FloatBuffer (Java 2 Platform SE v1.4.1_"07")

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JavaTM 2 Platform
Std. Ed. v1.4.1_"07"

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## java.nio
Class FloatBuffer

    java.lang.Object
      |
      +--java.nio.Buffer
            |
            +--java.nio.FloatBuffer

All Implemented Interfaces:
  Comparable

public abstract class FloatBuffer
extends Buffer
implements Comparable

A float buffer.

This class defines four categories of operations upon float buffers:

- Absolute and relative ``get`` and ``put`` methods that read and write single floats;

- Relative ``bulk get`` methods that transfer contiguous sequences of floats from this buffer into an array; and

- Relative ``bulk put`` methods that transfer contiguous sequences of floats from a float array or some other float buffer into this buffer; and

- Methods for ``compacting``, ``duplicating``, and ``slicing`` a float buffer.

Float buffers can be created either by ``allocation``, which allocates space for the buffer's content, by ``wrapping`` an existing float array into a buffer, or by creating a view of an existing byte buffer

Like a byte buffer, a float buffer is either direct or non-direct. A float buffer created via the `wrap` methods of this class will be non-direct. A float buffer created as a view of a byte buffer will be direct if, and only if, the byte buffer itself is direct. Whether or not a float buffer is direct may be determined by invoking the `isDirect` method.

Methods in this class that do not otherwise have a value to return are specified to return the buffer upon which they are invoked. This allows method invocations to be chained.

Since:
  1.4

Method Summary
`static FloatBuffer` | `allocate(int capacity)` Allocates a new float buffer.
`float[]` | `array()` Returns the float array that backs this buffer (optional operation).
`int` | `arrayOffset()` Returns the offset within this buffer's backing array of the first element of the buffer (optional operation).
`abstract FloatBuffer` | `asReadOnlyBuffer()` Creates a new, read-only float buffer that shares this buffer's content.
`abstract FloatBuffer` | `compact()` Compacts this buffer (optional operation).
`int` | `compareTo(Object ob)` Compares this buffer to another object.
`abstract FloatBuffer` | `duplicate()` Creates a new float buffer that shares this buffer's content.
`boolean` | `equals(Object ob)` Tells whether or not this buffer is equal to another object.
`abstract float` | `get()` Relative get method.
`FloatBuffer` | `get(float[] dst)` Relative bulk get method.
`FloatBuffer` | `get(float[] dst, int offset, int length)` Relative bulk get method.
`abstract float` | `get(int index)` Absolute get method.
`boolean` | `hasArray()` Tells whether or not this buffer is backed by an accessible float array.
`int` | `hashCode()` Returns the current hash code of this buffer.
`abstract boolean` | `isDirect()` Tells whether or not this float buffer is direct.
`abstract ByteOrder` | `order()` Retrieves this buffer's byte order.
`abstract FloatBuffer` | `put(float f)` Relative put method (optional operation).
`FloatBuffer` | `put(float[] src)` Relative bulk put method (optional operation).
`FloatBuffer` | `put(float[] src, int offset, int length)` Relative bulk put method (optional operation).
`FloatBuffer` | `put(FloatBuffer src)` Relative bulk put method (optional operation).
`abstract FloatBuffer` | `put(int index, float f)` Absolute put method (optional operation).
`abstract FloatBuffer` | `slice()` Creates a new float buffer whose content is a shared subsequence of this buffer's content.
`String` | `toString()` Returns a string summarizing the state of this buffer.
`static FloatBuffer` | `wrap(float[] array)` Wraps a float array into a buffer.
`static FloatBuffer` | `wrap(float[] array, int offset, int length)` Wraps a float array into a buffer.

Methods inherited from class java.nio.Buffer
`capacity, clear, flip, hasRemaining, isReadOnly, limit, limit, mark, position, position, remaining, reset, rewind`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Method Detail

### allocate

    public static FloatBuffer allocate(int capacity)

  Allocates a new float buffer.

