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LineNumberTable.javaAPI DocJava SE 6 API7998Tue Jun 10 00:22:18 BST 2008com.sun.org.apache.bcel.internal.classfile

LineNumberTable

public final class LineNumberTable extends Attribute
This class represents a table of line numbers for debugging purposes. This attribute is used by the Code attribute. It contains pairs of PCs and line numbers.
version
$Id: LineNumberTable.java,v 1.1.2.1 2005/07/31 23:46:20 jeffsuttor Exp $
author
M. Dahm
see
Code
see
LineNumber

Fields Summary
private int
line_number_table_length
private LineNumber[]
line_number_table
Constructors Summary
public LineNumberTable(LineNumberTable c)

    this(c.getNameIndex(), c.getLength(), c.getLineNumberTable(),
	 c.getConstantPool());
  
public LineNumberTable(int name_index, int length, LineNumber[] line_number_table, ConstantPool constant_pool)

    super(Constants.ATTR_LINE_NUMBER_TABLE, name_index, length, constant_pool);
    setLineNumberTable(line_number_table);
  
LineNumberTable(int name_index, int length, DataInputStream file, ConstantPool constant_pool)
Construct object from file stream.

param
name_index Index of name
param
length Content length in bytes
param
file Input stream
throws
IOException
param
constant_pool Array of constants

    this(name_index, length, (LineNumber[])null, constant_pool);
    line_number_table_length = (file.readUnsignedShort());
    line_number_table = new LineNumber[line_number_table_length];

    for(int i=0; i < line_number_table_length; i++)
      line_number_table[i] = new LineNumber(file);
  
Methods Summary
public voidaccept(com.sun.org.apache.bcel.internal.classfile.Visitor v)
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

    v.visitLineNumberTable(this);
  
public com.sun.org.apache.bcel.internal.classfile.Attributecopy(com.sun.org.apache.bcel.internal.classfile.ConstantPool constant_pool)

return
deep copy of this attribute

    LineNumberTable c = (LineNumberTable)clone();

    c.line_number_table = new LineNumber[line_number_table_length];
    for(int i=0; i < line_number_table_length; i++)
      c.line_number_table[i] = line_number_table[i].copy();

    c.constant_pool = constant_pool;
    return c;
  
public final voiddump(java.io.DataOutputStream file)
Dump line number table attribute to file stream in binary format.

param
file Output file stream
throws
IOException

    super.dump(file);
    file.writeShort(line_number_table_length);
    for(int i=0; i < line_number_table_length; i++)
      line_number_table[i].dump(file);
  
public final com.sun.org.apache.bcel.internal.classfile.LineNumber[]getLineNumberTable()

return
Array of (pc offset, line number) pairs.

 return line_number_table; 
public intgetSourceLine(int pos)
Map byte code positions to source code lines.

param
pos byte code offset
return
corresponding line in source code

    int l = 0, r = line_number_table_length-1;

    if(r < 0) // array is empty
      return -1;

    int min_index = -1, min=-1;
    
    /* Do a binary search since the array is ordered.
     */
    do {
      int i = (l + r) / 2;
      int j = line_number_table[i].getStartPC();

      if(j == pos)
	return line_number_table[i].getLineNumber();
      else if(pos < j) // else constrain search area
	r = i - 1;
      else // pos > j
	l = i + 1;

      /* If exact match can't be found (which is the most common case)
       * return the line number that corresponds to the greatest index less
       * than pos.
       */
      if(j < pos && j > min) {
        min       = j;
        min_index = i;
      }
    } while(l <= r);

    /* It's possible that we did not find any valid entry for the bytecode
     * offset we were looking for.
     */
    if (min_index < 0)
      return -1;

    return line_number_table[min_index].getLineNumber();
  
public final intgetTableLength()

 return line_number_table_length; 
public final voidsetLineNumberTable(com.sun.org.apache.bcel.internal.classfile.LineNumber[] line_number_table)

param
line_number_table.

    this.line_number_table = line_number_table;

    line_number_table_length = (line_number_table == null)? 0 :
      line_number_table.length;
  
public final java.lang.StringtoString()

return
String representation.

    StringBuffer buf  = new StringBuffer();
    StringBuffer line = new StringBuffer();

    for(int i=0; i < line_number_table_length; i++) {
      line.append(line_number_table[i].toString());

      if(i < line_number_table_length - 1)
	line.append(", ");

      if(line.length() > 72) {
	line.append('\n");
	buf.append(line);
	line.setLength(0);
      }
    }

    buf.append(line);

    return buf.toString();