Class BinaryMap

  • All Implemented Interfaces:
    Map

    public class BinaryMap
    extends AbstractMap
    Implements the Map interface to store Binary objects using Java's NIO buffers.
     The Buffer is used to hold blocks, which are either Entry or free blocks.
     Both share a common header:
    
       byte    length      type     description
       ------  ----------  -------  -------------------------------------------
            0           1  integer  type
            1           4  integer  offset of the next block in the Buffer
            5           4  integer  offset of the prev block in the Buffer
            9           4  integer  offset of the next entry in the list or -1=tail
           13           4  integer  offset of the prev entry in the list or -1=head
    
     The offset of the next block in the buffer provides the "length overall"
     (also known as LOA) of the block, such that a block located at offset
     "oCur" with a next block offset of "oNext" will have an LOA "l" of:
    
           l = oNext - oCur
    
     The additional structure for an Entry block is as follows:
    
       byte    length      type     description
       ------  ----------  -------  -------------------------------------------
           17           4  integer  hash code
           21           4  integer  key length (m)
           25           m  byte[]   key
         25+m           4  integer  value length (n)
         29+m           n  byte[]   value
       29+m+n  l-(29+m+n)  byte[]   fill
    
     The reason for supporting "fill" is to allow an entry to shrink and grow
     a little bit in place, for example since a free block has a minimum size
     and if the entry is followed immediately by another entry and shrinks, it
     would have to be moved if it doesn't shrink at least 17 bytes. Similarly,
     an entry could be padded to allow it to grow slightly.
    
     The additional structure for a free block is as follows:
    
       byte    length      type     description
       ------  ----------  -------  -------------------------------------------
           17        l-17  byte[]   fill
    
     The Buffer is a packed list of blocks, and each block is either an Entry or
     a free block. Contiguous free blocks are automatically merged so that there
     are never any contiguous free blocks at the end of an operation. Entries
     are expected to be contiguously allocated; compaction is the act of copying
     Entry blocks so that they are contiguous.
    
     The BinaryMap manages an array of hash buckets that hold the offsets of the
     first Entry in the linked list of entries stored in the Buffer. The offset
     will be NIL (-1) if there are no entries in that bucket since 0 is a valid
     offset into the Buffer.
    
     Incremental compaction occurs only on modifications (puts and removes).
     For a put, the compaction occurs before the put is processed, and for a
     remove, it occurs after the remove is processed, to make it slightly more
     likely that a put will have adequate free space and that the removed entry
     would not have been relocated by compaction.
    
     The BinaryMap categorizes empty blocks based on their size:
    
       code  free block size
       ----  -----------------------------------
          0  63 bytes or smaller
          1  64 to 127 bytes
          2  128 to 255 bytes
          3  256 to 511 bytes
          4  512 to 1023 bytes
          5  1024 to 2047 bytes
          6  2048 to 4095 bytes
          7  4096 to 8191 bytes
          8  8192 to 16383 bytes
          9  16384 to 32767 bytes
         10  32768 to 65535 bytes
         11  65536 to 131071 bytes
         12  131072 to 262143 bytes
         13  262144 to 524287 bytes
         14  524288 to 1048575 bytes
         15  1048576 to 2097151 bytes
         16  2097152 to 4194303 bytes
         17  4194304 to 8388607 bytes
         18  8388608 to 16777215 bytes
         19  16777216 to 33554431 bytes
         20  33554432 to 67108863 bytes
         21  67108864 to 134217727 bytes
         22  134217728 to 268435455 bytes
         23  268435456 to 536870911 bytes
         24  536870912 to 1073741823 bytes
         25  1073741824 to 2147483647 bytes
    
     For each category of free blocks, the BinaryMap maintains a linked list of
     free blocks that fit that category.
    
     To determine the size of a block in bytes, use the length() method. To
     calculate the code of a block, use the getSizeCode() method, or the static
     calculateSizeCode(int) method of BinaryMap.
    
