stylesheet.java

java1.6众多例子参考

	}
	
	// Compile in code to set the output configuration from <xsl:output>
	if (output != null) {
	    // Set all the output settings files in the translet
	    output.translate(classGen, constructor);
	}

	// Compile default decimal formatting symbols.
	// This is an implicit, nameless xsl:decimal-format top-level element.
	if (_numberFormattingUsed)
	    DecimalFormatting.translateDefaultDFS(classGen, constructor);

	il.append(RETURN);

	constructor.stripAttributes(true);
	constructor.setMaxLocals();
	constructor.setMaxStack();
	classGen.addMethod(constructor.getMethod());
    }

    /**
     * Compile a topLevel() method into the output class. This method is 
     * called from transform() to handle all non-template top-level elements.
     * Returns the signature of the topLevel() method.
     *
     * Global variables/params and keys are first sorted to resolve 
     * dependencies between them. The XSLT 1.0 spec does not allow a key 
     * to depend on a variable. However, for compatibility with Xalan
     * interpretive, that type of dependency is allowed. Note also that
     * the buildKeys() method is still generated as it is used by the 
     * LoadDocument class, but it no longer called from transform().
     */
    private String compileTopLevel(ClassGenerator classGen) {

	final ConstantPoolGen cpg = classGen.getConstantPool();

	final com.sun.org.apache.bcel.internal.generic.Type[] argTypes = {
	    Util.getJCRefType(DOM_INTF_SIG),
	    Util.getJCRefType(NODE_ITERATOR_SIG),
	    Util.getJCRefType(TRANSLET_OUTPUT_SIG)
	};

	final String[] argNames = {
	    DOCUMENT_PNAME, ITERATOR_PNAME, TRANSLET_OUTPUT_PNAME
	};

	final InstructionList il = new InstructionList();

	final MethodGenerator toplevel =
	    new MethodGenerator(ACC_PUBLIC,
				com.sun.org.apache.bcel.internal.generic.Type.VOID,
				argTypes, argNames,
				"topLevel", _className, il,
				classGen.getConstantPool());

	toplevel.addException("com.sun.org.apache.xalan.internal.xsltc.TransletException");

	// Define and initialize 'current' variable with the root node
	final LocalVariableGen current = 
	    toplevel.addLocalVariable("current",
				    com.sun.org.apache.bcel.internal.generic.Type.INT,
				    il.getEnd(), null);

	final int setFilter = cpg.addInterfaceMethodref(DOM_INTF,
			       "setFilter",
			       "(Lcom/sun/org/apache/xalan/internal/xsltc/StripFilter;)V");

	il.append(new PUSH(cpg, DTM.ROOT_NODE));
	il.append(new ISTORE(current.getIndex()));

        // Create a new list containing variables/params + keys
        Vector varDepElements = new Vector(_globals);
	Enumeration elements = elements();
	while (elements.hasMoreElements()) {
	    final Object element = elements.nextElement();
	    if (element instanceof Key) {
                varDepElements.add(element);
	    }
	}

        // Determine a partial order for the variables/params and keys
	varDepElements = resolveDependencies(varDepElements);

        // Translate vars/params and keys in the right order
	final int count = varDepElements.size();
	for (int i = 0; i < count; i++) {
	    final TopLevelElement tle = (TopLevelElement) varDepElements.elementAt(i);            
	    tle.translate(classGen, toplevel);            
	    if (tle instanceof Key) {
		final Key key = (Key) tle;
		_keys.put(key.getName(), key);
	    }
	}

	// Compile code for other top-level elements
	Vector whitespaceRules = new Vector();
        elements = elements();
	while (elements.hasMoreElements()) {
	    final Object element = elements.nextElement();
	    // xsl:decimal-format
	    if (element instanceof DecimalFormatting) {
		((DecimalFormatting)element).translate(classGen,toplevel);
	    }
	    // xsl:strip/preserve-space
	    else if (element instanceof Whitespace) {
		whitespaceRules.addAll(((Whitespace)element).getRules());
	    }
	}

