Module org.eclipse.jgit
Package 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>, ObjectIdSet
public class ObjectIdOwnerMap<V extends ObjectIdOwnerMap.Entry> extends Object implements Iterable<V>, ObjectIdSet
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.

  • Constructor Details

    • ObjectIdOwnerMap

      public ObjectIdOwnerMap()
      Create an empty map.

  • Method Details

    • 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 the objectId is contained within the collection.

      Returns true if this map contains the specified object.

      Specified by:
      contains in interface ObjectIdSet
      Parameters:
      toFind - the objectId to find
      Returns:
      whether the collection contains the objectId.

    • 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 values
      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 values
      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()
      Get number of objects in this map.
      Returns:
      number of objects in this map.

    • isEmpty

      public boolean isEmpty()
      Whether this map is empty
      Returns:
      true if size() is 0.

    • iterator

      public Iterator<V> iterator()
      Specified by:
      iterator in interface Iterable<V extends ObjectIdOwnerMap.Entry>