Tag (cryptix-asn1 JavaDoc)

java.lang.Object
- cryptix.asn1.lang.Tag

```
public class Tag
extends java.lang.Object
```
A class to handle ASN.1 Tag elements.
Copyright ©1997, 1998, 1999 Systemics Ltd on behalf of the Cryptix Development Team.
All rights reserved.
$Revision: 1.3 $

Author:

Raif S. Naffah, Eric Rescorla

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`APPLICATION`
`static int`	`BIT_STRING`
`static int`	`BOOLEAN`
`(package private) int`	`clazz`
`(package private) boolean`	`constructed`
`static int`	`CONTEXT`
`(package private) boolean`	`explicit`
`static int`	`IA5_STRING`
`static int`	`INTEGER`
`static int`	`NULL`
`static int`	`OBJECT_IDENTIFIER`
`static int`	`OCTET_STRING`
`static int`	`PRINT_STRING`
`static int`	`PRIVATE`
`static int`	`SEQUENCE`
`static int`	`SEQUENCE_OF`
`static int`	`SET`
`static int`	`SET_OF`
`static int`	`T61_STRING`
`static int`	`UNIVERSAL`
`static int`	`UTC_TIME`
`(package private) int`	`value`

Constructor Summary

Constructors
Constructor and Description
`Tag(int value, boolean explicit)` Convenience constructor.
`Tag(int clazz, int value, boolean explicit)` Convenience constructor.
`Tag(int clazz, int value, boolean explicit, boolean constructed)` Constructs an ASN.1 Tag instance.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static Tag`	`decode(java.io.InputStream in)` Constructs a `Tag` instance from the designated input stream.
`int`	`getClazz()` Returns the tag's class.
`static Tag`	`getExpectedTag(int expectedValue, java.io.InputStream in)` Convenience method similar to the method with same name and 3 arguments, except it assumes that the tag's class is UNIVERSAL.
`static Tag`	`getExpectedTag(int expectedClass, int expectedValue, java.io.InputStream in)` Returns the tag element of an ASN.1 object if it is of the designated expected class and type, or null otherwise.
`static Tag`	`getExpectedTag(Tag tag, java.io.InputStream in)` Convenience method similar to the method with same name and 3 arguments, except it uses the given tag's class and value.
`static byte[]`	`getTag(java.io.InputStream in)` Get a tag off the wire as a `byte[]`
`int`	`getValue()` Returns the tag's class number.
`boolean`	`isConstructed()` Returns true if the tag is constructed false otherwise.
`boolean`	`isExplicit()` Returns true if the tag is explicit, false otherwise.
`static Tag`	`peek(java.io.InputStream in)` Returns the Tag instance parsed from the given input stream, if one is there, without modifying the stram marker.
`java.lang.String`	`toString()`

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

- Field Detail
  - UNIVERSAL
```
public static final int UNIVERSAL
```
    See Also:
    
    Constant Field Values
  - APPLICATION
```
public static final int APPLICATION
```
    See Also:
    
    Constant Field Values
  - CONTEXT
```
public static final int CONTEXT
```
    See Also:
    
    Constant Field Values
  - PRIVATE
```
public static final int PRIVATE
```
    See Also:
    
    Constant Field Values
  - BOOLEAN
```
public static final int BOOLEAN
```
    See Also:
    
    Constant Field Values
  - INTEGER
```
public static final int INTEGER
```
    See Also:
    
    Constant Field Values
  - BIT_STRING
```
public static final int BIT_STRING
```
    See Also:
    
    Constant Field Values
  - OCTET_STRING
```
public static final int OCTET_STRING
```
    See Also:
    
    Constant Field Values
  - NULL
```
public static final int NULL
```
    See Also:
    
    Constant Field Values
  - OBJECT_IDENTIFIER
```
public static final int OBJECT_IDENTIFIER
```
    See Also:
    
    Constant Field Values
  - SEQUENCE
```
public static final int SEQUENCE
```
    See Also:
    
    Constant Field Values
  - SEQUENCE_OF
```
public static final int SEQUENCE_OF
```
    See Also:
    
    Constant Field Values
  - SET
```
public static final int SET
```
    See Also:
    
    Constant Field Values
  - SET_OF
```
public static final int SET_OF
```
    See Also:
    
    Constant Field Values
  - PRINT_STRING
```
public static final int PRINT_STRING
```
    See Also:
    
    Constant Field Values
  - T61_STRING
```
public static final int T61_STRING
```
    See Also:
    
    Constant Field Values
  - IA5_STRING
```
public static final int IA5_STRING
```
    See Also:
    
    Constant Field Values
  - UTC_TIME
```
public static final int UTC_TIME
```
    See Also:
    
    Constant Field Values
  - clazz
```
int clazz
```
  - value
```
int value
```
  - explicit
```
boolean explicit
```
  - constructed
```
boolean constructed
```
- Constructor Detail
  - Tag
```
Tag(int clazz,
    int value,
    boolean explicit,
    boolean constructed)
```
    Constructs an ASN.1 Tag instance.
    