     To open an existing block at a certain offset, use the method
     openBlock(int). To create and open a block at a certain offset, use the
     method initBlock(int). To allocate and open a free block of a certain size,
     use the method allocateBlock(int). An opened block should always be closed
     using the method Block.close(), which commits pending changes to the
     underlying buffer. The only time that a block should not be closed is when
     the block is being destroyed (e.g. when a free block is merged with another
     free block); in this case, use the method Block.discard().
    
     To merge free blocks that occur before and/or after a specific free block,
     use the method Block.merge(). To split a free block into two contiguous
     free blocks, use the method Block.split(int).
    
     To remove a block from its linked list, use Block.unlink(). Unless the
     block is being destroyed, it should be re-linked using the Block.link()
     method.
     
    Since:
    Coherence 2.2
    Version:
    1.00, 2002-09-06
    Author:
    cp
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected static int[] BUCKET_COUNTS
      These are potential bucket counts.
      static double DEFAULT_MAXLOADFACTOR
      Default value for the percentage of the modulo that the entry count must reach before going to the next bucket level.
      static double DEFAULT_MINLOADFACTOR
      Default value for the percentage of the next lower bucket level's modulo that the entry count must drop to before reverting to the next lower bucket level.
      protected static byte[] FILL_BUFFER
      Byte array used for wiping the buffer.
      protected static byte FILL_BYTE
      Byte used as a fill byte.
      protected BinaryMap.ValuesCollection m_colValues
      The collection of values backed by this map.
      protected BinaryMap.EntrySet m_set
      The set of entries backed by this map.
      protected BinaryMap.KeySet m_setKeys
      The set of keys backed by this map.
      protected static int MAX_OPEN_BLOCKS
      Maximum number of simultaneously open blocks to support.
      protected static int MAX_SIZE_CODES
      Number of size codes for free blocks.
      protected static boolean MODE_DEBUG
      True to enable debug mode.
      protected static int NIL
      Offset reserved for the "does-not-exist" block.
      protected static int SIZE_COPY_BUFFER
      Copy buffer size.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected BinaryMap()
      Construct a BinaryMap.
        BinaryMap​(ByteBufferManager bufmgr)
      Construct a BinaryMap using a buffer from the specified ByteBufferManager, and using the default modulo growth and shrinkage (load factor) settings.
        BinaryMap​(ByteBufferManager bufmgr, double dflMaxLoadFactor, double dflMinLoadFactor, boolean fStrict)
      Construct a BinaryMap using a buffer from the specified ByteBufferManager, and using the specified modulo growth and shrinkage (load factor) settings.
        BinaryMap​(ByteBuffer buffer)
      Construct a BinaryMap on a specific buffer with the default modulo growth and shrinkage (load factor) settings.
        BinaryMap​(ByteBuffer buffer, double dflMaxLoadFactor, double dflMinLoadFactor, boolean fStrict)
      Construct a BinaryMap on a specific buffer with the specified modulo growth and shrinkage (load factor) settings.
    • Field Detail

      • MODE_DEBUG

        protected static final boolean MODE_DEBUG
        True to enable debug mode.
        See Also:
        Constant Field Values
      • FILL_BYTE

        protected static final byte FILL_BYTE
        Byte used as a fill byte.
        See Also:
        Constant Field Values
      • FILL_BUFFER

        protected static final byte[] FILL_BUFFER
        Byte array used for wiping the buffer.
      • MAX_SIZE_CODES

        protected static final int MAX_SIZE_CODES
        Number of size codes for free blocks.
        See Also:
        Constant Field Values
      • BUCKET_COUNTS

        protected static final int[] BUCKET_COUNTS
        These are potential bucket counts.
      • SIZE_COPY_BUFFER

        protected static final int SIZE_COPY_BUFFER
        Copy buffer size.
        See Also:
        Constant Field Values
      • NIL

        protected static final int NIL
        Offset reserved for the "does-not-exist" block.
        See Also:
        Constant Field Values
      • MAX_OPEN_BLOCKS

        protected static final int MAX_OPEN_BLOCKS
        Maximum number of simultaneously open blocks to support.
        See Also:
        Constant Field Values
      • DEFAULT_MAXLOADFACTOR

