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1 package demo.bank.concurrency;
2
3 import org.omg.CORBA.*;
4 import org.omg.CORBA.ORBPackage.*;
5 import org.omg.CosTransactions.*;
6 import org.omg.CosConcurrencyControl.*;
7 import org.omg.CosNaming.*;
8 import java.io.*;
9
10 public class BankImpl
11 extends TheBankPOA
12 {
13 private ORB orb;
14 private org.omg.PortableServer.POA  poa;
15 private TransactionFactory transactionFactory;
16 private LockSetFactory lockSetFactory;
17
18 public BankImpl( ORB orb, org.omg.PortableServer.POA poa )
19 {
20 this.orb = orb;
21 this.poa = poa;
22 try
23 {
24 NamingContextExt nc =
26 NamingContextExtHelper.narrow(orb.resolve_initial_references("NameService"));
27 NameComponent [] name = new NameComponent[1];
28 name[0] =
29 new NameComponent( "TransactionService", "service");
30 transactionFactory =
31 TransactionFactoryHelper.narrow( nc.resolve(name));
32
33 name[0] =
35 new NameComponent( "ConcurrencyControlService",
36 "service");
37 lockSetFactory =
38 LockSetFactoryHelper.narrow( nc.resolve(name) );
39 }
40 catch( Exception n )
41 {
42 n.printStackTrace();
43 System.exit(1);
44 }
45 }
46
47 public Account open(String name, float initial_deposit)
48 {
49 try
50 {
51 TransactionalLockSet lock_set =
52 lockSetFactory.create_transactional();
53 AccountImpl acc =
54 new AccountImpl( lock_set, name,
55 initial_deposit, 0);
56 org.omg.CORBA.Object o = poa.servant_to_reference(acc);
57 return acc._this(orb);
58 }
59 catch( Exception e )
60 {
61 e.printStackTrace();
62 throw new org.omg.CORBA.UNKNOWN ();
63 }
64 }
65
66 public void transfer( Account source, Account destination, float amount )
67 throws InsufficientFunds
68 {
69 Control control = null;
70 try
71 {
72 System.err.println("begin transaction");
74
75 control = transactionFactory.create(20);
77 Coordinator coord = control.get_coordinator();
78
79 TransactionalLockSet lock_set = source.get_lock_set();
81 lock_set.lock( coord, lock_mode.upgrade );
82 lock_set = destination.get_lock_set();
83 lock_set.lock( coord, lock_mode.upgrade );
84
85 source.debit( amount, control );
86
87 System.err.println("debited");
88
89 destination.credit( amount, control );
90
91 System.err.println("credited");
92
93 System.err.println("commit transaction");
95 control.get_terminator().commit( true );
96 System.err.println("transaction comitted");
97 }
98 catch( InsufficientFunds isf )
99 {
100 try
101 {
102 control.get_terminator().rollback();
103 }
104 catch( org.omg.CosTransactions.Unavailable nt )
105 {
106 System.err.println("No transaction - give up: " + nt );
107 System.exit( 1 );
108 }
109 throw( isf );
110 }
111 catch( UserException ue )
112 {
113 System.err.println("transactional failure - give up: " + ue );
114 System.exit( 1 );
115 }
116 catch( SystemException se )
117 {
118 System.err.println("system exception - rollback transaction: " + se );
119 try
120 {
121 control.get_terminator().rollback();
122 }
123 catch( org.omg.CosTransactions.Unavailable nt )
124 {
125 System.err.println("No transaction - give up: " + nt );
126 System.exit( 1 );
127 }
128 throw( se );
129 }
130 }
131
132
133 }
134
135
136
137 |
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