batch mutate for the lazy

The following would work with ExampleDao if you make execute public. Just an example of how you can get real tight encapsulation with a command pattern. 

Given the following method on my "DAO" class:
    
public void batchInsert(final String key, final Map<String, String> columnMap) throws Exception {
    BatchMutationCallback batchInsertCallback = new BatchMutationCallback(columnFamilyName, buildTimestamp());        
    for (String colName : columnMap.keySet()) {
        batchInsertCallback.addInsertion(key, colName, columnMap.get(colName));  
    }
    execute(batchInsertCallback);
}
...

I have the following callback class (annonymous inner classes can get too messy sometimes):

public class BatchMutationCallback extends Command<Void> {
    private final long timestamp;
    private final String columnFamilyName;
    private final BatchMutation batchMutation;
    
    BatchMutationCallback(String columnFamilyName, long timestamp) {
        this.columnFamilyName = columnFamilyName; 
        this.timestamp = timestamp;
        batchMutation = new BatchMutation();
    }
    
    public void addInsertion(String key, String columnName, String columnValue) {
        batchMutation.addInsertion(key, Arrays.asList(columnFamilyName), 
                new Column(bytes(columnName), bytes(columnValue), timestamp));        
    }

    public Void execute(final Keyspace ks) throws Exception {        
        ks.batchMutate(batchMutation);
        return null;
    }
}