org.glassfish.hk2.api.ServiceLocatorFactory Maven / Gradle / Ivy
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package org.glassfish.hk2.api;
import org.glassfish.hk2.extension.ServiceLocatorGenerator;
import org.glassfish.hk2.internal.ServiceLocatorFactoryImpl;
/**
* This factory can be used to create new named ServiceLocators
*
* @author jwells
*/
public abstract class ServiceLocatorFactory {
private static ServiceLocatorFactory INSTANCE = new ServiceLocatorFactoryImpl();
/**
* This will return a factory where the ServiceLocatorGenerator
* is discovered from the META-INF/services of the process
*
* @return The factory to use to create service locators
*/
public static ServiceLocatorFactory getInstance() {
return INSTANCE;
}
/**
* Creates (or finds) a ServiceLocator.
*
* If there is already a ServiceLocator with the given
* name then this method will return that locator.
*
* @param name The name of this service locator. Passing a null
* name will result in a newly created service locator with a
* generated name and that will not be tracked by the system
* @return The created or found named ServiceLocator
*/
public abstract ServiceLocator create(String name);
/**
* Creates or finds a ServiceLocator.
*
* If there is already a ServiceLocator with the given
* name then this method will return that ServiceLocator. The
* parent argument will be ignored in that case
*
* @param name The name of this service locator. Passing a null
* name will result in a newly created service locator with a
* generated name and that will not be tracked by the system
* @param parent The parent of this ServiceLocator. Services can
* be found in the parent (and all grand-parents). May be null
* if the returned ServiceLocator should not be parented
* @return The created or found named ServiceLocator
*/
public abstract ServiceLocator create(String name,
ServiceLocator parent);
/**
* Creates or finds a ServiceLocator.
*
* If there is already a ServiceLocator with the given
* name then this method will return that ServiceLocator. The
* parent argument will be ignored in that case.
* If a null name is given then a new ServiceLocator with a
* generated name will be returned.
*
* @param name The name of this service locator. Passing a null
* name will result in a newly created service locator with a
* generated name and that will not be tracked by the system
* @param parent The parent of this ServiceLocator. Services can
* be found in the parent (and all grand-parents). May be null
* if the returned ServiceLocator should not be parented
* @param generator An implementation of the generator interface that
* can be used to provide an implementation of ServiceLocator. If
* null then the generator used will be discovered from the OSGi
* service registry or from META-INF/services
* @return The created or found named ServiceLocator
*/
public abstract ServiceLocator create(String name,
ServiceLocator parent,
ServiceLocatorGenerator generator);
/**
* Creates a ServiceLocator.
*
* If there is already a ServiceLocator with the given
* name then this method will honor the given CreatePolicy.
* return that ServiceLocator. The policies are
* - RETURN: Return the existing locator
* - DESTOY: Destroy the existing locator
* - ERROR: Throw an IllegalStateException exception
*
*
* @param name The name of this service locator. Passing a null
* name will result in a newly created service locator with a
* generated name and that will not be tracked by the system
* @param parent The parent of this ServiceLocator. Services can
* be found in the parent (and all grand-parents). May be null
* if the returned ServiceLocator should not be parented
* @param generator An implementation of the generator interface that
* can be used to provide an implementation of ServiceLocator. If
* null then the generator used will be discovered from the OSGi
* service registry or from META-INF/services
* @param policy The policy that should be used if there is an
* existing locator with the non-null name. If null the policy
* of RETURN will be used
* @return The created or found named ServiceLocator
*/
public abstract ServiceLocator create(String name,
ServiceLocator parent,
ServiceLocatorGenerator generator,
CreatePolicy policy);
/**
* Finds the ServiceLocator with this name
*
* @param name May not be null, is the name of the ServiceLocator to find
* @return The ServiceLocator with the given name, or null if there
* is no ServiceLocator with that name
*/
public abstract ServiceLocator find(String name);
/**
* Removes the ServiceLocator with this name
*
* All services associated with this ServiceLocator will be shutdown
*
* @param name The name of the ServiceLocator to destroy
*/
public abstract void destroy(String name);
/**
* Removes the given ServiceLocator
*
* All services associated with this ServiceLocator will be shutdown
*
* @param locator The ServiceLocator to destroy. If null this will do nothing.
* If the ServiceLocator given was already destroyed this will do nothing
*/
public abstract void destroy(ServiceLocator locator);
/**
* Adds a service listener to the unordered set of listeners that
* will be notified when named listeners are added or removed
* from the system. If this listener is already registered
* this method does nothing
*
* @param listener The non-null listener to add to the system
*/
public abstract void addListener(ServiceLocatorListener listener);
/**
* Removes a service listener from the set of listeners that
* are notified when named listeners are added or removed
* from the system
*
* @param listener The non-null listener to remove from the system
*/
public abstract void removeListener(ServiceLocatorListener listener);
/**
* Tells the create method what to do if an existing ServiceLocator
* with the given name exists
*
* @author jwells
*
*/
public enum CreatePolicy {
/** Return the existing ServiceLocator */
RETURN,
/** Destroy the existing ServiceLocator */
DESTROY,
/** Throw an IllegalStateException */
ERROR
}
}