Examples of FiddlerAdmin

com.sun.jini.fiddler.FiddlerAdmin
An administrative interface for the Fiddler implementation of the lookup discovery service (see {@linkplain com.sun.jini.fiddler Fiddler}). The comments that follow describe Fiddler with respect to the following methods:
- setLeaseBound
- getLeaseBound
- setPersistenceSnapshotWeight
- getPersistenceSnapshotWeight
- setPersistenceSnapshotThreshold
- getPersistenceSnapshotThreshold
The intent of the information contained in this note is to clarify the use of these methods and the effect that use will have on the configuration of Fiddler. Note that the phrase lookup discovery service as used throughout this note refers to the Fiddler implementation of that service. While such a lookup discovery service is running, the following sort of state changes can occur:
- Clients register and un-register (cancel their lease) with the lookup discovery service
- Leases on the registrations created for a client by the lookup discovery service are granted, renewed, cancelled and expired
- Managed sets of groups, locators and lookup services associated with the client registrations are added, modified, and removed from the lookup discovery service
In order to make the lookup discovery service's state persistent across system crashes or network outages, each of the state changes described above are written to a file referred to as the service's log file. The service's log file records, over time, the incremental changes -- or deltas -- made to the lookup discovery service's state.
To prevent the log file from growing indefinitely, the lookup discovery service's complete state is intermittently written to another file referred to as the service's snapshot file. When a snapshot of the service's state is logged to the service's snapshot file, the service's log file is cleared, and the incremental logging of deltas begins anew. When the service is started for the first time, the initial period prior to the creation of the first snapshot is referred to as the system ramp-up period. This ramp-up period is the only time where a log file exists without a corresponding snapshot file.
When recovering the system's state after a crash or network outage (or after the lookup discovery service or its ActivationGroup has been un-registered and then re-registered through the Activation daemon), a "base state" is first recovered by retrieving and applying the contents of the snapshot file (if it exists). Then, if the log file has length greater than zero, its contents are retrieved and applied in order to incrementally recover the state changes that occurred from the point of the base state.
The criteria used by the lookup discovery service to determine exactly when to "take a snapshot" depends on the current size of the log file relative to the size that the snapshot file will be. Note that whereas, the size of the log file depends on the total number of changes to the lookup discovery service's state, the size of the snapshot file depends on the number of registrations that are currently active; that is, the more registrations that have been created and which have valid leases, the larger the snapshot. For example, if only 10 registrations are active, the snapshot file will be relatively small; but lease renewals may be regularly requested on some of those registrations. The regular lease renewals will result in a very large log file.
A balance must be maintained between how large the log file is allowed to get and how often a snapshot is taken; taking snapshots too often can slow down processing significantly. The lookup discovery service is initially configured with a threshold value and a weighting factor that are employed in a computation that determines when to take a snapshot. The methods specified by this interface provide ways to access and modify those values. Thus, based on a particular lookup discovery service's makeup, these methods can be used by that service's administrative client to "tune" performance with respect to logging the service's persistent state.
```
 The following comparison is made to determine when to take a snapshot: if (logSize >= W*snapshotSize) && (snapshotSize >= T) { take a snapshot; } where W = persistenceSnapshotWeight T = persistenceSnapshotThreshold 
```
The first comparison is used to ensure that the log file does not grow too large. The second comparison ensures that snapshots are not taken too often.
Administrative clients of Fiddler should consider these relationships when using the methods specified by this interface to tune that service's persistence mechanism. @author Sun Microsystems, Inc.

Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, "run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
            +serviceName);
        }
  FiddlerAdmin serviceAdmin = 
      FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  long oldValue = serviceAdmin.getLeaseBound();
  logger.log(Level.FINE, "oldValue = " + oldValue);
  serviceAdmin.setLeaseBound(expectedValue);
  long newValue = serviceAdmin.getLeaseBound();
  logger.log(Level.FINE, "newValue = " + newValue);
  if(expectedValue != newValue) {
      throw new TestException("new value (" + newValue + ") "
          + "!= expected value ("+expectedValue+")");
  }

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Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, "run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
            +serviceName);
        }
  FiddlerAdmin serviceAdmin
      = FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  float oldValue = serviceAdmin.getPersistenceSnapshotWeight();
  logger.log(Level.FINE, "oldValue = " + oldValue);
  serviceAdmin.setPersistenceSnapshotWeight(expectedValue);
  float newValue = serviceAdmin.getPersistenceSnapshotWeight();
  logger.log(Level.FINE, "newValue = " + newValue);
  if(expectedValue != newValue) {
      throw new TestException("new value (" + newValue + ") "
          + "!= expected value ("+expectedValue+")");
  }

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Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, "run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
            +serviceName);
        }
  FiddlerAdmin serviceAdmin
      = FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  int oldValue = serviceAdmin.getPersistenceSnapshotThreshold();
  logger.log(Level.FINE, "oldValue = " + oldValue);
  serviceAdmin.setPersistenceSnapshotThreshold(expectedValue);
  int newValue = serviceAdmin.getPersistenceSnapshotThreshold();
  logger.log(Level.FINE, "newValue = " + newValue);
  if(expectedValue != newValue) {
      throw new TestException("new value (" + newValue + ") "
            + "!= expected value ("+expectedValue+")");
  }

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Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, "run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
          + serviceName);
        }
  FiddlerAdmin serviceAdmin
      = FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  float curValue = serviceAdmin.getPersistenceSnapshotWeight();
  logger.log(Level.FINE, "curValue = " + curValue);
  if(expectedValue != curValue) {
      throw new TestException("current value (" + curValue + ") "
          + "!= expected value ("+expectedValue+")");
  }

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Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, "run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
            +serviceName);
        }
  FiddlerAdmin serviceAdmin
      = FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  long curValue = serviceAdmin.getLeaseBound();
  logger.log(Level.FINE, "curValue = " + curValue);
  if(expectedValue != curValue) {
      throw new TestException("current value (" + curValue + ") "
            +"!= expected value ("+expectedValue+")");
  }

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Examples of com.sun.jini.fiddler.FiddlerAdmin

        logger.log(Level.FINE, ""+": run()");
        if(discoverySrvc == null) {
            throw new TestException("could not successfully start service "
            +serviceName);
        }
  FiddlerAdmin serviceAdmin
      = FiddlerAdminUtil.getFiddlerAdmin(discoverySrvc);
  
  int curValue = serviceAdmin.getPersistenceSnapshotThreshold();
  logger.log(Level.FINE, "curValue = "+curValue);
  if(expectedValue != curValue) {
      throw new TestException("current value (" + curValue + ") "
            +"!= expected value ("+expectedValue+")");
  }

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