literalelement.java

java1.6众多例子参考

/*
 * Copyright 2001-2004 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.
 */
/*
 * $Id: LiteralElement.java,v 1.2.4.1 2005/09/13 12:38:33 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;

import com.sun.org.apache.xml.internal.serializer.ElemDesc;
import com.sun.org.apache.xml.internal.serializer.ToHTMLStream;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 */
final class LiteralElement extends Instruction {

    private String _name;
    private LiteralElement _literalElemParent = null;
    private Vector _attributeElements = null;
    private Hashtable _accessedPrefixes = null;
    
    // True if all attributes of this LRE are unique, i.e. they all have
    // different names. This flag is set to false if some attribute
    // names are not known at compile time.
    private boolean _allAttributesUnique = false;
        
    private final static String XMLNS_STRING = "xmlns";

    /**
     * Returns the QName for this literal element
     */
    public QName getName() {
	return _qname;
    }
 
    /**
     * Displays the contents of this literal element
     */
    public void display(int indent) {
	indent(indent);
	Util.println("LiteralElement name = " + _name);
	displayContents(indent + IndentIncrement);
    }

    /**
     * Returns the namespace URI for which a prefix is pointing to
     */
    private String accessedNamespace(String prefix) {
        if (_literalElemParent != null) {
            String result = _literalElemParent.accessedNamespace(prefix);
            if (result != null) {
                return result;
            }
        }       
        return _accessedPrefixes != null ? 
            (String) _accessedPrefixes.get(prefix) : null;
    }

    /**
     * Method used to keep track of what namespaces that are references by
     * this literal element and its attributes. The output must contain a
     * definition for each namespace, so we stuff them in a hashtable.
     */
    public void registerNamespace(String prefix, String uri,
				  SymbolTable stable, boolean declared) {

	// Check if the parent has a declaration for this namespace
	if (_literalElemParent != null) {
	    final String parentUri = _literalElemParent.accessedNamespace(prefix);
	    if (parentUri != null && parentUri.equals(uri)) {
                return;
            }
	}

	// Check if we have any declared namesaces
	if (_accessedPrefixes == null) {
	    _accessedPrefixes = new Hashtable();
	}
	else {
	    if (!declared) {
		// Check if this node has a declaration for this namespace
		final String old = (String)_accessedPrefixes.get(prefix);
		if (old != null) {
		    if (old.equals(uri))
			return;
		    else 
			prefix = stable.generateNamespacePrefix();
		}
	    }
	}

	if (!prefix.equals("xml")) {
	    _accessedPrefixes.put(prefix,uri);
	}
    }

    /**
     * Translates the prefix of a QName according to the rules set in
     * the attributes of xsl:stylesheet. Also registers a QName to assure
     * that the output element contains the necessary namespace declarations.
     */
    private String translateQName(QName qname, SymbolTable stable) {
	// Break up the QName and get prefix:localname strings
	String localname = qname.getLocalPart();
	String prefix = qname.getPrefix();

	// Treat default namespace as "" and not null
	if (prefix == null)
	    prefix = Constants.EMPTYSTRING;
	else if (prefix.equals(XMLNS_STRING))
	    return(XMLNS_STRING);
	
	// Check if we must translate the prefix
	final String alternative = stable.lookupPrefixAlias(prefix);
	if (alternative != null) {
	    stable.excludeNamespaces(prefix);
	    prefix = alternative;
	}

	// Get the namespace this prefix refers to
	String uri = lookupNamespace(prefix);
	if (uri == null) return(localname);

	// Register the namespace as accessed
	registerNamespace(prefix, uri, stable, false);

	// Construct the new name for the element (may be unchanged)
	if (prefix != Constants.EMPTYSTRING)
	    return(prefix+":"+localname);
	else
	    return(localname);
    }

    /**
     * Add an attribute to this element
     */
    public void addAttribute(SyntaxTreeNode attribute) {
	if (_attributeElements == null) {
	    _attributeElements = new Vector(2);
	}
	_attributeElements.add(attribute);
    }

    /**
     * Set the first attribute of this element
     */
    public void setFirstAttribute(SyntaxTreeNode attribute) {
	if (_attributeElements == null) {
	    _attributeElements = new Vector(2);
	}
	_attributeElements.insertElementAt(attribute,0);
    }

    /**
     * Type-check the contents of this element. The element itself does not
     * need any type checking as it leaves nothign on the JVM's stack.
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	// Type-check all attributes
	if (_attributeElements != null) {
	    final int count = _attributeElements.size();
	    for (int i = 0; i < count; i++) {
		SyntaxTreeNode node = 
		    (SyntaxTreeNode)_attributeElements.elementAt(i);
		node.typeCheck(stable);
	    }
	}
	typeCheckContents(stable);
	return Type.Void;
    }

    /**
     * This method starts at a given node, traverses all namespace mappings,
     * and assembles a list of all prefixes that (for the given node) maps
     * to _ANY_ namespace URI. Used by literal result elements to determine
     */
    public Enumeration getNamespaceScope(SyntaxTreeNode node) {
	Hashtable all = new Hashtable();
	
	while (node != null) {
	    Hashtable mapping = node.getPrefixMapping();
	    if (mapping != null) {
		Enumeration prefixes = mapping.keys();
		while (prefixes.hasMoreElements()) {
		    String prefix = (String)prefixes.nextElement();
		    if (!all.containsKey(prefix)) {
			all.put(prefix, mapping.get(prefix));
		    }
		}
	    }
	    node = node.getParent();
	}
	return(all.keys());
    }

    /**
     * Determines the final QName for the element and its attributes.
     * Registers all namespaces that are used by the element/attributes
     */
    public void parseContents(Parser parser) {
	final SymbolTable stable = parser.getSymbolTable();
	stable.setCurrentNode(this);

	// Check if in a literal element context
	SyntaxTreeNode parent = getParent();
        if (parent != null && parent instanceof LiteralElement) {
            _literalElemParent = (LiteralElement) parent;
	}

	_name = translateQName(_qname, stable);

	// Process all attributes and register all namespaces they use
	final int count = _attributes.getLength();
	for (int i = 0; i < count; i++) {
	    final QName qname = parser.getQName(_attributes.getQName(i));
	    final String uri = qname.getNamespace();
	    final String val = _attributes.getValue(i);

	    // Handle xsl:use-attribute-sets. Attribute sets are placed first
	    // in the vector or attributes to make sure that later local
	    // attributes can override an attributes in the set.
	    if (qname == parser.getUseAttributeSets()) {
            	if (!Util.isValidQNames(val)) {
                    ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, val, this);
                    parser.reportError(Constants.ERROR, err);	
               }
		setFirstAttribute(new UseAttributeSets(val, parser));
	    }
	    // Handle xsl:extension-element-prefixes
	    else if (qname == parser.getExtensionElementPrefixes()) {
		stable.excludeNamespaces(val);
	    }
	    // Handle xsl:exclude-result-prefixes
	    else if (qname == parser.getExcludeResultPrefixes()) {
		stable.excludeNamespaces(val);
	    }
	    else {
		// Ignore special attributes (e.g. xmlns:prefix and xmlns)
		final String prefix = qname.getPrefix();
		if (prefix != null && prefix.equals(XMLNS_PREFIX) ||
		    prefix == null && qname.getLocalPart().equals("xmlns") ||
		    uri != null && uri.equals(XSLT_URI))
		{
		    continue;	
		}

		// Handle all other literal attributes
		final String name = translateQName(qname, stable);
		LiteralAttribute attr = new LiteralAttribute(name, val, parser, this);