Package org.h2.store

Class FileLock

  • All Implemented Interfaces:
    java.lang.Runnable
    public class FileLock
extends java.lang.Object
implements java.lang.Runnable
    The file lock is used to lock a database so that only one process can write to it. It uses a cooperative locking protocol. Usually a .lock.db file is used, but locking by creating a socket is supported as well.

    • Constructor Summary

      Constructors 
      Constructor Description
      FileLock​(TraceSystem traceSystem, java.lang.String fileName, int sleep)
      Create a new file locking object.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static FileLockMethod getFileLockMethod​(java.lang.String method)
      Get the file locking method type given a method name.
      java.lang.String getUniqueId()  
      java.util.Properties load()
      Load the properties file.
      void lock​(FileLockMethod fileLockMethod)
      Lock the file if possible.
      void run()  
      java.util.Properties save()
      Save the lock file.
      void setProperty​(java.lang.String key, java.lang.String value)
      Add or change a setting to the properties.
      void unlock()
      Unlock the file.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • FileLock

        public FileLock​(TraceSystem traceSystem,
                java.lang.String fileName,
                int sleep)
        Create a new file locking object.
        Parameters:
        traceSystem - the trace system to use
        fileName - the file name
        sleep - the number of milliseconds to sleep

    • Method Detail

      • lock

        public void lock​(FileLockMethod fileLockMethod)
        Lock the file if possible. A file may only be locked once.
        Parameters:
        fileLockMethod - the file locking method to use
        Throws:
        DbException - if locking was not successful

      • unlock

        public void unlock()
        Unlock the file. The watchdog thread is stopped. This method does nothing if the file is already unlocked.

      • setProperty

        public void setProperty​(java.lang.String key,
                        java.lang.String value)
        Add or change a setting to the properties. This call does not save the file.
        Parameters:
        key - the key
        value - the value

      • save

        public java.util.Properties save()
        Save the lock file.
        Returns:
        the saved properties

      • load

        public java.util.Properties load()
        Load the properties file.
        Returns:
        the properties

      • getFileLockMethod

        public static FileLockMethod getFileLockMethod​(java.lang.String method)
        Get the file locking method type given a method name.
        Parameters:
        method - the method name
        Returns:
        the method type
        Throws:
        DbException - if the method name is unknown

      • getUniqueId

        public java.lang.String getUniqueId()

      • run

        public void run()
        Specified by:
        run in interface java.lang.Runnable