AbsolutePathPattern.java :  » XML » xalan » org » apache » xalan » xsltc » compiler » Java Open Source

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/*
 * 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: AbsolutePathPattern.java,v 1.10 2004/02/16 22:24:29 minchau Exp $
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.bcel.generic.BranchHandle;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GOTO_W;
import org.apache.bcel.generic.IF_ICMPEQ;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.ISTORE;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;
import org.apache.xml.dtm.DTM;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
final class AbsolutePathPattern extends LocationPathPattern {
    private final RelativePathPattern _left; // may be null

    public AbsolutePathPattern(RelativePathPattern left) {
  _left = left;
  if (left != null) {
      left.setParent(this);
  }
    }

    public void setParser(Parser parser) {
  super.setParser(parser);
  if (_left != null)
      _left.setParser(parser);
    }
    
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  return _left == null ? Type.Root : _left.typeCheck(stable);
    }

    public boolean isWildcard() {
  return false;
    }
  
    public StepPattern getKernelPattern() {
  return _left != null ? _left.getKernelPattern() : null;
    }
  
    public void reduceKernelPattern() {
  _left.reduceKernelPattern();
    }
  
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();

  if (_left != null) {
      if (_left instanceof StepPattern) {
    final LocalVariableGen local = 
        // absolute path pattern temporary
        methodGen.addLocalVariable2("apptmp", 
            Util.getJCRefType(NODE_SIG),
            il.getEnd());
    il.append(DUP);
    il.append(new ISTORE(local.getIndex()));
    _left.translate(classGen, methodGen);
    il.append(methodGen.loadDOM());
    local.setEnd(il.append(new ILOAD(local.getIndex())));
    methodGen.removeLocalVariable(local);
      }
      else {
    _left.translate(classGen, methodGen);
      }
  }

  final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
              GET_PARENT,
              GET_PARENT_SIG);
  final int getType = cpg.addInterfaceMethodref(DOM_INTF,
                  "getExpandedTypeID",
                                                      "(I)I");

  InstructionHandle begin = il.append(methodGen.loadDOM());
  il.append(SWAP);
  il.append(new INVOKEINTERFACE(getParent, 2));
  if (_left instanceof AncestorPattern) {  
      il.append(methodGen.loadDOM());
      il.append(SWAP);
  }
  il.append(new INVOKEINTERFACE(getType, 2));
  il.append(new PUSH(cpg, DTM.DOCUMENT_NODE));
  
  final BranchHandle skip = il.append(new IF_ICMPEQ(null));
  _falseList.add(il.append(new GOTO_W(null)));
  skip.setTarget(il.append(NOP));

  if (_left != null) {
      _left.backPatchTrueList(begin);
      
      /*
       * If _left is an ancestor pattern, backpatch this pattern's false
       * list to the loop that searches for more ancestors.
       */
      if (_left instanceof AncestorPattern) {
    final AncestorPattern ancestor = (AncestorPattern) _left;
    _falseList.backPatch(ancestor.getLoopHandle());    // clears list
      }
      _falseList.append(_left._falseList);
  }
    }
  
    public String toString() {
  return "absolutePathPattern(" + (_left != null ? _left.toString() : ")");
    }
}
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