flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From zentol <...@git.apache.org>
Subject [GitHub] flink pull request #3838: [FLINK-5886] Python API for streaming applications
Date Mon, 22 May 2017 11:59:11 GMT
Github user zentol commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3838#discussion_r117724239
  
    --- Diff: flink-libraries/flink-streaming-python/src/main/java/org/apache/flink/streaming/python/api/datastream/PythonDataStream.java
---
    @@ -0,0 +1,262 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +package org.apache.flink.streaming.python.api.datastream;
    +
    +import org.apache.flink.annotation.Public;
    +import org.apache.flink.annotation.PublicEvolving;
    +import org.apache.flink.api.common.functions.FilterFunction;
    +import org.apache.flink.api.common.functions.FlatMapFunction;
    +import org.apache.flink.api.common.functions.MapFunction;
    +import org.apache.flink.api.java.functions.KeySelector;
    +import org.apache.flink.core.fs.FileSystem.WriteMode;
    +import org.apache.flink.streaming.api.collector.selector.OutputSelector;
    +import org.apache.flink.streaming.api.datastream.DataStream;
    +import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
    +import org.apache.flink.streaming.api.functions.sink.SinkFunction;
    +import org.apache.flink.streaming.python.api.functions.PyKey;
    +import org.apache.flink.streaming.python.api.functions.PythonFilterFunction;
    +import org.apache.flink.streaming.python.api.functions.PythonFlatMapFunction;
    +import org.apache.flink.streaming.python.api.functions.PythonKeySelector;
    +import org.apache.flink.streaming.python.api.functions.PythonMapFunction;
    +import org.apache.flink.streaming.python.api.functions.PythonOutputSelector;
    +import org.apache.flink.streaming.python.api.functions.PythonSinkFunction;
    +import org.apache.flink.streaming.python.util.serialization.PythonSerializationSchema;
    +import org.apache.flink.streaming.util.serialization.SerializationSchema;
    +import org.python.core.PyObject;
    +
    +import java.io.IOException;
    +import java.util.ArrayList;
    +
    +
    +/**
    + * A {@code PythonDataStream} is a thin wrapper layer over {@link DataStream}, which
represents a
    + * stream of elements of the same type. A {@code PythonDataStream} can be transformed
into
    + * another {@code PythonDataStream} by applying various transformation functions, such
as
    + * <ul>
    + * <li>{@link PythonDataStream#map}
    + * <li>{@link PythonDataStream#split}
    + * </ul>
    + *
    + * <p>A thin wrapper layer means that the functionality itself is performed by
the
    + * {@link DataStream}, however instead of working directly with the streaming data sets,
    + * this layer handles Python wrappers (e.g. {@code PythonDataStream}) to comply with
the
    + * Python standard coding styles.</p>
    + */
    +@Public
    +public class PythonDataStream<D extends DataStream<PyObject>> {
    +	protected final D stream;
    +
    +	public PythonDataStream(D stream) {
    +		this.stream = stream;
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#union(DataStream[])}.
    +	 *
    +	 * @param streams
    +	 *            The Python DataStreams to union output with.
    +	 * @return The {@link PythonDataStream}.
    +	 */
    +	@SafeVarargs
    +	@SuppressWarnings("unchecked")
    +	public final PythonDataStream union(PythonDataStream... streams) {
    +		ArrayList<DataStream<PyObject>> dsList = new ArrayList<>();
    +		for (PythonDataStream ps : streams) {
    +			dsList.add(ps.stream);
    +		}
    +		DataStream<PyObject>[] dsArray = new DataStream[dsList.size()];
    +		return new PythonDataStream(stream.union(dsList.toArray(dsArray)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#split(OutputSelector)}.
    +	 *
    +	 * @param output_selector
    +	 *            The user defined {@link OutputSelector} for directing the tuples.
    +	 * @return The {@link PythonSplitStream}
    +	 */
    +	public PythonSplitStream split(OutputSelector<PyObject> output_selector) throws
IOException {
    +		return new PythonSplitStream(this.stream.split(new PythonOutputSelector(output_selector)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#filter(FilterFunction)}.
    +	 *
    +	 * @param filter
    +	 *            The FilterFunction that is called for each element of the DataStream.
    +	 * @return The filtered {@link PythonDataStream}.
    +	 */
    +	public PythonSingleOutputStreamOperator filter(FilterFunction<PyObject> filter)
throws IOException {
    +		return new PythonSingleOutputStreamOperator(stream.filter(new PythonFilterFunction(filter)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#map(MapFunction)}.
    +	 *
    +	 * @param mapper
    +	 *            The MapFunction that is called for each element of the
    +	 *            DataStream.
    +	 * @return The transformed {@link PythonDataStream}.
    +	 */
    +	public PythonDataStream<SingleOutputStreamOperator<PyObject>> map(
    +		MapFunction<PyObject, PyObject> mapper) throws IOException {
    +		return new PythonDataStream<>(stream.map(new PythonMapFunction(mapper)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#flatMap(FlatMapFunction)}.
    +	 *
    +	 * @param flat_mapper
    +	 *            The FlatMapFunction that is called for each element of the
    +	 *            DataStream
    +	 *
    +	 * @return The transformed {@link PythonDataStream}.
    +	 */
    +	public PythonDataStream<SingleOutputStreamOperator<PyObject>> flat_map(
    +		FlatMapFunction<PyObject, PyObject> flat_mapper) throws IOException {
    +		return new PythonDataStream<>(stream.flatMap(new PythonFlatMapFunction(flat_mapper)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#keyBy(KeySelector)}.
    +	 *
    +	 * @param selector
    +	 *            The KeySelector to be used for extracting the key for partitioning
    +	 * @return The {@link PythonDataStream} with partitioned state (i.e. {@link PythonKeyedStream})
    +	 */
    +	public PythonKeyedStream key_by(KeySelector<PyObject, PyKey> selector) throws
IOException {
    +		return new PythonKeyedStream(stream.keyBy(new PythonKeySelector(selector)));
    +	}
    +
    +	/**
    +	 * A thin wrapper layer over {@link DataStream#print()}.
    +	 */
    +	@PublicEvolving
    +	public void print() { stream.print(); }
    --- End diff --
    
    `stream.print();` should be on a separate line.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message