| Frames | No Frames |
1: /* java.beans.beancontext.BeanContextChild 2: Copyright (C) 1999 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.beans.beancontext; 40: 41: import java.beans.PropertyChangeListener; 42: import java.beans.PropertyVetoException; 43: import java.beans.VetoableChangeListener; 44: 45: /** 46: * Beans implement this to get information about the execution environment and 47: * its services and to be placed in the hierarchy. 48: * <P> 49: * 50: * The difference between a <code>BeanContext</code> and a 51: * <code>BeanContextChild</code>, mainly, is that a 52: * <code>BeanContext</code> may be a parent. 53: * <P> 54: * 55: * <code>BeanContextChild</code> instances will be serialized at some 56: * point in their life, but you need to make sure your bean context does 57: * not contain a serializable reference (directly or indirectly) to the 58: * parent <code>BeanContext</code>, to any of the other 59: * <code>BeanContext</code>s in the tree, or to any resources obtained 60: * via the <code>BeanContextServices</code> interface. One way to do this 61: * is to mark any fields that contain such references as 62: * <code>transient</code>. Another way is to use a custom serializer. 63: * <P> 64: * 65: * If you do not do this, when the <code>BeanContext</code> is serialized, 66: * all the other <code>BeanContext</code>s and other unnecessary things 67: * will be serialized along with it. 68: * <P> 69: * 70: * Before dying, a <code>BeanContextChild</code> should call 71: * <code>getBeanContext().remove(this)</code> to detach from the 72: * hierarchy and exit cleanly. 73: * 74: * @author John Keiser 75: * @since JDK1.2 76: * @see java.beans.beancontext.BeanContext 77: */ 78: 79: public interface BeanContextChild { 80: /** 81: * Set the parent <code>BeanContext</code>. 82: * <P> 83: * 84: * This method is called from <code>BeanContext.add()</code> and 85: * should not be called directly. 86: * <P> 87: * 88: * When this Object is being added to a new BeanContext or moved 89: * from an old one, a non-null value will be passed in. 90: * <P> 91: * 92: * When this Object is being removed from the current 93: * <code>BeanContext</code>, <code>setBeanContext()</code> will 94: * receive the parameter <code>null</code>. 95: * <P> 96: * 97: * When being removed from the current <code>BeanContext</code>, 98: * it is the <code>BeanContextChild</code>'s responsibility to 99: * release all services it has obtained. 100: * <P> 101: * 102: * This change should generate <code>PropertyChangeEvent</code> 103: * and <code>VetoableChangeEvent</code>s with the property name 104: * "beanContext". If the change is vetoed, it must re-throw the 105: * exception and not change anything. In this way, the parent 106: * <code>BeanContextChild</code>, who has registered himself with 107: * you, will have a chance to remove this child from its 108: * collection. 109: * <P> 110: * 111: * If the Bean does not wish to change the parent or be removed 112: * from one, it may throw the <code>PropertyVetoException</code>. 113: * If you veto a <code>setBeanContext(null)</code> call, then you 114: * should try your hardest to remedy whatever problem is keeping 115: * you from being removed from the <code>BeanContext</code> so 116: * that you can <em>not</em> veto it the next time. 117: * Otherwise, nasty pathological recursion stuff could occur in 118: * certain situations. 119: * <P> 120: * 121: * If you do veto the change, you must first back out any changes 122: * you made prior to the veto. Best not to make any such changes 123: * prior to the veto in the first place. 124: * <P> 125: * 126: * This method is called from <code>BeanContext.add()</code> and 127: * should not be called directly. 128: * 129: * @param parent the new parent for the <code>BeanContextChild</code>, 130: * or <code>null</code> to signify removal from a tree. 131: * @exception PropertyVetoException if the 132: * <code>BeanContextChild</code> implementor does not 133: * wish to have its parent changed. 134: */ 135: void setBeanContext(BeanContext parent) 136: throws PropertyVetoException; 137: 138: /** 139: * Get the parent <code>BeanContext</code>. 140: * @return the parent <code>BeanContext</code>. 141: */ 142: BeanContext getBeanContext(); 143: 144: /** 145: * Add a listener that will be notified when a specific property changes. 146: * @param prop the name of the property to listen on 147: * @param listener the listener to listen on the property. 148: */ 149: void addPropertyChangeListener(String prop, PropertyChangeListener listener); 150: 151: /** 152: * Remove a listener to a certain property. 153: * @param prop the name of the property being listened on 154: * @param listener the listener listening on the property. 155: */ 156: void removePropertyChangeListener(String prop, PropertyChangeListener listener); 157: 158: /** 159: * Add a listener that will be notified when a specific property 160: * change is requested (a PropertyVetoException may be thrown) as 161: * well as after the change is successfully made. 162: * 163: * @param prop the name of the property to listen on 164: * @param listener the listener to listen on the property. 165: */ 166: void addVetoableChangeListener(String prop, VetoableChangeListener listener); 167: 168: /** 169: * Remove a listener to a certain property. 170: * @param prop the name of the property being listened on 171: * @param listener the listener listening on the property. 172: */ 173: void removeVetoableChangeListener(String prop, VetoableChangeListener listener); 174: }