Package org.glassfish.rmic.iiop

Class StaticStringsHash

  • public class StaticStringsHash
extends java.lang.Object
    StaticStringsHash takes an array of constant strings and uses several different hash methods to try to find the 'best' one for that set. The set of methods is currently fixed, but with a little work could be made extensible thru subclassing.

    The current set of methods is:

    1. length() - works well when all strings are different length.
    2. charAt(n) - works well when one offset into all strings is different.
    3. hashCode() - works well with larger arrays.
    After constructing an instance over the set of strings, the getKey(String) method can be used to use the selected hash method to produce a key. The method string will contain "length()", "charAt(n)", or "hashCode()", and is intended for use by code generators.

    The keys array will contain the full set of unique keys.

    The buckets array will contain a set of arrays, one for each key in the keys, where buckets[x][y] is an index into the strings array.

    • Constructor Summary

      Constructors 
      Constructor Description
      StaticStringsHash​(java.lang.String[] strings)
      Constructor

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private void addKey​(int key)  
      private int findUnusedKey()  
      int getKey​(java.lang.String str)
      Get a key for the given string using the selected hash method.
      private int getKeys​(int methodKind)  
      static void main​(java.lang.String[] args)
      Print an optimized 'contains' method for the argument strings
      private void resetKeys​(int keyKind)  
      private void setMinStringLength()  

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • strings

        public java.lang.String[] strings
        The set of strings upon which the hash info is created

      • keys

        public int[] keys
        Unique hash keys

      • buckets

        public int[][] buckets
        Buckets for each key, where buckets[x][y] is an index into the strings[] array.

      • method

        public java.lang.String method
        The method to invoke on String to produce the hash key

      • length

        private int length

      • tempKeys

        private int[] tempKeys

      • bucketSizes

        private int[] bucketSizes

      • bucketCount

        private int bucketCount

      • maxDepth

        private int maxDepth

      • minStringLength

        private int minStringLength

      • keyKind

        private int keyKind

      • charAt

        private int charAt

    • Constructor Detail

      • StaticStringsHash

        public StaticStringsHash​(java.lang.String[] strings)
        Constructor
        Parameters:
        strings - the set of strings upon which to find an optimal hash method. Must not contain duplicates.

    • Method Detail

      • getKey

        public int getKey​(java.lang.String str)
        Get a key for the given string using the selected hash method.
        Parameters:
        str - the string to return a key for.
        Returns:
        the key.

      • main

        public static void main​(java.lang.String[] args)
        Print an optimized 'contains' method for the argument strings

      • resetKeys

        private void resetKeys​(int keyKind)

      • setMinStringLength

        private void setMinStringLength()

      • findUnusedKey

        private int findUnusedKey()

      • getKeys

        private int getKeys​(int methodKind)

      • addKey

        private void addKey​(int key)