Package org.apache.xalan.xsltc.compiler.util

Source Code of org.apache.xalan.xsltc.compiler.util.ResultTreeType

/*
* 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.
*/
/*
* $Id: ResultTreeType.java 468649 2006-10-28 07:00:55Z minchau $
*/

package org.apache.xalan.xsltc.compiler.util;

import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.CHECKCAST;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GETFIELD;
import org.apache.bcel.generic.IFEQ;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKESPECIAL;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.NEW;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.Constants;
import org.apache.xalan.xsltc.compiler.FlowList;

/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
* @author Morten Jorgensen
*/
public final class ResultTreeType extends Type {
    private final String _methodName;

    protected ResultTreeType() {
  _methodName = null;
    }

    public ResultTreeType(String methodName) {
  _methodName = methodName;
    }

    public String toString() {
  return "result-tree";
    }

    public boolean identicalTo(Type other) {
  return (other instanceof ResultTreeType);
    }

    public String toSignature() {
  return DOM_INTF_SIG;
    }

    public org.apache.bcel.generic.Type toJCType() {
  return Util.getJCRefType(toSignature());
    }

    public String getMethodName() {
  return _methodName;
    }

    public boolean implementedAsMethod() {
  return _methodName != null;
    }

    /**
     * Translates a result tree to object of internal type <code>type</code>.
     * The translation to int is undefined since result trees
     * are always converted to reals in arithmetic expressions.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of the type to translate the result tree to
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          Type type) {
  if (type == Type.String) {
      translateTo(classGen, methodGen, (StringType)type);
  }
  else if (type == Type.Boolean) {
      translateTo(classGen, methodGen, (BooleanType)type);
  }
  else if (type == Type.Real) {
      translateTo(classGen, methodGen, (RealType)type);
  }
  else if (type == Type.NodeSet) {
      translateTo(classGen, methodGen, (NodeSetType)type);
  }
  else if (type == Type.Reference) {
      translateTo(classGen, methodGen, (ReferenceType)type);
  }
  else if (type == Type.Object) {
      translateTo(classGen, methodGen, (ObjectType) type);
  }
  else {
      ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
          toString(), type.toString());
      classGen.getParser().reportError(Constants.FATAL, err);
  }
    }

    /**
     * Expects an result tree on the stack and pushes a boolean.
     * Translates a result tree to a boolean by first converting it to string.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of BooleanType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          BooleanType type) {
  // A result tree is always 'true' when converted to a boolean value,
  // since the tree always has at least one node (the root).
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();
  il.append(POP);      // don't need the DOM reference
  il.append(ICONST_1); // push 'true' on the stack
    }

    /**
     * Expects an result tree on the stack and pushes a string.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of StringType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          StringType type) {
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();
 
  if (_methodName == null) {
      int index = cpg.addInterfaceMethodref(DOM_INTF,
              "getStringValue",
              "()"+STRING_SIG);
      il.append(new INVOKEINTERFACE(index, 1));
  }
  else {
      final String className = classGen.getClassName();
      final int current = methodGen.getLocalIndex("current");
     
      // Push required parameters
      il.append(classGen.loadTranslet());
      if (classGen.isExternal()) {
    il.append(new CHECKCAST(cpg.addClass(className)));
      }
      il.append(DUP);
      il.append(new GETFIELD(cpg.addFieldref(className, "_dom",
               DOM_INTF_SIG)));

      // Create a new instance of a StringValueHandler
      int index = cpg.addMethodref(STRING_VALUE_HANDLER, "<init>", "()V");
      il.append(new NEW(cpg.addClass(STRING_VALUE_HANDLER)));
      il.append(DUP);
      il.append(DUP);
      il.append(new INVOKESPECIAL(index));
     
      // Store new Handler into a local variable
      final LocalVariableGen handler =
    methodGen.addLocalVariable("rt_to_string_handler",
             Util.getJCRefType(STRING_VALUE_HANDLER_SIG),
             null, null);
      handler.setStart(il.append(new ASTORE(handler.getIndex())));

      // Call the method that implements this result tree
      index = cpg.addMethodref(className, _methodName,
             "("+DOM_INTF_SIG+TRANSLET_OUTPUT_SIG+")V");
      il.append(new INVOKEVIRTUAL(index));
     
