Data ("Entrust Authority Security Toolkit for the Java Platform")

java.lang.Object
- iaik.cms.DataStream
- - iaik.cms.Data

All Implemented Interfaces:

Content, ContentStream
```
public class Data
extends DataStream
implements Content
```
This class represents the non-stream implementation of the CMS content type Data.
Each CMS content type is associated with a specific object identifier, derived from:
```
 pkcs-7 OBJECT IDENTIFIER ::=
   { iso(1) member-body(2) US(840) rsadsi(113549)
       pkcs(1) 7 }
 
```
The object identifier for the Data content type is defined as:
data OBJECT IDENTIFIER ::= { pkcs-7 1 }
which corresponds to the OID string "1.2.840.1.113549.1.7.1".
The Cryptographic Message Syntax (CMS, RFC 2630) specifies the Data content type as base type without any cryptographic enhancements. Please note that in difference to PKCS#7, CMS specifies the Data as arbitrary octet strings, such as ASCII text files; the interpretation is left to the application. From this point of view the CMS type Data itself does not have an ASN.1 respresentation in contrast to its PKCS#7 equivalent where Data is defined as ASN.1 OCTET STRING:
Data ::= OCTET STRING
This class only may be used for compatibility to PKCS#7 for allowing to include Data objects into ContentInfos. Within SignedData or EnvelopedData objects the internal content always is wrapped by an EncapsulatedContentInfo object. Since an EncapsulatedContentInfo anytime is encoded as OCTET STRING backwards compatibility to PKCS#7 is preserved even when the inner content type is Data
Use the Data(byte[] content) constructor to create a new Data object for the given raw data bytes:
```
 byte[] value = ...;
 Data data = new Data(value);
 
```
Some applications - for instance some versions of Netscape Navigator - use the indefinite constructed encoding method for generating an octet string that is composed of a certain number of definite primitive encoded octet strings:
```
 0x24 0x80
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
                ...
 0x00 0x00
 
```
For being compatible to such applications, this class provides a constructor where a particular blocksize may be specified to give an encoding result as described above:
```
 Data data = new Data(value, blockSize);
 
```
In contrast to the stream-variant of the CMS Data type (implemented by the DataStream), where the raw data is supplied from an input stream and therefore can be read only once, it may be obtained arbitrarily often from a non-stream Data object by utilizing the getData method.
After transforming a Data object to an ASN1Object by means of the toASN1Object method, it may be parsed back again by using the Data(ASN1Object obj) constructor. In general, the getEncoded method returns this Data object as definite primitive encoded octet string:
```
 0x04 <length> <data>
 
```
However, if a positive blocksize has been specified when creating this Data object, the encoding will be indefinite constructed.
For handling large amounts of data, the parent DataStream class should be used.
See Also:
Content, ContentInfo

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Data()` Default constructor for dynamic object creation in ContentInfo.
	`Data(ASN1Object obj)` Creates a CMS Data object from an ASN1Object.
	`Data(byte[] content)` Creates a CMS `Data` object from a byte array supplying the data value.
	`Data(byte[] content, int blockSize)` Creates a CMS `Data` object from a byte array supplying the data value and a blockSize specifying the encoding scheme.
	`Data(java.io.InputStream is)` Creates a new CMS Data from a DER encoded InputStream.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`decode(ASN1Object obj)` Reads and decodes the Data from an ASN1Object.
`void`	`decode(java.io.InputStream is)` Reads and decodes the Data from an InputStream.
`byte[]`	`getData()` Returns a byte array holding the value of this `Data` object.
`byte[]`	`getEncoded()` Returns the DER encoding of this `Data` object as byte array.
`java.io.InputStream`	`getInputStream()` Returns an InputStream from which the contents of this object can be read.
`ASN1Object`	`toASN1Object()` Returns this CMS `Data` as ASN1Object.
`java.lang.String`	`toString(boolean detailed)` Returns a string giving some - if requested - detailed information about this `Data` object.

