streampipes-pipeline-elements-examples-processors-jvm/src/main/java/org/apache/streampipes/pe/examples/jvm/staticproperty/RuntimeResolvableSingleValue.java

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 * 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
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package org.apache.streampipes.pe.examples.jvm.staticproperty;

import org.apache.streampipes.extensions.api.extractor.IStaticPropertyExtractor;
import org.apache.streampipes.extensions.api.pe.IStreamPipesDataProcessor;
import org.apache.streampipes.extensions.api.pe.context.EventProcessorRuntimeContext;
import org.apache.streampipes.extensions.api.pe.param.IDataProcessorParameters;
import org.apache.streampipes.extensions.api.pe.routing.SpOutputCollector;
import org.apache.streampipes.extensions.api.runtime.ResolvesContainerProvidedOptions;
import org.apache.streampipes.model.runtime.Event;
import org.apache.streampipes.model.staticproperty.Option;
import org.apache.streampipes.sdk.builder.ProcessingElementBuilder;
import org.apache.streampipes.sdk.builder.StreamRequirementsBuilder;
import org.apache.streampipes.sdk.builder.processor.DataProcessorConfiguration;
import org.apache.streampipes.sdk.helpers.EpRequirements;
import org.apache.streampipes.sdk.helpers.Labels;
import org.apache.streampipes.sdk.helpers.OutputStrategies;
import org.apache.streampipes.sdk.helpers.SupportedFormats;
import org.apache.streampipes.sdk.helpers.SupportedProtocols;

import org.apache.kafka.clients.consumer.KafkaConsumer;

import java.util.Arrays;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import java.util.stream.Collectors;

public class RuntimeResolvableSingleValue implements IStreamPipesDataProcessor, ResolvesContainerProvidedOptions {

  private static final String KafkaHost = "kafka-host";
  private static final String KafkaPort = "kafka-port";

  @Override
  public DataProcessorConfiguration declareConfig() {
    return DataProcessorConfiguration.create(
        RuntimeResolvableSingleValue::new,
        ProcessingElementBuilder.create("org.apache.streampipes.examples.staticproperty" +
                ".runtimeresolvablesingle", "Runtime-resolvable single value example", "")
            .requiredStream(StreamRequirementsBuilder.
                create()
                .requiredProperty(EpRequirements.anyProperty())
                .build())
            .outputStrategy(OutputStrategies.keep())
            .supportedProtocols(SupportedProtocols.kafka())
            .supportedFormats(SupportedFormats.jsonFormat())
            .requiredTextParameter(Labels.from(KafkaHost, "Kafka Host", ""))
            .requiredIntegerParameter(Labels.from(KafkaPort, "Kafka Port", ""))

            // create a single value selection parameter that is resolved at runtime
            .requiredSingleValueSelectionFromContainer(Labels.from("id", "Example Name", "Example " +
                "Description"), Arrays.asList(KafkaHost, KafkaPort))

            .build()
    );
  }

  @Override
  public void onPipelineStarted(IDataProcessorParameters params, SpOutputCollector collector, EventProcessorRuntimeContext runtimeContext) {

    // Extract the text parameter value
    String selectedSingleValue = params.extractor().selectedSingleValue("id", String.class);

  }

  @Override
  public void onEvent(Event event, SpOutputCollector collector) {

  }

  @Override
  public void onPipelineStopped() {

  }

  @Override
  public List<Option> resolveOptions(String requestId, IStaticPropertyExtractor extractor) {
    String host = extractor.singleValueParameter(KafkaHost, String.class);
    Integer port = extractor.singleValueParameter(KafkaPort, Integer.class);

    String kafkaAddress = host + ":" + port;

    Properties props = new Properties();
    props.put("bootstrap.servers", kafkaAddress);
    props.put("group.id", "test-consumer-group");
    props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
    props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");

    KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(props);
    Set<String> topics = consumer.listTopics().keySet();
    consumer.close();
    return topics.stream().map(Option::new).collect(Collectors.toList());
  }
}