Class DataStorage

java.lang.Object
org.apfloat.spi.DataStorage
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
DiskDataStorage, DoubleMemoryDataStorage, FloatMemoryDataStorage, IntMemoryDataStorage, LongMemoryDataStorage

public abstract class DataStorage extends Object implements Serializable
Generic data storage class.

Initially when a data storage is created, it is mutable (it can be modified). After the contents have been properly set, the user should call setReadOnly() to set the storage to be immutable. After this the data storage can be safely shared between different users.

Access to DataStorage objects is generally not internally synchronized. Accessing multiple non-overlapping parts of the storage concurrently with the getArray(int,long,int), getArray(int,int,int,int) or getTransposedArray(int,int,int,int) method and with iterators over non-overlapping parts is permitted. Invoking other methods must generally be externally synchronized.

Version:
1.8.1
Author:
Mikko Tommila
See Also:
Serialized Form
  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    protected class 
    Abstract base class for iterators iterating through this DataStorage.
    static class 
    Iterator for iterating through elements of the data storage.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static int
    Read access mode specifier.
    static int
    Read-write access mode specifier.
    static int
    Write access mode specifier.
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    Default constructor.
    protected
    DataStorage​(DataStorage dataStorage, long offset, long length)
    Subsequence constructor.
  • Method Summary

    Modifier and Type
    Method
    Description
    void
    copyFrom​(DataStorage dataStorage)
    Copies all data from another data storage to this data storage.
    void
    copyFrom​(DataStorage dataStorage, long size)
    Copies the specified number of elements from another data storage to this data storage.
    getArray​(int mode, int startColumn, int columns, int rows)
    Maps a block of data to a memory array when the data is treated as a matrix.
    getArray​(int mode, long offset, int length)
    Gets an array access to the data of this data storage when the data is treated as a linear block.
    protected long
    Return the sub-sequence offset.
    long
    Return the size of the data storage, or the length of this sub-sequence if this data storage is a sub-sequence.
    getTransposedArray​(int mode, int startColumn, int columns, int rows)
    Maps a transposed block of data to a memory array when the data is treated as a matrix.
    protected abstract void
    implCopyFrom​(DataStorage dataStorage, long size)
    Copies the specified number of elements from another data storage to this data storage.
    protected abstract ArrayAccess
    implGetArray​(int mode, int startColumn, int columns, int rows)
    Maps a block of data to a memory array when the data is treated as a matrix.
    protected abstract ArrayAccess
    implGetArray​(int mode, long offset, int length)
    Gets an array access to the data of this data storage when it is treated as a linear block.
    protected abstract long
    Return the size of the whole data storage, not including sub-sequence settings.
    protected abstract ArrayAccess
    implGetTransposedArray​(int mode, int startColumn, int columns, int rows)
    Maps a transposed block of data to a memory array when the data is treated as a matrix.
    protected abstract void
    implSetSize​(long size)
    Sets the size of the data storage.
    protected abstract DataStorage
    implSubsequence​(long offset, long length)
    Implementation of getting a subsequence of this data storage.
    abstract boolean
    Is this object cached in memory.
    boolean
    Returns the read-only state of this data storage.
    boolean
    Is this object a subsequence of some other object, or do subsequences of this object exist.
    iterator​(int mode, long startPosition, long endPosition)
    Constructs a new iterator.
    void
    Sets this data storage as read-only.
    void
    setSize​(long size)
    Sets the size of the data storage.
    subsequence​(long offset, long length)
    Get a subsequence of this data storage.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • READ

      public static final int READ
      Read access mode specifier.
      See Also:
      Constant Field Values
    • WRITE

      public static final int WRITE
      Write access mode specifier.
      See Also:
      Constant Field Values
    • READ_WRITE

      public static final int READ_WRITE
      Read-write access mode specifier. For convenience, equivalent to READ | WRITE.
      See Also:
      Constant Field Values
  • Constructor Details

    • DataStorage

      protected DataStorage()
      Default constructor. To be called by subclasses when creating a new empty DataStorage.
    • DataStorage

      protected DataStorage(DataStorage dataStorage, long offset, long length)
      Subsequence constructor. To be called by subclasses when creating a subsequence of an existing DataStorage.
      Parameters:
      dataStorage - The originating data storage.
      offset - The subsequence starting position.
      length - The subsequence length.
  • Method Details

