How to use

readConstant

method

in

org.apache.bcel.classfile.Constant

/**
 * Read constants from given input stream.
 *
 * @param input Input stream
 * @throws IOException
 * @throws ClassFormatException
 */
public ConstantPool(final DataInput input) throws IOException, ClassFormatException {
  byte tag;
  final int constant_pool_count = input.readUnsignedShort();
  constant_pool = new Constant[constant_pool_count];
  /* constant_pool[0] is unused by the compiler and may be used freely
   * by the implementation.
   */
  for (int i = 1; i < constant_pool_count; i++) {
    constant_pool[i] = Constant.readConstant(input);
    /* Quote from the JVM specification:
     * "All eight byte constants take up two spots in the constant pool.
     * If this is the n'th byte in the constant pool, then the next item
     * will be numbered n+2"
     *
     * Thus we have to increment the index counter.
     */
    tag = constant_pool[i].getTag();
    if ((tag == Const.CONSTANT_Double) || (tag == Const.CONSTANT_Long)) {
      i++;
    }
  }
}

/**
 * Read constants from given file stream.
 *
 * @param file Input stream
 * @throws IOException
 * @throws ClassFormatException
 */
ConstantPool(DataInputStream file) throws IOException, ClassFormatException
{
 byte tag;
 constant_pool_count = file.readUnsignedShort();
 constant_pool       = new Constant[constant_pool_count];
 /* constant_pool[0] is unused by the compiler and may be used freely
  * by the implementation.
  */
 for(int i=1; i < constant_pool_count; i++) {
  constant_pool[i] = Constant.readConstant(file);
  
  /* Quote from the JVM specification:
   * "All eight byte constants take up two spots in the constant pool.
   * If this is the n'th byte in the constant pool, then the next item
   * will be numbered n+2"
   * 
   * Thus we have to increment the index counter.
   */
  tag = constant_pool[i].getTag();
  if((tag == Constants.CONSTANT_Double) || (tag == Constants.CONSTANT_Long))
 i++;
 }
}