Package org.apache.camel.component.file

Interface GenericFileExclusiveReadLockStrategy<T>

All Known Implementing Classes:
FileChangedExclusiveReadLockStrategy, FileIdempotentChangedRepositoryReadLockStrategy, FileIdempotentRenameRepositoryReadLockStrategy, FileIdempotentRepositoryReadLockStrategy, FileLockExclusiveReadLockStrategy, FileRenameExclusiveReadLockStrategy, GenericFileRenameExclusiveReadLockStrategy, MarkerFileExclusiveReadLockStrategy
public interface GenericFileExclusiveReadLockStrategy<T>
Strategy for acquiring exclusive read locks for files to be consumed. After granting the read lock it is released, we just want to make sure that when we start consuming the file its not currently in progress of being written by third party.

Camel supports out of the box the following strategies:

  • FileRenameExclusiveReadLockStrategy waiting until its possible to rename the file.
  • FileLockExclusiveReadLockStrategy acquiring a RW file lock for the duration of the processing.
  • MarkerFileExclusiveReadLockStrategy using a marker file for acquiring read lock.
  • FileChangedExclusiveReadLockStrategy using a file changed detection for acquiring read lock.
  • FileIdempotentRepositoryReadLockStrategy using a IdempotentRepository to hold the read locks which allows to support clustering.

  • Method Details

    • prepareOnStartup

      void prepareOnStartup(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint) throws Exception
      Allows custom logic to be run on startup preparing the strategy, such as removing old lock files etc.
      Parameters:
      operations - generic file operations
      endpoint - the endpoint
      Throws:
      Exception - can be thrown in case of errors

    • acquireExclusiveReadLock

      boolean acquireExclusiveReadLock(GenericFileOperations<T> operations, GenericFile<T> file, org.apache.camel.Exchange exchange) throws Exception
      Acquires exclusive read lock to the file.
      Parameters:
      operations - generic file operations
      file - the file
      exchange - the exchange
      Returns:
      true if read lock was acquired. If false Camel will skip the file and try it on the next poll
      Throws:
      Exception - can be thrown in case of errors

    • releaseExclusiveReadLockOnAbort

      void releaseExclusiveReadLockOnAbort(GenericFileOperations<T> operations, GenericFile<T> file, org.apache.camel.Exchange exchange) throws Exception
      Releases the exclusive read lock granted by the acquireExclusiveReadLock method due an abort operation (acquireExclusiveReadLock returned false).
      Parameters:
      operations - generic file operations
      file - the file
      exchange - the exchange
      Throws:
      Exception - can be thrown in case of errors

    • releaseExclusiveReadLockOnRollback

      void releaseExclusiveReadLockOnRollback(GenericFileOperations<T> operations, GenericFile<T> file, org.apache.camel.Exchange exchange) throws Exception
      Releases the exclusive read lock granted by the acquireExclusiveReadLock method due a rollback operation (Exchange processing failed)
      Parameters:
      operations - generic file operations
      file - the file
      exchange - the exchange
      Throws:
      Exception - can be thrown in case of errors

    • releaseExclusiveReadLockOnCommit

      void releaseExclusiveReadLockOnCommit(GenericFileOperations<T> operations, GenericFile<T> file, org.apache.camel.Exchange exchange) throws Exception
      Releases the exclusive read lock granted by the acquireExclusiveReadLock method due a commit operation (Exchange processing succeeded)
      Parameters:
      operations - generic file operations
      file - the file
      exchange - the exchange
      Throws:
      Exception - can be thrown in case of errors

    • setTimeout

      void setTimeout(long timeout)
      Sets an optional timeout period.

      If the readlock could not be granted within the time period then the wait is stopped and the acquireExclusiveReadLock method returns false.

      Parameters:
      timeout - period in millis

    • setCheckInterval

      void setCheckInterval(long checkInterval)
      Sets the check interval period.

      The check interval is used for sleeping between attempts to acquire read lock. Setting a high value allows to cater for slow writes in case the producer of the file is slow.

      The default period is 1000 millis.

      Parameters:
      checkInterval - interval in millis

    • setReadLockLoggingLevel

      void setReadLockLoggingLevel(org.apache.camel.LoggingLevel readLockLoggingLevel)
      Sets logging level used when a read lock could not be acquired.

      Logging level used when a read lock could not be acquired.

      The default logging level is WARN

      Parameters:
      readLockLoggingLevel - LoggingLevel

    • setMarkerFiler

      void setMarkerFiler(boolean markerFile)
      Sets whether marker file should be used or not.
      Parameters:
      markerFile - true to use marker files.

    • setDeleteOrphanLockFiles

      void setDeleteOrphanLockFiles(boolean deleteOrphanLockFiles)
      Sets whether orphan marker files should be deleted upon startup
      Parameters:
      deleteOrphanLockFiles - true to delete files, false to skip this check