/*
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* The contents of this file are subject to the terms of the Common Development and
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* Distribution License (the License). You may not use this file except in compliance with the
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* License.
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*
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* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
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* specific language governing permission and limitations under the License.
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*
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* When distributing Covered Software, include this CDDL Header Notice in each file and include
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* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
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* Header, with the fields enclosed by brackets [] replaced by your own identifying
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* information: "Portions Copyright [year] [name of copyright owner]".
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*
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* Copyright 2006-2010 Sun Microsystems, Inc.
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* Portions Copyright 2014-2015 ForgeRock AS.
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*/
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package org.opends.server.api;
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import java.util.List;
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import java.util.concurrent.Executors;
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import java.util.concurrent.ScheduledExecutorService;
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import java.util.concurrent.ScheduledFuture;
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import java.util.concurrent.ThreadFactory;
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import java.util.concurrent.TimeUnit;
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import org.forgerock.i18n.LocalizableMessage;
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import org.forgerock.opendj.config.server.ConfigException;
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import org.opends.server.admin.std.server.MonitorProviderCfg;
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import org.opends.server.types.Attribute;
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import org.opends.server.types.DirectoryConfig;
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import org.opends.server.types.InitializationException;
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import org.opends.server.types.ObjectClass;
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import static org.opends.server.util.ServerConstants.*;
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/**
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* This class defines the set of methods and structures that must be
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* implemented by a Directory Server module that can provide usage,
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* performance, availability, or other kinds of monitor information to clients.
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*
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* @param <T> The type of configuration handled by this monitor provider.
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*/
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@org.opends.server.types.PublicAPI(
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stability=org.opends.server.types.StabilityLevel.VOLATILE,
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mayInstantiate=false,
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mayExtend=true,
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mayInvoke=false)
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public abstract class MonitorProvider<T extends MonitorProviderCfg>
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{
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/** The scheduler. */
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private static final ScheduledExecutorService SCHEDULER =
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Executors.newSingleThreadScheduledExecutor(
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new MonitorThreadFactory());
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/** Thread factory used by the scheduled execution service. */
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private static final class MonitorThreadFactory implements ThreadFactory
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{
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@Override
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public Thread newThread(Runnable r)
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{
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Thread t = new DirectoryThread(r, "Monitor Provider State Updater");
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t.setDaemon(true);
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return t;
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}
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}
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private ScheduledFuture<?> scheduledFuture;
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/**
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* Initializes this monitor provider based on the information in the provided configuration entry.
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*
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* @param configuration
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* The configuration to use to initialize this monitor provider.
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* @throws ConfigException
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* If an unrecoverable problem arises in the process of performing the initialization.
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* @throws InitializationException
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* If a problem occurs during initialization that is not related to the server
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* configuration.
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*/
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public void initializeMonitorProvider(T configuration) throws ConfigException, InitializationException
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{
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// here to override
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}
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/**
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* Indicates whether the provided configuration is acceptable for
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* this monitor provider. It should be possible to call this method
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* on an uninitialized monitor provider instance in order to
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* determine whether the monitor provider would be able to use the
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* provided configuration.
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* <BR><BR>
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* Note that implementations which use a subclass of the provided
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* configuration class will likely need to cast the configuration
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* to the appropriate subclass type.
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*
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* @param configuration The monitor provider configuration
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* for which to make the determination.
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* @param unacceptableReasons A list that may be used to hold the
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* reasons that the provided
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* configuration is not acceptable.
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*
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* @return {@code true} if the provided configuration is acceptable
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* for this monitor provider, or {@code false} if not.
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*/
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public boolean isConfigurationAcceptable(
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MonitorProviderCfg configuration,
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List<LocalizableMessage> unacceptableReasons)
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{
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// This default implementation does not perform any special
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// validation. It should be overridden by monitor provider
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// implementations that wish to perform more detailed validation.
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return true;
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}
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/**
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* Finalizes this monitor provider so that it may be unloaded and
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* taken out of service. This method should be overridden by any
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* monitor provider that has resources that should be released when
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* the monitor is no longer needed. Any monitor that does override
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* this method must first invoke this version by calling
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* {@code super.finalizeMonitorProvider}.
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*/
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public void finalizeMonitorProvider()
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{
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if(scheduledFuture != null)
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{
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scheduledFuture.cancel(true);
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}
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}
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/**
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* Retrieves the name of this monitor provider. It should be unique
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* among all monitor providers, including all instances of the same
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* monitor provider.
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*
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* @return The name of this monitor provider.
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*/
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public abstract String getMonitorInstanceName();
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/**
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* Retrieves the objectclass that should be included in the monitor
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* entry created from this monitor provider. This may be overridden
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* by subclasses that wish to include their own custom objectclass
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* in the monitor entry (e.g., to make it easier to search for
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* monitor entries of that type). The default implementation
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* returns the "extensibleObject" objectclass.
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*
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* @return The objectclass that should be included in the monitor
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* entry created from this monitor provider.
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*/
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public ObjectClass getMonitorObjectClass()
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{
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return DirectoryConfig.getObjectClass(OC_EXTENSIBLE_OBJECT_LC, true);
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}
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/**
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* Schedules any periodic processing that may be desired
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* to update the information associated with this monitor. Note
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* that best-effort attempts will be made to ensure that calls to
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* this method come {@code getUpdateInterval} milliseconds apart,
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* but no guarantees will be made.
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*
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* @param updater The updater to execute.
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* @param initialDelay The time to delay first execution.
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* @param period The period between successive executions.
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* @param unit The time unit of the initialDelay and period
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* parameters.
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*/
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protected final void scheduleUpdate(Runnable updater,
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long initialDelay,
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long period, TimeUnit unit)
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{
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if(scheduledFuture != null)
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{
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scheduledFuture.cancel(true);
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}
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scheduledFuture = SCHEDULER.scheduleAtFixedRate(updater, initialDelay, period, unit);
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}
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/**
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* Retrieves a set of attributes containing monitor data that should
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* be returned to the client if the corresponding monitor entry is
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* requested.
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*
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* @return A set of attributes containing monitor data that should
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* be returned to the client if the corresponding monitor
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* entry is requested.
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*/
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public abstract List<Attribute> getMonitorData();
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}
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