python/src/pywy/platforms/jvm/operator/jvm_unary_filter.py

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#  this work for additional information regarding copyright ownership.
#  The ASF licenses this file to You under the Apache License, Version 2.0
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#      http://www.apache.org/licenses/LICENSE-2.0
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from typing import Set, List, Type

from pywy.core.channel import CH_T, ChannelDescriptor
from pywy.operators.unary import FilterOperator
from pywy.platforms.jvm.channels import DISPATCHABLE_CHANNEL_DESCRIPTOR, DispatchableChannel
from pywy.platforms.jvm.operator.jvm_execution_operator import JVMExecutionOperator
from pywy.platforms.commons.channels import (
    CommonsCallableChannel
)
from pywy.platforms.jvm.serializable.wayang_jvm_operator import WayangJVMMappartitionOperator, WayangJVMOperator


class JVMFilterOperator(FilterOperator, JVMExecutionOperator):

    def __init__(self, origin: FilterOperator = None):
        predicate = None if origin is None else origin.predicate
        super().__init__(predicate)
        pass

    def execute(self, inputs: List[Type[CH_T]], outputs: List[Type[CH_T]]):
        self.validate_channels(inputs, outputs)
        udf = self.predicate
        if isinstance(inputs[0], DispatchableChannel):
            py_in_dispatch_channel: DispatchableChannel = inputs[0]
            py_out_dispatch_channel: DispatchableChannel = outputs[0]

            def func(iterator):
                return filter(udf, iterator)

            py_out_dispatch_channel.accept_callable(
                CommonsCallableChannel.concatenate(
                    func,
                    py_in_dispatch_channel.provide_callable()
                )
            )

            op: WayangJVMOperator = py_in_dispatch_channel.provide_dispatchable()

            if isinstance(op, WayangJVMMappartitionOperator):
                py_out_dispatch_channel.accept_dispatchable(op)
                return

            current: WayangJVMMappartitionOperator = WayangJVMMappartitionOperator(self.name)
            # TODO check for the case where the index matter
            op.connect_to(0, current, 0)
            py_out_dispatch_channel.accept_dispatchable(current)

        else:
            raise Exception("Channel Type does not supported")

    def get_input_channeldescriptors(self) -> Set[ChannelDescriptor]:
        return {DISPATCHABLE_CHANNEL_DESCRIPTOR}

    def get_output_channeldescriptors(self) -> Set[ChannelDescriptor]:
        return {DISPATCHABLE_CHANNEL_DESCRIPTOR}