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Diffstat (limited to 'bundles/org.eclipse.osgi/core/framework/org/eclipse/osgi/framework/internal/core/ServiceReference.java')
| -rw-r--r-- | bundles/org.eclipse.osgi/core/framework/org/eclipse/osgi/framework/internal/core/ServiceReference.java | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/bundles/org.eclipse.osgi/core/framework/org/eclipse/osgi/framework/internal/core/ServiceReference.java b/bundles/org.eclipse.osgi/core/framework/org/eclipse/osgi/framework/internal/core/ServiceReference.java new file mode 100644 index 000000000..09ca761dc --- /dev/null +++ b/bundles/org.eclipse.osgi/core/framework/org/eclipse/osgi/framework/internal/core/ServiceReference.java @@ -0,0 +1,232 @@ +/******************************************************************************* + * Copyright (c) 2003 IBM Corporation and others. + * All rights reserved. This program and the accompanying materials + * are made available under the terms of the Common Public License v1.0 + * which accompanies this distribution, and is available at + * http://www.eclipse.org/legal/cpl-v10.html + * + * Contributors: + * IBM Corporation - initial API and implementation + *******************************************************************************/ + +package org.eclipse.osgi.framework.internal.core; + + +/** + * A reference to a service. + * + * The framework returns ServiceReference objects from the + * {@link BundleContext#getServiceReference BundleContext.getServiceReference} and + * {@link BundleContext#getServiceReferences BundleContext.getServiceReferences} methods. + * <p>A ServiceReference may be shared between bundles and + * can be used to examine the properties of the service and to + * get the service object + * (See {@link BundleContext#getService BundleContext.getService}). + * <p>A registered service <i>may</i> have multiple, distinct ServiceReference + * objects which refer to it. + * However these ServiceReference objects will have + * the same <code>hashCode</code> and the <code>equals</code> method + * will return <code>true</code> when compared. + */ + +public class ServiceReference implements org.osgi.framework.ServiceReference, Comparable +{ + /** Registered Service object. */ + protected ServiceRegistration registration; + + /** + * Construct a reference. + * + */ + protected ServiceReference(ServiceRegistration registration) + { + this.registration = registration; + } + + /** + * Get the value of a service's property. + * + * <p>This method will continue to return property values after the + * service has been unregistered. This is so that references to + * unregistered service can be interrogated. + * (For example: ServiceReference objects stored in the log.) + * + * @param key Name of the property. + * @return Value of the property or <code>null</code> if there is + * no property by that name. + */ + public Object getProperty(String key) + { + return(registration.getProperty(key)); + } + + /** + * Get the list of key names for the service's properties. + * + * <p>This method will continue to return the keys after the + * service has been unregistered. This is so that references to + * unregistered service can be interrogated. + * (For example: ServiceReference objects stored in the log.) + * + * @return The list of property key names. + */ + public String[] getPropertyKeys() + { + return(registration.getPropertyKeys()); + } + + /** + * Return the bundle which registered the service. + * + * <p>This method will always return <code>null</code> when the + * service has been unregistered. This can be used to + * determine if the service has been unregistered. + * + * @return The bundle which registered the service. + * @see BundleContext#registerService + */ + public org.osgi.framework.Bundle getBundle() + { + return(registration.getBundle()); + } + + /** + * Return the list of bundles which are using the service. + * + * <p>This method will always return <code>null</code> when the + * service has been unregistered. + * + * @return The array of bundles using the service or null if + * no bundles are using the service. + * @see BundleContext#getService + */ + public org.osgi.framework.Bundle[] getUsingBundles() + { + return(registration.getUsingBundles()); + } + + /** + * Return the classes under which the referenced service was registered. + * + * @return array of class names. + */ + protected String[] getClasses() + { + return(registration.clazzes); + } + + /** + * Return the serviceid of the ServiceRegistration. + * + * @return service.id of the service + */ + protected long getId() + { + return(registration.serviceid); + } + + /** + * Return the serviceranking of the ServiceRegistration. + * + * @return service.ranking of the service + */ + protected int getRanking() + { + return(registration.serviceranking); + } + + /** + * Returns a hash code value for the object. + * + * @return a hash code value for this object. + */ + public int hashCode() + { + return(registration.hashCode()); + } + + /** + * Indicates whether some other object is "equal to" this one. + * + * @param obj the reference object with which to compare. + * @return <code>true</code> if this object is the same as the obj + * argument; <code>false</code> otherwise. + */ + public boolean equals(Object obj) + { + if (obj == this) + { + return (true); + } + + if (!(obj instanceof ServiceReference)) + { + return (false); + } + + ServiceReference other = (ServiceReference) obj; + + return(registration == other.registration); + } + + /** + * Return a string representation of this reference. + * + * @return String + */ + public String toString() + { + return(registration.toString()); + } + + /** + * + * Compares two service objects and returns an indication as to which is higher ranked + * based on service ranking and service_ID. + * + * The service with the higher service ranking (as specified in its service.ranking property) + * is defined to be higher ranked. + * + * If there is a tie in ranking, the service with the lowest + * service ID (as specified in its service.id property); that is, + * the service that was registered first is returned. + * + * This is the same algorithm used by BundleContext.getServiceReference. + * + * @return int + * int = 0 if this object's ranking and + * service id are equivalent + * + * int < 0 if this object's ranking is lower + * than the argument's ranking or if the + * rankings are equal, this object's service + * id is greater than the argument's service + * id. + * + * int > 0 if this object's ranking is higher + * than than the argument's ranking or if the + * rankings are equal, this object's service + * id is less than the argument's service id. + * + * + * @param another Object + * an object to compare the receiver to + * @exception ClassCastException + * if the argument can not be converted + * into something comparable with the + * receiver. + */ + public int compareTo(Object object) + { + ServiceReference other = (ServiceReference)object; + + int compare = this.getRanking() - other.getRanking(); + + if (compare == 0) /* rankings are equal */ + { /* check service id */ + return (int)(other.getId() - this.getId()); + } + + return compare; + } +} |