Java Code Examples for org.apache.bcel.Constants#CONSTANT_Class

/**
 * Read one constant from the given file, the type depends on a tag byte.
 *
 * @param file Input stream
 * @return Constant object
 */
static final Constant readConstant(DataInputStream file)
  throws IOException, ClassFormatException
{
  byte b = file.readByte(); // Read tag byte

  switch(b) {
  case Constants.CONSTANT_Class:              return new ConstantClass(file);
  case Constants.CONSTANT_Fieldref:           return new ConstantFieldref(file);
  case Constants.CONSTANT_Methodref:          return new ConstantMethodref(file);
  case Constants.CONSTANT_InterfaceMethodref: return new 
			ConstantInterfaceMethodref(file);
  case Constants.CONSTANT_String:             return new ConstantString(file);
  case Constants.CONSTANT_Integer:            return new ConstantInteger(file);
  case Constants.CONSTANT_Float:              return new ConstantFloat(file);
  case Constants.CONSTANT_Long:               return new ConstantLong(file);
  case Constants.CONSTANT_Double:             return new ConstantDouble(file);
  case Constants.CONSTANT_NameAndType:        return new ConstantNameAndType(file);
  case Constants.CONSTANT_Utf8:               return new ConstantUtf8(file);
  default:                          
    throw new ClassFormatException("Invalid byte tag in constant pool: " + b);
  }
}
 

public static String[] getClassDependencies(final ConstantPool pool) {
    final String[] tempArray = new String[pool.getLength()];
    int size = 0;
    final StringBuilder buf = new StringBuilder();

    for (int idx = 0; idx < pool.getLength(); idx++) {
        final Constant c = pool.getConstant(idx);
        if (c != null && c.getTag() == Constants.CONSTANT_Class) {
            final ConstantUtf8 c1 = (ConstantUtf8) pool.getConstant(((ConstantClass) c).getNameIndex());
            buf.setLength(0);
            buf.append(c1.getBytes());
            for (int n = 0; n < buf.length(); n++) {
                if (buf.charAt(n) == '/') {
                    buf.setCharAt(n, '.');
                }
            }

            tempArray[size++] = buf.toString();
        }
    }

    final String[] dependencies = new String[size];
    System.arraycopy(tempArray, 0, dependencies, 0, size);
    return dependencies;
}
 

/**
 * Get string from constant pool and bypass the indirection of 
 * `ConstantClass' and `ConstantString' objects. I.e. these classes have
 * an index field that points to another entry of the constant pool of
 * type `ConstantUtf8' which contains the real data.
 *
 * @param  index Index in constant pool
 * @param  tag Tag of expected constant, either ConstantClass or ConstantString
 * @return Contents of string reference
 * @see    ConstantClass
 * @see    ConstantString
 * @throws  ClassFormatException
 */
public String getConstantString(int index, byte tag) 
     throws ClassFormatException
{
  Constant c;
  int    i;

  c = getConstant(index, tag);

  /* This switch() is not that elegant, since the two classes have the
   * same contents, they just differ in the name of the index
   * field variable.
   * But we want to stick to the JVM naming conventions closely though
   * we could have solved these more elegantly by using the same
   * variable name or by subclassing.
   */
  switch(tag) {
  case Constants.CONSTANT_Class:  i = ((ConstantClass)c).getNameIndex();    break;
  case Constants.CONSTANT_String: i = ((ConstantString)c).getStringIndex(); break;
  default:
    throw new RuntimeException("getConstantString called with illegal tag " + tag);
  }

  // Finally get the string from the constant pool
  c = getConstant(i, Constants.CONSTANT_Utf8);
  return ((ConstantUtf8)c).getBytes();
}
 

public void visitConstantClass(ConstantClass obj){
	if (obj.getTag() != Constants.CONSTANT_Class){
		throw new ClassConstraintException("Wrong constant tag in '"+tostring(obj)+"'.");
	}
	checkIndex(obj, obj.getNameIndex(), CONST_Utf8);

}
 

/**
 * Add this class to allClasses. Then go through all its dependents
 * and add them to the dependents list if they are not in allClasses
 */
void addDependents(final JavaClass clazz) throws IOException {
    final String name = clazz.getClassName().replace('.', '/');
    allClasses.put(name, clazz);
    final ConstantPool pool = clazz.getConstantPool();
    for (int i = 1; i < pool.getLength(); i++) {
        final Constant cons = pool.getConstant(i);
        //System.out.println("("+i+") " + cons );
        if (cons != null && cons.getTag() == Constants.CONSTANT_Class) {
            final int idx = ((ConstantClass) pool.getConstant(i)).getNameIndex();
            final String clas = ((ConstantUtf8) pool.getConstant(idx)).getBytes();
            addClassString(clas, name);
        }
    }
}
 

/**
 * Resolve constant to a string representation.
 *
 * @param  constant Constant to be printed
 * @return String representation
 */
public String constantToString(Constant c)
     throws ClassFormatException  
{
  String   str;
  int      i;
  byte     tag = c.getTag();

  switch(tag) {
  case Constants.CONSTANT_Class: 
    i   = ((ConstantClass)c).getNameIndex();
    c   = getConstant(i, Constants.CONSTANT_Utf8);
    str = Utility.compactClassName(((ConstantUtf8)c).getBytes(), false);
    break;

  case Constants.CONSTANT_String:
    i   = ((ConstantString)c).getStringIndex();
    c   = getConstant(i, Constants.CONSTANT_Utf8);
    str = "\"" + escape(((ConstantUtf8)c).getBytes()) + "\"";
    break;

  case Constants.CONSTANT_Utf8:    str = ((ConstantUtf8)c).getBytes();         break;
  case Constants.CONSTANT_Double:  str = "" + ((ConstantDouble)c).getBytes();  break;
  case Constants.CONSTANT_Float:   str = "" + ((ConstantFloat)c).getBytes();   break;
  case Constants.CONSTANT_Long:    str = "" + ((ConstantLong)c).getBytes();    break;
  case Constants.CONSTANT_Integer: str = "" + ((ConstantInteger)c).getBytes(); break;

  case Constants.CONSTANT_NameAndType:
    str = (constantToString(((ConstantNameAndType)c).getNameIndex(),
	      Constants.CONSTANT_Utf8) + " " +
    constantToString(((ConstantNameAndType)c).getSignatureIndex(),
	      Constants.CONSTANT_Utf8));
    break;

  case Constants.CONSTANT_InterfaceMethodref: case Constants.CONSTANT_Methodref:
  case Constants.CONSTANT_Fieldref:
    str = (constantToString(((ConstantCP)c).getClassIndex(),
	      Constants.CONSTANT_Class) + "." + 
    constantToString(((ConstantCP)c).getNameAndTypeIndex(),
	      Constants.CONSTANT_NameAndType));	     
    break;

  default: // Never reached
    throw new RuntimeException("Unknown constant type " + tag);
  }
	
  return str;
}
 

/**
 * @param name_index Name index in constant pool.  Should refer to a
 * ConstantUtf8.
 */
public ConstantClass(int name_index) {
  super(Constants.CONSTANT_Class);
  this.name_index = name_index;
}