	// Translate all whitespace strip/preserve rules
	if (whitespaceRules.size() > 0) {
	    Whitespace.translateRules(whitespaceRules,classGen);
	}

	if (classGen.containsMethod(STRIP_SPACE, STRIP_SPACE_PARAMS) != null) {
	    il.append(toplevel.loadDOM());
	    il.append(classGen.loadTranslet());
	    il.append(new INVOKEINTERFACE(setFilter, 2));
	}

	il.append(RETURN);

	// Compute max locals + stack and add method to class
	toplevel.stripAttributes(true);
	toplevel.setMaxLocals();
	toplevel.setMaxStack();
	toplevel.removeNOPs();

	classGen.addMethod(toplevel.getMethod());
	
	return("("+DOM_INTF_SIG+NODE_ITERATOR_SIG+TRANSLET_OUTPUT_SIG+")V");
    }

    /**
     * This method returns a vector with variables/params and keys in the 
     * order in which they are to be compiled for initialization. The order
     * is determined by analyzing the dependencies between them. The XSLT 1.0 
     * spec does not allow a key to depend on a variable. However, for 
     * compatibility with Xalan interpretive, that type of dependency is 
     * allowed and, therefore, consider to determine the partial order.
     */
    private Vector resolveDependencies(Vector input) {
	/* DEBUG CODE - INGORE 
	for (int i = 0; i < input.size(); i++) {
	    final TopLevelElement e = (TopLevelElement) input.elementAt(i);
	    System.out.println("e = " + e + " depends on:");
            Vector dep = e.getDependencies();
            for (int j = 0; j < (dep != null ? dep.size() : 0); j++) {
                System.out.println("\t" + dep.elementAt(j));
            }
	}
	System.out.println("=================================");	
        */

	Vector result = new Vector();
	while (input.size() > 0) {
	    boolean changed = false;
	    for (int i = 0; i < input.size(); ) {
		final TopLevelElement vde = (TopLevelElement) input.elementAt(i);
		final Vector dep = vde.getDependencies();
		if (dep == null || result.containsAll(dep)) {
		    result.addElement(vde);
		    input.remove(i);
		    changed = true;
		}
		else {
		    i++;
		}
	    }

	    // If nothing was changed in this pass then we have a circular ref
	    if (!changed) {
		ErrorMsg err = new ErrorMsg(ErrorMsg.CIRCULAR_VARIABLE_ERR,
					    input.toString(), this);
		getParser().reportError(Constants.ERROR, err);
		return(result);
	    }
	}

	/* DEBUG CODE - INGORE 
	System.out.println("=================================");
	for (int i = 0; i < result.size(); i++) {
	    final TopLevelElement e = (TopLevelElement) result.elementAt(i);
	    System.out.println("e = " + e);
	}
        */

	return result;
    }

    /**
     * Compile a buildKeys() method into the output class. Note that keys 
     * for the input document are created in topLevel(), not in this method. 
     * However, we still need this method to create keys for documents loaded
     * via the XPath document() function. 
     */
    private String compileBuildKeys(ClassGenerator classGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();

	final com.sun.org.apache.bcel.internal.generic.Type[] argTypes = {
	    Util.getJCRefType(DOM_INTF_SIG),
	    Util.getJCRefType(NODE_ITERATOR_SIG),
	    Util.getJCRefType(TRANSLET_OUTPUT_SIG),
	    com.sun.org.apache.bcel.internal.generic.Type.INT
	};

	final String[] argNames = {
	    DOCUMENT_PNAME, ITERATOR_PNAME, TRANSLET_OUTPUT_PNAME, "current"
	};

	final InstructionList il = new InstructionList();

	final MethodGenerator buildKeys =
	    new MethodGenerator(ACC_PUBLIC,
				com.sun.org.apache.bcel.internal.generic.Type.VOID,
				argTypes, argNames,
				"buildKeys", _className, il,
				classGen.getConstantPool());

	buildKeys.addException("com.sun.org.apache.xalan.internal.xsltc.TransletException");
	
	final Enumeration elements = elements();
	while (elements.hasMoreElements()) {
	    // xsl:key
	    final Object element = elements.nextElement();
	    if (element instanceof Key) {
		final Key key = (Key)element;
		key.translate(classGen, buildKeys);
		_keys.put(key.getName(),key);
	    }
	}
	
	il.append(RETURN);
	
