Should handle 'index_options' for CUSTOM type index

[ghost]

When building a CUSTOM secondary index on a column, the custom index class name should be provided.

With cassandra-cli, we can do it like below:

create column family test with
    comparator = UTF8Type and
    key_validation_class=UTF8Type and
    column_metadata = [
        {
            column_name : col1, 
            validation_class: UTF8Type, 
            index_type : CUSTOM,
            index_options : {class_name : 'net.abc.MyIndex'}
        },
        ...
    ];

And in Cassandra, index_options will be checked like below:

if (c.index_type == IndexType.CUSTOM) {
    if (c.index_options == null || !c.index_options.containsKey(SecondaryIndex.CUSTOM_INDEX_OPTION_NAME))
                        throw new InvalidRequestException("Required index option missing: " + SecondaryIndex.CUSTOM_INDEX_OPTION_NAME);                    
}

In org.apache.cassandra.thrift.ColumnDef, there is a method can set this option.

public ColumnDef setIndex_options(Map<String,String> index_options)

But in Hector, in me.prettyprint.cassandra.service.ThriftColumnDef, seems it doesn't handle the index_options.

public ThriftColumnDef(ColumnDef cd) {
    Assert.notNull(cd, "ColumnDef is null");
    name = cd.name;
    validationClass = cd.validation_class;
    indexType = indexTypeFromThrift(cd.index_type);
    indexName = cd.index_name;
}

So if we try to build a CUSTOM secondary index with Hector, it will fail and cause an exception.

Exception in thread "main" me.prettyprint.hector.api.exceptions.HInvalidRequestException: InvalidRequestException(why:Required index option missing: class_name)