        public static final double DEFAULT_MAXLOADFACTOR
        Default value for the percentage of the modulo that the entry count must reach before going to the next bucket level.
        See Also:
        Constant Field Values
      • DEFAULT_MINLOADFACTOR

        public static final double DEFAULT_MINLOADFACTOR
        Default value for the percentage of the next lower bucket level's modulo that the entry count must drop to before reverting to the next lower bucket level.
        See Also:
        Constant Field Values
      • m_set

        protected transient BinaryMap.EntrySet m_set
        The set of entries backed by this map.
      • m_setKeys

        protected transient BinaryMap.KeySet m_setKeys
        The set of keys backed by this map.
    • Constructor Detail

      • BinaryMap

        public BinaryMap​(ByteBuffer buffer)
        Construct a BinaryMap on a specific buffer with the default modulo growth and shrinkage (load factor) settings.
        Parameters:
        buffer - the ByteBuffer that the map will store its data in
      • BinaryMap

        public BinaryMap​(ByteBuffer buffer,
                         double dflMaxLoadFactor,
                         double dflMinLoadFactor,
                         boolean fStrict)
        Construct a BinaryMap on a specific buffer with the specified modulo growth and shrinkage (load factor) settings.
        Parameters:
        buffer - the ByteBuffer that the map will store its data in
        dflMaxLoadFactor - the percentage of the ratio of keys to the modulo at which the modulo will increase; for example, 0.9 implies that the modulo will grow when the number of keys reaches 90% of the modulo value
        dflMinLoadFactor - the percentage of the ratio of keys to the next lower modulo at which the modulo will decrease; this value must be less than the maximum load factor value
        fStrict - true to enable the strict (clean buffer) option, which will degrade performance slightly
      • BinaryMap

        public BinaryMap​(ByteBufferManager bufmgr)
        Construct a BinaryMap using a buffer from the specified ByteBufferManager, and using the default modulo growth and shrinkage (load factor) settings.
        Parameters:
        bufmgr - the ByteBufferManager that is responsible for providing and managing the ByteBuffer
      • BinaryMap

        public BinaryMap​(ByteBufferManager bufmgr,
                         double dflMaxLoadFactor,
                         double dflMinLoadFactor,
                         boolean fStrict)
        Construct a BinaryMap using a buffer from the specified ByteBufferManager, and using the specified modulo growth and shrinkage (load factor) settings.
        Parameters:
        bufmgr - the ByteBufferManager that is responsible for providing and managing the ByteBuffer
        dflMaxLoadFactor - the percentage of the ratio of keys to the modulo at which the modulo will increase; for example, 0.9 implies that the modulo will grow when the number of keys reaches 90% of the modulo value
        dflMinLoadFactor - the percentage of the ratio of keys to the next lower modulo at which the modulo will decrease; this value must be less than the maximum load factor value
        fStrict - true to enable the strict (clean buffer) option, which will degrade performance slightly
      • BinaryMap

        protected BinaryMap()
        Construct a BinaryMap. This constructor is provided solely for inheriting implementations to avoid the requirements imposed by the public constructors.
    • Method Detail

      • size

        public int size()
        Returns the number of key-value mappings in this map.
        Specified by:
        size in interface Map
        Overrides:
        size in class AbstractMap
        Returns:
        the number of entries in this map
      • isEmpty

        public boolean isEmpty()
        Returns true if this map contains no key-value mappings.
        Specified by:
        isEmpty in interface Map
        Overrides:
        isEmpty in class AbstractMap
        Returns:
        true if this map contains no key-value mappings
      • containsKey

        public boolean containsKey​(Object oKey)
        Returns true if this map contains a mapping for the specified key.
        Specified by:
        containsKey in interface Map
        Overrides:
        containsKey in class AbstractMap
        Parameters:
        oKey - key whose presence in this map is to be tested
        Returns:
        true if this map contains a mapping for the specified key
      • get

        public Object get​(Object oKey)
        Returns the value to which this map maps the specified key. Returns null if the map contains no mapping for this key.
        Specified by:
        get in interface Map
        Overrides:
        get in class AbstractMap
        Parameters:
        oKey - key whose associated value is to be returned
        Returns:
        the value to which this map maps the specified key, or null if the map contains no mapping for this key
      • put

