codec.asn1
Class ASN1AbstractCollection

java.lang.Object
  |
  +--java.util.AbstractCollection
        |
        +--java.util.AbstractList
              |
              +--java.util.ArrayList
                    |
                    +--codec.asn1.ASN1AbstractCollection

All Implemented Interfaces:

ASN1Collection, ASN1Type, Cloneable, Collection, Externalizable, List, Serializable

Direct Known Subclasses:

ASN1AbstractCollectionOf, ASN1Sequence, ASN1Set

public abstract class ASN1AbstractCollection

extends ArrayList

implements ASN1Collection, Cloneable, Externalizable

Represents an abstract collection of ASN.1 types such as a SEQUENCE or a SET. Since this class inherits from the Collection framework class ArrayList, ASN.1 types may be added conveniently just as object instances are added to a list.

Please note that constraints of collections are validated before encoding and after decoding. Invalid modification of a collection type can be detected on importing and exporting abstract collections. On DER encoding a collection its constraint is validated twice since the DER encoding is a two-pass process.

Version:

"$Id: ASN1AbstractCollection.java,v 1.5 2005/03/22 16:12:45 flautens Exp $"

Author:

Volker Roth

See Also:

Serialized Form

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

ASN1AbstractCollection()
Method declarations with default implementation.

ASN1AbstractCollection(int capacity)
Creates an instance with the given capacity.

Method Summary

void	checkConstraints() Checks the constraint on this type if it is set.
void	decode(Decoder dec) Reads this collection from the given Decoder.
void	encode(Encoder enc) Writes this collection to the given encoder.
Collection	getCollection() Returns the Java type that corresponds to this ASN.1 type.
Constraint	getConstraint() Returns the Constraint of this type or null if there is none.
abstract int	getTag() Abstract method declarations.
int	getTagClass() This default implementation returns UNIVERSAL.
Object	getValue() Returns the Java type that corresponds to this ASN.1 type.
boolean	isExplicit()
boolean	isOptional()
boolean	isType(int tag, int tagclass) Returns true if the given tag and tag class matches the tag and tag class of this instance.
void	readExternal(ObjectInput in) The writeExternal and readExternal methods of the Externalizable interface are implemented by a class to give the serializable class complete control over the format and contents of the stream for an object and its supertypes.
void	setConstraint(Constraint constraint) Sets the Constraint of this type.
void	setExplicit(boolean explicit) Sets the tagging of this type as either EXPLICIT or IMPLICIT.
void	setOptional(boolean optional) Optional types may be present in an encoding but they need not be.
String	toString() Prints this collection.
void	writeExternal(ObjectOutput out) The writeExternal and readExternal methods of the Externalizable interface are implemented by a class to give the serializable class complete control over the format and contents of the stream for an object and its supertypes.

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, clone, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, remove, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

equals, hashCode, iterator, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

containsAll, remove, removeAll, retainAll

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray

Methods inherited from interface java.util.List

containsAll, equals, hashCode, iterator, listIterator, listIterator, remove, removeAll, retainAll, subList

Constructor Detail

ASN1AbstractCollection

public ASN1AbstractCollection()

Method declarations with default implementation.

ASN1AbstractCollection

public ASN1AbstractCollection(int capacity)

Creates an instance with the given capacity.

Parameters:

capacity - The capacity.

Method Detail

getTag

public abstract int getTag()

Abstract method declarations.

Specified by:

getTag in interface ASN1Type

Returns:

corresponding ASN1 tag

getValue

public Object getValue()

Returns the Java type that corresponds to this ASN.1 type.

Specified by:

getValue in interface ASN1Type

Returns:

The collection used internally for storing the elements in this constructed ASN.1 type.

getCollection

public Collection getCollection()

Returns the Java type that corresponds to this ASN.1 type.

Specified by:

getCollection in interface ASN1Collection

Returns:

The collection used internally for storing the elements in this constructed ASN.1 type.

setOptional

public void setOptional(boolean optional)

Optional types may be present in an encoding but they need not be.

