001// Copyright 2004, 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry.contrib.table.model.common; 016 017import java.lang.ref.WeakReference; 018import java.util.ArrayList; 019import java.util.Iterator; 020import java.util.List; 021 022import org.apache.tapestry.contrib.table.model.CTableDataModelEvent; 023import org.apache.tapestry.contrib.table.model.ITableDataModel; 024import org.apache.tapestry.contrib.table.model.ITableDataModelListener; 025 026/** 027 * An implementation of the listener support in the ITableDataModel interface 028 * 029 * @author mindbridge 030 */ 031public abstract class AbstractTableDataModel implements ITableDataModel 032{ 033 private List m_arrListeners; 034 035 public AbstractTableDataModel() 036 { 037 m_arrListeners = new ArrayList(); 038 } 039 040 /** 041 * Method fireTableDataModelEvent. 042 * Fires a change event to all listeners 043 * @param objEvent the event to pass to the listeners 044 */ 045 protected void fireTableDataModelEvent(CTableDataModelEvent objEvent) 046 { 047 synchronized (m_arrListeners) { 048 List arrEmptyReferences = null; 049 050 for (Iterator it = m_arrListeners.iterator(); it.hasNext();) 051 { 052 WeakReference objRef = (WeakReference) it.next(); 053 ITableDataModelListener objListener = 054 (ITableDataModelListener) objRef.get(); 055 if (objListener != null) 056 objListener.tableDataChanged(objEvent); 057 else { 058 if (arrEmptyReferences == null) 059 arrEmptyReferences = new ArrayList(); 060 arrEmptyReferences.add(objRef); 061 } 062 } 063 064 if (arrEmptyReferences != null) 065 m_arrListeners.removeAll(arrEmptyReferences); 066 } 067 } 068 069 /** 070 * @see org.apache.tapestry.contrib.table.model.ITableDataModel#addTableDataModelListener(ITableDataModelListener) 071 */ 072 public void addTableDataModelListener(ITableDataModelListener objListener) 073 { 074 synchronized (m_arrListeners) { 075 m_arrListeners.add(new WeakReference(objListener)); 076 } 077 } 078 079 /** 080 * @see org.apache.tapestry.contrib.table.model.ITableDataModel#removeTableDataModelListener(ITableDataModelListener) 081 */ 082 public void removeTableDataModelListener(ITableDataModelListener objListener) 083 { 084 synchronized (m_arrListeners) { 085 List arrEmptyReferences = null; 086 087 for (Iterator it = m_arrListeners.iterator(); it.hasNext();) 088 { 089 WeakReference objRef = (WeakReference) it.next(); 090 ITableDataModelListener objStoredListener = 091 (ITableDataModelListener) objRef.get(); 092 if (objListener == objStoredListener || objStoredListener == null) { 093 if (arrEmptyReferences == null) 094 arrEmptyReferences = new ArrayList(); 095 arrEmptyReferences.add(objRef); 096 } 097 } 098 099 if (arrEmptyReferences != null) 100 m_arrListeners.removeAll(arrEmptyReferences); 101 } 102 } 103 104}