1 /* 2 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.corba.se.impl.ior ; 27 28 import java.util.Collection ; 29 import java.util.List ; 30 import java.util.AbstractList ; 31 import java.util.ListIterator ; 32 import java.util.Iterator ; 33 34 import com.sun.corba.se.spi.ior.MakeImmutable ; 35 36 /** Simple class that delegates all List operations to 37 * another list. It also can be frozen, which means that 38 * a number of operations can be performed on the list, 39 * and then the list can be made immutable, so that no 40 * further changes are possible. A FreezableList is frozen 41 * using the makeImmutable method. 42 */ 43 public class FreezableList extends AbstractList { 44 private List delegate = null ; 45 private boolean immutable = false ; 46 47 public boolean equals( Object obj ) 48 { 49 if (obj == null) 50 return false ; 51 52 if (!(obj instanceof FreezableList)) 53 return false ; 54 55 FreezableList other = (FreezableList)obj ; 56 57 return delegate.equals( other.delegate ) && 58 (immutable == other.immutable) ; 59 } 60 61 public int hashCode() 62 { 63 return delegate.hashCode() ; 64 } 65 66 public FreezableList( List delegate, boolean immutable ) 67 { 68 this.delegate = delegate ; 69 this.immutable = immutable ; 70 } 71 72 public FreezableList( List delegate ) 73 { 74 this( delegate, false ) ; 75 } 76 77 public void makeImmutable() 78 { 79 immutable = true ; 80 } 81 82 public boolean isImmutable() 83 { 84 return immutable ; 85 } 86 87 public void makeElementsImmutable() 88 { 89 Iterator iter = iterator() ; 90 while (iter.hasNext()) { 91 Object obj = iter.next() ; 92 if (obj instanceof MakeImmutable) { 93 MakeImmutable element = (MakeImmutable)obj ; 94 element.makeImmutable() ; 95 } 96 } 97 } 98 99 // Methods overridden from AbstractList 100 101 public int size() 102 { 103 return delegate.size() ; 104 } 105 106 public Object get(int index) 107 { 108 return delegate.get(index) ; 109 } 110 111 public Object set(int index, Object element) 112 { 113 if (immutable) 114 throw new UnsupportedOperationException() ; 115 116 return delegate.set(index, element) ; 117 } 118 119 public void add(int index, Object element) 120 { 121 if (immutable) 122 throw new UnsupportedOperationException() ; 123 124 delegate.add(index, element) ; 125 } 126 127 public Object remove(int index) 128 { 129 if (immutable) 130 throw new UnsupportedOperationException() ; 131 132 return delegate.remove(index) ; 133 } 134 135 // We also override subList so that the result is a FreezableList. 136 public List subList(int fromIndex, int toIndex) 137 { 138 List list = delegate.subList(fromIndex, toIndex) ; 139 List result = new FreezableList( list, immutable ) ; 140 return result ; 141 } 142 }