        public Object put​(Object oKey,
                          Object oValue)
        Associates the specified value with the specified key in this map.
        Specified by:
        put in interface Map
        Overrides:
        put in class AbstractMap
        Parameters:
        oKey - key with which the specified value is to be associated
        oValue - value to be associated with the specified key
        Returns:
        previous value associated with specified key, or null if there was no mapping for key
      • remove

        public Object remove​(Object oKey)
        Removes the mapping for this key from this map if present.
        Specified by:
        remove in interface Map
        Overrides:
        remove in class AbstractMap
        Parameters:
        oKey - key whose mapping is to be removed from the map
        Returns:
        previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key, if the implementation supports null values
      • clear

        public void clear()
        Removes all mappings from this map.
        Specified by:
        clear in interface Map
        Overrides:
        clear in class AbstractMap
      • entrySet

        public Set entrySet()
        Returns a set view of the mappings contained in this map. Each element in the returned set is a Map.Entry. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.
        Specified by:
        entrySet in interface Map
        Specified by:
        entrySet in class AbstractMap
        Returns:
        a set view of the mappings contained in this map.
      • keySet

        public Set keySet()
        Returns a Set view of the keys contained in this map. The Set is backed by the map, so changes to the map are reflected in the Set, and vice-versa. (If the map is modified while an iteration over the Set is in progress, the results of the iteration are undefined.) The Set supports element removal, which removes the corresponding entry from the map, via the Iterator.remove, Set.remove, removeAll retainAll, and clear operations. It does not support the add or addAll operations.

        Specified by:
        keySet in interface Map
        Overrides:
        keySet in class AbstractMap
        Returns:
        a Set view of the keys contained in this map
      • values

        public Collection values()
        Returns a collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.
        Specified by:
        values in interface Map
        Overrides:
        values in class AbstractMap
        Returns:
        a collection view of the values contained in this map
      • getEntryBlockCount

        public int getEntryBlockCount()
        Returns the number of entry blocks.
        Returns:
        the number of entry blocks
      • findEntryBlock

        protected BinaryMap.Block findEntryBlock​(Binary binKey)
        Find the Entry block with the specified key.
        Parameters:
        binKey - the Binary key object
        Returns:
        a matching Entry block or null if that key is not in the map
      • toArray

        protected Object[] toArray​(Object[] ao,
                                   Converter conv)
        Returns an array with a runtime type is that of the specified array and that contains data from all of the entries in this Map. See the documentation for toArray for the key set, entry set and values collection of the map.
        Parameters:
        ao - the array into which the data from the map entires are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose
        conv - an object that converts a Block object into either a key, entry or value, depending on the collection which is delegating to this method
        Returns:
        an array containing the entry data (key, entry or value)
        Throws:
        ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type required to hold the keys, entries or values
      • validateKey

        protected RuntimeException validateKey​(Object key,
                                               RuntimeException e)
        If the passed key is not Binary, then throw an exception to specify that the key is not Binary, otherwise throw the original exception.
        Parameters:
        key - the object that should be of type Binary
        e - the original RuntimeException
        Throws:
        RuntimeException - this method always throws some form of RuntimeException
      • validateEntry

        protected RuntimeException validateEntry​(Object key,
                                                 Object value,
                                                 RuntimeException e)
        If the passed key and/or value is not a Binary object, then throw an exception to specify that the key is not Binary, otherwise throw the original exception.
        Parameters:
        key - the key object that should be of type Binary
        value - the value object that should be of type Binary
        e - the original RuntimeException
        Throws:
        RuntimeException - this method always throws some form of RuntimeException
      • reportOutOfMemory

        protected RuntimeException reportOutOfMemory​(int cbRequired)
        Report on an insufficient memory problem.
        Parameters:
        cbRequired - the amount of space required
        Throws:
        RuntimeException - this method always throws some form of RuntimeException
      • instantiateEntrySet

        protected BinaryMap.EntrySet instantiateEntrySet()
        Factory pattern.
        Returns:
        a new instance of the EntrySet class (or a subclass thereof)
      • instantiateKeySet