Methods inherited from class iaik.cms.DataStream
getBlockSize, getContentType, setBlockSize, toString, writeTo

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface iaik.cms.ContentStream
getBlockSize, getContentType, setBlockSize

- Constructor Detail
  - Data
```
protected Data()
```
    Default constructor for dynamic object creation in ContentInfo. Shall be not used by an application.
  - Data
```
public Data(byte[] content)
```
    Creates a CMS Data object from a byte array supplying the data value.
    Use this constructor for supplying the content value, e.g.:
```
 Data data = new Data("Test data".getBytes());
 
```
    Parameters:
    content - the data value in a byte array
  - Data
```
public Data(byte[] content,
    int blockSize)
```
    Creates a CMS Data object from a byte array supplying the data value and a blockSize specifying the encoding scheme. If blockSize is not positive this Data object will be encoded as definite primitive octet string:
```
 0x04 <length> <data>
 
```
    If blockSize is positive this Data object will be encoded as indefinite constructed octet string being composed of a certain number of definite primitive octet strings of blockSize length:
```
 0x24 0x80
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
                ...
 0x00 0x00
 
```
    Parameters:
    content - the data value in a byte array
    blockSize - for defining the encoding scheme - and specifiying the octet string component length, if positive
  - Data
```
public Data(ASN1Object obj)
     throws CMSParsingException
```
    Creates a CMS Data object from an ASN1Object. Do not use this constructor for supplying the content value. This constructor may be used for parsing an already exisiting Data object, supplied as ASN1Object that may have been created by calling toASN1Object.
    Use the Data(byte[] content) constructor for supplying the content value when creating a Data object.
    
    Parameters:
    obj - the CMS Data as ASN1Object
    
    Throws:
    
    CMSParsingException - if an parsing error occurs
  - Data
```
public Data(java.io.InputStream is)
     throws java.io.IOException,
            CMSParsingException
```
    Creates a new CMS Data from a DER encoded InputStream. Do not use this constructor for supplying the content value. This constructor may be used for decoding and parsing an already exisiting Data object, supplied as DER encoding from an input stream.
    
    Parameters:
    is - the input stream supplying the DER encoded Data
    
    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
```
public void decode(ASN1Object obj)
            throws CMSParsingException
```
    Reads and decodes the Data from an ASN1Object.
    
    Specified by:
    
    decode in interface Content
    
    Parameters:
    obj - the CMS Data object as ASN1Object
    
    Throws:
    
    CMSParsingException - if an error occurs while parsing the object
  - decode
```
public void decode(java.io.InputStream is)
            throws java.io.IOException,
                   CMSParsingException
```
    Reads and decodes the Data from an InputStream.
    
    Specified by:
    
    decode in interface ContentStream
    
    Overrides:
    
    decode in class DataStream
    
    Parameters:
    is - the InputStream holding a DER encoded CMS Data 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
  - getData
```
public byte[] getData()
```
    Returns a byte array holding the value of this Data object.
    
    Returns:
    the value of this Data object, as byte array
  - getInputStream
```
public java.io.InputStream getInputStream()
```
    Returns an InputStream from which the contents of this object can be read.
    This method only overrides the corresponding getInputStream method of the parent DataStream class for returning the content of this Data object. There should be no real necessity for using this method since the raw data bytes immediately can be obtained by the getData method. However, in contrast to the equivalent getInputStream method of the parent DataStream class, this method may be called arbitrarly often; it only returns a ByteArrayInputStream that is initialized with the raw content bytes.
    
    Overrides:
    
    getInputStream in class DataStream
    
    Returns:
    an InputStream with the contents of this Data object
  - toASN1Object
```
public ASN1Object toASN1Object()
                        throws CMSException
```
    Returns this CMS Data as ASN1Object. From the internal value an ASN.1 OCTET STRING object is created.
    
    Specified by:
    
    toASN1Object in interface ContentStream
    
    Overrides:
    
    toASN1Object in class DataStream
    
    Returns:
    this Data as ASN1Object (OCTET_STRING)
    
    Throws:
    
    CMSException - if an ASN.1 parsing error occurs
  - getEncoded
```
public byte[] getEncoded()
                  throws CMSException
```
    Returns the DER encoding of this Data object as byte array. In general, the data is returned as primitive definte encoded octet string:
```
 0x04 <length> <data>
 
```
    However, if a positive blocksize has been specified when creating this Data object, the encoding will be indefinite constructed:
```
 0x24 0x80
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
                ...
 0x00 0x00
 
```
    Returns:
    the DER encoding of this Data
    
    Throws:
    
    CMSException - if an encoding error occurs
  - toString
```
public java.lang.String toString(boolean detailed)
```
    Returns a string giving some - if requested - detailed information about this Data object.
    
    Specified by:
    
    toString in interface ContentStream
    
    Overrides:
    
    toString in class DataStream
    
    Parameters:
    detailed - - whether or not to give detailed information
    
    Returns:
    the string representation

Class Data

Constructor Summary

Method Summary

Methods inherited from class iaik.cms.DataStream

Methods inherited from class java.lang.Object

Methods inherited from interface iaik.cms.ContentStream

Constructor Detail

Data

Data

Data

Data

Data

Method Detail

decode

decode

getData

getInputStream

toASN1Object

getEncoded

toString