Package java.nio

Class DoubleBuffer

java.lang.Object
java.nio.Buffer
java.nio.DoubleBuffer
All Implemented Interfaces:
Comparable<DoubleBuffer>
public abstract class DoubleBuffer
extends Buffer
implements Comparable<DoubleBuffer>
A buffer of doubles.

A double buffer can be created in either one of the following ways:

  • Allocate a new double array and create a buffer based on it;
  • Wrap an existing double array to create a new buffer;
  • Use ByteBuffer.asDoubleBuffer to create a double buffer based on a byte buffer.

  • Method Summary

    Modifier and Type Method Description
    static DoubleBuffer allocate​(int capacity)
    Creates a double buffer based on a newly allocated double array.
    double[] array()
    Returns the array that backs this buffer (optional operation).
    int arrayOffset()
    Returns the offset into the array returned by array of the first element of the buffer (optional operation).
    abstract DoubleBuffer asReadOnlyBuffer()
    Returns a read-only buffer that shares its content with this buffer.
    abstract DoubleBuffer compact()
    Compacts this double buffer.
    int compareTo​(DoubleBuffer otherBuffer)
    Compare the remaining doubles of this buffer to another double buffer's remaining doubles.
    abstract DoubleBuffer duplicate()
    Returns a duplicated buffer that shares its content with this buffer.
    boolean equals​(Object other)
    Checks whether this double buffer is equal to another object.
    abstract double get()
    Returns the double at the current position and increases the position by 1.
    DoubleBuffer get​(double[] dst)
    Reads doubles from the current position into the specified double array and increases the position by the number of doubles read.
    DoubleBuffer get​(double[] dst, int dstOffset, int doubleCount)
    Reads doubles from the current position into the specified double array, starting from the specified offset, and increases the position by the number of doubles read.
    abstract double get​(int index)
    Returns a double at the specified index; the position is not changed.
    boolean hasArray()
    Returns true if array and arrayOffset won't throw.
    int hashCode()
    Calculates this buffer's hash code from the remaining chars.
    abstract boolean isDirect()
    Indicates whether this buffer is direct.
    abstract ByteOrder order()
    Returns the byte order used by this buffer when converting doubles from/to bytes.
    abstract DoubleBuffer put​(double d)
    Writes the given double to the current position and increases the position by 1.
    DoubleBuffer put​(double[] src)
    Writes doubles from the given double array to the current position and increases the position by the number of doubles written.
    DoubleBuffer put​(double[] src, int srcOffset, int doubleCount)
    Writes doubles from the given double array, starting from the specified offset, to the current position and increases the position by the number of doubles written.
    abstract DoubleBuffer put​(int index, double d)
    Write a double to the specified index of this buffer and the position is not changed.
    DoubleBuffer put​(DoubleBuffer src)
    Writes all the remaining doubles of the src double buffer to this buffer's current position, and increases both buffers' position by the number of doubles copied.
    abstract DoubleBuffer slice()
    Returns a sliced buffer that shares its content with this buffer.
    static DoubleBuffer wrap​(double[] array)
    Creates a new double buffer by wrapping the given double array.
    static DoubleBuffer wrap​(double[] array, int start, int doubleCount)
    Creates a new double buffer by wrapping the given double array.

    Methods inherited from class java.nio.Buffer

    capacity, clear, flip, hasRemaining, isReadOnly, limit, limit, mark, position, position, remaining, reset, rewind, toString

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Method Details

    • allocate

      public static DoubleBuffer allocate​(int capacity)
      Creates a double buffer based on a newly allocated double array.
      Parameters:
      capacity - the capacity of the new buffer.
      Returns:
      the created double buffer.
      Throws:
      IllegalArgumentException - if capacity is less than zero.

    • wrap

      public static DoubleBuffer wrap​(double[] array)
      Creates a new double buffer by wrapping the given double array.

      Calling this method has the same effect as wrap(array, 0, array.length).

      Parameters:
      array - the double array which the new buffer will be based on.
      Returns:
      the created double buffer.

    • wrap

      public static DoubleBuffer wrap​(double[] array, int start, int doubleCount)
      Creates a new double buffer by wrapping the given double array.

      The new buffer's position will be start, limit will be start + doubleCount, capacity will be the length of the array.

