src/main/java/org/apache/sling/discovery/impl/NoClusterDiscoveryService.java - sling-org-apache-sling-discovery-api - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * 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
  *
  * 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.apache.sling.discovery.impl;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;

 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.ConfigurationPolicy;
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.ReferencePolicy;
 import org.apache.felix.scr.annotations.Service;
 import org.apache.sling.discovery.ClusterView;
 import org.apache.sling.discovery.DiscoveryService;
 import org.apache.sling.discovery.InstanceDescription;
 import org.apache.sling.discovery.InstanceFilter;
 import org.apache.sling.discovery.PropertyProvider;
 import org.apache.sling.discovery.TopologyEvent;
 import org.apache.sling.discovery.TopologyEvent.Type;
 import org.apache.sling.discovery.TopologyEventListener;
 import org.apache.sling.discovery.TopologyView;
 import org.apache.sling.settings.SlingSettingsService;
 import org.osgi.framework.Constants;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 /**
  * This is a simple implementation of the discovery service
  * which can be used for a cluster less installation (= single instance).
  * It is disabled by default and can be enabled through a OSGi configuration.
  */
 @Component(policy = ConfigurationPolicy.REQUIRE, immediate=true)
 @Service(value = {DiscoveryService.class})
 public class NoClusterDiscoveryService implements DiscoveryService {

     /** The logger. */
     private final Logger logger = LoggerFactory.getLogger(this.getClass());

     /**
      * Sling settings service to get the Sling ID and run modes.
      */
     @Reference
     private SlingSettingsService settingsService;

     /**
      * All topology event listeners.
      */
     @Reference(cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE, policy = ReferencePolicy.DYNAMIC)
     private TopologyEventListener[] listeners = new TopologyEventListener[0];

     /**
      * All property providers.
      */
     @Reference(cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE, policy = ReferencePolicy.DYNAMIC,
                referenceInterface=PropertyProvider.class, updated="updatedPropertyProvider")
     private List<ProviderInfo> providerInfos = new ArrayList<ProviderInfo>();

     /**
      * Special lock object to sync data structure access
      */
     private final Object lock = new Object();

     /**
      * The current topology view.
      */
     private TopologyView topologyView;

     private Map<String, String> cachedProperties = new HashMap<String, String>();

     /**
      * Activate this service
      * Create a new description.
      */
     @Activate
     protected void activate() {
         logger.debug("NoClusterDiscoveryService started.");
         final InstanceDescription myDescription = new InstanceDescription() {

             public boolean isLocal() {
                 return true;
             }

             public boolean isLeader() {
                 return true;
             }

             public String getSlingId() {
                 return settingsService.getSlingId();
             }

             public String getProperty(final String name) {
             	synchronized(lock) {
             		return cachedProperties.get(name);
             	}
             }

 			public Map<String, String> getProperties() {
 				synchronized(lock) {
 					return Collections.unmodifiableMap(cachedProperties);
 				}
 			}

 			public ClusterView getClusterView() {
 				final Collection<ClusterView> clusters = topologyView.getClusterViews();
 				if (clusters==null || clusters.size()==0) {
 					return null;
 				}
 				return clusters.iterator().next();
 			}
         };
         final Set<InstanceDescription> instances = new HashSet<InstanceDescription>();
         instances.add(myDescription);

         final TopologyEventListener[] registeredServices;
 		synchronized ( lock ) {
             registeredServices = this.listeners;
             final ClusterView clusterView = new ClusterView() {

                 public InstanceDescription getLeader() {
                     return myDescription;
                 }

                 public List<InstanceDescription> getInstances() {
                     return new LinkedList<InstanceDescription>(instances);
                 }

 				public String getId() {
 					return "0";
 				}
             };
             this.topologyView = new TopologyView() {

     			public InstanceDescription getLocalInstance() {
     				return myDescription;
     			}

     			public boolean isCurrent() {
     				return true;
     			}

     			public Set<InstanceDescription> getInstances() {
     				return instances;
     			}

     			public Set<InstanceDescription> findInstances(InstanceFilter picker) {
     				Set<InstanceDescription> result = new HashSet<InstanceDescription>();
     				for (Iterator<InstanceDescription> it = getTopology().getInstances().iterator(); it.hasNext();) {
     					InstanceDescription instance = it.next();
     					if (picker.accept(instance)) {
     						result.add(instance);
     					}
     				}
     				return result;
     			}

     			public Set<ClusterView> getClusterViews() {
     				Set<ClusterView> clusters = new HashSet<ClusterView>();
     				clusters.add(clusterView);
     				return clusters;
     			}

