Glassfish example source code file (InsnConstOp.java)

This example Glassfish source code file (InsnConstOp.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

constbasic, constbasicmemberref, constfieldref, constfieldref, constinterfacemethodref, constmethodref, constvalue, insnconstop, insnerror, insnerror, io, noi18n, noi18n, string, string

The Glassfish InsnConstOp.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.jdo.api.persistence.enhancer.classfile;


import java.io.PrintStream;

/**
 * An instruction which requires a single constant from the constant
 * pool as an immediate operand 
 */

public class InsnConstOp extends Insn {
  /* The constant from the constant pool */
  private ConstBasic constValue;

  /* public accessors */

  public int nStackArgs() {
    int n = VMOp.ops[opcode()].nStackArgs();
    if (n >= 0) 
      return n;
    switch (opcode()) {
    case opc_putstatic:
    case opc_putfield:
      {
	ConstFieldRef fld = (ConstFieldRef) constValue;
	String sig = fld.nameAndType().signature().asString();
	if (sig.equals("J") || sig.equals("D"))//NOI18N
	  return (opcode() == opc_putfield) ? 3 : 2;
	return (opcode() == opc_putfield) ? 2 : 1;
      }
    case opc_invokevirtual:
    case opc_invokespecial:
    case opc_invokestatic:
      /* handle interface invoke too */
    case opc_invokeinterface:
      {
	ConstBasicMemberRef meth = (ConstBasicMemberRef) constValue;
	String sig = meth.nameAndType().signature().asString();
	int nMethodArgWords = Descriptor.countMethodArgWords(sig);
	return nMethodArgWords +
	  ((opcode() == opc_invokestatic) ? 0 : 1);
      }
    default:
        throw new InsnError("unexpected variable opcode");//NOI18N
    }
  }

  public int nStackResults() {
    int n = VMOp.ops[opcode()].nStackResults();
    if (n >= 0) 
      return n;
    switch (opcode()) {
    case opc_getstatic:
    case opc_getfield:
      {
	ConstFieldRef fld = (ConstFieldRef) constValue;
	String sig = fld.nameAndType().signature().asString();
	if (sig.equals("J") || sig.equals("D"))//NOI18N
	  return 2;
	return 1;
      }
    case opc_invokevirtual:
    case opc_invokespecial:
    case opc_invokestatic:
      /* handle interface invoke too */
    case opc_invokeinterface:
      {
	ConstBasicMemberRef meth = (ConstBasicMemberRef) constValue;
	return Descriptor.countMethodReturnWords(
	  meth.nameAndType().signature().asString());
      }
    default:
        throw new InsnError("unexpected variable opcode");//NOI18N
    }
  }

  public String argTypes() {
    switch (opcode()) {
    case opc_putstatic:
    case opc_putfield:
      {
	ConstFieldRef fld = (ConstFieldRef) constValue;
	String sig = fld.nameAndType().signature().asString();
	if (opcode() == opc_putstatic)
	  return sig;
	else
	  return descriptorTypeOfObject(fld) + sig;
      }
    case opc_invokevirtual:
    case opc_invokespecial:
    case opc_invokestatic:
      /* handle interface invoke too */
    case opc_invokeinterface:
      {
	ConstBasicMemberRef meth = (ConstBasicMemberRef) constValue;
	String argSig =
	  Descriptor.extractArgSig(meth.nameAndType().signature().asString());
	if (opcode() == opc_invokestatic)
	  return argSig;
	else
	  return descriptorTypeOfObject(meth) + argSig;
      }
    default:
      return VMOp.ops[opcode()].argTypes();
    }
  }

  public String resultTypes() {
    switch (opcode()) {
    case opc_invokevirtual:
    case opc_invokespecial:
    case opc_invokestatic:
      /* handle interface invoke too */
    case opc_invokeinterface:
      {
	ConstBasicMemberRef meth = (ConstBasicMemberRef) constValue;
	String resultSig = Descriptor.extractResultSig(
	  meth.nameAndType().signature().asString());
	if (resultSig.equals("V"))//NOI18N
            return "";//NOI18N
	return resultSig;
      }
    case opc_getstatic:
    case opc_getfield:
      {
	ConstFieldRef fld = (ConstFieldRef) constValue;
	return fld.nameAndType().signature().asString();
      }
    case opc_ldc:
    case opc_ldc_w:
    case opc_ldc2_w:
      {
	ConstValue constVal = (ConstValue) constValue;
	return constVal.descriptor();
      }
    default:
      return VMOp.ops[opcode()].resultTypes();
    }
  }

  public boolean branches() {
    /* invokes don't count as a branch */
    return false;
  }

