content: /*
   * 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
   * <p/>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p/>
   * 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.siddhi;
  
  import org.apache.flink.annotation.PublicEvolving;
  import org.apache.flink.api.common.functions.MapFunction;
  import org.apache.flink.api.common.typeinfo.TypeInformation;
  import org.apache.flink.api.java.functions.KeySelector;
  import org.apache.flink.api.java.tuple.Tuple;
  import org.apache.flink.api.java.tuple.Tuple2;
  import org.apache.flink.api.java.typeutils.TypeExtractor;
  import org.apache.flink.streaming.api.datastream.DataStream;
  import org.apache.flink.streaming.api.datastream.KeyedStream;
  import org.apache.flink.streaming.siddhi.operator.SiddhiOperatorContext;
  import org.apache.flink.streaming.siddhi.utils.SiddhiStreamFactory;
  import org.apache.flink.streaming.siddhi.utils.SiddhiTypeFactory;
  import org.apache.flink.util.Preconditions;
  
  import java.util.Arrays;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Siddhi CEP Stream API
   */
  @PublicEvolving
  public abstract class SiddhiStream {
      private final SiddhiCEP cepEnvironment;
  
      /**
       * @param cepEnvironment SiddhiCEP cepEnvironment.
       */
      public SiddhiStream(SiddhiCEP cepEnvironment) {
          Preconditions.checkNotNull(cepEnvironment,"SiddhiCEP cepEnvironment is null");
          this.cepEnvironment = cepEnvironment;
      }
  
      /**
       * @return current SiddhiCEP cepEnvironment.
       */
      protected SiddhiCEP getCepEnvironment() {
          return this.cepEnvironment;
      }
  
      /**
       * @return Transform SiddhiStream to physical DataStream
       */
      protected abstract DataStream<Tuple2<String, Object>> toDataStream();
  
      /**
       * Convert DataStream&lt;T&gt; to DataStream&lt;Tuple2&lt;String,T&gt;&gt;.
       * If it's KeyedStream. pass through original keySelector
       */
      protected <T> DataStream<Tuple2<String, Object>> convertDataStream(DataStream<T> dataStream, String streamId) {
          final String streamIdInClosure = streamId;
          DataStream<Tuple2<String, Object>> resultStream = dataStream.map(new MapFunction<T, Tuple2<String, Object>>() {
              @Override
              public Tuple2<String, Object> map(T value) throws Exception {
                  return Tuple2.of(streamIdInClosure, (Object) value);
              }
          });
          if (dataStream instanceof KeyedStream) {
              final KeySelector<T, Object> keySelector = ((KeyedStream<T, Object>) dataStream).getKeySelector();
              final KeySelector<Tuple2<String, Object>, Object> keySelectorInClosure = new KeySelector<Tuple2<String, Object>, Object>() {
                  @Override
                  public Object getKey(Tuple2<String, Object> value) throws Exception {
                      return keySelector.getKey((T) value.f1);
                  }
              };
              return resultStream.keyBy(keySelectorInClosure);
          } else {
              return resultStream;
          }
      }
  
      /**
       * ExecutableStream context to define execution logic, i.e. SiddhiCEP execution plan.
       */
      public abstract static class ExecutableStream extends SiddhiStream {
          public ExecutableStream(SiddhiCEP environment) {
              super(environment);
          }
  
          /**
           * Siddhi Continuous Query Language (CQL)
           *
           * @param executionPlan Siddhi SQL-Like execution plan query
           * @return ExecutionSiddhiStream context
           */
          public ExecutionSiddhiStream cql(String executionPlan) {
              Preconditions.checkNotNull(executionPlan,"executionPlan");
              return new ExecutionSiddhiStream(this.toDataStream(), executionPlan, getCepEnvironment());
          }
      }
  
      /**
       * Initial Single Siddhi Stream Context
       */
      public static class SingleSiddhiStream<T> extends ExecutableStream {
          private final String streamId;
  
          public SingleSiddhiStream(String streamId, SiddhiCEP environment) {
              super(environment);
              environment.checkStreamDefined(streamId);
              this.streamId = streamId;
          }
  
  
          /**
           * Define siddhi stream with streamId, source <code>DataStream</code> and stream schema and as the first stream of {@link UnionSiddhiStream}
           *
           * @param streamId Unique siddhi streamId
           * @param dataStream DataStream to bind to the siddhi stream.
           * @param fieldNames Siddhi stream schema field names
           *
           * @return {@link UnionSiddhiStream} context
           */
          public UnionSiddhiStream<T> union(String streamId, DataStream<T> dataStream, String... fieldNames) {
              getCepEnvironment().registerStream(streamId, dataStream, fieldNames);
              return union(streamId);
          }
  
          /**
           * @param streamIds Defined siddhi streamIds to union
           * @return {@link UnionSiddhiStream} context
           */
          public UnionSiddhiStream<T> union(String... streamIds) {
              Preconditions.checkNotNull(streamIds,"streamIds");
              return new UnionSiddhiStream<T>(this.streamId, Arrays.asList(streamIds), this.getCepEnvironment());
          }
  
          @Override
          protected DataStream<Tuple2<String, Object>> toDataStream() {
              return convertDataStream(getCepEnvironment().getDataStream(this.streamId), this.streamId);
          }
      }
  
      public static class UnionSiddhiStream<T> extends ExecutableStream {
          private String firstStreamId;
          private List<String> unionStreamIds;
  
          public UnionSiddhiStream(String firstStreamId, List<String> unionStreamIds, SiddhiCEP environment) {
              super(environment);
              Preconditions.checkNotNull(firstStreamId,"firstStreamId");
              Preconditions.checkNotNull(unionStreamIds,"unionStreamIds");
              environment.checkStreamDefined(firstStreamId);
              for (String unionStreamId : unionStreamIds) {
                  environment.checkStreamDefined(unionStreamId);
              }
              this.firstStreamId = firstStreamId;
              this.unionStreamIds = unionStreamIds;
          }
  
