Database


1   // You can redistribute this software and/or modify it under the terms of
2   // the Ozone Library License version 1 published by ozone-db.org.
3   //
4   // The original code and portions created by SMB are
5   // Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
6   //
7   // $Id: Database.java,v 1.15 2004/01/03 10:39:41 per_nyfelt Exp $
8   
9   package org.ozoneDB;
10  
11  import org.ozoneDB.core.DbRemote.CommandThread;
12  import org.ozoneDB.core.DbRemote.DbXMLForObj;
13  import org.ozoneDB.core.*;
14  import org.ozoneDB.util.LogWriter;
15  import org.ozoneDB.xml.util.SAXChunkConsumer;
16  import org.w3c.dom.Document  ;
17  import org.w3c.dom.Node  ;
18  import org.xml.sax.ContentHandler  ;
19  
20  
21  /**
22   * This class represents the database for OzoneObjects within the server.<p>
23   *
24   * Note: The method parameters of type {@link OzoneRemote} are supposed to by
25   * proxy objects (of type {@link OzoneProxy}). However, since we are inside the
26   * server it's possible to pass an database object (of type {@link
27   * OzoneCompatible}) as a parameter. In this case the parameter should be
28   * substituted. Currently this is done by the invoke() method only.
29   *
30   * @author <a HREF="http://www.softwarebuero.de/">SMB</a>
31   * @author <a HREF="http://www.medium.net/">Medium.net</a>
32   * @version $Revision: 1.15 $Date: 2004/01/03 10:39:41 $
33   * @see OzoneInterface
34   */
35  public final class Database extends AbstractDatabase {
36  
37      protected transient Env env;
38  
39      public Database(Env _env) {
40          this.env = _env;
41          AbstractFactory.setDefaultDatabase(this);
42      }
43  
44  
45      public void reloadClasses() throws Exception   {
46          throw new Exception  ("reloadClasses() must not be called from within the server.");
47      }
48  
49  
50      public User currentOwner() {
51          Thread   thread = Thread.currentThread();
52          /*
53          if (thread instanceof Transaction) {
54             return ((Transaction)thread).owner();
55             }
56           */
57          if (thread instanceof CommandThread) {
58              return ((CommandThread) thread).owner();
59          } else {
60              env.fatalError(this, "Current thread is not a transaction or command!", null);
61              return null;
62          }
63      }
64  
65  
66      public OzoneProxy createObject(String   className,int access,String   objName,String   sig,Object  [] args) throws RuntimeException  ,OzoneObjectException {
67          env.logWriter.newEntry( this, "createObject()...", LogWriter.DEBUG3 );
68          try {
69              ObjectContainer container = env.transactionManager.currentTA().createObject( className, access, objName, sig, args, null );
70  
71              try {
72                  OzoneProxy result = container.ozoneProxy();
73                  // env.logWriter.newEntry ("return: " + result.getClass().getName(), LogWriter.DEBUG);
74                  return result;
75              } finally {
76                  container.unpin();
77              }
78          } catch (java.lang.reflect.InvocationTargetException   e) {
79              throw new OzoneObjectException("Caught during deleteObject()", e);
80          } catch (OzoneObjectException e) {
81              throw e;
82          } catch (Exception   e) {
83              env.logWriter.newEntry(this,"createObject(): caught",e,LogWriter.DEBUG3 );
84              throw new RuntimeException  ("Caught during createObject(): ", e);
85          }
86      }
87  
88  
89      public OzoneProxy copyObject(OzoneRemote rObj) throws Exception   {
90          env.logWriter.newEntry(this, "copyObject()...", LogWriter.DEBUG3);
91          ObjectContainer container = env.transactionManager.currentTA().copyObject( ((OzoneProxy)rObj).remoteID() );
92          try {
93              return container.ozoneProxy();
94          } finally {
95              container.unpin();
96          }
97      }
98  
99  
100     public void deleteObject( OzoneRemote rObj ) throws RuntimeException  ,OzoneObjectException {
101         try {
102             if (false) {
103                 env.logWriter.newEntry( this, "deleteObject()...", LogWriter.DEBUG3 );
104             }
105             env.transactionManager.currentTA().deleteObject( ((OzoneProxy)rObj).remoteID() );
106         } catch (OzoneObjectException e) {
107             throw e;
108         } catch (Exception   e) {
109             throw new RuntimeException  ("Caught during deleteObject(): ", e);
110         }
111     }
112 
113 
114     public void nameObject(OzoneRemote rObj, String   name) throws Exception   {
115         if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
116             env.logWriter.newEntry(this, "nameObject()...", LogWriter.DEBUG3);
117         }
118         env.transactionManager.currentTA().nameObject(((OzoneProxy) rObj).remoteID(), name);
119     }
120 
121 
122     public String  [] objectNames() throws Exception   {
123        if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
124             env.logWriter.newEntry(this, "objectNames()...", LogWriter.DEBUG3);
125         }
126         Object  [] keys = env.transactionManager.currentTA().objectNames().toArray();
127         String  [] names = new String  [keys.length];
128         for (int i = 0; i < keys.length; i++) {
129             names[i] = (String  ) keys[i];
130         }
131         return names;
132     }
133 
134     public OzoneProxy objectForName(String   name) throws Exception   {
135         env.logWriter.newEntry(this, "objectForName()... ", LogWriter.DEBUG3);
136         return env.transactionManager.currentTA().objectForName(name);
137     }
138 
139     public OzoneProxy objectForHandle(String   handle) throws Exception   {
140         env.logWriter.newEntry(this, "objectForHandle()... ", LogWriter.DEBUG3);
141         return env.transactionManager.currentTA().objectForID(new ObjectID(handle));
142     }
143 
144     public Object   invoke(OzoneProxy rObj, String   methodName, String   sig, Object  [] args, int lockLevel)
145             throws Exception   {
146 
147         //one argument could have been "this", then we have to give
148         //a proxy instead of the actual object
149         for (int i = 0; i < args.length; i++) {
150             args[i] = ResultConverter.substituteOzoneCompatibles(args[i]);
151         }
152 
153         Object   result = env.transactionManager.currentTA().invokeObject(rObj.remoteID(), methodName, sig, args, lockLevel);
154 
155         //also return could have been "this"...
