java/server/src/org/openqa/grid/internal/ActiveTestSessions.java

/*
Copyright 2011 Selenium committers
Copyright 2011 Software Freedom Conservancy

Licensed 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.openqa.grid.internal;

import net.jcip.annotations.ThreadSafe;
import org.openqa.grid.common.exception.GridException;

import java.util.Collections;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.logging.Logger;

/**
 * The set of active test sessions.
 */
@ThreadSafe
class ActiveTestSessions {

  private static final Logger log = Logger.getLogger(ActiveTestSessions.class.getName());

  private final Set<TestSession> activeTestSessions = new CopyOnWriteArraySet<TestSession>();

  private final
  Queue<ExternalSessionKey>
      terminatedSessions =
      new ConcurrentLinkedQueue<ExternalSessionKey>();
  private final
  Map<ExternalSessionKey, SessionTerminationReason>
      reasons =
      new ConcurrentHashMap<ExternalSessionKey, SessionTerminationReason>();


  public boolean add(TestSession testSession) {
    final boolean added = activeTestSessions.add(testSession);
    if (!added) {
      log.severe("Error adding session : " + testSession);
    }
    return added;
  }

  public boolean remove(TestSession o, SessionTerminationReason reason) {
    updateReason(o, reason);
    return activeTestSessions.remove(o);
  }

  private void updateReason(TestSession o, SessionTerminationReason reason) {
    if (o.getExternalKey() == null) {
      if (SessionTerminationReason.CREATIONFAILED != reason) { // Should not happen. Yeah.
        log.info(
            "Removed a session that had not yet assigned an external key " + o.getInternalKey() +
            ", indicates failure in session creation " + reason);
      }
      return;
    }

    terminatedSessions.add(o.getExternalKey());
    reasons.put(o.getExternalKey(), reason);
    if (reasons.size() > 1000) {
      ExternalSessionKey remove = terminatedSessions.remove();
      reasons.remove(remove);
    }
  }

  public TestSession findSessionByInternalKey(String internalKey) {
    if (internalKey == null) {
      return null;
    }

    for (TestSession session : activeTestSessions) {
      if (internalKey.equals(session.getInternalKey())) {
        return session;
      }
    }
    return null;
  }

  public TestSession getExistingSession(ExternalSessionKey externalkey) {
    TestSession sessionByExternalKey = findSessionByExternalKey(externalkey);
    if (sessionByExternalKey == null) {
      SessionTerminationReason sessionTerminationReason = reasons.get(externalkey);
      String keyId = externalkey != null ? externalkey.getKey() : "(null externalkey)";
      if (sessionTerminationReason != null) {
          String msg = "Session [" + keyId + "] was terminated due to " + sessionTerminationReason;
          log.fine(msg);
          throw new GridException(msg);
      } else {
          String msg = "Session [" + keyId + "] not available and is not among the last 1000 terminated sessions.\n"
                  + "Active sessions are" + this.unmodifiableSet();
          log.fine(msg);
          throw new GridException(msg);
      }
    }
    return sessionByExternalKey;
  }

  public TestSession findSessionByExternalKey(ExternalSessionKey externalkey) {
    if (externalkey == null) {
      return null;
    }

    for (TestSession session : activeTestSessions) {
      if (externalkey.equals(session.getExternalKey())) {
        return session;
      }
    }
    return null;
  }

  public Set<TestSession> unmodifiableSet() {
    return Collections.unmodifiableSet(activeTestSessions);
  }

}