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Diffstat (limited to 'libjava/classpath/java/beans/beancontext/BeanContext.java')
| -rw-r--r-- | libjava/classpath/java/beans/beancontext/BeanContext.java | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/libjava/classpath/java/beans/beancontext/BeanContext.java b/libjava/classpath/java/beans/beancontext/BeanContext.java new file mode 100644 index 000000000..803cb36ff --- /dev/null +++ b/libjava/classpath/java/beans/beancontext/BeanContext.java @@ -0,0 +1,272 @@ +/* java.beans.beancontext.BeanContext + 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., 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 java.beans.beancontext; + +import java.beans.DesignMode; +import java.beans.Visibility; +import java.io.IOException; +import java.io.InputStream; +import java.net.URL; +import java.util.Collection; + +/** + * Acts as a container for sub-beans and as a sub-bean, + * so that an entire hierarchy of beans can be made up of + * <code>BeanContext</code>s. + * <P> + * + * Since I can't sprinkle the <code>Collections</code> interface + * documentation with special information for <code>BeanContext</code> + * implementors, I'll have to document special requirements for + * implementors of those functions here. + * <P> + * + * <code><strong>add()</strong></code> or <code>addAll()</code>: + * <br> + * <OL> + * <LI> + * May add any <code>Object</code> into the hierarchy as well as a + * <code>BeanContextChild</code>, <code>BeanContext</code> or + * <code>BeanContextProxy</code> object. + * This way, any Bean can be in the hierarchy. + * </LI> + * <LI> + * Must synchronize on <code>BeanContext.globalHierarchyLock</code>. + * </LI> + * <LI> + * Don't add the <code>Object</code> if it's already there (only once + * per <code>BeanContext</code>). + * </LI> + * <LI> + * If it is a <code>BeanContextChild</code> implementor, call + * <code>setBeanContext()</code> on it. If it's a + * <code>BeanContextProxy</code> implementor, call + * <code>getBeanContextProxy().setBeanContext()</code> on it. + * If <code>setBeanContext()</code> vetoes the change, back out + * all changes so far and throw <code>IllegalStateException</code>. + * </LI> + * <LI> + * If it (or its proxy) implements <code>Visibility</code>, call + * <code>dontUseGui()</code> or <code>okToUseGui()</code> on it, + * depending on whether you (the <code>BeanContext</code>) feel like + * allowing it to use the GUI or not. + * </LI> + * <LI> + * If it implements <code>BeanContextChild</code> or + * <code>BeanContextProxy</code>, register yourself (the + * <code>BeanContext</code>) as both a + * <code>PropertyChangeListener</code> and + * <code>VetoableChangeListener</code> on the "beanContext" + * property (it may also add itself on any other properties it wishes + * to). + * </LI> + * <LI> + * If it is a listener or event source that you (the + * <code>BeanContext</code>) are interested in, you may register + * yourself to it or register it to you. + * </LI> + * <LI> + * Fire a <code>java.beans.beancontext.BeanContextMembershipEvent</code> + * before exiting. <code>addAll()</code> should wait until everything + * is done changing before firing the event (or events) so that if a + * failure occurs, the backing-out process can proceed without any + * events being fired at all. + * </LI> + * </OL> + * <P> + * + * <code><strong>remove()</strong></code> or <code>removeAll()</code>: + * <br> + * <OL> + * <LI> + * Must synchronize on <code>BeanContext.globalHierarchyLock</code>. + * </LI> + * <LI> + * If the specified <code>Object</code> is not a child of this + * <code>BeanContext</code>, just exit without performing any actions. + * </LI> + * <LI> + * Remove the <code>Object</code> from your collection of children. + * </LI> + * <LI> + * If it is a <code>BeanContextChild</code> implementor, call + * <code>setBeanContext(null)</code> on it. If it's a + * <code>BeanContextProxy</code> implementor, call + * <code>getBeanContextProxy().setBeanContext(null)</code> on it. + * If <code>setBeanContext()</code> vetoes the change, back out + * all changes so far and throw <code>IllegalStateException</code>. + * </LI> + * <LI> + * If you registered the <code>Object</code> to listen to you or + * registered yourself as a listener on the <code>Object</code> during + * <code>add()</code> or <code>addAll()</code>, undo the registration + * bycalling the appropriate <code>removeListener()</code> method. + * </LI> + * <LI> + * Fire a <code>java.beans.beancontext.BeanContextMembershipEvent</code> + * before exiting. <code>removeAll()</code> should wait until + * everything