org.eclipse.jgit.lib
Class ObjectIdOwnerMap<V extends ObjectIdOwnerMap.Entry>

java.lang.Object
  org.eclipse.jgit.lib.ObjectIdOwnerMap<V>

Type Parameters:

V - type of subclass of ObjectId that will be stored in the map.

All Implemented Interfaces:

Iterable<V>

public class ObjectIdOwnerMap<V extends ObjectIdOwnerMap.Entry>
extends Object
implements Iterable<V>

Fast, efficient map for ObjectId subclasses in only one map.

To use this map type, applications must have their entry value type extend from ObjectIdOwnerMap.Entry, which itself extends from ObjectId.

Object instances may only be stored in ONE ObjectIdOwnerMap. This restriction exists because the map stores internal map state within each object instance. If an instance is be placed in another ObjectIdOwnerMap it could corrupt one or both map's internal state.

If an object instance must be in more than one map, applications may use ObjectIdOwnerMap for one of the maps, and ObjectIdSubclassMap for the other map(s). It is encouraged to use ObjectIdOwnerMap for the map that is accessed most often, as this implementation runs faster than the more general ObjectIdSubclassMap implementation.

Nested Class Summary

static class

ObjectIdOwnerMap.Entry Type of entry stored in the ObjectIdOwnerMap.

Constructor Summary

ObjectIdOwnerMap()
Create an empty map.

Method Summary

<Q extends V> void	add(Q newValue) Store an object for future lookup.
<Q extends V> V	addIfAbsent(Q newValue) Store an object for future lookup.
void	clear() Remove all entries from this map.
boolean	contains(AnyObjectId toFind) Returns true if this map contains the specified object.
V	get(AnyObjectId toFind) Lookup an existing mapping.
boolean	isEmpty()
Iterator<V>	iterator()
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectIdOwnerMap

public ObjectIdOwnerMap()

Create an empty map.

Method Detail

clear

public void clear()

Remove all entries from this map.

get

public V get(AnyObjectId toFind)

Lookup an existing mapping.

Parameters:

toFind - the object identifier to find.

Returns:

the instance mapped to toFind, or null if no mapping exists.

contains

public boolean contains(AnyObjectId toFind)

Returns true if this map contains the specified object.

Parameters:

toFind - object to find.

Returns:

true if the mapping exists for this object; false otherwise.

add

public <Q extends V> void add(Q newValue)

Store an object for future lookup.

An existing mapping for must not be in this map. Callers must first call get(AnyObjectId) to verify there is no current mapping prior to adding a new mapping, or use addIfAbsent(Entry).

Type Parameters:

Q - type of instance to store.

Parameters:

newValue - the object to store.

addIfAbsent

public <Q extends V> V addIfAbsent(Q newValue)

Store an object for future lookup.

Stores newValue, but only if there is not already an object for the same object name. Callers can tell if the value is new by checking the return value with reference equality:

 V obj = ...;
 boolean wasNew = map.addIfAbsent(obj) == obj;
 

Type Parameters:

Q - type of instance to store.

Parameters:

newValue - the object to store.

Returns:

newValue if stored, or the prior value already stored and that would have been returned had the caller used get(newValue) first.

size

public int size()

Returns:

number of objects in this map.

isEmpty

public boolean isEmpty()

Returns:

true if size() is 0.

iterator

public Iterator<V> iterator()

Specified by:

iterator in interface Iterable<V extends ObjectIdOwnerMap.Entry>