	// Compute max locals + stack and add method to class
	buildKeys.stripAttributes(true);
	buildKeys.setMaxLocals();
	buildKeys.setMaxStack();
	buildKeys.removeNOPs();

	classGen.addMethod(buildKeys.getMethod());
	
	return("("+DOM_INTF_SIG+NODE_ITERATOR_SIG+TRANSLET_OUTPUT_SIG+"I)V");
    }

    /**
     * Compile transform() into the output class. This method is used to 
     * initialize global variables and global parameters. The current node
     * is set to be the document's root node.
     */
    private void compileTransform(ClassGenerator classGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();

	/* 
	 * Define the the method transform with the following signature:
	 * void transform(DOM, NodeIterator, HandlerBase)
	 */
	final com.sun.org.apache.bcel.internal.generic.Type[] argTypes = 
	    new com.sun.org.apache.bcel.internal.generic.Type[3];
	argTypes[0] = Util.getJCRefType(DOM_INTF_SIG);
	argTypes[1] = Util.getJCRefType(NODE_ITERATOR_SIG);
	argTypes[2] = Util.getJCRefType(TRANSLET_OUTPUT_SIG);

	final String[] argNames = new String[3];
	argNames[0] = DOCUMENT_PNAME;
	argNames[1] = ITERATOR_PNAME;
	argNames[2] = TRANSLET_OUTPUT_PNAME;

	final InstructionList il = new InstructionList();
	final MethodGenerator transf =
	    new MethodGenerator(ACC_PUBLIC,
				com.sun.org.apache.bcel.internal.generic.Type.VOID,
				argTypes, argNames,
				"transform",
				_className,
				il,
				classGen.getConstantPool());
	transf.addException("com.sun.org.apache.xalan.internal.xsltc.TransletException");

	// Define and initialize current with the root node
	final LocalVariableGen current = 
	    transf.addLocalVariable("current",
				    com.sun.org.apache.bcel.internal.generic.Type.INT,
				    il.getEnd(), null);
	final String applyTemplatesSig = classGen.getApplyTemplatesSig();
	final int applyTemplates = cpg.addMethodref(getClassName(),
						    "applyTemplates",
						    applyTemplatesSig);
	final int domField = cpg.addFieldref(getClassName(),
					     DOM_FIELD,
					     DOM_INTF_SIG);

	// push translet for PUTFIELD
	il.append(classGen.loadTranslet());
	// prepare appropriate DOM implementation
	
	if (isMultiDocument()) {
	    il.append(new NEW(cpg.addClass(MULTI_DOM_CLASS)));
	    il.append(DUP);
	}
	
	il.append(classGen.loadTranslet());
	il.append(transf.loadDOM());
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
						     "makeDOMAdapter",
						     "("+DOM_INTF_SIG+")"+
						     DOM_ADAPTER_SIG)));
	// DOMAdapter is on the stack

	if (isMultiDocument()) {
	    final int init = cpg.addMethodref(MULTI_DOM_CLASS,
					      "<init>",
					      "("+DOM_INTF_SIG+")V");
	    il.append(new INVOKESPECIAL(init));
	    // MultiDOM is on the stack
	}
	
	//store to _dom variable
	il.append(new PUTFIELD(domField));

	// continue with globals initialization
	il.append(new PUSH(cpg, DTM.ROOT_NODE));
	il.append(new ISTORE(current.getIndex()));

	// Transfer the output settings to the output post-processor
	il.append(classGen.loadTranslet());
	il.append(transf.loadHandler());
	final int index = cpg.addMethodref(TRANSLET_CLASS,
					   "transferOutputSettings",
					   "("+OUTPUT_HANDLER_SIG+")V");
	il.append(new INVOKEVIRTUAL(index));