  The new buffer's position will be zero, its limit will be its capacity, and its mark will be undefined. It will have a ``backing array``, and its ``array offset`` will be zero.

  Parameters:
    `capacity` - The new buffer's capacity, in floats
  Returns:
    The new float buffer

### wrap

    public static FloatBuffer wrap(float[] array,
                                   int offset,
                                   int length)

  Wraps a float array into a buffer.

  The new buffer will be backed by the the given float array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity will be `array.length`, its position will be `offset`, its limit will be `offset + length`, and its mark will be undefined. Its ``backing array`` will be the given array, and its ``array offset`` will be zero.

  Parameters:
    `array` - The array that will back the new buffer
    `offset` - The offset of the subarray to be used; must be non-negative and no larger than `array.length`. The new buffer's position will be set to this value.
    `length` - The length of the subarray to be used; must be non-negative and no larger than `array.length - offset`. The new buffer's limit will be set to `offset + length`.
  Returns:
    The new float buffer
  Throws:
    `IndexOutOfBoundsException` - If the preconditions on the `offset` and `length` parameters do not hold

### wrap

    public static FloatBuffer wrap(float[] array)

  Wraps a float array into a buffer.

  The new buffer will be backed by the the given float array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity and limit will be `array.length`, its position will be zero, and its mark will be undefined. Its ``backing array`` will be the given array, and its ``array offset`` will be zero.

  Parameters:
    `array` - The array that will back this buffer
  Returns:
    The new float buffer

### slice

    public abstract FloatBuffer slice()

  Creates a new float buffer whose content is a shared subsequence of this buffer's content.

  The content of the new buffer will start at this buffer's current position. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

  The new buffer's position will be zero, its capacity and its limit will be the number of floats remaining in this buffer, and its mark will be undefined. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

  Returns:
    The new float buffer

### duplicate

    public abstract FloatBuffer duplicate()

  Creates a new float buffer that shares this buffer's content.

  The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

  The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

  Returns:
    The new float buffer

### asReadOnlyBuffer

    public abstract FloatBuffer asReadOnlyBuffer()

  Creates a new, read-only float buffer that shares this buffer's content.

  The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer; the new buffer itself, however, will be read-only and will not allow the shared content to be modified. The two buffers' position, limit, and mark values will be independent.

  The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer.

  If this buffer is itself read-only then this method behaves in exactly the same way as the `duplicate` method.

  Returns:
    The new, read-only float buffer

### get

    public abstract float get()

  Relative get method. Reads the float at this buffer's current position, and then increments the position.

  Returns:
    The float at the buffer's current position
  Throws:
    `BufferUnderflowException` - If the buffer's current position is not smaller than its limit

### put

    public abstract FloatBuffer put(float f)

  Relative put method (optional operation).

  Writes the given float into this buffer at the current position, and then increments the position.

  Parameters:
    `f` - The float to be written
  Returns:
    This buffer
  Throws:
    `BufferOverflowException` - If this buffer's current position is not smaller than its limit
    `ReadOnlyBufferException` - If this buffer is read-only

### get

    public abstract float get(int index)

  Absolute get method. Reads the float at the given index.

  Parameters:
    `index` - The index from which the float will be read
  Returns:
    The float at the given index
  Throws:
    `IndexOutOfBoundsException` - If `index` is negative or not smaller than the buffer's limit

### put

    public abstract FloatBuffer put(int index,
                                    float f)

  Absolute put method (optional operation).

  Writes the given float into this buffer at the given index.

  Parameters:
    `index` - The index at which the float will be written
    `f` - The float value to be written
  Returns:
    This buffer
  Throws:
    `IndexOutOfBoundsException` - If `index` is negative or not smaller than the buffer's limit
    `ReadOnlyBufferException` - If this buffer is read-only

### get

    public FloatBuffer get(float[] dst,
                           int offset,
                           int length)

  Relative bulk get method.

