constantnameandtype.java

代码是一个分类器的实现,其中使用了部分weka的源代码。可以将项目导入eclipse运行

package de.fub.bytecode.classfile;

import  de.fub.bytecode.Constants;
import  java.io.*;

/** 
 * This class is derived from the abstract 
 * <A HREF="de.fub.bytecode.classfile.Constant.html">Constant</A> class 
 * and represents a reference to the name and signature
 * of a field or method.
 *
 * @version $Id: ConstantNameAndType.java,v 1.4 2001/08/08 14:01:11 dahm Exp $
 * @author  <A HREF="http://www.berlin.de/~markus.dahm/">M. Dahm</A>
 * @see     Constant
 */
public final class ConstantNameAndType extends Constant {
  private int name_index;      // Name of field/method
  private int signature_index; // and its signature.

  /**
   * Initialize from another object.
   */
  public ConstantNameAndType(ConstantNameAndType c) {
    this(c.getNameIndex(), c.getSignatureIndex());
  }
 
  /**
   * Initialize instance from file data.
   *
   * @param file Input stream
   * @throw IOException
   */
  ConstantNameAndType(DataInputStream file) throws IOException
  {    
    this((int)file.readUnsignedShort(), (int)file.readUnsignedShort());
  }

  /**
   * @param name_index Name of field/method
   * @param signature_index and its signature
   */
  public ConstantNameAndType(int name_index,
			     int signature_index)
  {
    super(Constants.CONSTANT_NameAndType);
    this.name_index      = name_index;
    this.signature_index = signature_index;
  }

  /**
   * Called by objects that are traversing the nodes of the tree implicitely
   * defined by the contents of a Java class. I.e., the hierarchy of methods,
   * fields, attributes, etc. spawns a tree of objects.
   *
   * @param v Visitor object
   */
  public void accept(Visitor v) {
    v.visitConstantNameAndType(this);
  }

  /**
   * Dump name and signature index to file stream in binary format.
   *
   * @param file Output file stream
   * @throw IOException
   */ 
  public final void dump(DataOutputStream file) throws IOException
  {
    file.writeByte(tag);
    file.writeShort(name_index);
    file.writeShort(signature_index);
  }

  /**
   * @return Name index in constant pool of field/method name.
   */  
  public final int getNameIndex()      { return name_index; }

  /** @return name
   */
  public final String getName(ConstantPool cp) {
    return cp.constantToString(getNameIndex(), Constants.CONSTANT_Utf8);
  }

  /**
   * @return Index in constant pool of field/method signature.
   */  
  public final int getSignatureIndex() { return signature_index; }

  /** @return signature
   */
  public final String getSignature(ConstantPool cp) {
    return cp.constantToString(getSignatureIndex(), Constants.CONSTANT_Utf8);
  }

  /**
   * @param name_index.
   */
  public final void setNameIndex(int name_index) {
    this.name_index = name_index;
  }

  /**
   * @param signature_index.
   */
  public final void setSignatureIndex(int signature_index) {
    this.signature_index = signature_index;
  }

  /**
   * @return String representation
   */
  public final String toString() {
    return super.toString() + "(name_index = " + name_index + 
      ", signature_index = " + signature_index + ")";
  }    
}