utils/streamscope/src/main/java/org/apache/edgent/streamscope/StreamScopeRegistryBean.java

/*
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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.edgent.streamscope;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.edgent.execution.services.ControlService;
import org.apache.edgent.streamscope.mbeans.StreamScopeMXBean;
import org.apache.edgent.streamscope.mbeans.StreamScopeRegistryMXBean;

/**
 * An implementation of {@link StreamScopeRegistryMXBean}.
 */
public class StreamScopeRegistryBean implements StreamScopeRegistryMXBean {
  private final StreamScopeRegistry rgy;
  private final ControlService cs;
  
  // streamId -> controlId for StreamScopeBean registered for streamId
  // TODO: seems like if we can cs.getControl(type,alias) to find a control
  // then there should be an cs.unregister(type,alias).
  // lacking that we need to record controls that were registered.
  private final Map<String,String> controlIdMap = new HashMap<>();
  
  public StreamScopeRegistryBean(StreamScopeRegistry rgy, ControlService cs) {
    this.rgy = rgy;
    this.cs = cs;
  }
  
  @Override
  public StreamScopeMXBean lookup(String jobId, String opletId, int oport) {
    // lazy-register the mbeans
    String streamId = StreamScopeRegistry.mkStreamId(jobId, opletId, oport);
    StreamScopeMXBean mbean = cs.getControl(StreamScopeMXBean.TYPE, streamId, StreamScopeMXBean.class);
    
    if (mbean == null) {
      String name = StreamScopeRegistry.nameForStreamId(streamId);
      StreamScope<?> ss = rgy.lookup(name);
      if (ss != null) {
        mbean = new StreamScopeBean(ss);
        String controlId = cs.registerControl(StreamScopeMXBean.TYPE, 
            StreamScopeMXBean.TYPE+streamId, streamId,
            StreamScopeMXBean.class, mbean);
        controlIdMap.put(name, controlId);
      }
    }
    
    return mbean;
  }
  
  /**
   * Unregister all StreamScopeMXBean for the oplet.
   * no-op if none registered.
   * <BR>
   * N.B. This does not unregister StreamScopes from the underlying StreamScopeRegistry.
   * @param jobId
   * @param opletId
   */
  void unregister(String jobId, String opletId) {
    for (String controlId : controlIds(jobId, opletId)) {
      cs.unregister(controlId);
    }
  }
  
  private List<String> controlIds(String jobId, String opletId) {
    String namePrefix = StreamScopeRegistry.mkStreamIdNamePrefix(jobId, opletId);
    List<String> controlIds = new ArrayList<>();
    for (String streamId : controlIdMap.keySet()) {
      if (streamId.startsWith(namePrefix))
        controlIds.add(controlIdMap.get(streamId));
    }
    return controlIds;
  }
  
}