mode.java

java1.6众多例子参考

    ilLoop.append(RETURN);
	final InstructionHandle ihLoop = ilLoop.getStart();

	// Compile default handling of elements (traverse children)
	InstructionList ilRecurse =
	    compileDefaultRecursion(classGen, methodGen, ihLoop);
	InstructionHandle ihRecurse = ilRecurse.getStart();

	// Compile default handling of text/attribute nodes (output text)
	InstructionList ilText =
	    compileDefaultText(classGen, methodGen, ihLoop);
	InstructionHandle ihText = ilText.getStart();

	// Distinguish attribute/element/namespace tests for further processing
	final int[] types = new int[DTM.NTYPES + names.size()];
	for (int i = 0; i < types.length; i++) {
	    types[i] = i;
	}

	final boolean[] isAttribute = new boolean[types.length];
	final boolean[] isNamespace = new boolean[types.length];
	for (int i = 0; i < names.size(); i++) {
	    final String name = (String)names.elementAt(i);
	    isAttribute[i+DTM.NTYPES] = isAttributeName(name);
	    isNamespace[i+DTM.NTYPES] = isNamespaceName(name);
	}

	// Compile all templates - regardless of pattern type
	compileTemplateCalls(classGen, methodGen, ihLoop, min, max);

	// Handle template with explicit "*" pattern
	final TestSeq elemTest = _testSeq[DTM.ELEMENT_NODE];
	InstructionHandle ihElem = ihRecurse;
	if (elemTest != null) {
	    ihElem = elemTest.compile(classGen, methodGen, ihLoop);
	}

	// Handle template with explicit "@*" pattern
	final TestSeq attrTest = _testSeq[DTM.ATTRIBUTE_NODE];
	InstructionHandle ihAttr = ihLoop;
	if (attrTest != null) {
	    ihAttr = attrTest.compile(classGen, methodGen, ihAttr);
	}

	// Do tests for id() and key() patterns first
	InstructionList ilKey = null;
	if (_idxTestSeq != null) {
	    ilKey = _idxTestSeq.getInstructionList();
	}

	// If there is a match on node() we need to replace ihElem
	// and ihText if the priority of node() is higher
	if (_childNodeTestSeq != null) {
	    // Compare priorities of node() and "*"
	    double nodePrio = _childNodeTestSeq.getPriority();
	    int    nodePos  = _childNodeTestSeq.getPosition();
	    double elemPrio = (0 - Double.MAX_VALUE);
	    int    elemPos  = Integer.MIN_VALUE;

	    if (elemTest != null) {
		elemPrio = elemTest.getPriority();
		elemPos  = elemTest.getPosition();
	    }

	    if (elemPrio == Double.NaN || elemPrio < nodePrio || 
		(elemPrio == nodePrio && elemPos < nodePos)) 
	    {
		ihElem = _childNodeTestSeq.compile(classGen, methodGen, ihLoop);
	    }

	    // Compare priorities of node() and text()
	    final TestSeq textTest = _testSeq[DTM.TEXT_NODE];
	    double textPrio = (0 - Double.MAX_VALUE);
	    int    textPos  = Integer.MIN_VALUE;

	    if (textTest != null) {
		textPrio = textTest.getPriority();
		textPos  = textTest.getPosition();
	    }

	    if (textPrio == Double.NaN || textPrio < nodePrio ||
	        (textPrio == nodePrio && textPos < nodePos)) 
	    {
		ihText = _childNodeTestSeq.compile(classGen, methodGen, ihLoop);
		_testSeq[DTM.TEXT_NODE] = _childNodeTestSeq;
	    }
	}

	// Handle templates with "ns:*" pattern
	InstructionHandle elemNamespaceHandle = ihElem;
	InstructionList nsElem = compileNamespaces(classGen, methodGen,
						   isNamespace, isAttribute,
						   false, ihElem);
	if (nsElem != null) elemNamespaceHandle = nsElem.getStart();

	// Handle templates with "ns:@*" pattern
	InstructionList nsAttr = compileNamespaces(classGen, methodGen,
						   isNamespace, isAttribute,
						   true, ihAttr);
	InstructionHandle attrNamespaceHandle = ihAttr;
	if (nsAttr != null) attrNamespaceHandle = nsAttr.getStart();

	// Handle templates with "ns:elem" or "ns:@attr" pattern
	final InstructionHandle[] targets = new InstructionHandle[types.length];
	for (int i = DTM.NTYPES; i < targets.length; i++) {
	    final TestSeq testSeq = _testSeq[i];
	    // Jump straight to namespace tests ?
	    if (isNamespace[i]) {
		if (isAttribute[i])
		    targets[i] = attrNamespaceHandle;
		else
		    targets[i] = elemNamespaceHandle;
	    }
	    // Test first, then jump to namespace tests
	    else if (testSeq != null) {
		if (isAttribute[i])
		    targets[i] = testSeq.compile(classGen, methodGen,
						 attrNamespaceHandle);
		else
		    targets[i] = testSeq.compile(classGen, methodGen,
						 elemNamespaceHandle);
	    }
	    else {
		targets[i] = ihLoop;
	    }
	}