        protected BinaryMap.KeySet instantiateKeySet()
        Factory pattern.
        Returns:
        a new instance of the KeySet class (or subclass thereof)
      • instantiateValuesCollection

        protected BinaryMap.ValuesCollection instantiateValuesCollection()
        Factory pattern.
        Returns:
        a new instance of the ValuesCollection class (or subclass thereof)
      • instantiateEntry

        protected BinaryMap.Entry instantiateEntry​(Binary binKey,
                                                   Binary binValue)
        Factory pattern: Instantiate an Entry object.
        Parameters:
        binKey - a Binary object for the key
        binValue - a Binary object for the value
        Returns:
        a new instance of the Entry class (or a subclass thereof)
      • getBufferManager

        public ByteBufferManager getBufferManager()
        Obtain the ByteBufferManager that provides the ByteBuffer objects.
        Returns:
        the ByteBufferManager object or null if there is none
      • setBufferManager

        protected void setBufferManager​(ByteBufferManager bufmgr)
        Specify the ByteBufferManager for this map.
        Parameters:
        bufmgr - the ByteBufferManager object (or null)
      • checkBufferGrow

        protected void checkBufferGrow​(int cbAdditional)
        If there is a buffer manager, check if the current buffer should be grown.
        Parameters:
        cbAdditional - the number of bytes pending to be allocated in addition to the bytes currently used
      • checkBufferShrink

        protected void checkBufferShrink()
        If there is a buffer manager, check if the current buffer should be shrunk.
      • getBuffer

        protected ByteBuffer getBuffer()
        Obtain the ByteBuffer that the BinaryMap is backed by.
        Returns:
        the ByteBuffer object (never null)
      • setBuffer

        protected void setBuffer​(ByteBuffer buffer)
        Specify the ByteBuffer that the BinaryMap will be backed by.
        Parameters:
        buffer - the new ByteBuffer object
      • getCapacity

        protected int getCapacity()
        Determine the capacity of the map in bytes.
        Returns:
        the number of bytes that the buffer can hold
      • getFreeCapacity

        protected int getFreeCapacity()
        Determine the free capacity of the map in bytes.
        Returns:
        the number of bytes in the buffer that are free
      • getUsedCapacity

        protected int getUsedCapacity()
        Determine the number of types in the buffer that are in use by Entry blocks.
        Returns:
        the number of bytes in the buffer that are used
      • getLastBlockOffset

        protected int getLastBlockOffset()
        Get the offset of the last block in the buffer.
        Returns:
        the offset of the last block in the buffer
      • setLastBlockOffset

        protected void setLastBlockOffset​(int ofBlock)
        Set the offset of the last block in the buffer.
        Parameters:
        ofBlock - the offset of the last block in the buffer
      • isStrict

        protected boolean isStrict()
        Determine if the buffer should be initialized and if blocks should be cleared when not in use.
        Returns:
        true if freed parts of the buffer should be initialized
      • setStrict

        protected void setStrict​(boolean fStrict)
        Specify if the buffer should be initialized and if blocks should be cleared when not in use.
        Parameters:
        fStrict - pass true to always initialize unused portions of the buffer (which is slower but hides unused data)
      • clearBuffer

        protected void clearBuffer()
        Create one big free block in the buffer.
      • getBufferInput

        protected DataInputStream getBufferInput()
        Get the DataInputStream that maps to the underlying ByteBuffer.
        Returns:
        the DataInputStream that reads from the underlying ByteBuffer
      • getBufferOutput

        protected DataOutputStream getBufferOutput()
        Get the DataOutputStream that maps to the underlying ByteBuffer.
        Returns:
        the DataOutputStream that writes to the underlying ByteBuffer
      • wipe

        protected void wipe​(int of,
                            int cb)
        Wipe a portion of the buffer.
        Parameters:
        of - the offset into the buffer to wipe at
        cb - the number of bytes to wipe
      • check

        public void check​(String sDesc)
        Debugging support: Validate the buffer's data structures, the hash buckets, free lists, etc.
        Parameters:
        sDesc - a description of what is going on when this is called
      • main