    • subsequence

      public final DataStorage subsequence(long offset, long length) throws IllegalArgumentException, ApfloatRuntimeException
      Get a subsequence of this data storage.
      Parameters:
      offset - The subsequence starting position.
      length - The subsequence length.
      Returns:
      Data storage that represents the specified part of this data storage.
      Throws:
      IllegalArgumentException - If the requested subsequence is out of range.
      ApfloatRuntimeException
    • implSubsequence

      protected abstract DataStorage implSubsequence(long offset, long length) throws ApfloatRuntimeException
      Implementation of getting a subsequence of this data storage. The validity of the arguments of this method do not need to be checked.
      Parameters:
      offset - The subsequence starting position.
      length - The subsequence length.
      Returns:
      Data storage that represents the specified part of this data storage.
      Throws:
      ApfloatRuntimeException
    • copyFrom

      public final void copyFrom(DataStorage dataStorage) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Copies all data from another data storage to this data storage.
      Parameters:
      dataStorage - The data storage where the data should be copied from.
      Throws:
      IllegalArgumentException - If the origin data source has a size of zero.
      IllegalStateException - If this data storage is read-only or has subsequences.
      ApfloatRuntimeException
    • copyFrom

      public final void copyFrom(DataStorage dataStorage, long size) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Copies the specified number of elements from another data storage to this data storage.
      Parameters:
      dataStorage - The data storage where the data should be copied from.
      size - The number of elements to be copied.
      Throws:
      IllegalArgumentException - If the size is invalid or zero.
      IllegalStateException - If this data storage is read-only or has subsequences.
      ApfloatRuntimeException
    • implCopyFrom

      protected abstract void implCopyFrom(DataStorage dataStorage, long size) throws ApfloatRuntimeException
      Copies the specified number of elements from another data storage to this data storage. The validity of the arguments of this method do not need to be checked.
      Parameters:
      dataStorage - The data storage where the data should be copied from.
      size - The number of elements to be copied.
      Throws:
      ApfloatRuntimeException
    • getSize

      public final long getSize() throws ApfloatRuntimeException
      Return the size of the data storage, or the length of this sub-sequence if this data storage is a sub-sequence.
      Returns:
      The size of the data storage.
      Throws:
      ApfloatRuntimeException
    • implGetSize

      protected abstract long implGetSize() throws ApfloatRuntimeException
      Return the size of the whole data storage, not including sub-sequence settings.
      Returns:
      The size of the whole data storage, not including sub-sequence settings.
      Throws:
      ApfloatRuntimeException
    • setSize

      public final void setSize(long size) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Sets the size of the data storage.
      Parameters:
      size - The size of the data storage.
      Throws:
      IllegalArgumentException - If the size is invalid or zero.
      IllegalStateException - If this data storage is read-only or has subsequences.
      ApfloatRuntimeException
    • implSetSize

      protected abstract void implSetSize(long size) throws ApfloatRuntimeException
      Sets the size of the data storage. The validity of the arguments of this method do not need to be checked.
      Parameters:
      size - The size of the data storage.
      Throws:
      ApfloatRuntimeException
    • isReadOnly

      public final boolean isReadOnly()
      Returns the read-only state of this data storage.
      Returns:
      true if this data storage is read-only, otherwise false.
    • setReadOnly

      public final void setReadOnly() throws ApfloatRuntimeException
      Sets this data storage as read-only. All existing sub-sequences (recursively) of this data storage are set to read-only as well.
      Throws:
      ApfloatRuntimeException
    • getArray

      public final ArrayAccess getArray(int mode, long offset, int length) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Gets an array access to the data of this data storage when the data is treated as a linear block.
      Parameters:
      mode - Access mode for the array access: READ, WRITE or both.
      offset - Starting position of the array access in the data storage.
      length - Number of accessible elements in the array access.
      Returns:
      The array access.
      Throws:
      IllegalArgumentException - If the offset or length are out of bounds of the data storage.
      IllegalStateException - If write access is requested for a read-only data storage.
      ApfloatRuntimeException
    • implGetArray

      protected abstract ArrayAccess implGetArray(int mode, long offset, int length) throws ApfloatRuntimeException
      Gets an array access to the data of this data storage when it is treated as a linear block. The validity of the arguments of this method do not need to be checked.
      Parameters:
      mode - Access mode for the array access: READ, WRITE or both.
      offset - Starting position of the array access in the data storage.
      length - Number of accessible elements in the array access.
      Returns:
      The array access.
      Throws:
      ApfloatRuntimeException
    • getArray

      public final ArrayAccess getArray(int mode, int startColumn, int columns, int rows) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Maps a block of data to a memory array when the data is treated as a matrix. The matrix size is n1 x n2. The following picture illustrates the block being accessed (in gray):
      Matrix
      ← startColumn → ← columns →
      n1

