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 * @author Les Hazlewood
029 * @see org.apache.shiro.subject.SubjectContext SubjectContext
030 * @see org.apache.shiro.session.mgt.SessionContext SessionContext
031 * @since 1.0
032 */
033 public class MapContext implements Map<String, Object>, Serializable {
034
035 private static final long serialVersionUID = 5373399119017820322L;
036
037 private final Map<String, Object> backingMap;
038
039 public MapContext() {
040 this.backingMap = new HashMap<String, Object>();
041 }
042
043 public MapContext(Map<String, Object> map) {
044 this();
045 if (!CollectionUtils.isEmpty(map)) {
046 this.backingMap.putAll(map);
047 }
048 }
049
050 /**
051 * Performs a {@link #get get} operation but additionally ensures that the value returned is of the specified
052 * {@code type}. If there is no value, {@code null} is returned.
053 *
054 * @param key the attribute key to look up a value
055 * @param type the expected type of the value
056 * @param <E> the expected type of the value
057 * @return the typed value or {@code null} if the attribute does not exist.
058 */
059 @SuppressWarnings({"unchecked"})
060 protected <E> E getTypedValue(String key, Class<E> type) {
061 E found = null;
062 Object o = backingMap.get(key);
063 if (o != null) {
064 if (!type.isAssignableFrom(o.getClass())) {
065 String msg = "Invalid object found in SubjectContext Map under key [" + key + "]. Expected type " +
066 "was [" + type.getName() + "], but the object under that key is of type " +
067 "[" + o.getClass().getName() + "].";
068 throw new IllegalArgumentException(msg);
069 }
070 found = (E) o;
071 }
072 return found;
073 }
074
075 /**
076 * Places a value in this context map under the given key only if the given {@code value} argument is not null.
077 *
078 * @param key the attribute key under which the non-null value will be stored
079 * @param value the non-null value to store. If {@code null}, this method does nothing and returns immediately.
080 */
081 protected void nullSafePut(String key, Object value) {
082 if (value != null) {
083 put(key, value);
084 }
085 }
086
087 public int size() {
088 return backingMap.size();
089 }
090
091 public boolean isEmpty() {
092 return backingMap.isEmpty();
093 }
094
095 public boolean containsKey(Object o) {
096 return backingMap.containsKey(o);
097 }
098
099 public boolean containsValue(Object o) {
100 return backingMap.containsValue(o);
101 }
102
103 public Object get(Object o) {
104 return backingMap.get(o);
105 }
106
107 public Object put(String s, Object o) {
108 return backingMap.put(s, o);
109 }
110
111 public Object remove(Object o) {
112 return backingMap.remove(o);
113 }
114
115 public void putAll(Map<? extends String, ?> map) {
116 backingMap.putAll(map);
117 }
118
119 public void clear() {
120 backingMap.clear();
121 }
122
123 public Set<String> keySet() {
124 return Collections.unmodifiableSet(backingMap.keySet());
125 }
126
127 public Collection<Object> values() {
128 return Collections.unmodifiableCollection(backingMap.values());
129 }
130
131 public Set<Entry<String, Object>> entrySet() {
132 return Collections.unmodifiableSet(backingMap.entrySet());
133 }
134 }