        public static void main​(String[] asArg)
        Debugging support: Command line test.
        Parameters:
        asArg - command line arguments
      • dump

        public void dump()
        Debugging support: Dump the inner structures of the BinaryMap to stdout.
      • formatIndex

        protected static String formatIndex​(int n)
        Format an index to a String.
        Parameters:
        n - the index that (may be NIL)
        Returns:
        a decimal String (or "nil") containing the index in a readable form
      • formatOffset

        protected static String formatOffset​(int of)
        Format an offset to a String.
        Parameters:
        of - the offset that (may be NIL)
        Returns:
        a hex String (or "nil") containing the offset in a readable form
      • formatOffsetArray

        protected static String formatOffsetArray​(int[] an)
        Format an array of offsets to be readable in a dump.
        Parameters:
        an - the array of offsets
        Returns:
        a String containing the offsets in a readable fashion
      • bin

        protected static Binary bin​(String s)
        Internal debugging support: Turn a String into a Binary.
        Parameters:
        s - a String (not null)
        Returns:
        a Binary containing the String's value (kind of like ASCII)
      • str

        protected static String str​(Object bin)
        Internal debugging support: Turn a Binary into a String.
        Parameters:
        bin - a Binary object or null
        Returns:
        a String with the Binary's contents unicode-extended or "<null>" if the passed Binary is null
      • initializeFreeLists

        protected void initializeFreeLists()
        Create an array of references to lists of free blocks indexed by size code.
      • clearFreeLists

        protected void clearFreeLists()
        Clear out all references in the array of free lists.
      • getFreeListCount

        protected int getFreeListCount()
        Determine the number of free lists (ie the number of size codes).
        Returns:
        the number of free lists
      • getFreeBlockOffset

        protected int getFreeBlockOffset​(int nCode)
        Get the first free block in the linked list of free blocks that have a certain size code.
        Parameters:
        nCode - the free block size code
        Returns:
        the offset of the first free block of that size code or NIL
      • setFreeBlockOffset

        protected void setFreeBlockOffset​(int nCode,
                                          int ofBlock)
        Set the head of the free block linked list for a certain size code.
        Parameters:
        nCode - the free block size code
        ofBlock - the offset of the first free block of that size code or NIL
      • initializeBuckets

        protected void initializeBuckets()
        Create an initial array of hash buckets.
      • getBucketLevel

        protected int getBucketLevel()
        Determine the hash bucket level. Each level is associated with a specific pre-selected modulo.
        Returns:
        the current hash bucket level
      • setBucketLevel

        protected void setBucketLevel​(int nLevel)
        Configure the hash bucket level. Each level is associated with a specific pre-selected modulo. This mutator also sets the Modulo, GrowthCount and ShrinkageCount properties.
        Parameters:
        nLevel - the new hash bucket level
      • getBucketCount

        protected int getBucketCount()
        Determine the number of hash buckets. This is not necessarily the modulo.
        Returns:
        the number of hash buckets
      • setBucketCount

        protected void setBucketCount​(int cBuckets)
        Configure the number of hash buckets. This does not change any offset values that are stored in the hash buckets; any additional buckets are initialized to NIL.
        Parameters:
        cBuckets - the new number of hash buckets
      • getBucketOffset

        protected int getBucketOffset​(int nBucket)
        Get the first Entry block in the linked list of Entry blocks that fall into a certain hash bucket.
        Parameters:
        nBucket - the bucket number
        Returns:
        the offset of the first Entry block in that bucket, or NIL
      • setBucketOffset

        protected void setBucketOffset​(int nBucket,
                                       int ofBlock)
        Set the head of the hash bucket linked list for a certain bucket.
        Parameters:
        nBucket - the bucket number
        ofBlock - the offset of the first Entry block in that bucket, or NIL
      • getMaxLoadFactor

        protected double getMaxLoadFactor()
        Determine the load factor for the map. This is a value typically greater than zero and less than one, although technically it can be greater than one. This value, multiplied by the current modulo, provides the number of entries that will force growth of the map's modulo.
        Returns:
        the load factor (aka the growth threshold)
      • setMaxLoadFactor