        /*
         * Compile buildKeys() method. Note that this method is not 
         * invoked here as keys for the input document are now created
         * in topLevel(). However, this method is still needed by the
         * LoadDocument class.
         */        
        final String keySig = compileBuildKeys(classGen);
        final int keyIdx = cpg.addMethodref(getClassName(),
                                               "buildKeys", keySig);
                
        // Look for top-level elements that need handling
	final Enumeration toplevel = elements();
	if (_globals.size() > 0 || toplevel.hasMoreElements()) {
	    // Compile method for handling top-level elements
	    final String topLevelSig = compileTopLevel(classGen);
	    // Get a reference to that method
	    final int topLevelIdx = cpg.addMethodref(getClassName(),
						     "topLevel",
						     topLevelSig);
	    // Push all parameters on the stack and call topLevel()
	    il.append(classGen.loadTranslet()); // The 'this' pointer
	    il.append(classGen.loadTranslet());
	    il.append(new GETFIELD(domField));  // The DOM reference
	    il.append(transf.loadIterator());
	    il.append(transf.loadHandler());    // The output handler
	    il.append(new INVOKEVIRTUAL(topLevelIdx));
	}	

	// start document
	il.append(transf.loadHandler());
	il.append(transf.startDocument());

	// push first arg for applyTemplates
	il.append(classGen.loadTranslet());
	// push translet for GETFIELD to get DOM arg
	il.append(classGen.loadTranslet());
	il.append(new GETFIELD(domField));
	// push remaining 2 args
	il.append(transf.loadIterator());
	il.append(transf.loadHandler());
	il.append(new INVOKEVIRTUAL(applyTemplates));
	// endDocument
	il.append(transf.loadHandler());
	il.append(transf.endDocument());

	il.append(RETURN);

	// Compute max locals + stack and add method to class
	transf.stripAttributes(true);
	transf.setMaxLocals();
	transf.setMaxStack();
	transf.removeNOPs();

	classGen.addMethod(transf.getMethod());
    }

    /**
     * Peephole optimization: Remove sequences of [ALOAD, POP].
     */
    private void peepHoleOptimization(MethodGenerator methodGen) {
	final String pattern = "`aload'`pop'`instruction'";
	final InstructionList il = methodGen.getInstructionList();
	final InstructionFinder find = new InstructionFinder(il);
	for(Iterator iter=find.search(pattern); iter.hasNext(); ) {
	    InstructionHandle[] match = (InstructionHandle[])iter.next();
	    try {
		il.delete(match[0], match[1]);
	    } 
	    catch (TargetLostException e) {
            	// TODO: move target down into the list
            }
	}
    }

    public int addParam(Param param) {
	_globals.addElement(param);
	return _globals.size() - 1;
    }

    public int addVariable(Variable global) {
	_globals.addElement(global);
	return _globals.size() - 1;
    }

    public void display(int indent) {
	indent(indent);
	Util.println("Stylesheet");
	displayContents(indent + IndentIncrement);
    }

    // do we need this wrapper ?????
    public String getNamespace(String prefix) {
	return lookupNamespace(prefix);
    }

    public String getClassName() {
	return _className;
    }

    public Vector getTemplates() {
	return _templates;
    }

    public Vector getAllValidTemplates() {
        // Return templates if no imported/included stylesheets
        if (_includedStylesheets == null) {
            return _templates;
        }
        
        // Is returned value cached?
        if (_allValidTemplates == null) {
           Vector templates = new Vector();
           templates.addAll(_templates);
            int size = _includedStylesheets.size();
            for (int i = 0; i < size; i++) {
                Stylesheet included =(Stylesheet)_includedStylesheets.elementAt(i);
                templates.addAll(included.getAllValidTemplates());
            }
            //templates.addAll(_templates);

            // Cache results in top-level stylesheet only
            if (_parentStylesheet != null) {
                return templates;
            }
            _allValidTemplates = templates;
         }
        
        return _allValidTemplates;
    }
    
    protected void addTemplate(Template template) {
        _templates.addElement(template);
    }
}