     		};
         }
         for(final TopologyEventListener da: registeredServices) {
         	da.handleTopologyEvent(new TopologyEvent(Type.TOPOLOGY_INIT, null, topologyView));
         }
     }

     /**
      * Deactivate this service.
      */
     @Deactivate
     protected void deactivate() {
         logger.debug("NoClusterDiscoveryService stopped.");
         this.topologyView = null;
     }

     /**
      * Bind a new property provider.
      */
     @SuppressWarnings("unused")
 	private void bindPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
     	logger.debug("bindPropertyProvider: Binding PropertyProvider {}", propertyProvider);

         final TopologyEventListener[] awares;
         synchronized (lock) {
             final ProviderInfo info = new ProviderInfo(propertyProvider, props);
             this.providerInfos.add(info);
             Collections.sort(this.providerInfos);
             this.updatePropertiesCache();
             if ( this.topologyView == null ) {
                 awares = null;
             } else {
                 awares = this.listeners;
             }
         }
         if ( awares != null ) {
             for(final TopologyEventListener da : awares) {
                 da.handleTopologyEvent(new TopologyEvent(Type.PROPERTIES_CHANGED, this.topologyView, this.topologyView));
             }
         }
     }

     /**
      * Update a property provider.
      */
     @SuppressWarnings("unused")
     private void updatedPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
         logger.debug("bindPropertyProvider: Updating PropertyProvider {}", propertyProvider);

         this.unbindPropertyProvider(propertyProvider, props, false);
         this.bindPropertyProvider(propertyProvider, props);
     }

     /**
      * Unbind a property provider
      */
     @SuppressWarnings("unused")
 	private void unbindPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
         this.unbindPropertyProvider(propertyProvider, props, true);
     }

     /**
      * Unbind a property provider
      */
     @SuppressWarnings("unused")
     private void unbindPropertyProvider(final PropertyProvider propertyProvider,
             final Map<String, Object> props,
             final boolean inform) {
     	logger.debug("unbindPropertyProvider: Releasing PropertyProvider {}", propertyProvider);

     	final TopologyEventListener[] awares;
         synchronized (lock) {
             final ProviderInfo info = new ProviderInfo(propertyProvider, props);
             this.providerInfos.remove(info);
             this.updatePropertiesCache();
             if ( this.topologyView == null ) {
                 awares = null;
             } else {
                 awares = this.listeners;
             }
         }
         if ( inform && awares != null ) {
             for(final TopologyEventListener da : awares) {
                 da.handleTopologyEvent(new TopologyEvent(Type.PROPERTIES_CHANGED, this.topologyView, this.topologyView));
             }
         }
     }

     private void updatePropertiesCache() {
         final Map<String, String> newProps = new HashMap<String, String>();
         for(final ProviderInfo info : this.providerInfos) {
             newProps.putAll(info.properties);
         }
         this.cachedProperties = newProps;
         if ( this.logger.isDebugEnabled() ) {
             this.logger.debug("New properties: {}", this.cachedProperties);
         }
     }

     @SuppressWarnings("unused")
     private void bindTopologyEventListener(final TopologyEventListener clusterAware) {

         logger.debug("bindTopologyEventListener: Binding TopologyEventListener {}", clusterAware);

         boolean inform = true;
         synchronized (lock) {
             List<TopologyEventListener> currentList = new ArrayList<TopologyEventListener>(
                 Arrays.asList(listeners));
             currentList.add(clusterAware);
             this.listeners = currentList.toArray(new TopologyEventListener[currentList.size()]);
             if ( this.topologyView == null ) {
                 inform = false;
             }
         }

         if ( inform ) {
         	clusterAware.handleTopologyEvent(new TopologyEvent(Type.TOPOLOGY_INIT, null, topologyView));
         }
     }

     @SuppressWarnings("unused")
     private void unbindTopologyEventListener(final TopologyEventListener clusterAware) {

         logger.debug("unbindTopologyEventListener: Releasing TopologyEventListener {}", clusterAware);

         synchronized (lock) {
             List<TopologyEventListener> currentList = new ArrayList<TopologyEventListener>(
                 Arrays.asList(listeners));
             currentList.remove(clusterAware);
             this.listeners = currentList.toArray(new TopologyEventListener[currentList.size()]);
         }
     }

