module poaBank
{
interface Account
{
| exception InsufficientFunds {};
|
| float deposit(in float sum);
|
| float withdraw(in float sum) raises (InsufficientFunds);
|
| readonly attribute float balance;
};
interface Bank
{
| exception noSuchAccount {};
|
| Account getAccount(in long accountNum) raises (noSuchAccount);
};
};
package poaBankDefSrvnt;
import util.Util;
import org.omg.CORBA.ORB;
import org.omg.CORBA.Policy;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContext;
import org.omg.CosNaming.NamingContextHelper;
import org.omg.CosNaming.NamingContextPackage.NotFound;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.Servant;
import org.omg.PortableServer.LifespanPolicyValue;
import org.omg.PortableServer.IdAssignmentPolicyValue;
import poaBank.Bank;
import poaBank.BankHelper;
public class Server
{
public static void main(String[] args)
{
| try {
| |
| | // create the jBroker ORB
| | ORB orb = ORB.init(args, null);
| |
| | // get the root POA
| | POA rootPOA = (POA) orb.resolve_initial_references("RootPOA");
| |
| | // create a persistent user assigned ids POA
| | POA bankPOA = rootPOA.create_POA("bankPOA",
| | rootPOA.the_POAManager(),
| | new Policy[] {
| | | rootPOA.create_id_assignment_policy(
| | | IdAssignmentPolicyValue.USER_ID),
| | | rootPOA.create_lifespan_policy(
| | | LifespanPolicyValue.PERSISTENT)
| | });
| |
| | // create and activate bank servant
| | Servant bank = new BankImpl(bankPOA, args[0]);
| | bankPOA.activate_object_with_id("bank".getBytes(), bank);
| |
| | // get the root of the NameService
| | NamingContext root = NamingContextHelper.narrow(
| | orb.resolve_initial_references("NameService"));
| |
| | // if not done before, publish the bank objref
| | NameComponent nc = new NameComponent("bank3", "");
| | NameComponent[] name = new NameComponent[] { nc };
| | try {
| | | root.resolve(name);
| | } catch (NotFound ex) {
| | | // create the bank objref
| | | Bank bankObj = BankHelper.narrow(bankPOA.
| | | create_reference_with_id("bank".getBytes(),
| | | bank._all_interfaces(null, null)[0]));
| | |
| | | System.out.println(orb.object_to_string(bankObj));
| | | root.rebind(name, bankObj);
| | }
| |
| | // activate bankPOA
| | bankPOA.the_POAManager().activate();
| |
| | // wait for invocations
| | System.out.println("waiting for invocations ...");
| | orb.run();
| |
| } catch (Exception ex) {
| | ex.printStackTrace();
| }
}
}
package poaBankDefSrvnt;
import java.io.File;
import org.omg.CORBA.Policy;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.Servant;
import org.omg.PortableServer.IdUniquenessPolicyValue;
import org.omg.PortableServer.IdAssignmentPolicyValue;
import org.omg.PortableServer.ServantRetentionPolicyValue;
import org.omg.PortableServer.RequestProcessingPolicyValue;
import poaBank.BankPOA;
import poaBank.Account;
import poaBank.AccountHelper;
import poaBank.BankPackage.noSuchAccount;
public class BankImpl extends BankPOA
{
POA _acctPOA;
String _acctRepId; // repository Id for Account Objects
Servant _defaultServant;
BankImpl(POA bankPOA, String dir) throws Exception
{
| // make sure that the DB dir exists
| File dbDir = new File (dir);
| if (!dbDir.exists()) dbDir.mkdir();
|
| // create the POA for Transient Account Objects
| _acctPOA = bankPOA.create_POA("acctPOA", bankPOA.the_POAManager(),
| new Policy[] {
| | bankPOA.create_id_assignment_policy(
| | IdAssignmentPolicyValue.USER_ID),
| | bankPOA.create_request_processing_policy(
| | RequestProcessingPolicyValue.USE_DEFAULT_SERVANT),
| | bankPOA.create_id_uniqueness_policy(
| | IdUniquenessPolicyValue.MULTIPLE_ID)
| });
|
| // set the servant manager in Acct POA
| _defaultServant = new AccountImpl(dbDir);
| _acctPOA.set_servant(_defaultServant);
|
| // compute the repository id for Account objects
| _acctRepId = _defaultServant._all_interfaces(null, null)[0];
}
public Account getAccount(int acctNum) throws noSuchAccount
{
| Account account = null;
|
| if ((acctNum >= 100) && (acctNum < 110)) {
| |
| | // construct the object id for account
| | byte objectId[] = new byte[1];
| | objectId[0] = (byte) (acctNum & 0xFF);
| |
| | try {
| | | account = AccountHelper.narrow(_acctPOA.
