/* Class method reads one attribute from the input data stream.
* This method must not be accessible from the outside. It is
* called by the Field and Method constructor methods.
*
* @see Field
* @see Method
* @param file Input stream
* @param constant_pool Array of constants
* @return Attribute
* @throws IOException
* @throws ClassFormatException
*/
public static final Attribute readAttribute(DataInputStream file, ConstantPool constant_pool)
throws IOException, ClassFormatException {
ConstantUtf8 c;
String name;
int name_index;
int length;
byte tag = Constants.ATTR_UNKNOWN; // Unknown attribute
// Get class name from constant pool via `name_index' indirection
name_index = (int) file.readUnsignedShort();
c = (ConstantUtf8) constant_pool.getConstant(name_index, Constants.CONSTANT_Utf8);
name = c.getBytes();
// Length of data in bytes
length = file.readInt();
// Compare strings to find known attribute
for (byte i = 0; i < Constants.KNOWN_ATTRIBUTES; i++) {
if (name.equals(Constants.ATTRIBUTE_NAMES[i])) {
tag = i; // found!
break;
}
}
// Call proper constructor, depending on `tag'
switch (tag) {
case Constants.ATTR_UNKNOWN:
AttributeReader r = (AttributeReader) readers.get(name);
if (r != null) return r.createAttribute(name_index, length, file, constant_pool);
else return new Unknown(name_index, length, file, constant_pool);
case Constants.ATTR_CONSTANT_VALUE:
return new ConstantValue(name_index, length, file, constant_pool);
case Constants.ATTR_SOURCE_FILE:
return new SourceFile(name_index, length, file, constant_pool);
case Constants.ATTR_CODE:
return new Code(name_index, length, file, constant_pool);
case Constants.ATTR_EXCEPTIONS:
return new ExceptionTable(name_index, length, file, constant_pool);
case Constants.ATTR_LINE_NUMBER_TABLE:
return new LineNumberTable(name_index, length, file, constant_pool);
case Constants.ATTR_LOCAL_VARIABLE_TABLE:
return new LocalVariableTable(name_index, length, file, constant_pool);
case Constants.ATTR_INNER_CLASSES:
return new InnerClasses(name_index, length, file, constant_pool);
case Constants.ATTR_SYNTHETIC:
return new Synthetic(name_index, length, file, constant_pool);
case Constants.ATTR_DEPRECATED:
return new Deprecated(name_index, length, file, constant_pool);
case Constants.ATTR_PMG:
return new PMGClass(name_index, length, file, constant_pool);
case Constants.ATTR_SIGNATURE:
return new Signature(name_index, length, file, constant_pool);
case Constants.ATTR_STACK_MAP:
return new StackMap(name_index, length, file, constant_pool);
default: // Never reached
throw new IllegalStateException("Ooops! default case reached.");
}
}
public String getName() {
ConstantUtf8 c = (ConstantUtf8) constant_pool.getConstant(name_index, Constants.CONSTANT_Utf8);
return c.getBytes();
}
/** @return Signature. */
public final String getSignature() {
ConstantUtf8 c;
c = (ConstantUtf8) constant_pool.getConstant(signature_index, CONSTANT_Utf8);
return c.getBytes();
}
/** Initialize from another object. */
public ConstantUtf8(ConstantUtf8 c) {
this(c.getBytes());
}