  This method transfers floats from this buffer into the given destination array. If there are fewer floats remaining in the buffer than are required to satisfy the request, that is, if `length` `>` `remaining()`, then no floats are transferred and a `BufferUnderflowException` is thrown.

  Otherwise, this method copies `length` floats from this buffer into the given array, starting at the current position of this buffer and at the given offset in the array. The position of this buffer is then incremented by `length`.

  In other words, an invocation of this method of the form `src.get(dst, off, len)` has exactly the same effect as the loop

           for (int i = off; i < off + len; i++)
               dst[i] = src.get();

  except that it first checks that there are sufficient floats in this buffer and it is potentially much more efficient.

  Parameters:
    `dst` - The array into which floats are to be written
    `offset` - The offset within the array of the first float to be written; must be non-negative and no larger than `dst.length`
    `length` - The maximum number of floats to be written to the given array; must be non-negative and no larger than `dst.length - offset`
  Returns:
    This buffer
  Throws:
    `BufferUnderflowException` - If there are fewer than `length` floats remaining in this buffer
    `IndexOutOfBoundsException` - If the preconditions on the `offset` and `length` parameters do not hold

### get

    public FloatBuffer get(float[] dst)

  Relative bulk get method.

  This method transfers floats from this buffer into the given destination array. An invocation of this method of the form `src.get(a)` behaves in exactly the same way as the invocation

           src.get(a, 0, a.length)

  Returns:
    This buffer
  Throws:
    `BufferUnderflowException` - If there are fewer than `length` floats remaining in this buffer

### put

    public FloatBuffer put(FloatBuffer src)

  Relative bulk put method (optional operation).

  This method transfers the floats remaining in the given source buffer into this buffer. If there are more floats remaining in the source buffer than in this buffer, that is, if `src.remaining()` `>` `remaining()`, then no floats are transferred and a `BufferOverflowException` is thrown.

  Otherwise, this method copies n = `src.remaining()` floats from the given buffer into this buffer, starting at each buffer's current position. The positions of both buffers are then incremented by n.

  In other words, an invocation of this method of the form `dst.put(src)` has exactly the same effect as the loop

           while (src.hasRemaining())
               dst.put(src.get());

  except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

  Parameters:
    `src` - The source buffer from which floats are to be read; must not be this buffer
  Returns:
    This buffer
  Throws:
    `BufferOverflowException` - If there is insufficient space in this buffer for the remaining floats in the source buffer
    `IllegalArgumentException` - If the source buffer is this buffer
    `ReadOnlyBufferException` - If this buffer is read-only

### put

    public FloatBuffer put(float[] src,
                           int offset,
                           int length)

  Relative bulk put method (optional operation).

  This method transfers floats into this buffer from the given source array. If there are more floats to be copied from the array than remain in this buffer, that is, if `length` `>` `remaining()`, then no floats are transferred and a `BufferOverflowException` is thrown.

  Otherwise, this method copies `length` floats from the given array into this buffer, starting at the given offset in the array and at the current position of this buffer. The position of this buffer is then incremented by `length`.

  In other words, an invocation of this method of the form `dst.put(src, off, len)` has exactly the same effect as the loop

           for (int i = off; i < off + len; i++)
               dst.put(a[i]);

  except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

  Parameters:
    `offset` - The offset within the array of the first float to be read; must be non-negative and no larger than `array.length`
    `length` - The number of floats to be read from the given array; must be non-negative and no larger than `array.length - offset`
  Returns:
    This buffer
  Throws:
    `BufferOverflowException` - If there is insufficient space in this buffer
    `IndexOutOfBoundsException` - If the preconditions on the `offset` and `length` parameters do not hold
    `ReadOnlyBufferException` - If this buffer is read-only

### put

    public final FloatBuffer put(float[] src)

  Relative bulk put method (optional operation).