| | | create_reference_with_id(objectId, _acctRepId));
| | } catch (Exception ex) {
| | | // org.omg.PortableServer.POAPackage.WrongPolicy
| | | // thrown on JDK 1.2 and 1.3
| | | ex.printStackTrace();
| | }
| }
|
| if (account == null) throw new noSuchAccount();
|
| return account;
}
}
package poaBankDefSrvnt;
import java.io.File;
import org.omg.CORBA.ORB;
import org.omg.CORBA.PERSIST_STORE;
import poaBank.AccountPOA;
import poaBank.AccountPackage.InsufficientFunds;
public class AccountImpl extends AccountPOA
{
AccountBalances _accountsDb;
public AccountImpl(File acctDb)
{
| _accountsDb = new AccountBalances(acctDb);
}
public float deposit(float sum)
{
| int acctNum = getAccountNumber();
|
| AccountRecord record = _accountsDb.getAccount(acctNum);
|
| float balance = 0;
| synchronized (record) {
| | balance = record.getBalance() + sum;
| | record.setBalance(balance);
| }
|
| return balance;
}
public float withdraw(float sum) throws InsufficientFunds
{
| int acctNum = getAccountNumber();
|
| AccountRecord record = _accountsDb.getAccount(acctNum);
|
| float balance = 0;
| synchronized (record) {
| | balance = record.getBalance();
| | if ((balance - sum) < 0)
| | throw new InsufficientFunds();
| | balance -= sum;
| | record.setBalance(balance);
| }
|
| return balance;
}
public float balance()
{
| return _accountsDb.getAccount(getAccountNumber()).getBalance();
}
private int getAccountNumber()
{
| return _object_id()[0] & 0x000000FF;
}
}
5.1 Account Balances
package poaBankDefSrvnt; import java.io.File; import java.util.Hashtable; // Datastore for Account Balances class AccountBalances { File _dbDir; Hashtable _table; AccountBalances(File dbDir) { | _dbDir = dbDir; | _table = new Hashtable(19); } synchronized AccountRecord getAccount(int acctNum) { | Integer AcctNum = new Integer(acctNum); | | AccountRecord record = (AccountRecord) _table.get(AcctNum); | | if (record == null) { | | record = new AccountRecord(0, new File(_dbDir, | | AcctNum.toString())); | | _table.put(AcctNum, record); | } | | return record; } }5.2 Account Record
package poaBankDefSrvnt; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import org.omg.CORBA.PERSIST_STORE; class AccountRecord { private float _balance; private File _file; AccountRecord(float balance, File file) { | _file = file; | _balance = balance; | | // if file exists read balance | if (_file.exists()) { | | try { | | | FileInputStream fis = new FileInputStream(_file); | | | ObjectInputStream ois = new ObjectInputStream(fis); | | | _balance = ((Float) ois.readObject()).floatValue(); | | | ois.close(); | | } catch (Exception ex) { | | | throw new PERSIST_STORE(); | | } | } } float getBalance() { | return _balance; } void setBalance(float balance) { | _balance = balance; | | try { | | FileOutputStream fos = new FileOutputStream(_file); | | ObjectOutputStream oos = new ObjectOutputStream(fos); | | oos.writeObject(new Float(_balance)); | | oos.close(); | } catch (Exception ex) { | | throw new PERSIST_STORE(); | } } }
server.main=poaBankDefSrvnt.Server server.alias=bank3 server.classpath=/usr/local/jbroker30/examples/lib server.args=/usr/local/jbroker30/examples/src/poaBankDefSrvnt/db
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