org.xins.common.service

Class GroupDescriptor

java.lang.Object

org.xins.common.service.Descriptor

org.xins.common.service.GroupDescriptor

All Implemented Interfaces:

Serializable, Iterable<TargetDescriptor>

public final class GroupDescriptor
extends Descriptor

Descriptor for a group of services. Each GroupDescriptor has at least 2 members.

Since:

XINS 1.0.0

Version:

$Revision: 1.34 $ $Date: 2012/03/03 10:41:19 $

Author:

Ernst de Haan

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GroupDescriptor.Type Type of a group.

Field Summary

Fields

Modifier and Type	Field and Description
static GroupDescriptor.Type	ORDERED_TYPE The ordered group type.
static String	ORDERED_TYPE_ID The identifier of the ordered group type.
static GroupDescriptor.Type	RANDOM_TYPE The random group type.
static String	RANDOM_TYPE_ID The identifier of the random group type.

Constructor Summary

Constructors

Constructor and Description
GroupDescriptor(GroupDescriptor.Type type, Descriptor[] members) Constructs a new GroupDescriptor.

Method Summary

Methods

Modifier and Type	Method and Description
Descriptor[]	getMembers() Returns the members of this group.
TargetDescriptor	getTargetByCRC(int crc) Returns the TargetDescriptor that matches the specified CRC-32 checksum.
int	getTargetCount() Counts the total number of target descriptors in/under this descriptor.
GroupDescriptor.Type	getType() Returns the type of this group.
static GroupDescriptor.Type	getType(String identifier) Gets a group type by identifier.
boolean	isGroup() Checks if this descriptor denotes a group of descriptors.
Iterator	iterateTargets() Iterates over all leaves, the target descriptors.
Iterator<TargetDescriptor>	iterator()
String	toString() Presents this object as a text string.

Methods inherited from class java.lang.Object

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

Field Detail

RANDOM_TYPE_ID

public static final String RANDOM_TYPE_ID

The identifier of the random group type.

See Also:

Constant Field Values

ORDERED_TYPE_ID

public static final String ORDERED_TYPE_ID

The identifier of the ordered group type.

See Also:

Constant Field Values

RANDOM_TYPE

public static final GroupDescriptor.Type RANDOM_TYPE

The random group type.

ORDERED_TYPE

public static final GroupDescriptor.Type ORDERED_TYPE

The ordered group type.

Constructor Detail

GroupDescriptor

public GroupDescriptor(GroupDescriptor.Type type,
               Descriptor[] members)
                throws IllegalArgumentException

Constructs a new GroupDescriptor. The members to be included must be passed. The array of members cannot contain any null elements. It may contain duplicates, though.

Since XINS 1.1.0, the array of members cannot be empty, but needs to contain at least 2 descriptors.

Parameters:

type - the type of group, cannot be null.

members - list of members of the group, cannot be null.

Throws:

IllegalArgumentException - if type == null || members == null || members.length < 2 || members[n] == null (where 0 <= n < members.length).

Method Detail

toString

public String toString()

Presents this object as a text string.

Overrides:

toString in class Object

Returns:

this object as a String, never null.

getType

public static GroupDescriptor.Type getType(String identifier)
                                    throws IllegalArgumentException

Gets a group type by identifier.

Parameters:

identifier - the identifier for the group, cannot be null.

Returns:

the type with the specified identifier, or null if there is no matching type.

Throws:

IllegalArgumentException - if identifier == null.

isGroup

public boolean isGroup()

Checks if this descriptor denotes a group of descriptors.

Specified by:

isGroup in class Descriptor

Returns:

true, since this descriptor denotes a group.

iterateTargets

public Iterator iterateTargets()

Iterates over all leaves, the target descriptors.

The returned Iterator will not support Iterator.remove(). The iterator will only return TargetDescriptor instances, no instances of other classes and no null values.

Also, this iterator is guaranteed to return getTargetCount() instances of class TargetDescriptor.

Specified by:

iterateTargets in class Descriptor

Returns:

iterator over the leaves, the target descriptors, in this descriptor, in the correct order, never null.

iterator

public Iterator<TargetDescriptor> iterator()

getTargetCount

public int getTargetCount()

Counts the total number of target descriptors in/under this descriptor.

Specified by:

getTargetCount in class Descriptor

Returns:

the total number of target descriptors, always >= 2.

getType

public GroupDescriptor.Type getType()

Returns the type of this group.

Returns:

the type of this group, not null.

getMembers

public Descriptor[] getMembers()

Returns the members of this group.

Returns:

the members of this group as a new array, not null.

getTargetByCRC

public TargetDescriptor getTargetByCRC(int crc)

Returns the TargetDescriptor that matches the specified CRC-32 checksum.

Specified by:

getTargetByCRC in class Descriptor

Parameters:

crc - the CRC-32 checksum.

Returns:

the TargetDescriptor that matches the specified checksum, or null, if none could be found in this descriptor.