      // Restore new handler and call getValue()
      handler.setEnd(il.append(new ALOAD(handler.getIndex())));
      index = cpg.addMethodref(STRING_VALUE_HANDLER,
             "getValue",
             "()" + STRING_SIG);
      il.append(new INVOKEVIRTUAL(index));
  }
    }

    /**
     * Expects an result tree on the stack and pushes a real.
     * Translates a result tree into a real by first converting it to string.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of RealType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          RealType type) {
  translateTo(classGen, methodGen, Type.String);
  Type.String.translateTo(classGen, methodGen, Type.Real)
    }

    /**
     * Expects a result tree on the stack and pushes a boxed result tree.
     * Result trees are already boxed so the translation is just a NOP.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of ReferenceType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          ReferenceType type) {
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();

  if (_methodName == null) {
      il.append(NOP);
  }
  else {
      LocalVariableGen domBuilder, newDom;
      final String className = classGen.getClassName();
      final int current = methodGen.getLocalIndex("current");

      // Push required parameters
      il.append(classGen.loadTranslet());
      if (classGen.isExternal()) {
    il.append(new CHECKCAST(cpg.addClass(className)));
      }
      il.append(methodGen.loadDOM());

      // Create new instance of DOM class (with RTF_INITIAL_SIZE nodes)
      il.append(methodGen.loadDOM());
      int index = cpg.addInterfaceMethodref(DOM_INTF,
         "getResultTreeFrag",
         "(IZ)" + DOM_INTF_SIG);
      il.append(new PUSH(cpg, RTF_INITIAL_SIZE));
      il.append(new PUSH(cpg, false));
      il.append(new INVOKEINTERFACE(index,3));
      il.append(DUP);
     
      // Store new DOM into a local variable
      newDom = methodGen.addLocalVariable("rt_to_reference_dom",
            Util.getJCRefType(DOM_INTF_SIG),
            null, null);
      il.append(new CHECKCAST(cpg.addClass(DOM_INTF_SIG)));
      newDom.setStart(il.append(new ASTORE(newDom.getIndex())));

      // Overwrite old handler with DOM handler
      index = cpg.addInterfaceMethodref(DOM_INTF,
         "getOutputDomBuilder",
         "()" + TRANSLET_OUTPUT_SIG);

      il.append(new INVOKEINTERFACE(index,1));
      //index = cpg.addMethodref(DOM_IMPL,
    //         "getOutputDomBuilder",
    //         "()" + TRANSLET_OUTPUT_SIG);
      //il.append(new INVOKEVIRTUAL(index));
      il.append(DUP);
      il.append(DUP);

      // Store DOM handler in a local in order to call endDocument()
      domBuilder =
    methodGen.addLocalVariable("rt_to_reference_handler",
             Util.getJCRefType(TRANSLET_OUTPUT_SIG),
             null, null);
      domBuilder.setStart(il.append(new ASTORE(domBuilder.getIndex())));

      // Call startDocument on the new handler
      index = cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE,
                "startDocument", "()V");
      il.append(new INVOKEINTERFACE(index, 1));

      // Call the method that implements this result tree
      index = cpg.addMethodref(className,
             _methodName,
             "("
             + DOM_INTF_SIG
             + TRANSLET_OUTPUT_SIG
             +")V");
      il.append(new INVOKEVIRTUAL(index));

      // Call endDocument on the DOM handler
      domBuilder.setEnd(il.append(new ALOAD(domBuilder.getIndex())));
      index = cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE,
                "endDocument", "()V");
      il.append(new INVOKEINTERFACE(index, 1));

      // Push the new DOM on the stack
      newDom.setEnd(il.append(new ALOAD(newDom.getIndex())));
  }
    }

    /**
     * Expects a result tree on the stack and pushes a node-set (iterator).
     * Note that the produced iterator is an iterator for the DOM that
     * contains the result tree, and not the DOM that is currently in use.
     * This conversion here will therefore not directly work with elements
     * such as <xsl:apply-templates> and <xsl:for-each> without the DOM
     * parameter/variable being updates as well.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of NodeSetType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          NodeSetType type) {
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();

  // Put an extra copy of the result tree (DOM) on the stack
  il.append(DUP);

