Identifying Key Owner without the Associated Key

Question

Suppose my entity Key class implements the KeyAssociation interface to create "Data Affinity":
class MyKeyClass implements KeyAssociation {
private String key, associated;
public MyKeyClass ( String key, String associated ) ... // set fields
public String getKey() { return key; }
public String getAssociatedKey () { return associated; }
Now I wish to get the "Key Owner", but I without knowledge of the Associated Key. I.e., I at this time I only know the "main" key:
MyKeyClass keyClass = new MyKeyClass ("ABC123", null) // <-- pass null as the Associated key, because I don't know it yet!
partitionedService.getKeyOwner(keyClass);
Question - Will this work? Can Coherence provide me with the Key Owner using "ACB123" alone? Or will it try and call "getAssociatedKey()" and fail, because "null" is returned from that method.
Reasoning - I want to avoid an extra lookup. For example, my key may be {key:ABC123, associated:XYZ789}. To find "XYZ789" I have to do a lookup in a cache, which I really do not want to do.
Thanks.

Answer 1

899446 wrote:
Suppose my entity Key class implements the KeyAssociation interface to create "Data Affinity":
class MyKeyClass implements KeyAssociation {
private String key, associated;
public MyKeyClass ( String key, String associated ) ... // set fields
public String getKey() { return key; }
public String getAssociatedKey () { return associated; }
Now I wish to get the "Key Owner", but I without knowledge of the Associated Key. I.e., I at this time I only know the "main" key:
MyKeyClass keyClass = new MyKeyClass ("ABC123", null) // <-- pass null as the Associated key, because I don't know it yet!
partitionedService.getKeyOwner(keyClass);
Question - Will this work? Can Coherence provide me with the Key Owner using "ACB123" alone? Or will it try and call "getAssociatedKey()" and fail, because "null" is returned from that method.
Reasoning - I want to avoid an extra lookup. For example, my key may be {key:ABC123, associated:XYZ789}. To find "XYZ789" I have to do a lookup in a cache, which I really do not want to do.
Thanks.Hi,
In your example, MyKeyClass is the key for the object and the attributes {String key, String associated} must uniquely define this key. Passing "null" might it make it non-unique and also you cannot set the attributes of the objects' key later. The getAssociatedKey() leverages the attributes in your MyKeyClass to group the objects that share the same attribute. If "null" is used for the {associated} then all the keys with attribute "associated=null" will coexisit but the getAssociatedKey() call will not fail.
Re, the lookup you will use the same key as below:
MyKeyClass keyClass = new MyKeyClass ("ABC123", "XYZ789")
partitionedService.getKeyOwner(keyClass);You don't have any extra hop for this lookup as you pass the keyobject and get the owner of that key.
Hope this helps!
Cheers,
NJ
Edited by: user738616 on Mar 27, 2012 11:47 AM