	// Handle pattern with match on root node - default: traverse children
	targets[DTM.ROOT_NODE] = _rootPattern != null
	    ? getTemplateInstructionHandle(_rootPattern.getTemplate())
	    : ihRecurse;
	// Handle pattern with match on root node - default: traverse children
	targets[DTM.DOCUMENT_NODE] = _rootPattern != null
	    ? getTemplateInstructionHandle(_rootPattern.getTemplate())
	    : ihRecurse;    // %HZ%:  Was ihLoop in XSLTC_DTM branch
	
	// Handle any pattern with match on text nodes - default: loop
	targets[DTM.TEXT_NODE] = _testSeq[DTM.TEXT_NODE] != null
	    ? _testSeq[DTM.TEXT_NODE].compile(classGen, methodGen, ihText)
	    : ihText;

	// This DOM-type is not in use - default: process next node
	targets[DTM.NAMESPACE_NODE] = ihLoop;

	// Match unknown element in DOM - default: check for namespace match
	targets[DTM.ELEMENT_NODE] = elemNamespaceHandle;

	// Match unknown attribute in DOM - default: check for namespace match
	targets[DTM.ATTRIBUTE_NODE] = attrNamespaceHandle;

	// Match on processing instruction - default: loop
	InstructionHandle ihPI = ihLoop;
	if (_childNodeTestSeq != null) ihPI = ihElem;
	if (_testSeq[DTM.PROCESSING_INSTRUCTION_NODE] != null) {
	    targets[DTM.PROCESSING_INSTRUCTION_NODE] =
		_testSeq[DTM.PROCESSING_INSTRUCTION_NODE].
		compile(classGen, methodGen, ihPI);
	}
	else {
	    targets[DTM.PROCESSING_INSTRUCTION_NODE] = ihPI;
	}
	
	// Match on comments - default: process next node
	InstructionHandle ihComment = ihLoop;
	if (_childNodeTestSeq != null) ihComment = ihElem;
	targets[DTM.COMMENT_NODE] = _testSeq[DTM.COMMENT_NODE] != null
	    ? _testSeq[DTM.COMMENT_NODE].compile(classGen, methodGen, ihComment)
	    : ihComment;
	    
	        // This DOM-type is not in use - default: process next node
	targets[DTM.CDATA_SECTION_NODE] = ihLoop;

	// This DOM-type is not in use - default: process next node
	targets[DTM.DOCUMENT_FRAGMENT_NODE] = ihLoop;
	
	// This DOM-type is not in use - default: process next node
	targets[DTM.DOCUMENT_TYPE_NODE] = ihLoop;

	// This DOM-type is not in use - default: process next node
	targets[DTM.ENTITY_NODE] = ihLoop;

	// This DOM-type is not in use - default: process next node
	targets[DTM.ENTITY_REFERENCE_NODE] = ihLoop;
	
	// This DOM-type is not in use - default: process next node
	targets[DTM.NOTATION_NODE] = ihLoop;



	// Now compile test sequences for various match patterns:
	for (int i = DTM.NTYPES; i < targets.length; i++) {
	    final TestSeq testSeq = _testSeq[i];
	    // Jump straight to namespace tests ?
	    if ((testSeq == null) || (isNamespace[i])) {
		if (isAttribute[i])
		    targets[i] = attrNamespaceHandle;
		else
		    targets[i] = elemNamespaceHandle;
	    }
	    // Match on node type
	    else {
		if (isAttribute[i])
		    targets[i] = testSeq.compile(classGen, methodGen,
						 attrNamespaceHandle);
		else
		    targets[i] = testSeq.compile(classGen, methodGen,
						 elemNamespaceHandle);
	    }
	}

	if (ilKey != null) body.insert(ilKey);

	// Append first code in applyTemplates() - get type of current node
	final int getType = cpg.addInterfaceMethodref(DOM_INTF,
						      "getExpandedTypeID",
                                                      "(I)I");
	body.append(methodGen.loadDOM());
	body.append(new ILOAD(_currentIndex));
	body.append(new INVOKEINTERFACE(getType, 2));

	// Append switch() statement - main dispatch loop in applyTemplates()
	InstructionHandle disp = body.append(new SWITCH(types,targets,ihLoop));

	// Append all the "case:" statements
	appendTestSequences(body);
	// Append the actual template code
	appendTemplateCode(body);

	// Append NS:* node tests (if any)
	if (nsElem != null) body.append(nsElem);
	// Append NS:@* node tests (if any)
	if (nsAttr != null) body.append(nsAttr);

	// Append default action for element and root nodes
	body.append(ilRecurse);
	// Append default action for text and attribute nodes
	body.append(ilText);

	// putting together constituent instruction lists
	mainIL.append(body);
	// fall through to ilLoop
	mainIL.append(ilLoop);

	peepHoleOptimization(methodGen);
	methodGen.stripAttributes(true);
	
	methodGen.setMaxLocals();
	methodGen.setMaxStack();
	methodGen.removeNOPs();
	classGen.addMethod(methodGen.getMethod());

