/*
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*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
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*
* Copyright 2006-2010 Sun Microsystems, Inc.
*/
package org.opends.server.api;
import org.opends.messages.Message;
import java.util.List;
import java.util.concurrent.*;
import org.opends.server.admin.std.server.MonitorProviderCfg;
import org.opends.server.config.ConfigException;
import org.opends.server.types.Attribute;
import org.opends.server.types.DirectoryConfig;
import org.opends.server.types.InitializationException;
import org.opends.server.types.ObjectClass;
import static org.opends.server.util.ServerConstants.*;
/**
* This class defines the set of methods and structures that must be
* implemented by a Directory Server module that can provide usage,
* performance, availability, or other kinds of monitor information
* to clients.
*
* @param <T> The type of configuration handled by this monitor
* provider.
*/
@org.opends.server.types.PublicAPI(
stability=org.opends.server.types.StabilityLevel.VOLATILE,
mayInstantiate=false,
mayExtend=true,
mayInvoke=false)
public abstract class MonitorProvider<T extends MonitorProviderCfg>
{
// The scheduler.
private static final ScheduledExecutorService SCHEDULER =
Executors.newSingleThreadScheduledExecutor(
new MonitorThreadFactory());
/**
* Thread factory used by the scheduled execution service.
*/
private static final class MonitorThreadFactory implements
ThreadFactory
{
/**
* {@inheritDoc}
*/
public Thread newThread(Runnable r)
{
Thread t =
new DirectoryThread(r, "Monitor Provider State Updater");
t.setDaemon(true);
return t;
}
}
private ScheduledFuture<?> scheduledFuture;
/**
* Initializes this monitor provider based on the information in the
* provided configuration entry.
*
* @param configuration The configuration to use to initialize
* this monitor provider.
*
* @throws ConfigException If an unrecoverable problem arises in
* the process of performing the
* initialization.
*
* @throws InitializationException If a problem occurs during
* initialization that is not
* related to the server
* configuration.
*/
public abstract void initializeMonitorProvider(T configuration)
throws ConfigException, InitializationException;
/**
* Indicates whether the provided configuration is acceptable for
* this monitor provider. It should be possible to call this method
* on an uninitialized monitor provider instance in order to
* determine whether the monitor provider would be able to use the
* provided configuration.
* <BR><BR>
* Note that implementations which use a subclass of the provided
* configuration class will likely need to cast the configuration
* to the appropriate subclass type.
*
* @param configuration The monitor provider configuration
* for which to make the determination.
* @param unacceptableReasons A list that may be used to hold the
* reasons that the provided
* configuration is not acceptable.
*
* @return {@code true} if the provided configuration is acceptable
* for this monitor provider, or {@code false} if not.
*/
public boolean isConfigurationAcceptable(
MonitorProviderCfg configuration,
List<Message> unacceptableReasons)
{
// This default implementation does not perform any special
// validation. It should be overridden by monitor provider
// implementations that wish to perform more detailed validation.
return true;
}
/**
* Finalizes this monitor provider so that it may be unloaded and
* taken out of service. This method should be overridden by any
* monitor provider that has resources that should be released when
* the monitor is no longer needed. Any monitor that does override
* this method must first invoke this version by calling
* {@code super.finalizeMonitorProvider}.
*/
public void finalizeMonitorProvider()
{
if(scheduledFuture != null)
{
scheduledFuture.cancel(true);
}
}
/**
* Retrieves the name of this monitor provider. It should be unique
* among all monitor providers, including all instances of the same
* monitor provider.
*
* @return The name of this monitor provider.
*/
public abstract String getMonitorInstanceName();
/**
* Retrieves the objectclass that should be included in the monitor
* entry created from this monitor provider. This may be overridden
* by subclasses that wish to include their own custom objectclass
* in the monitor entry (e.g., to make it easier to search for
* monitor entries of that type). The default implementation
* returns the "extensibleObject" objectclass.
*
* @return The objectclass that should be included in the monitor
* entry created from this monitor provider.
*/
public ObjectClass getMonitorObjectClass()
{
return DirectoryConfig.getObjectClass(OC_EXTENSIBLE_OBJECT_LC,
true);
}
/**
* Schedules any periodic processing that may be desired
* to update the information associated with this monitor. Note
* that best-effort attempts will be made to ensure that calls to
* this method come {@code getUpdateInterval} milliseconds apart,
* but no guarantees will be made.
*
* @param updater The updater to execute.
* @param initialDelay The time to delay first execution.
* @param period The period between successive executions.
* @param unit The time unit of the initialDelay and period
* parameters.
*/
protected final void scheduleUpdate(Runnable updater,
long initialDelay,
long period, TimeUnit unit)
{
if(scheduledFuture != null)
{
scheduledFuture.cancel(true);
}
scheduledFuture =
SCHEDULER.scheduleAtFixedRate(updater, initialDelay,
period, unit);
}
/**
* Retrieves a set of attributes containing monitor data that should
* be returned to the client if the corresponding monitor entry is
* requested.
*
* @return A set of attributes containing monitor data that should
* be returned to the client if the corresponding monitor
* entry is requested.
*/
public abstract List<Attribute> getMonitorData();
}