is done changing before firing the event (or events) so + * that if a failure occurs, the backing-out process can proceed + * without any events being fired at all. + * </LI> + * </OL> + * <P> + * + * <code>addAll()</code>, <code>removeAll()</code>, + * <code>retainAll()</code> and <code>clear()</code> do not need to be + * implemented, but may be if so desired. + * <P> + * + * Similarly, <code>Visibility</code> and <code>DesignMode</code> methods + * should propagate changed values to children that implement interfaces + * of the same name. + * <P> + * + * A hierarchy of beans is mainly useful so that different sets of beans + * can be established, each with their own set of resources. + * + * @author John Keiser + * @since JDK1.2 + */ + +public interface BeanContext + extends Collection, BeanContextChild, Visibility, DesignMode { + + /** + * The global lock on changing any BeanContext hierarchy. + * It kinda sucks that there is only one lock, since there can be + * multiple hierarchies. Oh well, I didn't design, I just code. + * <P> + * + * Methods that must (or do) synchronize on the global lock: + * <BR> + * <UL> + * <LI> + * Implementors of <CODE>BeanContext.add()</CODE> and <code>addAll()</code> + * </LI> + * </UL> + * @fixme fill in the rest of the methods which use the global lock. + */ + Object globalHierarchyLock = new Object(); + + /** + * Instantiate a Bean using this Bean's <code>ClassLoader</code> + * and this <code>BeanContext</code> as the parent. + * <P> + * + * This method exists mainly so that <code>BeanContext</code> + * implementations can perform extra actions on Beans that are + * created within them. + * + * @param beanName the name of the bean to instantiate + * @return the created Bean + * + * @see java.beans.Beans#instantiate(java.lang.ClassLoader,java.lang.String) + * @see java.beans.Beans#instantiate(java.lang.ClassLoader,java.lang.String,java.beans.beancontext.BeanContext) + * @exception IOException if there is an I/O problem during + * instantiation. + * @exception ClassNotFoundException if a serialized Bean's class + * is not found. + */ + Object instantiateChild(String beanName) + throws IOException, + ClassNotFoundException; + + /** + * Get a resource. The <code>BeanContext</code> will typically + * call <code>ClassLoader.getResource()</code>, but may do it any + * way it wants to. This allows a <code>BeanContext</code> to + * have its own set of resources separate from the rest of the + * system. + * <P> + * + * Beans should call this method on their parent rather than the + * associated <code>ClassLoader</code> method. + * <P> + * + * I am assuming, but am not entirely sure, that if a + * <code>BeanContext</code> cannot find a resource, its + * responsibility is to call the <code>getResource</code> method + * of its parent <code>BeanContext</code>. + * + * @return a URL to the requested resource. + * @param resourceName the name of the resource requested. + * @param requestor a reference to the child requesting the resource. + * @see java.lang.ClassLoader#getResource(java.lang.String) + */ + URL getResource(String resourceName, BeanContextChild requestor); + + /** + * Get a resource as a stream. The <code>BeanContext</code> will + * typically call <code>ClassLoader.getResourceAsStream()</code>, + * but may do it any way it wants to. This allows a + * <code>BeanContext</code>'s children to have their own set of + * resources separate from the rest of the system. + * <P> + * + * Beans should call this method on their parent rather than the + * associated <code>ClassLoader</code> method. + * <P> + * + * I am assuming, but am not entirely sure, that if a + * <code>BeanContext</code> cannot find a resource, its + * responsibility is to call the <code>getResourceAsStream</code> + * method of its parent <code>BeanContext</code>. + * + * @return the requested resource as a stream. + * @param resourceName the name of the resource requested. + * @param requestor a reference to the child requesting the resource. + * @see java.lang.ClassLoader#getResourceAsStream(java.lang.String) + */ + InputStream getResourceAsStream(String resourceName, BeanContextChild requestor); + + /** + * Add a listener on changes to the membership of this + * <code>BeanContext</code> object. + * @param listener the listener to add. + */ + void addBeanContextMembershipListener(BeanContextMembershipListener listener); + + /** + * Remove a listener on changes to the membership of this + * <code>BeanContext</code> object. + * @param listener the listener to remove. + */ + void removeBeanContextMembershipListener(BeanContextMembershipListener listener); +} |