Examples with CombineFunction org.apache.flink.api.common.functions.CombineFunction used on opensource projects

Example 1 with CombineFunction

use of org.apache.flink.api.common.functions.CombineFunction in project flink by apache.

the class GroupReduceOperator method checkCombinability.

private boolean checkCombinability() {
    if (function instanceof GroupCombineFunction || function instanceof CombineFunction) {
        // check if the generic types of GroupCombineFunction and GroupReduceFunction match, i.e.,
        //   GroupCombineFunction<IN, IN> and GroupReduceFunction<IN, OUT>.
        // This is a best effort check. If the check cannot be done, we might fail at runtime.
        Type[] reduceTypes = null;
        Type[] combineTypes = null;
        Type[] genInterfaces = function.getClass().getGenericInterfaces();
        for (Type genInterface : genInterfaces) {
            if (genInterface instanceof ParameterizedType) {
                // get parameters of GroupReduceFunction
                if (((ParameterizedType) genInterface).getRawType().equals(GroupReduceFunction.class)) {
                    reduceTypes = ((ParameterizedType) genInterface).getActualTypeArguments();
                // get parameters of GroupCombineFunction
                } else if ((((ParameterizedType) genInterface).getRawType().equals(GroupCombineFunction.class)) || (((ParameterizedType) genInterface).getRawType().equals(CombineFunction.class))) {
                    combineTypes = ((ParameterizedType) genInterface).getActualTypeArguments();
                }
            }
        }
        if (reduceTypes != null && reduceTypes.length == 2 && combineTypes != null && combineTypes.length == 2) {
            if (reduceTypes[0].equals(combineTypes[0]) && reduceTypes[0].equals(combineTypes[1])) {
                return true;
            } else {
                LOG.warn("GroupCombineFunction cannot be used as combiner for GroupReduceFunction. " + "Generic types are incompatible.");
                return false;
            }
        } else if (reduceTypes == null || reduceTypes.length != 2) {
            LOG.warn("Cannot check generic types of GroupReduceFunction. " + "Enabling combiner but combine function might fail at runtime.");
            return true;
        } else {
            LOG.warn("Cannot check generic types of GroupCombineFunction. " + "Enabling combiner but combine function might fail at runtime.");
            return true;
        }
    }
    return false;
}