Module kala.compress.compressors.pack200
Package kala.compress.harmony.unpack200

Class SegmentConstantPoolArrayCache

  • public class SegmentConstantPoolArrayCache
extends java.lang.Object
    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.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      protected class  SegmentConstantPoolArrayCache.CachedArray
      Keeps track of the last known size of an array as well as a HashMap that knows the mapping from element values to the indices of the array which contain that value.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected boolean arrayIsCached​(java.lang.String[] array)
      Tests whether a String array is correctly cached.
      protected void cacheArray​(java.lang.String[] array)
      Caches the array passed in as the argument
      java.util.List<java.lang.Integer> indexesForArrayKey​(java.lang.String[] array, java.lang.String key)
      Gets the indices for the given key in the given array.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • lastIndexes

        protected java.util.List<java.lang.Integer> lastIndexes

      • lastArray

        protected java.lang.String[] lastArray

      • lastKey

        protected java.lang.String lastKey

    • Constructor Detail

      • SegmentConstantPoolArrayCache

        public SegmentConstantPoolArrayCache()

    • Method Detail

      • arrayIsCached

        protected boolean arrayIsCached​(java.lang.String[] array)
        Tests whether a String array is correctly cached. Return false if the array is not cached, or if the array cache is outdated.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​(java.lang.String[] array)
        Caches the array passed in as the argument
        Parameters:
        array - String[] to cache

      • indexesForArrayKey

        public java.util.List<java.lang.Integer> indexesForArrayKey​(java.lang.String[] array,
                                                            java.lang.String key)
        Gets 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