1 /* 2 * Copyright (C) 2010 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.clearsilver.jsilver.data; 18 19 import com.google.clearsilver.jsilver.autoescape.EscapeMode; 20 21 import java.util.Iterator; 22 23 /** 24 * Data wrapper that prevents modifying the delegated Data node or its tree. 25 */ 26 public class UnmodifiableData extends DelegatedData { 27 28 private static final String MODIFICATION_ERROR_MSG = "Cannot modify this Data object."; 29 UnmodifiableData(Data delegate)30 public UnmodifiableData(Data delegate) { 31 super(delegate); 32 } 33 34 @Override newInstance(Data newDelegate)35 protected DelegatedData newInstance(Data newDelegate) { 36 return newDelegate == null ? null : new UnmodifiableData(newDelegate); 37 } 38 39 @Override copy(Data from)40 public void copy(Data from) { 41 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 42 } 43 44 @Override copy(String toPath, Data from)45 public void copy(String toPath, Data from) { 46 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 47 } 48 49 /** 50 * {@link #createChild} calls {@link #getChild} and throws {@link UnsupportedOperationException} 51 * if no object was found. 52 */ 53 @Override createChild(String path)54 public Data createChild(String path) { 55 // Check if child already exists 56 Data child = getChild(path); 57 58 if (child == null) { 59 // If the child described by path does not exist we throw 60 // an exception as we cannot create a new one. 61 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 62 } 63 return child; 64 } 65 66 protected class UnmodifiableIterator extends DelegatedIterator { UnmodifiableIterator(Iterator<? extends Data> iterator)67 UnmodifiableIterator(Iterator<? extends Data> iterator) { 68 super(iterator); 69 } 70 remove()71 public void remove() { 72 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 73 } 74 } 75 76 /** 77 * Override in order to not allow modifying children with remove(). 78 */ 79 @Override newChildIterator()80 protected Iterator<DelegatedData> newChildIterator() { 81 return new UnmodifiableIterator(getDelegate().getChildren().iterator()); 82 } 83 84 // Below we disable modification operations. 85 86 @Override setSymlink(String sourcePath, Data destination)87 public void setSymlink(String sourcePath, Data destination) { 88 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 89 } 90 91 @Override setSymlink(String sourcePath, String destinationPath)92 public void setSymlink(String sourcePath, String destinationPath) { 93 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 94 } 95 96 @Override setSymlink(Data symLink)97 public void setSymlink(Data symLink) { 98 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 99 } 100 101 @Override setAttribute(String key, String value)102 public void setAttribute(String key, String value) { 103 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 104 } 105 106 @Override removeTree(String path)107 public void removeTree(String path) { 108 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 109 } 110 111 @Override setValue(String path, String value)112 public void setValue(String path, String value) { 113 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 114 } 115 116 @Override setValue(String value)117 public void setValue(String value) { 118 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 119 } 120 121 @Override setEscapeMode(EscapeMode mode)122 public void setEscapeMode(EscapeMode mode) { 123 throw new UnsupportedOperationException(MODIFICATION_ERROR_MSG); 124 } 125 } 126