156         result = ResultConverter.substituteOzoneCompatibles(result);
157         
158         return result;
159     }
160 
161 
162     public Object   invoke(OzoneProxy rObj, int methodIndex, Object  [] args, int lockLevel) throws Exception   {
163 
164         //one argument could have been "this", then we have to give
165         //a proxy instead of the actual object
166         for (int i = 0; i < args.length; i++) {
167             args[i] = ResultConverter.substituteOzoneCompatibles(args[i]);
168         }
169 
170         Object   result = env.transactionManager.currentTA().invokeObject(rObj.remoteID(), methodIndex, args, lockLevel);
171 
172         //also return could have been "this"...
173         result = ResultConverter.substituteOzoneCompatibles(result);
174         
175         return result;
176     }
177 
178 
179     public OzoneCompatible fetch(OzoneProxy rObj, int lockLevel) throws /*Exception*/ org.ozoneDB.ObjectNotFoundException, java.io.IOException  , java.lang.ClassNotFoundException  , org.ozoneDB.TransactionException, org.ozoneDB.core.TransactionError {
180         // env.logWriter.newEntry (this, "fetch()...", LogWriter.DEBUG3);
181 
182         Transaction         currentTransaction  =   getCurrentTransaction();
183         ObjectID            id                  =   rObj.remoteID();
184 
185         ObjectContainer     container           =   currentTransaction.acquireObject( id, lockLevel );
186 
187         try {
188             return container.target();
189         } finally {
190             container.unpin();
191         }
192     }
193 
194 
195     public Node   xmlForObject(OzoneRemote rObj, Document   domFactory) throws Exception   {
196 
197         // creating the chunk is not really needed but should work ;)
198         DbXMLForObj command = new DbXMLForObj((OzoneProxy) rObj);
199         command.perform(env.transactionManager.currentTA());
200         byte[] bytes = (byte[]) command.result;
201 
202         SAXChunkConsumer consumer = new SAXChunkConsumer(domFactory, null);
203         consumer.processChunk(bytes);
204 
205         return consumer.getResultNode();
206     }
207 
208 
209     public void xmlForObject(OzoneRemote rObj, ContentHandler   ch) throws Exception   {
210 
211         // creating the chunk is not really needed but should work ;)
212         DbXMLForObj command = new DbXMLForObj((OzoneProxy) rObj);
213         command.perform(env.transactionManager.currentTA());
214         byte[] bytes = (byte[]) command.result;
215 
216         SAXChunkConsumer consumer = new SAXChunkConsumer(ch);
217         consumer.processChunk(bytes);
218     }
219 
220     /**
221         Internal method. This method is called by {@link OzoneProxy}s when they are dying (during finalize()). This
222         is required, as the database may track the references the database client has to objects within the database
223         in order to properly support garbage collection. If this method is called from anyone else than from the
224         {@link OzoneProxy#finalize()}-Method, data loss may occur!
225 
226         @param proxy the OzoneProxy object which is dying. It may call this method exaclty once.
227     */
228     public void notifyProxyDeath(OzoneProxy proxy) {
229         // We do nothing here as we do not care wether OzoneProxys within the local databases die.
230     }
231         
232     /**
233         For internal use.
234     */
235     public Env getEnv() {
236         return env;
237     }
238     
239     /**
240         For internal use.
241     */
242     public Transaction getCurrentTransaction() {
243         TransactionManager  transactionManager  =   getEnv().getTransactionManager();
244         Transaction         currentTransaction  =   transactionManager.currentTA();
245         
246         return currentTransaction;
247     }
248 }
249 // :indentSize=4:tabSize=4:noTabs=true:
250
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