr != null) {
            return attr;
        }

        NamedAttribute namedAttribute = getNamedAttributeNode(name);
        if (namedAttribute == null) {
            return null;
        }

        return namedAttribute.getText();
    }

    /**
     * Searches all subnodes of this node for jsp:attribute standard actions
     * with the given name, and returns the NamedAttribute node of the matching
     * named attribute, nor null if no such node is found.
     * <p>
     * This should always be called and only be called for nodes that accept
     * dynamic runtime attribute expressions.
     */
    public NamedAttribute getNamedAttributeNode(String name) {
        NamedAttribute result = null;

        // Look for the attribute in NamedAttribute children
        Nodes nodes = getNamedAttributeNodes();
        int numChildNodes = nodes.size();
        for (int i = 0; i < numChildNodes; i++) {
            NamedAttribute na = (NamedAttribute) nodes.getNode(i);
            boolean found = false;
            int index = name.indexOf(':');
            if (index != -1) {
                // qualified name
                found = na.getName().equals(name);
            } else {
                found = na.getLocalName().equals(name);
            }
            if (found) {
                result = na;
                break;
            }
        }

        return result;
    }

    /**
     * Searches all subnodes of this node for jsp:attribute standard actions,
     * and returns that set of nodes as a Node.Nodes object.
     * 
     * @return Possibly empty Node.Nodes object containing any jsp:attribute
     *         subnodes of this Node
     */
    public Node.Nodes getNamedAttributeNodes() {

        if (namedAttributeNodes != null) {
            return namedAttributeNodes;
        }

        Node.Nodes result = new Node.Nodes();

        // Look for the attribute in NamedAttribute children
        Nodes nodes = getBody();
        if (nodes != null) {
            int numChildNodes = nodes.size();
            for (int i = 0; i < numChildNodes; i++) {
                Node n = nodes.getNode(i);
                if (n instanceof NamedAttribute) {
                    result.add(n);
                } else if (!(n instanceof Comment)) {
                    // Nothing can come before jsp:attribute, and only
                    // jsp:body can come after it.
                    break;
                }
            }
        }

        namedAttributeNodes = result;
        return result;
    }

    public Nodes getBody() {
        return body;
    }

    public void setBody(Nodes body) {
        this.body = body;
    }

    public String getText() {
        return text;
    }

    public Mark getStart() {
        return startMark;
    }

    public Node getParent() {
        return parent;
    }

    public int getBeginJavaLine() {
        return beginJavaLine;
    }

    public void setBeginJavaLine(int begin) {
        beginJavaLine = begin;
    }

    public int getEndJavaLine() {
        return endJavaLine;
    }

    public void setEndJavaLine(int end) {
        endJavaLine = end;
    }

    public boolean isDummy() {
        return isDummy;
    }

    public Node.Root getRoot() {
        Node n = this;
        while (!(n instanceof Node.Root)) {
            n = n.getParent();
        }
        return (Node.Root) n;
    }

    public String getInnerClassName() {
        return innerClassName;
    }

    public void setInnerClassName(String icn) {
        innerClassName = icn;
    }

    /**
     * Selects and invokes a method in the visitor class based on the node type.
     * This is abstract and should be overrode by the extending classes.
     * 
     * @param v
     *            The visitor class
     */
    abstract void accept(Visitor v) throws JasperException;

    // *********************************************************************
    // Private utility methods

    /*
     * Adds this Node to the body of the given parent.
     */
    private void addToParent(Node parent) {
        if (parent != null) {
            this.parent = parent;
            Nodes parentBody = parent.getBody();
            if (parentBody == null) {
                parentBody = new Nodes();
                parent.setBody(parentBody);
            }
            parentBody.add(this);
        }
    }