  /**
   * Return the constant pool entry which is the immediate operand
   */
  public ConstBasic value() {
    return constValue;
  }
    
  /**
   * Modify the referenced constant
   */
  public void setValue(ConstBasic newValue) {
    checkConstant(newValue);
    constValue = newValue;
  }
    
  /* package local methods */

  void print (PrintStream out, int indent) {
    ClassPrint.spaces(out, indent);
    out.println(offset() + "  " + opName(opcode()) + "  pool(" + //NOI18N
		constValue.getIndex() + ")");//NOI18N
  }

  int store(byte[] buf, int index) {
    if (opcode() == opc_ldc && !isNarrowldc())
      buf[index++] = (byte) opc_ldc_w;
    else
      buf[index++] = (byte) opcode();
    int constIndex = constValue.getIndex();
    if (size() == 3)
      buf[index++] = (byte) (constIndex >> 8);
    buf[index++] = (byte)(constIndex & 0xff);
    return index;
  }

  int size() {
    return isNarrowldc() ? 2 : 3;
  }

  private boolean isNarrowldc() {
    return (opcode() == opc_ldc && constValue.getIndex() < 256);
  }
    

  InsnConstOp (int theOpcode, ConstBasic theOperand) {
    this(theOpcode, theOperand, NO_OFFSET);
  }

  InsnConstOp (int theOpcode, ConstBasic theOperand, int pc) {
    super(theOpcode, pc);
    constValue = theOperand;
    checkConstant(theOperand);
    if (theOpcode == opc_invokeinterface) 
        throw new InsnError("attempt to create an " + opName(theOpcode) +//NOI18N
                            " as an InsnConstOp instead of InsnInterfaceInvoke");//NOI18N
  }

  /* used only by InsnInterfaceInvoke, to make sure that opc_invokeinterface cannot
   * come through the wrong path and miss its extra nArgsOp */
  InsnConstOp (int theOpcode, ConstInterfaceMethodRef theOperand, int pc) {
    super(theOpcode, pc);
    constValue = theOperand;
    checkConstant(theOperand);
  }

  private void checkConstant (ConstBasic operand) {
    switch(opcode()) {
    case opc_ldc:
    case opc_ldc_w:
    case opc_ldc2_w:
      /* ConstValue */
      if (operand == null ||
	  (! (operand instanceof ConstValue)))
          throw new InsnError ("attempt to create an " + opName(opcode()) +//NOI18N
                               " without a ConstValue operand");//NOI18N
      break;

    case opc_getstatic:
    case opc_putstatic:
    case opc_getfield:
    case opc_putfield:
      /* ConstFieldRef */
      if (operand == null ||
	  (! (operand instanceof ConstFieldRef)))
          throw new InsnError ("attempt to create an " + opName(opcode()) +//NOI18N
                               " without a ConstFieldRef operand");//NOI18N
      break;

    case opc_invokevirtual:
    case opc_invokespecial:
    case opc_invokestatic:
      /* ConstMethodRef */
      if (operand == null ||
	  (! (operand instanceof ConstMethodRef)))
          throw new InsnError ("attempt to create an " + opName(opcode()) +//NOI18N
                               " without a ConstMethodRef operand");//NOI18N
      break;
      
    case opc_invokeinterface:
      /* ConstInterfaceMethodRef */
      if (operand == null ||
	  (! (operand instanceof ConstInterfaceMethodRef)))
          throw new InsnError("Attempt to create an " + opName(opcode()) +//NOI18N
                              " without a ConstInterfaceMethodRef operand");//NOI18N
      break;

    case opc_new:
    case opc_anewarray:
    case opc_checkcast:
    case opc_instanceof:
      /* ConstClass */
      if (operand == null ||
	  (! (operand instanceof ConstClass)))
          throw new InsnError ("attempt to create an " + opName(opcode()) +//NOI18N
                               " without a ConstClass operand");//NOI18N
      break;

    default:
        throw new InsnError ("attempt to create an " + opName(opcode()) +//NOI18N
                             " with a constant operand");//NOI18N
    }
  }

  private final String descriptorTypeOfObject(ConstBasicMemberRef memRef) {
    String cname = memRef.className().className().asString();
    return "L" + cname + ";";//NOI18N
  }

}