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Diffstat (limited to 'libjava/java/beans/beancontext/BeanContextServices.java')
| -rw-r--r-- | libjava/java/beans/beancontext/BeanContextServices.java | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/libjava/java/beans/beancontext/BeanContextServices.java b/libjava/java/beans/beancontext/BeanContextServices.java new file mode 100644 index 00000000000..e67687b6efe --- /dev/null +++ b/libjava/java/beans/beancontext/BeanContextServices.java @@ -0,0 +1,195 @@ +/* java.beans.beancontext.BeanContextServices + Copyright (C) 1999 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ + + +package java.beans.beancontext; + +import java.util.Iterator; + +/** + * Allows a <code>BeanContext</code> to provide services to its children. + * + * @specnote it is unclear whether a <code>BeanContextServices</code> + * should delegate unhandled requests to parents. I assume so. + * @author John Keiser + * @since JDK1.2 + */ + +public interface BeanContextServices extends BeanContext, BeanContextServicesListener { + /** + * Register a service to make it available to others. + * This class may refuse to add the service based on whatever + * information it can gather, including whether the service + * provider is trusted. + * + * @param serviceClass the service class. + * @param provider the factory that will actually provide the service. + * @return whether the service was added or not. + */ + public boolean addService(Class serviceClass, BeanContextServiceProvider provider); + + /** + * Make it so that no one else can use this service. + * <P> + * + * If <code>revokeNow</code> is <code>false</code>, the only + * effect of this method is to make all subsequent calls to + * <code>getService()</code> on this service class fail. + * <P> + * + * If it is <code>true</code>, a message is also sent out to all + * listeners on the service and all references to it are released. + * + * @param serviceClass the service class to revoke. + * @param provider the service provider providing the service class. + * @param revokeNow whether to release all current references to + * the service. + */ + public void revokeService(Class serviceClass, BeanContextServiceProvider provider, boolean revokeNow); + + /** + * Release your copy of this service. + * <P> + * + * If all copies of the service's class have been relinquished by + * the requestor, the <code>BeanContextServiceRevokedListener</code> + * previously registered by <code>getService()</code> will be + * unregistered. + * + * @param requestorChild the original <code>BeanContextChild</code> + * requesting the service. + * @param requestor the original requestor of the service. + * @param service the service to relinquish + * @see #getService(java.beans.beancontext.BeanContextChild,java.lang.Object,java.lang.Class,java.lang.Object,java.beans.beancontext.BeanContextServiceRevokedListener) + */ + public void releaseService(BeanContextChild requestorChild, Object requestor, Object service); + + /** + * Get a service from this <code>BeanContextServices</code>. + * <P> + * + * The specified listener will be registered to receive a + * revocation notice for the specified serviceClass. One + * notification per service class per requestor object will be + * sent. + * <P> + * + * The listener will be unregistered when all services that were + * obtained by that requestor for that service class are released. + * <P> + * + * If the requested service class is not available, or if this + * <code>BeanContextServices</code> object chooses not honor the + * request because the service class has been revoked or for some + * other reason, then this method will return <code>null</code>. + * <P> + * + * This method may throw unchecked exceptions, so watch out. + * + * @specnote it is not specified what happens when two subsequent + * calls are made to <code>getService()</code> with the + * same requestor object and service class but different + * listeners. Which listener is to be notified? + * + * @param requestorChild the <code>BeanContextChild</code> + * associated with the requestor. Typically this will be + * the same as the requestor itself, but since any + * <code>Object</code>, even one outside the hierarchy, may + * make a request, this parameter is necessary. Only weak + * references to this will be retained, and it will never + * be changed, only queried in a read-only manner. + * @param requestor the actual requestor of the service. Only + * weak references to this will be retained, and it will + * never be changed, only queried in a read-only manner. + * @param serviceClass the <code>Class</code> of the service being + * requested. + * @param serviceSelector a parameter to customize the service + * returned with. + * @param listener a listener that will be notified if the service + * being requested is revoked. + * @return an instance of <code>serviceClass</code> (such that + * <code>instanceof</code> serviceClass is true), or + * <code>null</code>. + */ + public Object getService(BeanContextChild requestorChild, Object requestor, Class serviceClass, Object serviceSelector, BeanContextServiceRevokedListener listener); + + /** + * Get a list of all service classes supported. + * <P> + * + * This method must synchronize on + * <code>BeanContext.globalHierarchyLock</code>. + * + * @return a list of all service classes supported. + * @see java.beans.beancontext.BeanContext#globalHierarchyLock + */ + public Iterator getCurrentServiceClasses(); + + /** + * Get a list of valid service selectors for the specified service class. + * <P> + * + * If the specified service class does not have a finite number of + * valid service selectors, it should return <code>null</code>. + * If it takes a general <code>Integer</code> parameter, for + * example, you may as well return <code>null</code> or the poor + * soul who called this method will be iterating all day. + * <P> + * + * If it has no valid service selectors, it should still return an empty + * <code>Iterator</code>. + * + * @param serviceClass the service class to get selectors for. + * @return a list of valid service selectors for the service + * class, or <code>null</code>. + */ + public Iterator getCurrentServiceSelectors(Class serviceClass); + + /** + * Tell whether the specified service class is available. + * Iff getService() could return a non-null value for the + * specified service, this method will return <code>true</code>. + * + * @param serviceClass the service class to check on. + * @return whether the specified service class is availabe. + */ + public boolean hasService(Class serviceClass); + + /** + * Add a listener on all adds and removes of services. + * @param listener the listener to add. + */ + public void addBeanContextServicesListener(BeanContextServicesListener listener); + + /** + * Remove a listener on all adds and removes of services. + * @specnote it is not certain whether this should remove this + * listener if it was specified in + * <code>getService()</code>. + * @param listener the listener to add. + */ + public void removeBeanContextServicesListener(BeanContextServicesListener listener); +} |
