iaik.cms

Class EncapsulatedContentInfoStream

java.lang.Object

iaik.cms.EncapsulatedContentInfoStream

Direct Known Subclasses:

EncapsulatedContentInfo

public class EncapsulatedContentInfoStream
extends java.lang.Object

This class represents the stream implemention of the CMS EncapsulatedContentInfo type.

The CMS Cryptographic Message Syntax (RFC 2630) specifies the EncapsualtedContentInfo type for carrying the inherent content of an CMS object:

 EncapsulatedContentInfo ::= SEQUENCE {
      eContentType ContentType,
      eContent [0] EXPLICIT OCTET STRING OPTIONAL }

 ContentType ::= OBJECT IDENTIFIER

 

The eContentType field associates a content type with some particular content, encoded as OCTET STRING. The content field may be omitted to transmit the content by other means.

The non-stream supporting equivalent to this class is implemented by the EncapsualtedContentInfo class.

This class does NOT interpret the content to be transmitted, i.e. the content is only treated as byte material. When creating a new EncapsulatedContentInfo to be sent use the EncapsulatedContentInfoStream(InputStream content, ObjectID contentType) constructor for supplying content bytes and content type and subsequently call the toASN1Object or writeTo method, e.g.:

 // the content bytes to be read from a stream:
 InputStream content = ...;
 // the content type (e.g. cms data):
 ObjectID contentType = ObjectID.cms_data;
 // create a EncapsulatedContentInfoStream object and encode it to a stream:
 EncapsulatedContentInfoStream ecis = new EncapsulatedContentInfoStream(content, contentType);
 // use block encoding
 int blockSize = ...;
 ecis.setBlockSize(blockSize);
 // encode to an output stream
 OutputStream encoded_stream = ...;
 ecis.writeTo(encoded_stream);
 

When using method setBlockSize(int) setBlockSize for specifying a particular blockSize an indefinite constructed encoding is enforced for the inherent content instead of the default definite primitive encoding, e.g:

 0x24 0x80
           0x04 0x02 0x01 0xAB
           0x04 0x02 0x23 0x7F
           0x04 0x01 0xCA
 0x00 0x00 
 

instead of:

 0x04 0x05 0x01 0xAB 0x23 0x7F 0xCA
 

for encoding the five data bytes 0x01 0xAB 0x23 0x7F 0xCA. The indefinte constrcuted encoding scheme may be preferable when intending to be compatible to the encoding practice of some particular application (for instance some versions of Netscape Navigator).

If you want to use an EncapsulatedContentInfo without any content, you only have to supply the content type identifier when creating an EncapsulatedContentInfoStream object, e.g.:

 EncapsulatedContentInfoStream ecis = new EncapsulatedContentInfoStream(ObjectID.cms_data);
 ecis.writeTo(encoded_stream);
 

For pasrsing an already existing EncapsulatedContentInfo (given as BER encoding) use the EncapsulatedContentInfo(InputStream is) constructor.

However, GENERALLY there should be no need for an application to immediately access this class at all. This library implemets the CMS types in a way that handles the EncapsulatedContentInfo type transparent inside the corresponding classes (e.g. SignedDataStream, ...).

Field Summary

Fields

Modifier and Type	Field and Description
protected int	blockSize_ The block size for block encoding.
protected java.io.InputStream	contentData_ The content data supplied from an input stream.
protected ObjectID	contentType_ The content type.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	EncapsulatedContentInfoStream() Default constructor.
	EncapsulatedContentInfoStream(java.io.InputStream is) Creates a new EncapsulatedContentInfo where the BER encoded data is read from the given InputStream.
	EncapsulatedContentInfoStream(java.io.InputStream content, ObjectID contentType) Creates a CMS EncapsulatedContentInfoStream from given content and content type.
	EncapsulatedContentInfoStream(ObjectID contentType) Creates an empty CMS EncapsulatedContentInfoStream from the given content type.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	decode(DerInputStream is) Reads and decodes an encoded EncapsulatedContentInfo from an input stream.
java.io.InputStream	getContentInputStream() Returns an InputStream supplying the content bytes of this CMS EncapsulatedContentInfo.
ObjectID	getContentType() Returns the content type of this CMS EncapsulatedContentInfoStream.
boolean	hasContent() Returns true if this EncapsulatedContentInfoStream has a content.
void	setBlockSize(int blockSize) Sets the block size for defining the length of each definite primitive encoded octet string component.
ASN1Object	toASN1Object() Returns this CMS EncapsulatedContentInfoStream as ASN1Object.
java.lang.String	toString() Returns a string giving some information about this CMS EncapsulatedContentInfoStream.
java.lang.String	toString(boolean detailed) Returns a string giving some - if requested - detailed information about this CMS EncapsulatedContentInfoStream.
void	writeTo(java.io.OutputStream os) Writes the DER encoding of this object to the given OutputStream.