          /**
           * Define siddhi stream with streamId, source <code>DataStream</code> and stream schema and continue to union it with current stream.
           *
           * @param streamId Unique siddhi streamId
           * @param dataStream DataStream to bind to the siddhi stream.
           * @param fieldNames Siddhi stream schema field names
           *
           * @return {@link UnionSiddhiStream} context
           */
          public UnionSiddhiStream<T> union(String streamId, DataStream<T> dataStream, String... fieldNames) {
              Preconditions.checkNotNull(streamId,"streamId");
              Preconditions.checkNotNull(dataStream,"dataStream");
              Preconditions.checkNotNull(fieldNames,"fieldNames");
              getCepEnvironment().registerStream(streamId, dataStream, fieldNames);
              return union(streamId);
          }
  
          /**
           * @param streamId another defined streamId to union with.
           * @return {@link UnionSiddhiStream} context
           */
          public UnionSiddhiStream<T> union(String... streamId) {
              List<String> newUnionStreamIds = new LinkedList<>();
              newUnionStreamIds.addAll(unionStreamIds);
              newUnionStreamIds.addAll(Arrays.asList(streamId));
              return new UnionSiddhiStream<T>(this.firstStreamId, newUnionStreamIds, this.getCepEnvironment());
          }
  
          @Override
          protected DataStream<Tuple2<String, Object>> toDataStream() {
              final String localFirstStreamId = firstStreamId;
              final List<String> localUnionStreamIds = this.unionStreamIds;
              DataStream<Tuple2<String, Object>> dataStream = convertDataStream(getCepEnvironment().<T>getDataStream(localFirstStreamId), this.firstStreamId);
              for (String unionStreamId : localUnionStreamIds) {
                  dataStream = dataStream.union(convertDataStream(getCepEnvironment().<T>getDataStream(unionStreamId), unionStreamId));
              }
              return dataStream;
          }
      }
  
      public static class ExecutionSiddhiStream {
          private final DataStream<Tuple2<String, Object>> dataStream;
          private final SiddhiCEP environment;
          private final String executionPlan;
  
          public ExecutionSiddhiStream(DataStream<Tuple2<String, Object>> dataStream, String executionPlan, SiddhiCEP environment) {
              this.executionPlan = executionPlan;
              this.dataStream = dataStream;
              this.environment = environment;
          }
  
          /**
           * @param outStreamId The <code>streamId</code> to return as data stream.
           * @param <T>         Type information should match with stream definition.
           *                    During execution phase, it will automatically build type information based on stream definition.
           * @return Return output stream as Tuple
           * @see SiddhiTypeFactory
           */
          public <T extends Tuple> DataStream<T> returns(String outStreamId) {
              SiddhiOperatorContext siddhiContext = new SiddhiOperatorContext();
              siddhiContext.setExecutionPlan(executionPlan);
              siddhiContext.setInputStreamSchemas(environment.getDataStreamSchemas());
              siddhiContext.setTimeCharacteristic(environment.getExecutionEnvironment().getStreamTimeCharacteristic());
              siddhiContext.setOutputStreamId(outStreamId);
              siddhiContext.setExtensions(environment.getExtensions());
              siddhiContext.setExecutionConfig(environment.getExecutionEnvironment().getConfig());
              TypeInformation<T> typeInformation =
                  SiddhiTypeFactory.getTupleTypeInformation(siddhiContext.getFinalExecutionPlan(), outStreamId);
              siddhiContext.setOutputStreamType(typeInformation);
              return returnsInternal(siddhiContext, outStreamId);
          }
  
          /**
           * @return Return output stream as <code>DataStream&lt;Map&lt;String,Object&gt;&gt;</code>,
           * out type is <code>LinkedHashMap&lt;String,Object&gt;</code> and guarantee field order
           * as defined in siddhi execution plan
           * @see java.util.LinkedHashMap
           */
          public DataStream<Map<String, Object>> returnAsMap(String outStreamId) {
              return this.returnsInternal(outStreamId, SiddhiTypeFactory.getMapTypeInformation());
          }
  
          /**
           * @param outStreamId OutStreamId
           * @param outType     Output type class
           * @param <T>         Output type
           * @return Return output stream as POJO class.
           */
          public <T> DataStream<T> returns(String outStreamId, Class<T> outType) {
              TypeInformation<T> typeInformation = TypeExtractor.getForClass(outType);
              return returnsInternal(outStreamId, typeInformation);
          }
  
          private <T> DataStream<T> returnsInternal(String outStreamId, TypeInformation<T> typeInformation) {
              SiddhiOperatorContext siddhiContext = new SiddhiOperatorContext();
              siddhiContext.setExecutionPlan(executionPlan);
              siddhiContext.setInputStreamSchemas(environment.getDataStreamSchemas());
              siddhiContext.setTimeCharacteristic(environment.getExecutionEnvironment().getStreamTimeCharacteristic());
              siddhiContext.setOutputStreamId(outStreamId);
              siddhiContext.setOutputStreamType(typeInformation);
              siddhiContext.setExtensions(environment.getExtensions());
              siddhiContext.setExecutionConfig(environment.getExecutionEnvironment().getConfig());
              return returnsInternal(siddhiContext, outStreamId);
          }
  
          private <T> DataStream<T> returnsInternal(SiddhiOperatorContext siddhiContext, String outStreamId) {
              return SiddhiStreamFactory.createDataStream(siddhiContext, this.dataStream, outStreamId);
          }
      }
  }
  