     /**
      * @see DiscoveryService#getTopology()
      */
     public TopologyView getTopology() {
     	return topologyView;
     }

     /**
      * Internal class caching some provider infos like service id and ranking.
      */
     private final static class ProviderInfo implements Comparable<ProviderInfo> {

         public final PropertyProvider provider;
         public final int ranking;
         public final long serviceId;
         public final Map<String, String> properties = new HashMap<String, String>();

         public ProviderInfo(final PropertyProvider provider, final Map<String, Object> serviceProps) {
             this.provider = provider;
             final Object sr = serviceProps.get(Constants.SERVICE_RANKING);
             if ( sr == null || !(sr instanceof Integer)) {
                 this.ranking = 0;
             } else {
                 this.ranking = (Integer)sr;
             }
             this.serviceId = (Long)serviceProps.get(Constants.SERVICE_ID);
             final Object namesObj = serviceProps.get(PropertyProvider.PROPERTY_PROPERTIES);
             if ( namesObj instanceof String ) {
                 final String val = provider.getProperty((String)namesObj);
                 if ( val != null ) {
                     this.properties.put((String)namesObj, val);
                 }
             } else if ( namesObj instanceof String[] ) {
                 for(final String name : (String[])namesObj ) {
                     final String val = provider.getProperty(name);
                     if ( val != null ) {
                         this.properties.put(name, val);
                     }
                 }
             }
         }

         /**
          * @see java.lang.Comparable#compareTo(java.lang.Object)
          */
         public int compareTo(final ProviderInfo o) {
             // Sort by rank in ascending order.
             if ( this.ranking < o.ranking ) {
                 return -1; // lower rank
             } else if (this.ranking > o.ranking ) {
                 return 1; // higher rank
             }
             // If ranks are equal, then sort by service id in descending order.
             return (this.serviceId < o.serviceId) ? 1 : -1;
         }

         @Override
         public boolean equals(final Object obj) {
             if ( obj instanceof ProviderInfo ) {
                 return ((ProviderInfo)obj).serviceId == this.serviceId;
             }
             return false;
         }

         @Override
         public int hashCode() {
             return provider.hashCode();
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* 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
	*
	* 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.apache.sling.discovery.impl;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.LinkedList;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	import org.apache.felix.scr.annotations.Activate;
	import org.apache.felix.scr.annotations.Component;
	import org.apache.felix.scr.annotations.ConfigurationPolicy;
	import org.apache.felix.scr.annotations.Deactivate;
	import org.apache.felix.scr.annotations.Reference;
	import org.apache.felix.scr.annotations.ReferenceCardinality;
	import org.apache.felix.scr.annotations.ReferencePolicy;
	import org.apache.felix.scr.annotations.Service;
	import org.apache.sling.discovery.ClusterView;
	import org.apache.sling.discovery.DiscoveryService;
	import org.apache.sling.discovery.InstanceDescription;
	import org.apache.sling.discovery.InstanceFilter;
	import org.apache.sling.discovery.PropertyProvider;
	import org.apache.sling.discovery.TopologyEvent;
	import org.apache.sling.discovery.TopologyEvent.Type;
	import org.apache.sling.discovery.TopologyEventListener;
	import org.apache.sling.discovery.TopologyView;
	import org.apache.sling.settings.SlingSettingsService;
	import org.osgi.framework.Constants;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	/**
	* This is a simple implementation of the discovery service
	* which can be used for a cluster less installation (= single instance).
	* It is disabled by default and can be enabled through a OSGi configuration.
	*/
	@Component(policy = ConfigurationPolicy.REQUIRE, immediate=true)
	@Service(value = {DiscoveryService.class})
	public class NoClusterDiscoveryService implements DiscoveryService {

	/** The logger. */
	private final Logger logger = LoggerFactory.getLogger(this.getClass());

	/**
	* Sling settings service to get the Sling ID and run modes.
	*/
	@Reference
	private SlingSettingsService settingsService;

	/**
	* All topology event listeners.
	*/
	@Reference(cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE, policy = ReferencePolicy.DYNAMIC)
	private TopologyEventListener[] listeners = new TopologyEventListener[0];

	/**
	* All property providers.
	*/
	@Reference(cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE, policy = ReferencePolicy.DYNAMIC,
	referenceInterface=PropertyProvider.class, updated="updatedPropertyProvider")
	private List<ProviderInfo> providerInfos = new ArrayList<ProviderInfo>();

