Class SegmentConstantPoolArrayCache

java.lang.Object
org.apache.commons.compress.harmony.unpack200.SegmentConstantPoolArrayCache

The SegmentConstantPool spends a lot of time searching through large arrays of Strings looking for matches. This can be sped up by caching the arrays in HashMaps so the String keys are looked up and resolve to positions in the array rather than iterating through the arrays each time. Because the arrays only grow (never shrink or change) we can use the last known size as a way to determine if the array has changed. Note that this cache must be synchronized externally if it is shared.
  • Field Details

  • Constructor Details

  • Method Details

    • arrayIsCached

      protected boolean arrayIsCached(String[] array)
      Given a String array, answer true if the array is correctly cached. Answer false if the array is not cached, or if the array cache is outdated.
      Parameters:
      array - of String
      Returns:
      boolean true if up-to-date cache, otherwise false.
    • cacheArray

      protected void cacheArray(String[] array)
      Cache the array passed in as the argument
      Parameters:
      array - String[] to cache
    • indexesForArrayKey

      public List<Integer> indexesForArrayKey(String[] array, String key)
      Answer the indices for the given key in the given array. If no such key exists in the cached array, answer -1.
      Parameters:
      array - String[] array to search for the value
      key - String value for which to search
      Returns:
      List collection of index positions in the array