Specified by:

setOptional in interface ASN1Type

Parameters:

optional - true iff this type is optional.

isOptional

public boolean isOptional()

Specified by:

isOptional in interface ASN1Type

Returns:

true iff this type is optional.

getTagClass

public int getTagClass()

This default implementation returns UNIVERSAL.

Specified by:

getTagClass in interface ASN1Type

Returns:

The class of the ASN.1 tag.

setExplicit

public void setExplicit(boolean explicit)

Sets the tagging of this type as either EXPLICIT or IMPLICIT. The default is EXPLICIT. Encoders skip the encoding of identifier octets for types that are declared as IMPLICIT.

Specified by:

setExplicit in interface ASN1Type

Parameters:

explicit - true if this type shall be tagged EXPLICIT and false if it shall be encoded IMPLICIT.

isExplicit

public boolean isExplicit()

Specified by:

isExplicit in interface ASN1Type

Returns:

true if this type is tagged EXPLICIT and false if it is tagged IMPLICIT.

setConstraint

public void setConstraint(Constraint constraint)

Sets the Constraint of this type. For instance an ASN.1 INTEGER might be constrained to a certain range such as INTEGER (0..99). null can be passed as a constraint which disables constraint checking.

Specified by:

setConstraint in interface ASN1Type

Parameters:

constraint - The Constraint of this type.

getConstraint

public Constraint getConstraint()

Returns the Constraint of this type or null if there is none.

Specified by:

getConstraint in interface ASN1Type

Returns:

The Constraint or null.

checkConstraints

public void checkConstraints()
                      throws ConstraintException

Checks the constraint on this type if it is set. Otherwise this method returns silently.

Specified by:

checkConstraints in interface ASN1Type

Throws:

ConstraintException - if this type is not in the appropriate range of values.

isType

public boolean isType(int tag,
                      int tagclass)

Returns true if the given tag and tag class matches the tag and tag class of this instance. This method is used primarily by decoders and variable types such as ASN1Choice and ASN1OpenType. It enables decoders to query a variable type whether a decoded type is accepted.

This method provides a default implementation that matches the given tag and tag class against the values returned by getTag and getTagClass respectively.

Specified by:

isType in interface ASN1Type

Parameters:

tag - The tag to compare with.

tagclass - The tag class to compare with.

Returns:

true if the given tag and tag class matches this type and false otherwise.

encode

public void encode(Encoder enc)
            throws ASN1Exception,
                   IOException

Writes this collection to the given encoder.

Specified by:

encode in interface ASN1Type

Parameters:

enc - The encoder to write this type to.

decode

public void decode(Decoder dec)
            throws ASN1Exception,
                   IOException

Reads this collection from the given Decoder. This type is initialized with the decoded data. The components of the decoded collection must match the components of this collection. If they do then the components are also initialized with the decoded values. Otherwise an exception is thrown.

Specified by:

decode in interface ASN1Type

Parameters:

dec - The decoder to read from.

toString

public String toString()

Prints this collection. This default implementation derives a descriptive name from the name of the fully qualified name of this class (or that of the respective subclass). The last component of the class name is extracted and a prefix of "ASN1" is removed from it. Then the elements contained in this collection are printed.

Overrides:

toString in class AbstractCollection

Returns:

The string representation of this ASN.1 collection.

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

The writeExternal and readExternal methods of the Externalizable interface are implemented by a class to give the serializable class complete control over the format and contents of the stream for an object and its supertypes.

Specified by:

writeExternal in interface Externalizable

Parameters:

out - - the stream to write the object to

See Also:

Externalizable

readExternal

public void readExternal(ObjectInput in)
                  throws IOException

The writeExternal and readExternal methods of the Externalizable interface are implemented by a class to give the serializable class complete control over the format and contents of the stream for an object and its supertypes.

Specified by:

readExternal in interface Externalizable

Parameters:

in - - the stream to read data from in order to restore the object

See Also:

Externalizable