| /* gnu.java.beans.decoder.AbstractCreatableContext |
| Copyright (C) 2004 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., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| package gnu.java.beans.decoder; |
| |
| |
| /** AbstractCreatableObjectContext is the base class for all Context implementations |
| * which create a result object in their lifetime. It provides means for preventing |
| * to create the object twice. |
| * |
| * @author Robert Schuster |
| * |
| */ |
| abstract class AbstractCreatableObjectContext extends AbstractObjectContext |
| { |
| AbstractCreatableObjectContext() |
| { |
| } |
| |
| /** Adds a parameter object to this Context if the result object has not been |
| * created yet. Otherwise an AssemblyException is thrown that indicates a wrong |
| * behavior of the decoder. |
| */ |
| public final void addParameterObject(Object o) throws AssemblyException |
| { |
| if (object == null) |
| addParameterObjectImpl(o); |
| else |
| throw new AssemblyException(new IllegalStateException("No more parameter objects are allowed when the object as already been created.")); |
| } |
| |
| /** Adds a parameter object to this Context. Implement this without caring |
| * for illegal states because this has been done already. |
| * |
| * @param obj The parameter object to be added. |
| */ |
| protected abstract void addParameterObjectImpl(Object obj); |
| |
| /** Creates the result object if it does not exist already. |
| */ |
| public final void notifyStatement(Context outerContext) |
| throws AssemblyException |
| { |
| if (object != null) |
| return; |
| |
| object = createObject(outerContext); |
| } |
| |
| /** Creates the result object. This method is called only once. Implement this |
| * without checking for double invocations as this is already being prevented. |
| * |
| * @param outerContext The Context that exists around this one. |
| * @return The result object. |
| * @throws AssemblerException if the object creation fails somehow. |
| */ |
| protected abstract Object createObject(Context outerContext) |
| throws AssemblyException; |
| |
| /* (non-Javadoc) |
| * @see gnu.java.beans.decoder.Context#endContext(gnu.java.beans.decoder.Context) |
| */ |
| public final Object endContext(Context outerContext) |
| throws AssemblyException |
| { |
| notifyStatement(outerContext); |
| return object; |
| } |
| |
| /* (non-Javadoc) |
| * @see gnu.java.beans.decoder.Context#subContextFailed() |
| */ |
| public boolean subContextFailed() |
| { |
| /* Returns true when the AbstractCreatableObjectContext has not created the result object yet |
| * (A failed subcontext automatically lets this context fail too.) |
| */ |
| return object == null; |
| } |
| } |