fieldinstruction.java

该开源工具主要用于class文件的操作

package org.apache.bcel.generic;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import org.apache.bcel.classfile.ConstantPool;
import org.apache.bcel.classfile.ConstantUtf8;
import org.apache.bcel.classfile.ConstantNameAndType;
import org.apache.bcel.classfile.ConstantCP;
import org.apache.bcel.classfile.*;

/**
 * Super class for the GET/PUTxxx family of instructions.
 *
 * @version $Id: FieldInstruction.java,v 1.1.1.1 2001/10/29 20:00:12 jvanzyl Exp $
 * @author  <A HREF="mailto:[e-mail]">M. Dahm</A>
 */
public abstract class FieldInstruction extends FieldOrMethod
  implements TypedInstruction {
  /**
   * Empty constructor needed for the Class.newInstance() statement in
   * Instruction.readInstruction(). Not to be used otherwise.
   */
  FieldInstruction() {}

  /**
   * @param index to constant pool
   */
  protected FieldInstruction(short opcode, int index) {
    super(opcode, index);
  }

  /**
   * @return mnemonic for instruction with symbolic references resolved
   */
  public String toString(ConstantPool cp) {
    return org.apache.bcel.Constants.OPCODE_NAMES[opcode] + " " +
      cp.constantToString(index, org.apache.bcel.Constants.CONSTANT_Fieldref);
  }
  
  /** @return size of field (1 or 2)
   */
  protected int getFieldSize(ConstantPoolGen cpg) {
    return getType(cpg).getSize();
  }

  /** @return return type of referenced field
   */
  public Type getType(ConstantPoolGen cpg) {
    return getFieldType(cpg);
  }

  /** @return type of field
   */
  public Type getFieldType(ConstantPoolGen cpg) {
    return Type.getType(getSignature(cpg));
  }

  /** @return name of referenced field.
   */
  public String getFieldName(ConstantPoolGen cpg) {
    return getName(cpg);
  }
}