com.groiss.store
Class Lock

java.lang.Object
  com.groiss.store.PersistentObject
      com.groiss.store.Lock

All Implemented Interfaces:

KeyValuePair<Object,Object>, Persistent, Serializable, Cloneable

public class Lock
extends PersistentObject

Make a database lock.

See Also:

Serialized Form

Field Summary

static String

MAILBOX_LOCKNAME

Fields inherited from class com.groiss.store.PersistentObject

filled, oid

Constructor Summary

	Lock()
protected	Lock(long obj, String lockname)

Method Summary

Date	getLockdate()
String	getLockname()
String	getNodeid()
long	getObj()
String	getTableName() This method must return the table name of the database table in which this persistent object is stored.
static boolean	isLocked(long obj, String lockname) Returns true if the specified lock exists for the passed object, false otherwise.
static void	lock(long obj, String lockname) Try to make a database lock.
static void	unlock(long obj, String lockname) Remove the lock.

Methods inherited from class com.groiss.store.PersistentObject

clone, dbFields, equals, getKey, getOid, getStore, getValue, hashCode, isFilled, onDelete, onInsert, onRead, onUpdate, setFilled, setOid, setStore

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAILBOX_LOCKNAME

public static final String MAILBOX_LOCKNAME

See Also:

Constant Field Values

Constructor Detail

Lock

public Lock()

Lock

protected Lock(long obj,
               String lockname)

Method Detail

getLockdate

public Date getLockdate()

getLockname

public String getLockname()

getNodeid

public String getNodeid()

getObj

public long getObj()

getTableName

public String getTableName()

Description copied from interface: Persistent

This method must return the table name of the database table in which this persistent object is stored.

Returns:

The table name of the database table in which this persistent object is stored.

lock

public static void lock(long obj,
                        String lockname)

Try to make a database lock.

Parameters:

obj - the oid of an object to lock

lockname -

unlock

public static void unlock(long obj,
                          String lockname)

Remove the lock.

Parameters:

obj - the locked object

lockname - the name of the lock

isLocked

public static boolean isLocked(long obj,
                               String lockname)
                        throws Exception

Returns true if the specified lock exists for the passed object, false otherwise. Note: there is some uncertainty in the answer because if another thread did call lock(long, String) before you call this method but did not commit already, this method will return false allthough a subsequent call of lock(long, String) would cause an Exception. If you want to lock an object, do not call this method before calling lock(long, String) but call lock(long, String) directly which is guaranteed to be not successfull if a lock already exists.

Parameters:

obj - the locked object

lockname - the name of the lock

Returns:

true if the specified lock exists for the given object; else instead

Throws:

Exception