Implement the PartitionResolver interface to enable custom partitioning on the PartitionedRegion.
The Key class or callback arg can implement the PartitionResolver interface to enable custom partitioning, or you can configure your own PartitionResolver class in partition attributes (for instance when the Key is a primitive type or String):
- Implement the appropriate equals. For all implementations, you need to be sure to code the class equals method so it properly verifies equality for the PartitionResolver implementation. This might mean verifying that class names are the same or that the returned routing objects are the same etc. When you initiate the partitioned region on multiple nodes, Geode uses the equals method to ensure you are using the same PartitionResolver implementation for all of the nodes for the region.
- Geode uses the routing object's hashCode to determine where the data is being managed. Say, for example, you want to colocate all Trades by month and year. The key is implemented by a TradeKey class which also implements the PartitionResolver interface:
private String tradeID;
private Month month;
private Year year;
public TradingKey() { }
public TradingKey(Month month, Year year) {
this.month = month;
this.year = year;
}
return this.month + this.year;
}
}
In the example above, all trade entries with the same month and year are guaranteed to be colocated.