  // DOM adapters containing a result tree are not initialised with
  // translet-type to DOM-type mapping. This must be done now for
  // XPath expressions and patterns to work for the iterator we create.
  il.append(classGen.loadTranslet()); // get names array
  il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                 NAMES_INDEX,
                 NAMES_INDEX_SIG)));
  il.append(classGen.loadTranslet()); // get uris array
  il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                 URIS_INDEX,
                 URIS_INDEX_SIG)));
  il.append(classGen.loadTranslet()); // get types array
  il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                 TYPES_INDEX,
                 TYPES_INDEX_SIG)));
  il.append(classGen.loadTranslet()); // get namespaces array
  il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                 NAMESPACE_INDEX,
                 NAMESPACE_INDEX_SIG)));
  // Pass the type mappings to the DOM adapter
  final int mapping = cpg.addInterfaceMethodref(DOM_INTF,
                  "setupMapping",
                  "(["+STRING_SIG+
                  "["+STRING_SIG+
                  "[I" +
                  "["+STRING_SIG+")V");
  il.append(new INVOKEINTERFACE(mapping, 5));
  il.append(DUP);

  // Create an iterator for the root node of the DOM adapter
  final int iter = cpg.addInterfaceMethodref(DOM_INTF,
               "getIterator",
               "()"+NODE_ITERATOR_SIG);
  il.append(new INVOKEINTERFACE(iter, 1))
    }

    /**
     * Subsume result tree into ObjectType.
     *
     * @see  org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          ObjectType type) {
  methodGen.getInstructionList().append(NOP)
    }

    /**
     * Translates a result tree into a non-synthesized boolean.
     * It does not push a 0 or a 1 but instead returns branchhandle list
     * to be appended to the false list.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param type An instance of BooleanType (any)
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateToDesynthesized
     */
    public FlowList translateToDesynthesized(ClassGenerator classGen,
               MethodGenerator methodGen,
               BooleanType type) {
  final InstructionList il = methodGen.getInstructionList();
  translateTo(classGen, methodGen, Type.Boolean);
  return new FlowList(il.append(new IFEQ(null)));
    }

    /**
     * Translates a result tree to a Java type denoted by <code>clazz</code>.
     * Expects a result tree on the stack and pushes an object
     * of the appropriate type after coercion. Result trees are translated
     * to W3C Node or W3C NodeList and the translation is done
     * via node-set type.
     *
     * @param classGen A BCEL class generator
     * @param methodGen A BCEL method generator
     * @param clazz An reference to the Class to translate to
     * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
          Class clazz) {
  final String className = clazz.getName();
  final ConstantPoolGen cpg = classGen.getConstantPool();
  final InstructionList il = methodGen.getInstructionList();

  if (className.equals("org.w3c.dom.Node")) {
      translateTo(classGen, methodGen, Type.NodeSet);
      int index = cpg.addInterfaceMethodref(DOM_INTF,
              MAKE_NODE,
              MAKE_NODE_SIG2);
      il.append(new INVOKEINTERFACE(index, 2));
  }
  else if (className.equals("org.w3c.dom.NodeList")) {
      translateTo(classGen, methodGen, Type.NodeSet);
      int index = cpg.addInterfaceMethodref(DOM_INTF,
              MAKE_NODE_LIST,
              MAKE_NODE_LIST_SIG2);
      il.append(new INVOKEINTERFACE(index, 2));
  }
  else if (className.equals("java.lang.Object")) {
      il.append(NOP);
  }
        else if (className.equals("java.lang.String")) {
            translateTo(classGen, methodGen, Type.String);
        }
  else {
      ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
          toString(), className);
      classGen.getParser().reportError(Constants.FATAL, err);
  }
    }

    /**
     * Translates an object of this type to its boxed representation.
     */
    public void translateBox(ClassGenerator classGen,
           MethodGenerator methodGen) {
  translateTo(classGen, methodGen, Type.Reference);
    }

    /**
     * Translates an object of this type to its unboxed representation.
     */
    public void translateUnBox(ClassGenerator classGen,
             MethodGenerator methodGen) {
  methodGen.getInstructionList().append(NOP);
    }

    /**
     * Returns the class name of an internal type's external representation.
     */
    public String getClassName() {
  return(DOM_INTF);
    }

    public Instruction LOAD(int slot) {
  return new ALOAD(slot);
    }
 
    public Instruction STORE(int slot) {
  return new ASTORE(slot);
    }
}
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