001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019 package org.apache.shiro.util;
020
021 import java.io.Serializable;
022 import java.util.*;
023
024 /**
025 * A {@code MapContext} provides a common base for context-based data storage in a {@link Map}. Type-safe attribute
026 * retrieval is provided for subclasses with the {@link #getTypedValue(String, Class)} method.
027 *
028 * @see org.apache.shiro.subject.SubjectContext SubjectContext
029 * @see org.apache.shiro.session.mgt.SessionContext SessionContext
030 * @since 1.0
031 */
032 public class MapContext implements Map<String, Object>, Serializable {
033
034 private static final long serialVersionUID = 5373399119017820322L;
035
036 private final Map<String, Object> backingMap;
037
038 public MapContext() {
039 this.backingMap = new HashMap<String, Object>();
040 }
041
042 public MapContext(Map<String, Object> map) {
043 this();
044 if (!CollectionUtils.isEmpty(map)) {
045 this.backingMap.putAll(map);
046 }
047 }
048
049 /**
050 * Performs a {@link #get get} operation but additionally ensures that the value returned is of the specified
051 * {@code type}. If there is no value, {@code null} is returned.
052 *
053 * @param key the attribute key to look up a value
054 * @param type the expected type of the value
055 * @param <E> the expected type of the value
056 * @return the typed value or {@code null} if the attribute does not exist.
057 */
058 @SuppressWarnings({"unchecked"})
059 protected <E> E getTypedValue(String key, Class<E> type) {
060 E found = null;
061 Object o = backingMap.get(key);
062 if (o != null) {
063 if (!type.isAssignableFrom(o.getClass())) {
064 String msg = "Invalid object found in SubjectContext Map under key [" + key + "]. Expected type " +
065 "was [" + type.getName() + "], but the object under that key is of type " +
066 "[" + o.getClass().getName() + "].";
067 throw new IllegalArgumentException(msg);
068 }
069 found = (E) o;
070 }
071 return found;
072 }
073
074 /**
075 * Places a value in this context map under the given key only if the given {@code value} argument is not null.
076 *
077 * @param key the attribute key under which the non-null value will be stored
078 * @param value the non-null value to store. If {@code null}, this method does nothing and returns immediately.
079 */
080 protected void nullSafePut(String key, Object value) {
081 if (value != null) {
082 put(key, value);
083 }
084 }
085
086 public int size() {
087 return backingMap.size();
088 }
089
090 public boolean isEmpty() {
091 return backingMap.isEmpty();
092 }
093
094 public boolean containsKey(Object o) {
095 return backingMap.containsKey(o);
096 }
097
098 public boolean containsValue(Object o) {
099 return backingMap.containsValue(o);
100 }
101
102 public Object get(Object o) {
103 return backingMap.get(o);
104 }
105
106 public Object put(String s, Object o) {
107 return backingMap.put(s, o);
108 }
109
110 public Object remove(Object o) {
111 return backingMap.remove(o);
112 }
113
114 public void putAll(Map<? extends String, ?> map) {
115 backingMap.putAll(map);
116 }
117
118 public void clear() {
119 backingMap.clear();
120 }
121
122 public Set<String> keySet() {
123 return Collections.unmodifiableSet(backingMap.keySet());
124 }
125
126 public Collection<Object> values() {
127 return Collections.unmodifiableCollection(backingMap.values());
128 }
129
130 public Set<Entry<String, Object>> entrySet() {
131 return Collections.unmodifiableSet(backingMap.entrySet());
132 }
133 }