Methods inherited from class java.lang.Object

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

Field Detail

contentType_

protected ObjectID contentType_

The content type.

contentData_

protected java.io.InputStream contentData_

The content data supplied from an input stream.

blockSize_

protected int blockSize_

The block size for block encoding.

Constructor Detail

EncapsulatedContentInfoStream

protected EncapsulatedContentInfoStream()

Default constructor. Creates an empty object.

EncapsulatedContentInfoStream

public EncapsulatedContentInfoStream(java.io.InputStream content,
                             ObjectID contentType)

Creates a CMS EncapsulatedContentInfoStream from given content and content type.

Parameters:

content - the content byte material supplied from an InputStream

contentType - the content type

EncapsulatedContentInfoStream

public EncapsulatedContentInfoStream(ObjectID contentType)

Creates an empty CMS EncapsulatedContentInfoStream from the given content type.

Since no content is specified, it is set to null. The content may be transmitted by other means.

Parameters:

contentType - the type of the content, as ObjectID

EncapsulatedContentInfoStream

public EncapsulatedContentInfoStream(java.io.InputStream is)
                              throws java.io.IOException,
                                     CMSParsingException

Creates a new EncapsulatedContentInfo where the BER encoded data is read from the given InputStream. The given input stream supplies the BER encoding of an alredy existing EncapsulatedContentInfo object which may have been written to a stream by using the writeTo method of this class.

Parameters:

is - the InputStream holding a BER encoded CMS EncapsulatedContentInfo object

Throws:

java.io.IOException - if an I/O error occurs during reading from the InputStream

CMSParsingException - if an error occurs while parsing the object

Method Detail

decode

protected void decode(DerInputStream is)
               throws java.io.IOException,
                      CMSParsingException

Reads and decodes an encoded EncapsulatedContentInfo from an input stream.

Parameters:

is - the InputStream holding a DER encoded CMS EncapsulatedContentInfo object

Throws:

java.io.IOException - if an I/O error occurs during reading from the InputStream

CMSParsingException - if an error occurs while parsing the object

toASN1Object

public ASN1Object toASN1Object()
                        throws CMSException

Returns this CMS EncapsulatedContentInfoStream as ASN1Object.

Returns:

this CMS EncapsulatedContentInfoStream as ASN1Object

Throws:

CMSException

writeTo

public void writeTo(java.io.OutputStream os)
             throws java.io.IOException,
                    CMSException

Writes the DER encoding of this object to the given OutputStream. The ContentInfo structure is encoded as ASN.1 SEQUENCE using the indefinite length encoding scheme:

 30 80
    ...
    ...
 00 00
 

If a particular block size has been specified by method setBlockSize and the content field is not empty, the content is ancoded using the indefinite constructed BER encoding scheme.

Parameters:

os - the OutputStream where the encoding shall be written to

Throws:

java.io.IOException - if an I/O error occurs during writing to the OutputStream

CMSException - if an error occurs while encoding the object

setBlockSize

public void setBlockSize(int blockSize)

Sets the block size for defining the length of each definite primitive encoded octet string component. If the value of blockSize is smaller or equal to zero the whole data is encoded as definite primitive octet string.

Parameters:

blockSize - for defining the encoding scheme and setting the octet string component length, if positive

See Also:

OCTET_STRING

hasContent

public boolean hasContent()

Returns true if this EncapsulatedContentInfoStream has a content.

Returns:

true if this EncapsulatedContentInfoStream has a content

getContentInputStream

public java.io.InputStream getContentInputStream()

Returns an InputStream supplying the content bytes of this CMS EncapsulatedContentInfo.

Returns:

the content value to be read from an InputStream or null if there is no content

getContentType

public ObjectID getContentType()

Returns the content type of this CMS EncapsulatedContentInfoStream.

Returns:

the content type, as ObjectID

toString

public java.lang.String toString()

Returns a string giving some information about this CMS EncapsulatedContentInfoStream.

Overrides:

toString in class java.lang.Object

Returns:

the string representation

toString

public java.lang.String toString(boolean detailed)

Returns a string giving some - if requested - detailed information about this CMS EncapsulatedContentInfoStream.

Parameters:

detailed - - whether or not to give detailed information

Returns:

the string representation