	// Restore original (complete) set of templates for this transformation
	_templates = oldTemplates;
    }

    /**
      * Peephole optimization.
      */
    private void peepHoleOptimization(MethodGenerator methodGen) {
        InstructionList il = methodGen.getInstructionList();
        InstructionFinder find = new InstructionFinder(il);
	InstructionHandle ih;
	String pattern;

	// LoadInstruction, POP => (removed)
	// pattern = "LoadInstruction POP";
        // changed to lower case - changing to all lower case although only the instruction with capital I 
        // is creating a problem in the Turkish locale
        pattern = "loadinstruction pop";
        
	for (Iterator iter = find.search(pattern); iter.hasNext();) {
	    InstructionHandle[] match = (InstructionHandle[]) iter.next();
	    try {
		if (!match[0].hasTargeters() && !match[1].hasTargeters()) {
                    il.delete(match[0], match[1]);
                }
	    }
	    catch (TargetLostException e) {
                // TODO: move target down into the list
            }
	}
        
	// ILOAD_N, ILOAD_N, SWAP, ISTORE_N => ILOAD_N
	// pattern = "ILOAD ILOAD SWAP ISTORE";
        // changed to lower case - changing to all lower case although only the instruction with capital I 
        // is creating a problem in the Turkish locale
        pattern = "iload iload swap istore";
	for (Iterator iter = find.search(pattern); iter.hasNext();) {
            InstructionHandle[] match = (InstructionHandle[]) iter.next();
            try {              
                com.sun.org.apache.bcel.internal.generic.ILOAD iload1 = 
                    (com.sun.org.apache.bcel.internal.generic.ILOAD) match[0].getInstruction();
                com.sun.org.apache.bcel.internal.generic.ILOAD iload2 = 
                    (com.sun.org.apache.bcel.internal.generic.ILOAD) match[1].getInstruction();
                com.sun.org.apache.bcel.internal.generic.ISTORE istore = 
                    (com.sun.org.apache.bcel.internal.generic.ISTORE) match[3].getInstruction();
                
                if (!match[1].hasTargeters() &&
                    !match[2].hasTargeters() &&
                    !match[3].hasTargeters() &&
                    iload1.getIndex() == iload2.getIndex() &&
                    iload2.getIndex() == istore.getIndex())
                {
                    il.delete(match[1], match[3]);
                }
            }
            catch (TargetLostException e) {
                // TODO: move target down into the list
            }
        }

        // LoadInstruction_N, LoadInstruction_M, SWAP => LoadInstruction_M, LoadInstruction_N
        // pattern = "LoadInstruction LoadInstruction SWAP";
        // changed to lower case - changing to all lower case although only the instruction with capital I 
        // is creating a problem in the Turkish locale
        pattern = "loadinstruction loadinstruction swap";
	for (Iterator iter = find.search(pattern); iter.hasNext();) {
            InstructionHandle[] match = (InstructionHandle[])iter.next();
            try {
                if (!match[0].hasTargeters() &&
                    !match[1].hasTargeters() &&
                    !match[2].hasTargeters()) 
                {
                    Instruction load_m = match[1].getInstruction();
                    il.insert(match[0], load_m);
                    il.delete(match[1], match[2]);
                }
            }
            catch (TargetLostException e) {
                // TODO: move target down into the list
            }
        }
                       
        // ALOAD_N ALOAD_N => ALOAD_N DUP
	// pattern = "ALOAD ALOAD";
        // changed to lower case - changing to all lower case although only the instruction with capital I 
        // is creating a problem in the Turkish locale
        pattern = "aload aload";
        for (Iterator iter = find.search(pattern); iter.hasNext();) {
            InstructionHandle[] match = (InstructionHandle[])iter.next();
            try {
                if (!match[1].hasTargeters()) {
                    com.sun.org.apache.bcel.internal.generic.ALOAD aload1 = 
                        (com.sun.org.apache.bcel.internal.generic.ALOAD) match[0].getInstruction();
                    com.sun.org.apache.bcel.internal.generic.ALOAD aload2 = 
                        (com.sun.org.apache.bcel.internal.generic.ALOAD) match[1].getInstruction();
                    
                    if (aload1.getIndex() == aload2.getIndex()) {
                        il.insert(match[1], new DUP());
                        il.delete(match[1]);
                    }
                }
            }
            catch (TargetLostException e) {
                // TODO: move target down into the list
            }
        }
    }

    public InstructionHandle getTemplateInstructionHandle(Template template) {
	return (InstructionHandle)_templateIHs.get(template);
    }

    /**
     * Auxiliary method to determine if a qname is an attribute.
     */
    private static boolean isAttributeName(String qname) {
	final int col = qname.lastIndexOf(':') + 1;
	return (qname.charAt(col) == '@');
    }

    /**
     * Auxiliary method to determine if a qname is a namespace 
     * qualified "*".
     */
    private static boolean isNamespaceName(String qname) {
	final int col = qname.lastIndexOf(':');
	return (col > -1 && qname.charAt(qname.length()-1) == '*');
    }
}