        protected void setMaxLoadFactor​(double dflPercent)
        Set the load factor.
        Parameters:
        dflPercent - the new load factor
      • getMinLoadFactor

        protected double getMinLoadFactor()
        Determine the "unload factor" for the map. This is a value typically greater than zero and less than one, although technically it can be greater than one. In any case, it must be smaller than the growth threshold (load factor). This value, multiplied by the next smaller modulo than the current modulo (i.e. the next lower bucket level), provides the number of entries that will force shrinkage of the map's modulo.
        Returns:
        the "unload factor" (aka the shrinkage threshold)
      • setMinLoadFactor

        protected void setMinLoadFactor​(double dflPercent)
        Set the "unload factor".
        Parameters:
        dflPercent - the new "unload factor"
      • getGrowthCount

        protected int getGrowthCount()
        Determine the level at which the modulo will increase.
        Returns:
        the number of entries at which the modulo will grow
      • setGrowthCount

        protected void setGrowthCount​(int cEntries)
        Set the level at which the modulo will increase.
        Parameters:
        cEntries - the number of entries at which the modulo will grow
      • getShrinkageCount

        protected int getShrinkageCount()
        Determine the level at which the modulo will decrease.
        Returns:
        the number of entries at which the modulo will shrink
      • setShrinkageCount

        protected void setShrinkageCount​(int cEntries)
        Set the level at which the modulo will decrease.
        Parameters:
        cEntries - the number of entries at which the modulo will shrink
      • getModulo

        protected int getModulo()
        Determine the current modulo.
        Returns:
        the current modulo
      • setModulo

        protected void setModulo​(int nModulo)
        Set the new modulo.
        Parameters:
        nModulo - the new modulo
      • getPreviousModulo

        protected int getPreviousModulo()
        Determine the previous modulo. If a hash bucket resize is still being processed, the previous modulo will be different from the current modulo.
        Returns:
        the previous modulo
      • setPreviousModulo

        protected void setPreviousModulo​(int nModulo)
        Set the old modulo.
        Parameters:
        nModulo - the previous modulo
      • calculateBucket

        protected int calculateBucket​(int nHash)
        Calculate the bucket for the specified hash code.
        Parameters:
        nHash - the hash code for the key
        Returns:
        the bucket index
      • calculatePreviousBucket

        protected int calculatePreviousBucket​(int nHash)
        Calculate the old bucket for the specified hash code.
        Parameters:
        nHash - the hash code for the key
        Returns:
        the bucket index using the previous modulo
      • clearBucketOffsets

        protected void clearBucketOffsets()
        Clear out all references in the array of hash buckets.
      • clearBucketOffsets

        protected void clearBucketOffsets​(int nBucket)
        Clear out all references in the array of hash buckets starting with the specified bucket. int nBucket the first bucket to clear
      • checkModulo

        protected void checkModulo()
        Determine if the modulo should be changed. This should only be checked when the map is growing to avoid problems with iterators when removing all entries (don't want the map to rehash then).
      • isRehashing

        protected boolean isRehashing()
        Determine if the map is incrementally rehashing.
        Returns:
        true if the map is incrementally rehashing
      • getNextRehashBucket

        protected int getNextRehashBucket()
        Determine the next bucket to rehash.
        Returns:
        the next bucket to rehash
      • setNextRehashBucket

        protected void setNextRehashBucket​(int nBucket)
        Set the next bucket to rehash.
        Parameters:
        nBucket - the next bucket to rehash
      • rehashBegin

        protected void rehashBegin()
        Configure the incremental rehash.
      • rehash

        protected void rehash​(int nBucket)
        Rehash the specified bucket such that, when done, it will only contain keys that hash to it with the current modulo. Blocks can be in the "wrong" bucket because they are still hashed by the previous modulo; this is the result of incremental rehashing of buckets that allows a modulo change in a huge BinaryMap to occur instantly with the actual associated processing (rehashing) occuring gradually as the map is further used.
        Parameters:
        nBucket - the bucket index to rehash
      • rehashNext

