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1 package org.sapia.ubik.rmi.replication;
2
3 import org.sapia.ubik.net.ServerAddress;
4 import org.sapia.ubik.rmi.server.Hub;
5 import org.sapia.ubik.rmi.server.invocation.InvokeCommand;
6
7 import java.io.IOException  ;
8 import java.io.ObjectInput ;
9 import java.io.ObjectOutput ;
10
11 import java.rmi.RemoteException ;
12
13 import java.util.HashSet ;
14 import java.util.Set ;
15
16
17
30 public abstract class ReplicatedCommand extends InvokeCommand {
31 private Set _visited = new HashSet ();
32 private Set _targets;
33 private ReplicatedInvoker _invoker;
34 private boolean _executed;
35 private boolean _synchronous;
36 private boolean _disabled;
37
38
39 public ReplicatedCommand() {
40 }
41
42
49 public ReplicatedCommand(InvokeCommand cmd, Set targets,
50 ReplicatedInvoker invoker, boolean synchronous) {
51 super(cmd.getOID(), cmd.getMethodName(), cmd.getParams(),
52 cmd.getParameterTypes(), null);
53 _targets = targets;
54 _invoker = invoker;
55 _synchronous = synchronous;
56 }
57
58
72 public Object execute() throws Throwable {
73 if (_disabled) {
74 return super.execute();
75 }
76
77 Object toReturn;
78 Hub.serverRuntime.dispatchEvent(new ReplicationEvent(this));
79
80 Set siblings = _invoker.getSiblings();
81 ReplicationStrategy strat = new ReplicationStrategy(_visited, _targets,
82 siblings);
83 ServerAddress addr;
84 ServerAddress current = getServerAddress();
85
86 if (_executed) {
87 convertParams(_invoker.getClass().getClassLoader());
88 toReturn = _invoker.invoke(super.getMethodName(),
89 super.getParameterTypes(), super.getParams());
90 } else {
91 if (_targets != null) {
92 if (_targets.contains(current)) {
93 toReturn = super.execute();
94 _executed = true;
95 _targets.remove(current);
96 } else {
97 _executed = true;
98 toReturn = send(strat.selectNextSibling());
99
100 return toReturn;
101 }
102 } else {
103 toReturn = super.execute();
104 _executed = true;
105 }
106
107 if ((addr = strat.selectNextSibling()) != null) {
108 if (!_disabled) {
109 send(addr);
110 }
111 }
112 }
113
114 return toReturn;
115 }
116
117
120 public ReplicatedInvoker getReplicatedInvoker() {
121 return _invoker;
122 }
123
124
128 public void disable() {
129 _disabled = true;
130 }
131
132
135 public void readExternal(ObjectInput in)
136 throws IOException , ClassNotFoundException {
137 super.readExternal(in);
138 _visited = (Set ) in.readObject();
139 _targets = (Set ) in.readObject();
140 _invoker = (ReplicatedInvoker) in.readObject();
141 _executed = in.readBoolean();
142 _synchronous = in.readBoolean();
143 _disabled = in.readBoolean();
144 }
145
146
149 public void writeExternal(ObjectOutput out) throws IOException {
150 super.writeExternal(out);
151 out.writeObject(_visited);
152 out.writeObject(_targets);
153 out.writeObject(_invoker);
154 out.writeBoolean(_executed);
155 out.writeBoolean(_synchronous);
156 out.writeBoolean(_disabled);
157 }
158
159
167 protected Object send(ServerAddress next) throws RemoteException {
168 SendHelper helper = new SendHelper(this, next, _synchronous);
169
170 if (_synchronous) {
171 try {
172 return helper.send();
173 } catch (Throwable t) {
174 if (t instanceof RemoteException ) {
175 throw (RemoteException ) t;
176 }
177
178 throw new RemoteException ("Exception caught replicating command", t);
179 }
180 } else {
181 try {
182 helper.send();
183 } catch (Throwable t) {
184 if (t instanceof RemoteException ) {
185 throw (RemoteException ) t;
186 }
187
188 throw new RemoteException ("Exception caught replicating command", t);
189 }
190
191 return null;
192 }
193 }
194 }
195 |
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