    Parameters:
    
    clazz - The tag's class, default is UNIVERSAL.
    
    value - The tag's value.
    
    explicit - Whether this tag is explicit or implicit.
    
    constructed - Whether this tag is constructed or not. Default is not constrcuted.
  - Tag
```
Tag(int clazz,
    int value,
    boolean explicit)
```
    Convenience constructor. Constructs an ASN.1 Tag instance.
    
    Parameters:
    
    clazz - The tag's class, default is UNIVERSAL.
    
    value - The tag's value.
    
    explicit - Whether this tag is explicit or implicit.
  - Tag
```
Tag(int value,
    boolean explicit)
```
    Convenience constructor. Constructs an ASN.1 Tag instance.
    
    Parameters:
    
    value - The tag's value.
    
    explicit - Whether this tag is explicit or implicit.
- Method Detail
  - getClazz
```
public int getClazz()
```
    Returns the tag's class.
  - getValue
```
public int getValue()
```
    Returns the tag's class number.
  - isExplicit
```
public boolean isExplicit()
```
    Returns true if the tag is explicit, false otherwise.
  - isConstructed
```
public boolean isConstructed()
```
    Returns true if the tag is constructed false otherwise.
  - getExpectedTag
```
public static Tag getExpectedTag(int expectedClass,
                                 int expectedValue,
                                 java.io.InputStream in)
                          throws java.io.IOException
```
    Returns the tag element of an ASN.1 object if it is of the designated expected class and type, or null otherwise. If the stream does not contain the expected tag (of given type) this method ensures that the stream marker is not modified.
    
    Parameters:
    
    expectedClass - The tag's class expected to be found at the current marker location of the given input stream.
    
    expectedValue - The tag's number expected to be found at the current marker location of the given input stream.
    
    in - The input source stream.
    
    Returns:
    
    An instance of the Tag class containing the concrete Tag instance found in the input stream.
    
    Throws:
    
    java.io.IOException
  - getExpectedTag
```
public static Tag getExpectedTag(int expectedValue,
                                 java.io.InputStream in)
                          throws java.io.IOException
```
    Convenience method similar to the method with same name and 3 arguments, except it assumes that the tag's class is UNIVERSAL.
    
    Parameters:
    
    expectedValue - The tag's number expected to be found at the current marker location of the given input stream.
    
    in - The input source stream.
    
    Returns:
    
    An instance of the Tag class containing the concrete Tag instance found in the input stream.
    
    Throws:
    
    java.io.IOException
  - getExpectedTag
```
public static Tag getExpectedTag(Tag tag,
                                 java.io.InputStream in)
                          throws java.io.IOException
```
    Convenience method similar to the method with same name and 3 arguments, except it uses the given tag's class and value.
    
    Parameters:
    
    tag - The tag's instance (class and value) expected to be found at the current marker location of the given input stream.
    
    in - The input source stream.
    
    Returns:
    
    An instance of the Tag class containing the concrete Tag instance found in the input stream.
    
    Throws:
    
    java.io.IOException
  - getTag
```
public static byte[] getTag(java.io.InputStream in)
                     throws java.io.IOException
```
    Get a tag off the wire as a byte[]
    
    Parameters:
    
    in - The input stream
    
    Returns:
    
    a byte with the tag bytes
    
    Throws:
    
    java.io.IOException - --EKR
  - decode
```
public static Tag decode(java.io.InputStream in)
                  throws java.io.IOException
```
    Constructs a Tag instance from the designated input stream.
    
    Parameters:
    
    in - The input stream.
    
    Returns:
    
    A Tag instance parsed from an input stream.
    
    Throws:
    
    java.io.IOException - If an error occurs while parsing the input stream.
  - peek
```
public static Tag peek(java.io.InputStream in)
                throws java.io.IOException
```
    Returns the Tag instance parsed from the given input stream, if one is there, without modifying the stram marker.
    
    Parameters:
    
    in - The input stream.
    
    Returns:
    
    A Tag instance parsed from the designated input stream.
    
    Throws:
    
    java.io.IOException - If an error occurs while parsing the input stream.
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class Tag

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UNIVERSAL

APPLICATION

CONTEXT

PRIVATE

BOOLEAN

INTEGER

BIT_STRING

OCTET_STRING

NULL

OBJECT_IDENTIFIER

SEQUENCE

SEQUENCE_OF

SET

SET_OF

PRINT_STRING

T61_STRING

IA5_STRING

UTC_TIME

clazz

value

explicit

constructed

Constructor Detail

Tag

Tag

Tag

Method Detail

getClazz

getValue

isExplicit

isConstructed

getExpectedTag

getExpectedTag

getExpectedTag

getTag

decode

peek

toString