        protected void rehashNext()
        Rehash the next incremental rehash block.
      • rehashAll

        protected void rehashAll()
        Rehash all blocks such that no block will be linked into the wrong bucket. This is a no-op if a there is no re-hashing to do. Blocks can be in the "wrong" bucket because they are still hashed by the previous modulo; this is the result of incremental rehashing of buckets that allows a modulo change in a huge BinaryMap to occur instantly with the actual associated processing (rehashing) occuring gradually as the map is further used.
      • rehashComplete

        protected void rehashComplete()
        Complete the incremental rehash.
      • initBlock

        protected BinaryMap.Block initBlock​(int of)
        Obtain a Block object for a new block that will be located at the specified offset in the ByteBuffer. The returned block is in an open state.
        Returns:
        the Block object for the new block located at the specified offset
      • openBlock

        protected BinaryMap.Block openBlock​(int of)
        Obtain a Block object for the block located at the specified offset in the ByteBuffer. The returned block is in an open state.
        Returns:
        the Block object for the block located at the specified offset
      • allocateBlock

        protected BinaryMap.Block allocateBlock​(int cb)
        Allocate a free Block object of at least a certain size. Note that the returned block is both open and unlinked.
        Parameters:
        cb - the required block size
        Returns:
        a Block object of the required size
      • isCompacting

        protected boolean isCompacting()
        Determine if the map is incrementally compacting.
        Returns:
        true if the map is incrementally compacting
      • getNextCompactBlock

        protected int getNextCompactBlock()
        Determine the next block to compact.
        Returns:
        the next block to compact
      • setNextCompactBlock

        protected void setNextCompactBlock​(int ofBlock)
        Set the next block to compact.
        Parameters:
        ofBlock - the next block to compact
      • compactBegin

        protected void compactBegin()
        Configure the incremental compact.
      • compactUntil

        protected void compactUntil​(int cbReqFree)
        Perform an an incremental compact at the specified block.
        Parameters:
        cbReqFree - the number of bytes required to be free
      • compactNext

        protected void compactNext()
        Perform an incremental compaction of the next block.
      • compactAll

        protected void compactAll()
        Full linear compaction of the buffer.
      • compactComplete

        protected void compactComplete()
        Complete the incremental compact.
      • grabBlock

        protected BinaryMap.Block grabBlock​(int ofBlock)
        Grab a block object for the specified offset. This method returns an open block if one is open for that offset, or uses a recycled block if one is not already open for that offset.
        Parameters:
        ofBlock - the offset of the block to grab
        Returns:
        a block for the specified offset
      • adjustOpenBlockOffset

        protected void adjustOpenBlockOffset​(int ofOld,
                                             int ofNew)
        When an open block changes position in the buffer, this method is invoked to adjust the cache of open blocks.
        Parameters:
        ofOld - the old offset of the block
        ofNew - the new offset of the block
      • recycleBlock

        protected void recycleBlock​(BinaryMap.Block block)
        Release (recycle) the specified Block object. This method should not be called directly; instead, call block.close().
        Parameters:
        block - the Block object to release
      • buffercopy

        protected static void buffercopy​(ByteBuffer buffer,
                                         int ofCopyFrom,
                                         int ofCopyTo,
                                         int cbCopy,
                                         byte[] abBuf)
        Copy from one part of the buffer to another. This method only supports copying from a latter part of the buffer to an earlier part of the buffer.
        Parameters:
        buffer - the ByteBuffer containing the data to copy
        ofCopyFrom - the source offset into the ByteBuffer
        ofCopyTo - the destination offset into the ByteBuffer
        cbCopy - the number of bytes to copy
        abBuf - a temporary byte array available for use
      • calculateSizeCode

        protected static int calculateSizeCode​(int cbBlock)
        Determine which "free bucket" a block of a particular size would go into.
        Parameters:
        cbBlock - the size of the block
        Returns:
        the size code for a block of the specified size
      • instantiateBlock

        protected BinaryMap.Block instantiateBlock()
        Factory method: Create a Block object.
        Returns:
        a new instance of the Block class or subclass thereof