iaik.asn1

Class SET

java.lang.Object

iaik.asn1.ASN1Object

iaik.asn1.ConstructedType

iaik.asn1.SET

All Implemented Interfaces:

java.lang.Cloneable

public class SET
extends ConstructedType

This class implements the ASN.1 native type "SET". SET is a structured ASN.1 type identified by the UNIVERSAL TAG number 17. An ASN.1 SET object is composed of several unordered components. All the components may have the same type or may have different types.

A SET object is DER encoded using the constructed encoding practice by splitting it into separately encoded components. Therefore the SEQUENCE class is extended to be a subclass of the ConstructedType class. Each component can be added to the current SET object by using a proper addComponent method of the ConstructedType super class.

The constructed form can be recognized by bit 6 of the (first) identifier octet(s) of the DER encoded bit stream, which is set to 1.

The following example creates a new SET object and adds an INTERGER, BOOLEAN, and a PrintableString component:

 SET set = new SET();
 set.addComponent(new INTEGER(3));
 set.addComponent(new BOOLEAN(true));
 set.addComponent(new PrintableString("Test"));
 

Of course, sets may be nested meaning that one SET contains another SET as one of its components. The nesting may be of any depth.

Version:

File Revision 17

See Also:

ASN1Object, ASN, ConstructedType, ConstructedType.addComponent(iaik.asn1.ASN1Object)

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	sorted

Fields inherited from class iaik.asn1.ConstructedType

content_count, content_data

Fields inherited from class iaik.asn1.ASN1Object

asnType, constructed, encode_listener, indefinite_length, isStringType, stream_mode

Constructor Summary

Constructors

Constructor and Description
SET() Creates a new SET.
SET(boolean sorted) Creates a new SET.

Method Summary

Modifier and Type	Method and Description
protected void	decode(int length, java.io.InputStream is) Decodes the next available data from the InputStream.
protected void	encode(java.io.OutputStream os) DER encodes this ASN1Object and writes the result to the supplied OutputStream.
java.lang.String	toString() Returns a String that represents the value of this SET.

Methods inherited from class iaik.asn1.ConstructedType

addComponent, addComponent, addEncodeListener, clone, countComponents, getComponentAt, getComponents, getValue, removeComponent, removeComponent, setComponent, setValue

Methods inherited from class iaik.asn1.ASN1Object

addEncodeListener, encodeObject, getAsnType, indefiniteLength, isA, isConstructed, isStringType, setIndefiniteLength

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

sorted

protected boolean sorted

Constructor Detail

SET

public SET()

Creates a new SET.

Components may be added by means of the addComponent method of the ConstructedType super class.

SET

public SET(boolean sorted)

Creates a new SET. If the parameter sorted is set to true the components are sorted by their encodings. This constructor only shall be used for creating SET OF structures where all components have the same type. In this way, an application may prefer to call the createSetOf(ASN1Type[] array, boolean sorted) method of class ASN for creating the SET OF.

Parameters:

sorted - whether to sort the components by their encodings or not

Method Detail

toString

public java.lang.String toString()

Returns a String that represents the value of this SET.

Overrides:

toString in class ASN1Object

Returns:

the String representation

See Also:

ASN1Object.toString()

encode

protected void encode(java.io.OutputStream os)
               throws java.io.IOException

Description copied from class: ConstructedType

DER encodes this ASN1Object and writes the result to the supplied OutputStream. In stream mode the components are encoded in correct order and the indefinite length encoding method is used, in normal mode the components are encoded in reverse order to facilitate length determination. Indefinite length encoding may be preferable when dealing with large objects where whole the data is not known at beginning of the data transfer.

Overrides:

encode in class ConstructedType

Parameters:

os - the output stream to which to write the data

Throws:

java.io.IOException - if an error occurs while reading from the stream

decode

protected void decode(int length,
                      java.io.InputStream is)
               throws CodingException,
                      java.io.IOException

Decodes the next available data from the InputStream. The supplied input stream carries DER encoded data. The next length bytes represent the encoding of this ASN1Object to be decoded. If length < 0, the supplied ASN1Object has been encoded by means of the indefinite length encoding method, and so the encoding has to be parsed for two consecutive EOC octets of all zeros. Indefinite length encoding only is appropriate (and therefore allowed) for constructed ASN.1 types.

This is a protected method and will not be used by an application for DER decoding an encoded ASN1Object. An application will call one of the decode methods of the DerCoder class for performing the decoding. The DerCoder then determines the number of bytes (length) obtained by the particular ASN1Object and internally calls the decode method of that ASN1Object.

Overrides:

decode in class ConstructedType

Parameters:

length - the length of the ASN1Object which shall be decoded, i.e. the number of the bytes representing the ASN1Object to be decoded

is - the input stream from which the data is read in

Throws:

java.io.IOException - if an error occurs while reading from the stream

CodingException - if a decoding error occurs