      Parameters:
      array - the double array which the new buffer will be based on.
      start - the start index, must not be negative and not greater than array.length.
      doubleCount - the length, must not be negative and not greater than array.length - start.
      Returns:
      the created double buffer.
      Throws:
      IndexOutOfBoundsException - if either start or doubleCount is invalid.

    • array

      public final double[] array()
      Description copied from class: Buffer
      Returns the array that backs this buffer (optional operation). The returned value is the actual array, not a copy, so modifications to the array write through to the buffer.

      Subclasses should override this method with a covariant return type to provide the exact type of the array.

      Use hasArray to ensure this method won't throw. (A separate call to isReadOnly is not necessary.)

      Specified by:
      array in class Buffer
      Returns:
      the array

    • arrayOffset

      public final int arrayOffset()
      Description copied from class: Buffer
      Returns the offset into the array returned by array of the first element of the buffer (optional operation). The backing array (if there is one) is not necessarily the same size as the buffer, and position 0 in the buffer is not necessarily the 0th element in the array. Use buffer.array()[offset + buffer.arrayOffset() to access element offset in buffer.

      Use hasArray to ensure this method won't throw. (A separate call to isReadOnly is not necessary.)

      Specified by:
      arrayOffset in class Buffer
      Returns:
      the offset

    • asReadOnlyBuffer

      public abstract DoubleBuffer asReadOnlyBuffer()
      Returns a read-only buffer that shares its content with this buffer.

      The returned buffer is guaranteed to be a new instance, even if this buffer is read-only itself. The new buffer's position, limit, capacity and mark are the same as this buffer's.

      The new buffer shares its content with this buffer, which means that this buffer's change of content will be visible to the new buffer. The two buffer's position, limit and mark are independent.

      Returns:
      a read-only version of this buffer.

    • compact

      public abstract DoubleBuffer compact()
      Compacts this double buffer.

      The remaining doubles will be moved to the head of the buffer, staring from position zero. Then the position is set to remaining(); the limit is set to capacity; the mark is cleared.

      Returns:
      this buffer.
      Throws:
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • compareTo

      public int compareTo​(DoubleBuffer otherBuffer)
      Compare the remaining doubles of this buffer to another double buffer's remaining doubles.
      Specified by:
      compareTo in interface Comparable<DoubleBuffer>
      Parameters:
      otherBuffer - another double buffer.
      Returns:
      a negative value if this is less than other; 0 if this equals to other; a positive value if this is greater than other.
      Throws:
      ClassCastException - if other is not a double buffer.

    • duplicate

      public abstract DoubleBuffer duplicate()
      Returns a duplicated buffer that shares its content with this buffer.

      The duplicated buffer's position, limit, capacity and mark are the same as this buffer's. The duplicated buffer's read-only property and byte order are the same as this buffer's, too.

      The new buffer shares its content with this buffer, which means either buffer's change of content will be visible to the other. The two buffers' position, limit and mark are independent.

    • equals

      public boolean equals​(Object other)
      Checks whether this double buffer is equal to another object. If other is not a DoubleBuffer then false is returned.

      Two double buffers are equal if their remaining doubles are equal. Position, limit, capacity and mark are not considered.

      This method considers two doubles a and b to be equal if a == b or if a and b are both NaN. Unlike Double.equals(java.lang.Object), this method considers -0.0 and +0.0 to be equal.

      Overrides:
      equals in class Object
      Parameters:
      other - the object to compare with this double buffer.
      Returns:
      true if this double buffer is equal to other, false otherwise.
      See Also:
      Object.hashCode()

    • get

      public abstract double get()
      Returns the double at the current position and increases the position by 1.
      Returns:
      the double at the current position.
      Throws:
      BufferUnderflowException - if the position is equal or greater than limit.

    • get

      public DoubleBuffer get​(double[] dst)
      Reads doubles from the current position into the specified double array and increases the position by the number of doubles read.

      Calling this method has the same effect as get(dst, 0, dst.length).

      Parameters:
      dst - the destination double array.
      Returns:
      this buffer.
      Throws:
      BufferUnderflowException - if dst.length is greater than remaining().

    • get

      public DoubleBuffer get​(double[] dst, int dstOffset, int doubleCount)
      Reads doubles from the current position into the specified double array, starting from the specified offset, and increases the position by the number of doubles read.
      Parameters:
      dst - the target double array.
      dstOffset - the offset of the double array, must not be negative and not greater than dst.length.
      doubleCount - the number of doubles to read, must be no less than zero and not greater than dst.length - dstOffset.
      Returns:
      this buffer.
      Throws:
      IndexOutOfBoundsException - if either dstOffset or doubleCount is invalid.
      BufferUnderflowException - if doubleCount is greater than remaining().

