Package org.nuxeo.common.file

Class LRUFileCache

java.lang.Object
org.nuxeo.common.file.LRUFileCache
All Implemented Interfaces:
FileCache
public class LRUFileCache extends Object implements FileCache
A LRU cache of Files with maximum filesystem size.

Cache entries that are old enough and whose size makes the cache bigger than its maximum size are deleted.

The cache keys are restricted to a subset of ASCII: letters, digits and dashes. Usually a MD5 or SHA1 hash is used.

  • Field Details

    • SIMPLE_ASCII

      public static final Pattern SIMPLE_ASCII
      Allowed key pattern, used as file path.

    • CLEAR_OLD_ENTRIES_INTERVAL_MILLIS_DEFAULT

      public static final long CLEAR_OLD_ENTRIES_INTERVAL_MILLIS_DEFAULT
      See Also:

    • clearOldEntriesIntervalMillis

      protected long clearOldEntriesIntervalMillis

    • dir

      protected final Path dir

    • maxSize

      protected final long maxSize

    • maxCount

      protected final long maxCount

    • minAgeMillis

      protected final long minAgeMillis

    • clearOldEntriesLock

      protected Lock clearOldEntriesLock

    • clearOldEntriesLast

      protected long clearOldEntriesLast

  • Constructor Details

    • LRUFileCache

      public LRUFileCache(File dir, long maxSize, long maxCount, long minAge)
      Constructs a cache in the given directory with the given maximum size (in bytes).
      Parameters:
      dir - the directory to use to store cached files
      maxSize - the maximum size of the cache (in bytes)
      maxCount - the maximum number of files in the cache
      minAge - the minimum age of a file in the cache to be eligible for removal (in seconds)

  • Method Details

    • setClearOldEntriesIntervalMillis

      public void setClearOldEntriesIntervalMillis(long millis)

    • getSize

      public long getSize()
      Description copied from interface: FileCache
      Gets the size of the cache, in bytes.
      Specified by:
      getSize in interface FileCache

    • getNumberOfItems

      public int getNumberOfItems()
      Description copied from interface: FileCache
      Gets the number of items in the cache.
      Specified by:
      getNumberOfItems in interface FileCache

    • clear

      public void clear()
      Description copied from interface: FileCache
      Clears the cache.

      Files will not be deleted from the filesystm while the returned file objects are still referenced.

      Specified by:
      clear in interface FileCache

    • clearOldEntries

      protected void clearOldEntries()
      Clears cache entries if they are old enough and their size makes the cache bigger than its maximum size.

    • doClearOldEntries

      protected void doClearOldEntries()

    • getTempFile

      public File getTempFile() throws IOException
      Description copied from interface: FileCache
      Creates a temporary file.
      Specified by:
      getTempFile in interface FileCache
      Throws:
      IOException

    • checkKey

      protected void checkKey(String key) throws IllegalArgumentException
      Throws:
      IllegalArgumentException

    • putFile

      public File putFile(String key, InputStream in) throws IOException
      Puts a file in the cache.

      The key is used as a file name in the directory cache.

      Specified by:
      putFile in interface FileCache
      Parameters:
      key - the cache key
      in - the input stream to cache (closed afterwards)
      Returns:
      the cached file
      Throws:
      IOException

    • putFile

      public File putFile(String key, File file) throws IllegalArgumentException, IOException
      Puts a file in the cache.

      The file must have been created through FileCache.getTempFile(). The file is "given" to this method, who will delete it or rename it.

      The key is used as a file name in the directory cache.

      Specified by:
      putFile in interface FileCache
      Parameters:
      key - the cache key
      file - the file to cache
      Returns:
      the cached file
      Throws:
      IllegalArgumentException - if the key is illegal
      IOException

    • getFile

      public File getFile(String key)
      Description copied from interface: FileCache
      Gets a file from the cache.

      A returned file will never be deleted from the filesystem while the returned file object is still referenced, although it may be purged from the cache.

      Specified by:
      getFile in interface FileCache
      Parameters:
      key - the cache key
      Returns:
      the cached file, or null if absent

    • recordAccess

      protected void recordAccess(Path path)
      Records access to a file by changing its modification time.