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Java > Open Source Codes > com > jcorporate > expresso > kernel > management > ExpressoRuntimeMap


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64
65 package com.jcorporate.expresso.kernel.management;
66
67 import EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap;
68 import com.jcorporate.expresso.kernel.RootContainerInterface;
69
70 import java.util.Map JavaDoc;
71
72 /**
73  * This class allows controllers and other classes to potentially access
74  * Expresso Runtime Environments that they aren't necessarily a part of. This
75  * is critical for Management tools, which, by nature are outside of the Expresso
76  * container hierarchy.
77  *
78  * @author Michael Rimov
79  * @version $Revision: 1.5 $ on $Date: 2004/11/17 20:48:17 $
80  */
81
82 public final class ExpressoRuntimeMap {
83
84     /**
85      * The actual runtime map
86      */
87     private static Map runtimeMap = new ConcurrentReaderHashMap();
88
89     /**
90      * The default runtime if no key is specified.
91      */
92     private static RootContainerInterface defaultRuntime = null;
93
94     /**
95      * An object synchronizing access to the default variable runtime.
96      */
97     private static Object JavaDoc DefaultRuntimeLock = new Object JavaDoc();
98
99     /**
100      * Default constructor
101      */
102     public ExpressoRuntimeMap() {
103     }
104
105     /**
106      * Add this runtime to the system
107      *
108      * @param name Name of the runtime. If blank, it is automatically considered
109      * the default runtime. If it is the first runtime to be entered, it is also
110      * set as the default runtime until something else takes it place.
111      * @param expressoRuntime The Root Container of a particular runtime environment.
112      */
113     public synchronized static void registerRuntime(String JavaDoc name, RootContainerInterface expressoRuntime) {
114         if (expressoRuntime == null) {
115             throw new IllegalArgumentException JavaDoc("Cannot pass in a null Root Container");
116         }
117
118         if (name != null && name.length() > 0) {
119             runtimeMap.put(name, expressoRuntime);
120         }
121
122         synchronized (DefaultRuntimeLock) {
123             if (defaultRuntime == null || name == null || name.length() == 0) {
124                 defaultRuntime = expressoRuntime;
125             }
126         }
127     }
128
129     /**
130      * Retrieve a runtime environment as specified by the name parameter. If name
131      * is null or empty string, it returns the default runtime, if not, then
132      * it will return whatever is in the internal Runtime Map;
133      *
134      * @param name Name of the runtime to retrieve.
135      * @return the Expresso Root Container as specified by name.
136      */
137     public static RootContainerInterface getRuntime(String JavaDoc name) {
138         if (name == null || name.length() == 0) {
139             synchronized (DefaultRuntimeLock) {
140                 return defaultRuntime;
141             }
142         } else {
143             return (RootContainerInterface) runtimeMap.get(name);
144         }
145     }
146
147     /**
148      * Retrieve the default runtime.
149      *
150      * @return a Root Container interface for the default runtime in this JVM
151      */
152     public static synchronized RootContainerInterface getDefaultRuntime() {
153         synchronized (DefaultRuntimeLock) {
154             return defaultRuntime;
155         }
156     }
157
158     /**
159      * Unregister a runtime, this occurs when the runtime is being destroyed,
160      * either via a context reload or by a the container shutting down.
161      *
162      * @param name the Name of the context to unregister
163      */
164     public static synchronized void unregisterRuntime(String JavaDoc name) {
165         if (name == null || name.length() == 0) {
166             synchronized (DefaultRuntimeLock) {
167                 defaultRuntime = null;
168             }
169             return;
170         }
171
172         runtimeMap.remove(name);
173     }
174
175 }
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