      ← n2
      Parameters:
      mode - Whether the array is prepared for reading, writing or both. The value should be READ, WRITE or a combination of these.
      startColumn - The starting column where data is read.
      columns - The number of columns of data to read.
      rows - The number of rows of data to read. This should be equivalent to n1, number of rows in the matrix.
      Returns:
      Access to an array of size columns x rows containing the data.
      Throws:
      IllegalArgumentException - If the requested area is out of bounds of the data storage.
      IllegalStateException - If write access is requested for a read-only data storage.
      ApfloatRuntimeException
      Since:
      1.7.0
    • implGetArray

      protected abstract ArrayAccess implGetArray(int mode, int startColumn, int columns, int rows) throws ApfloatRuntimeException
      Maps a block of data to a memory array when the data is treated as a matrix. The validity of the arguments of this method do not need to be checked.
      Parameters:
      mode - Whether the array is prepared for reading, writing or both. The value should be READ, WRITE or a combination of these.
      startColumn - The starting column where data is read.
      columns - The number of columns of data to read.
      rows - The number of rows of data to read. This should be equivalent to n1, number of rows in the matrix.
      Returns:
      Access to an array of size columns x rows containing the data.
      Throws:
      ApfloatRuntimeException
      Since:
      1.7.0
    • getTransposedArray

      public final ArrayAccess getTransposedArray(int mode, int startColumn, int columns, int rows) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Maps a transposed block of data to a memory array when the data is treated as a matrix. The matrix size is n1 x n2. The accessed block is illustrated in gray in the following picture. The argument columns is the value b:
      Matrix
      ← startColumn → A
      n1

      B
      C
      D
      ← b →
      ← n2
      The data is read from an n1 x b area of the matrix, in blocks of b elements, to a b x n1 memory array as follows:
      Read matrix section
      A
      b

      B
      C
      D
      ← n1
      Each b x b block is transposed, to form the final b x n1 array in memory, where the columns are located linearly:
      Transposed matrix section
      A B C D
      b

      ← n1
      Parameters:
      mode - Whether the array is prepared for reading, writing or both. The value should be READ, WRITE or a combination of these.
      startColumn - The starting column where data is read.
      columns - The number of columns of data to read.
      rows - The number of rows of data to read. This should be equivalent to n1, number of rows in the matrix.
      Returns:
      Access to an array of size columns x rows containing the transposed data.
      Throws:
      IllegalArgumentException - If the requested area is out of bounds of the data storage.
      IllegalStateException - If write access is requested for a read-only data storage.
      ApfloatRuntimeException
    • implGetTransposedArray

      protected abstract ArrayAccess implGetTransposedArray(int mode, int startColumn, int columns, int rows) throws ApfloatRuntimeException
      Maps a transposed block of data to a memory array when the data is treated as a matrix. The validity of the arguments of this method do not need to be checked.
      Parameters:
      mode - Whether the array is prepared for reading, writing or both. The value should be READ, WRITE or a combination of these.
      startColumn - The starting column where data is read.
      columns - The number of columns of data to read.
      rows - The number of rows of data to read. This should be equivalent to n1, number of rows in the matrix.
      Returns:
      Access to an array of size columns x rows containing the transposed data.
      Throws:
      ApfloatRuntimeException
    • iterator

      public abstract DataStorage.Iterator iterator(int mode, long startPosition, long endPosition) throws IllegalArgumentException, IllegalStateException, ApfloatRuntimeException
      Constructs a new iterator. Elements can be iterated either in forward or in reverse order, depending on if startPosition is less than or greater than endPosition, correspondingly.
      Parameters:
      mode - Access mode for iterator: READ, WRITE or both.
      startPosition - Starting position of iterator in the data set. For reverse access, the first element in the iterator is startPosition - 1.
      endPosition - End position of iterator in the data set. For forward access, the last accessible element in the iterator is endPosition - 1.
      Returns:
      An iterator.
      Throws:
      IllegalArgumentException - If the requested area is out of bounds of the data storage.
      IllegalStateException - If write access is requested for a read-only data storage.
      ApfloatRuntimeException
    • isSubsequenced

      public final boolean isSubsequenced()
      Is this object a subsequence of some other object, or do subsequences of this object exist.
      Returns:
      true if this object is a subsequence of some other object, or if subsequences of this object exist, false otherwise.
    • isCached

      public abstract boolean isCached()
      Is this object cached in memory.
      Returns:
      true if this object is cached in memory, false if not.
      Since:
      1.7.0
    • getOffset

      protected final long getOffset()
      Return the sub-sequence offset.
      Returns:
      Absolute offset of the sub-sequence within the (top-level) base data storage.