    • get

      public abstract double get​(int index)
      Returns a double at the specified index; the position is not changed.
      Parameters:
      index - the index, must not be negative and less than limit.
      Returns:
      a double at the specified index.
      Throws:
      IndexOutOfBoundsException - if index is invalid.

    • hasArray

      public final boolean hasArray()
      Description copied from class: Buffer
      Returns true if array and arrayOffset won't throw. This method does not return true for buffers not backed by arrays because the other methods would throw UnsupportedOperationException, nor does it return true for buffers backed by read-only arrays, because the other methods would throw ReadOnlyBufferException.
      Specified by:
      hasArray in class Buffer

    • hashCode

      public int hashCode()
      Calculates this buffer's hash code from the remaining chars. The position, limit, capacity and mark don't affect the hash code.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code calculated from the remaining chars.
      See Also:
      Object.equals(java.lang.Object)

    • isDirect

      public abstract boolean isDirect()
      Indicates whether this buffer is direct. A direct buffer will try its best to take advantage of native memory APIs and it may not stay in the Java heap, so it is not affected by garbage collection.

      A double buffer is direct if it is based on a byte buffer and the byte buffer is direct.

      Specified by:
      isDirect in class Buffer
      Returns:
      true if this buffer is direct, false otherwise.

    • order

      public abstract ByteOrder order()
      Returns the byte order used by this buffer when converting doubles from/to bytes.

      If this buffer is not based on a byte buffer, then this always returns the platform's native byte order.

      Returns:
      the byte order used by this buffer when converting doubles from/to bytes.

    • put

      public abstract DoubleBuffer put​(double d)
      Writes the given double to the current position and increases the position by 1.
      Parameters:
      d - the double to write.
      Returns:
      this buffer.
      Throws:
      BufferOverflowException - if position is equal or greater than limit.
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • put

      public final DoubleBuffer put​(double[] src)
      Writes doubles from the given double array to the current position and increases the position by the number of doubles written.

      Calling this method has the same effect as put(src, 0, src.length).

      Parameters:
      src - the source double array.
      Returns:
      this buffer.
      Throws:
      BufferOverflowException - if remaining() is less than src.length.
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • put

      public DoubleBuffer put​(double[] src, int srcOffset, int doubleCount)
      Writes doubles from the given double array, starting from the specified offset, to the current position and increases the position by the number of doubles written.
      Parameters:
      src - the source double array.
      srcOffset - the offset of double array, must not be negative and not greater than src.length.
      doubleCount - the number of doubles to write, must be no less than zero and not greater than src.length - srcOffset.
      Returns:
      this buffer.
      Throws:
      BufferOverflowException - if remaining() is less than doubleCount.
      IndexOutOfBoundsException - if either srcOffset or doubleCount is invalid.
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • put

      public DoubleBuffer put​(DoubleBuffer src)
      Writes all the remaining doubles of the src double buffer to this buffer's current position, and increases both buffers' position by the number of doubles copied.
      Parameters:
      src - the source double buffer.
      Returns:
      this buffer.
      Throws:
      BufferOverflowException - if src.remaining() is greater than this buffer's remaining().
      IllegalArgumentException - if src is this buffer.
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • put

      public abstract DoubleBuffer put​(int index, double d)
      Write a double to the specified index of this buffer and the position is not changed.
      Parameters:
      index - the index, must not be negative and less than the limit.
      d - the double to write.
      Returns:
      this buffer.
      Throws:
      IndexOutOfBoundsException - if index is invalid.
      ReadOnlyBufferException - if no changes may be made to the contents of this buffer.

    • slice

      public abstract DoubleBuffer slice()
      Returns a sliced buffer that shares its content with this buffer.

      The sliced buffer's capacity will be this buffer's remaining(), and its zero position will correspond to this buffer's current position. The new buffer's position will be 0, limit will be its capacity, and its mark is cleared. The new buffer's read-only property and byte order are the same as this buffer's.

      The new buffer shares its content with this buffer, which means either buffer's change of content will be visible to the other. The two buffers' position, limit and mark are independent.