Class StringCache

java.lang.Object
org.apache.tomcat.util.buf.StringCache
public class StringCache extends Object
This class implements a String cache for ByteChunk and CharChunk.

  • Field Details

    • byteEnabled

      protected static boolean byteEnabled
      Enabled ?

    • charEnabled

      protected static boolean charEnabled
      Whether the char chunk string cache is enabled.

    • trainThreshold

      protected static int trainThreshold
      Number of toString calls required before the cache is built.

    • cacheSize

      protected static int cacheSize
      Maximum size of the string cache.

    • maxStringSize

      protected static final int maxStringSize
      Maximum length of strings to cache.

    • bcStats

      protected static final HashMap<StringCache.ByteEntry, int[]> bcStats
      Statistics hash map for byte chunk.

    • bcCount

      protected static int bcCount
      toString count for byte chunk.

    • bcCache

      protected static volatile StringCache.ByteEntry[] bcCache
      Cache for byte chunk.

    • ccStats

      protected static final HashMap<StringCache.CharEntry, int[]> ccStats
      Statistics hash map for char chunk.

    • ccCount

      protected static int ccCount
      toString count for char chunk.

    • ccCache

      protected static volatile StringCache.CharEntry[] ccCache
      Cache for char chunk.

    • accessCount

      protected static int accessCount
      Access count.

    • hitCount

      protected static int hitCount
      Hit count.

  • Constructor Details

    • StringCache

      public StringCache()
      Constructs a new StringCache with default settings.

  • Method Details

    • getCacheSize

      public int getCacheSize()
      Returns the maximum size of the string cache.
      Returns:
      the cache size

    • setCacheSize

      public void setCacheSize(int cacheSize)
      Sets the maximum size of the string cache.
      Parameters:
      cacheSize - the cache size

    • getByteEnabled

      public boolean getByteEnabled()
      Returns whether the byte chunk string cache is enabled.
      Returns:
      true if byte chunk caching is enabled

    • setByteEnabled

      public void setByteEnabled(boolean byteEnabled)
      Sets whether the byte chunk string cache is enabled.
      Parameters:
      byteEnabled - true if byte chunk caching should be enabled

    • getCharEnabled

      public boolean getCharEnabled()
      Returns whether the char chunk string cache is enabled.
      Returns:
      true if char chunk caching is enabled

    • setCharEnabled

      public void setCharEnabled(boolean charEnabled)
      Sets whether the char chunk string cache is enabled.
      Parameters:
      charEnabled - true if char chunk caching should be enabled

    • getTrainThreshold

      public int getTrainThreshold()
      Returns the number of toString calls required before the cache is built.
      Returns:
      the training threshold

    • setTrainThreshold

      public void setTrainThreshold(int trainThreshold)
      Sets the number of toString calls required before the cache is built.
      Parameters:
      trainThreshold - the training threshold

    • getAccessCount

      public int getAccessCount()
      Returns the total number of cache lookups performed.
      Returns:
      the access count

    • getHitCount

      public int getHitCount()
      Returns the number of cache hits.
      Returns:
      the hit count

    • reset

      public void reset()
      Resets all cache statistics and clears the cache.

    • toString

      public static String toString(ByteChunk bc)
      Converts the given ByteChunk to a String using the cache.
      Parameters:
      bc - the ByteChunk to convert
      Returns:
      the resulting String

    • toString

      public static String toString(ByteChunk bc, CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction) throws CharacterCodingException
      Converts the given ByteChunk to a String using the cache, with the specified error handling actions.
      Parameters:
      bc - the ByteChunk to convert
      malformedInputAction - action for malformed input
      unmappableCharacterAction - action for unmappable characters
      Returns:
      the resulting String
      Throws:
      CharacterCodingException - if a coding error occurs

    • toString

      public static String toString(CharChunk cc)
      Converts the given CharChunk to a String using the cache.
      Parameters:
      cc - the CharChunk to convert
      Returns:
      the resulting String

    • compare

      protected static int compare(ByteChunk name, byte[] compareTo)
      Compare given byte chunk with byte array.
      Parameters:
      name - The name to compare
      compareTo - The compared to data
      Returns:
      -1, 0 or +1 if inferior, equal, or superior to the String.

    • find

      @Deprecated protected static final String find(ByteChunk name)
      Deprecated.
      Unused. Will be removed in Tomcat 11. Use find(ByteChunk, CodingErrorAction, CodingErrorAction)
      Find an entry given its name in the cache and return the associated String.
      Parameters:
      name - The name to find
      Returns:
      the corresponding value

    • find

      protected static String find(ByteChunk name, CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction)
      Find an entry given its name in the cache and return the associated String.
      Parameters:
      name - The name to find
      malformedInputAction - Action to take if a malformed input is encountered
      unmappableCharacterAction - Action to take if an unmappable character is encountered
      Returns:
      the corresponding value

    • findClosest

      protected static int findClosest(ByteChunk name, StringCache.ByteEntry[] array, int len)
      Find an entry given its name in a sorted array of map elements. This will return the index for the closest inferior or equal item in the given array.
      Parameters:
      name - The name to find
      array - The array in which to look
      len - The effective length of the array
      Returns:
      the position of the best match

    • compare

      protected static int compare(CharChunk name, char[] compareTo)
      Compare given char chunk with char array.
      Parameters:
      name - The name to compare
      compareTo - The compared to data
      Returns:
      -1, 0 or +1 if inferior, equal, or superior to the String.

    • find

      protected static String find(CharChunk name)
      Find an entry given its name in the cache and return the associated String.
      Parameters:
      name - The name to find
      Returns:
      the corresponding value

    • findClosest

      protected static int findClosest(CharChunk name, StringCache.CharEntry[] array, int len)
      Find an entry given its name in a sorted array of map elements. This will return the index for the closest inferior or equal item in the given array.
      Parameters:
      name - The name to find
      array - The array in which to look
      len - The effective length of the array
      Returns:
      the position of the best match