Source code: com/techtrader/modules/tools/bytecode/LineNumberTableAttribute.java

   package com.techtrader.modules.tools.bytecode;
   
   
   import java.io.DataOutput;
   import java.io.DataInput;
   import java.io.IOException;
   import java.util.List;
   import java.util.LinkedList;
   import java.util.Iterator;
  
  import com.techtrader.modules.tools.bytecode.visitor.BCVisitor;
  
  
  /**
   *  A LineNumberTableAttributs holds a table of line number to program counter
   *  mappings, so that errors can be reported with the correct line number.
   *  TODO: Allow high-level manipulation of the line numbers.
   *  
   *  @author    Abe White
   */
  public class LineNumberTableAttribute
    extends Attribute
  {
    private List _lineNumbers = new LinkedList ();
  
  
    /**
     *  Protected constructor.
     */
    public LineNumberTableAttribute (int nameIndex, BCEntity owner)
    {
      super (nameIndex, owner);
    }
  
  
    /**
     *  Get the line numbers held in this table.
     */
    public LineNumber[] getLineNumbers ()
    {
      return (LineNumber[]) _lineNumbers.toArray 
        (new LineNumber[_lineNumbers.size ()]);
    }
  
  
    /**
     *  Import a line number from another method.
     */
    public LineNumber importLineNumber (LineNumber ln)
    {
      if (ln == null)
        throw new NullPointerException ();
  
      LineNumber newLine = addLineNumber ();
      newLine.setStartPc (ln.getStartPc ());
      newLine.setLineNumber (ln.getLineNumber ());
  
      return newLine;
    }
  
  
    /**
     *  Import all line numbers from another method.
     */
    public void importLineNumbers (LineNumberTableAttribute lns)
    {
      LineNumber[] ln = lns.getLineNumbers ();
      for (int i = 0; i < ln.length; i++)
        importLineNumber (ln[i]);
    }
  
  
    /**
     *  Add a new line number to this table.
     *
     *  @return    the index into the list at which the line number was added
     */
    public LineNumber addLineNumber ()
    {
      LineNumber lineNumber = new LineNumber (this);
      _lineNumbers.add (lineNumber);
  
      return lineNumber;
    }
  
  
    /**
     *  Clear the line numbers.
     */
    public void clearLineNumbers ()
    {
      _lineNumbers.clear ();
    }
  
  
    /**
     *  Remove the given LineNumber.
     */
    public boolean removeLineNumber (LineNumber ln)
   {
     if (ln == null || !_lineNumbers.remove (ln))
       return false;
     
     ln.invalidate ();
     return true;
   }  
 
 
   public int getLength ()
   {
     return 2 + 4 * _lineNumbers.size ();
   }
 
 
   protected void copy (Attribute other)
   {
     importLineNumbers ((LineNumberTableAttribute) other);
   }
 
 
   protected void readData (DataInput in, int length)
     throws IOException
   {
     _lineNumbers.clear ();
     int numLines = in.readUnsignedShort ();
 
     LineNumber lineNumber;
     for (int i = 0; i < numLines; i++)
     {
       lineNumber = addLineNumber ();
       lineNumber.readData (in);
     }
   }
 
 
   protected void writeData (DataOutput out, int length)
     throws IOException
   {
     out.writeShort (_lineNumbers.size ());
     for (Iterator i = _lineNumbers.iterator (); i.hasNext ();)
       ((LineNumber) i.next ()).writeData (out);
   }
 
 
   public void acceptVisit (BCVisitor visit)
   {
     visit.enterLineNumberTableAttribute (this);
 
     for (Iterator i = _lineNumbers.iterator (); i.hasNext ();)
       ((LineNumber) i.next ()).acceptVisit (visit);
 
     visit.exitLineNumberTableAttribute (this);
   }
 }