	/**
	* Special lock object to sync data structure access
	*/
	private final Object lock = new Object();

	/**
	* The current topology view.
	*/
	private TopologyView topologyView;

	private Map<String, String> cachedProperties = new HashMap<String, String>();

	/**
	* Activate this service
	* Create a new description.
	*/
	@Activate
	protected void activate() {
	logger.debug("NoClusterDiscoveryService started.");
	final InstanceDescription myDescription = new InstanceDescription() {

	public boolean isLocal() {
	return true;
	}

	public boolean isLeader() {
	return true;
	}

	public String getSlingId() {
	return settingsService.getSlingId();
	}

	public String getProperty(final String name) {
	synchronized(lock) {
	return cachedProperties.get(name);
	}
	}

	public Map<String, String> getProperties() {
	synchronized(lock) {
	return Collections.unmodifiableMap(cachedProperties);
	}
	}

	public ClusterView getClusterView() {
	final Collection<ClusterView> clusters = topologyView.getClusterViews();
	if (clusters==null \|\| clusters.size()==0) {
	return null;
	}
	return clusters.iterator().next();
	}
	};
	final Set<InstanceDescription> instances = new HashSet<InstanceDescription>();
	instances.add(myDescription);

	final TopologyEventListener[] registeredServices;
	synchronized ( lock ) {
	registeredServices = this.listeners;
	final ClusterView clusterView = new ClusterView() {

	public InstanceDescription getLeader() {
	return myDescription;
	}

	public List<InstanceDescription> getInstances() {
	return new LinkedList<InstanceDescription>(instances);
	}

	public String getId() {
	return "0";
	}
	};
	this.topologyView = new TopologyView() {

	public InstanceDescription getLocalInstance() {
	return myDescription;
	}

	public boolean isCurrent() {
	return true;
	}

	public Set<InstanceDescription> getInstances() {
	return instances;
	}

	public Set<InstanceDescription> findInstances(InstanceFilter picker) {
	Set<InstanceDescription> result = new HashSet<InstanceDescription>();
	for (Iterator<InstanceDescription> it = getTopology().getInstances().iterator(); it.hasNext();) {
	InstanceDescription instance = it.next();
	if (picker.accept(instance)) {
	result.add(instance);
	}
	}
	return result;
	}

	public Set<ClusterView> getClusterViews() {
	Set<ClusterView> clusters = new HashSet<ClusterView>();
	clusters.add(clusterView);
	return clusters;
	}

	};
	}
	for(final TopologyEventListener da: registeredServices) {
	da.handleTopologyEvent(new TopologyEvent(Type.TOPOLOGY_INIT, null, topologyView));
	}
	}

	/**
	* Deactivate this service.
	*/
	@Deactivate
	protected void deactivate() {
	logger.debug("NoClusterDiscoveryService stopped.");
	this.topologyView = null;
	}

	/**
	* Bind a new property provider.
	*/
	@SuppressWarnings("unused")
	private void bindPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
	logger.debug("bindPropertyProvider: Binding PropertyProvider {}", propertyProvider);

	final TopologyEventListener[] awares;
	synchronized (lock) {
	final ProviderInfo info = new ProviderInfo(propertyProvider, props);
	this.providerInfos.add(info);
	Collections.sort(this.providerInfos);
	this.updatePropertiesCache();
	if ( this.topologyView == null ) {
	awares = null;
	} else {
	awares = this.listeners;
	}
	}
	if ( awares != null ) {
	for(final TopologyEventListener da : awares) {
	da.handleTopologyEvent(new TopologyEvent(Type.PROPERTIES_CHANGED, this.topologyView, this.topologyView));
	}
	}
	}

	/**
	* Update a property provider.
	*/
	@SuppressWarnings("unused")
	private void updatedPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
	logger.debug("bindPropertyProvider: Updating PropertyProvider {}", propertyProvider);

	this.unbindPropertyProvider(propertyProvider, props, false);
	this.bindPropertyProvider(propertyProvider, props);
	}

	/**
	* Unbind a property provider
	*/
	@SuppressWarnings("unused")
	private void unbindPropertyProvider(final PropertyProvider propertyProvider, final Map<String, Object> props) {
	this.unbindPropertyProvider(propertyProvider, props, true);
	}

