/**
* Add a lock to this file
*
* @param lock FileLock
* @exception LockConflictException
*/
public final void addLock(FileLock lock) throws LockConflictException {
// Check if the lock list has been allocated
if (m_lockList == null) {
synchronized (this) {
// Allocate the lock list, check if the lock list has been allocated elsewhere
// as we may have been waiting for the lock
if (m_lockList == null) m_lockList = new FileLockList();
}
}
// Add the lock to the list, check if there are any lock conflicts
synchronized (m_lockList) {
// Check if the new lock overlaps with any existing locks
if (m_lockList.allowsLock(lock)) {
// Add the new lock to the list
m_lockList.addLock(lock);
} else throw new LockConflictException();
}
}
/**
* Remove a lock on this file
*
* @param lock FileLock
* @exception NotLockedException
*/
public final void removeLock(FileLock lock) throws NotLockedException {
// Check if the lock list has been allocated
if (m_lockList == null) throw new NotLockedException();
// Remove the lock from the active list
synchronized (m_lockList) {
// Remove the lock, check if we found the matching lock
if (m_lockList.removeLock(lock) == null) throw new NotLockedException();
}
}
/**
* Check if the file is writeable for the specified section of the file and process id
*
* @param offset long
* @param len long
* @param pid int
* @return boolean
*/
public final boolean canWriteFile(long offset, long len, int pid) {
// Check if the lock list is valid
if (m_lockList == null) return true;
// Check if the file section is writeable by the specified process
boolean writeOK = false;
synchronized (m_lockList) {
// Check if the file section is writeable
writeOK = m_lockList.canWriteFile(offset, len, pid);
}
// Return the write status
return writeOK;
}
/**
* Return the count of active locks on this file
*
* @return int
*/
public final int numberOfLocks() {
if (m_lockList != null) return m_lockList.numberOfLocks();
return 0;
}
/**
* Check if there are active locks on this file
*
* @return boolean
*/
public final boolean hasActiveLocks() {
if (m_lockList != null && m_lockList.numberOfLocks() > 0) return true;
return false;
}