	/**
	* Unbind a property provider
	*/
	@SuppressWarnings("unused")
	private void unbindPropertyProvider(final PropertyProvider propertyProvider,
	final Map<String, Object> props,
	final boolean inform) {
	logger.debug("unbindPropertyProvider: Releasing PropertyProvider {}", propertyProvider);

	final TopologyEventListener[] awares;
	synchronized (lock) {
	final ProviderInfo info = new ProviderInfo(propertyProvider, props);
	this.providerInfos.remove(info);
	this.updatePropertiesCache();
	if ( this.topologyView == null ) {
	awares = null;
	} else {
	awares = this.listeners;
	}
	}
	if ( inform && awares != null ) {
	for(final TopologyEventListener da : awares) {
	da.handleTopologyEvent(new TopologyEvent(Type.PROPERTIES_CHANGED, this.topologyView, this.topologyView));
	}
	}
	}

	private void updatePropertiesCache() {
	final Map<String, String> newProps = new HashMap<String, String>();
	for(final ProviderInfo info : this.providerInfos) {
	newProps.putAll(info.properties);
	}
	this.cachedProperties = newProps;
	if ( this.logger.isDebugEnabled() ) {
	this.logger.debug("New properties: {}", this.cachedProperties);
	}
	}

	@SuppressWarnings("unused")
	private void bindTopologyEventListener(final TopologyEventListener clusterAware) {

	logger.debug("bindTopologyEventListener: Binding TopologyEventListener {}", clusterAware);

	boolean inform = true;
	synchronized (lock) {
	List<TopologyEventListener> currentList = new ArrayList<TopologyEventListener>(
	Arrays.asList(listeners));
	currentList.add(clusterAware);
	this.listeners = currentList.toArray(new TopologyEventListener[currentList.size()]);
	if ( this.topologyView == null ) {
	inform = false;
	}
	}

	if ( inform ) {
	clusterAware.handleTopologyEvent(new TopologyEvent(Type.TOPOLOGY_INIT, null, topologyView));
	}
	}

	@SuppressWarnings("unused")
	private void unbindTopologyEventListener(final TopologyEventListener clusterAware) {

	logger.debug("unbindTopologyEventListener: Releasing TopologyEventListener {}", clusterAware);

	synchronized (lock) {
	List<TopologyEventListener> currentList = new ArrayList<TopologyEventListener>(
	Arrays.asList(listeners));
	currentList.remove(clusterAware);
	this.listeners = currentList.toArray(new TopologyEventListener[currentList.size()]);
	}
	}

	/**
	* @see DiscoveryService#getTopology()
	*/
	public TopologyView getTopology() {
	return topologyView;
	}

	/**
	* Internal class caching some provider infos like service id and ranking.
	*/
	private final static class ProviderInfo implements Comparable<ProviderInfo> {

	public final PropertyProvider provider;
	public final int ranking;
	public final long serviceId;
	public final Map<String, String> properties = new HashMap<String, String>();

	public ProviderInfo(final PropertyProvider provider, final Map<String, Object> serviceProps) {
	this.provider = provider;
	final Object sr = serviceProps.get(Constants.SERVICE_RANKING);
	if ( sr == null \|\| !(sr instanceof Integer)) {
	this.ranking = 0;
	} else {
	this.ranking = (Integer)sr;
	}
	this.serviceId = (Long)serviceProps.get(Constants.SERVICE_ID);
	final Object namesObj = serviceProps.get(PropertyProvider.PROPERTY_PROPERTIES);
	if ( namesObj instanceof String ) {
	final String val = provider.getProperty((String)namesObj);
	if ( val != null ) {
	this.properties.put((String)namesObj, val);
	}
	} else if ( namesObj instanceof String[] ) {
	for(final String name : (String[])namesObj ) {
	final String val = provider.getProperty(name);
	if ( val != null ) {
	this.properties.put(name, val);
	}
	}
	}
	}

	/**
	* @see java.lang.Comparable#compareTo(java.lang.Object)
	*/
	public int compareTo(final ProviderInfo o) {
	// Sort by rank in ascending order.
	if ( this.ranking < o.ranking ) {
	return -1; // lower rank
	} else if (this.ranking > o.ranking ) {
	return 1; // higher rank
	}
	// If ranks are equal, then sort by service id in descending order.
	return (this.serviceId < o.serviceId) ? 1 : -1;
	}

	@Override
	public boolean equals(final Object obj) {
	if ( obj instanceof ProviderInfo ) {
	return ((ProviderInfo)obj).serviceId == this.serviceId;
	}
	return false;
	}

	@Override
	public int hashCode() {
	return provider.hashCode();
	}
	}
	}