  This method transfers the entire content of the given source float array into this buffer. An invocation of this method of the form `dst.put(a)` behaves in exactly the same way as the invocation

           dst.put(a, 0, a.length)

  Returns:
    This buffer
  Throws:
    `BufferOverflowException` - If there is insufficient space in this buffer
    `ReadOnlyBufferException` - If this buffer is read-only

### hasArray

    public final boolean hasArray()

  Tells whether or not this buffer is backed by an accessible float array.

  If this method returns `true` then the `array` and `arrayOffset` methods may safely be invoked.

  Returns:
    `true` if, and only if, this buffer is backed by an array and is not read-only

### array

    public final float[] array()

  Returns the float array that backs this buffer (optional operation).

  Modifications to this buffer's content will cause the returned array's content to be modified, and vice versa.

  Invoke the `hasArray` method before invoking this method in order to ensure that this buffer has an accessible backing array.

  Returns:
    The array that backs this buffer
  Throws:
    `ReadOnlyBufferException` - If this buffer is backed by an array but is read-only
    `UnsupportedOperationException` - If this buffer is not backed by an accessible array

### arrayOffset

    public final int arrayOffset()

  Returns the offset within this buffer's backing array of the first element of the buffer (optional operation).

  If this buffer is backed by an array then buffer position p corresponds to array index p + `arrayOffset()`.

  Invoke the `hasArray` method before invoking this method in order to ensure that this buffer has an accessible backing array.

  Returns:
    The offset within this buffer's array of the first element of the buffer
  Throws:
    `ReadOnlyBufferException` - If this buffer is backed by an array but is read-only
    `UnsupportedOperationException` - If this buffer is not backed by an accessible array

### compact

    public abstract FloatBuffer compact()

  Compacts this buffer (optional operation).

  The floats between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the float at index p = `position()` is copied to index zero, the float at index p + 1 is copied to index one, and so forth until the float at index `limit()` - 1 is copied to index n = `limit()` - `1` - p. The buffer's position is then set to n+1 and its limit is set to its capacity. The mark, if defined, is discarded.

  The buffer's position is set to the number of floats copied, rather than to zero, so that an invocation of this method can be followed immediately by an invocation of another relative put method.

  Returns:
    This buffer
  Throws:
    `ReadOnlyBufferException` - If this buffer is read-only

### isDirect

    public abstract boolean isDirect()

  Tells whether or not this float buffer is direct.

  Returns:
    `true` if, and only if, this buffer is direct

### toString

    public String toString()

  Returns a string summarizing the state of this buffer.

  Overrides:
    `toString` in class `Object`
  Returns:
    A summary string

### hashCode

    public int hashCode()

  Returns the current hash code of this buffer.

  The hash code of a float buffer depends only upon its remaining elements; that is, upon the elements from `position()` up to, and including, the element at `limit()` - `1`.

  Because buffer hash codes are content-dependent, it is inadvisable to use buffers as keys in hash maps or similar data structures unless it is known that their contents will not change.

  Overrides:
    `hashCode` in class `Object`
  Returns:
    The current hash code of this buffer
  See Also:
    `Object.equals(java.lang.Object)`, `Hashtable`

### equals

    public boolean equals(Object ob)

  Tells whether or not this buffer is equal to another object.

  Two float buffers are equal if, and only if,

  1. They have the same element type,

  2. They have the same number of remaining elements, and

  3. The two sequences of remaining elements, considered independently of their starting positions, are pointwise equal.

  A float buffer is not equal to any other type of object.

  Overrides:
    `equals` in class `Object`
  Parameters:
    `ob` - The object to which this buffer is to be compared
  Returns:
    `true` if, and only if, this buffer is equal to the given object
  See Also:
    `Object.hashCode()`, `Hashtable`

### compareTo

    public int compareTo(Object ob)

  Compares this buffer to another object.

  Two float buffers are compared by comparing their sequences of remaining elements lexicographically, without regard to the starting position of each sequence within its corresponding buffer.

  A float buffer is not comparable to any other type of object.

  Specified by:
    `compareTo` in interface `Comparable`
  Parameters:
    `ob` - the Object to be compared.
  Returns:
    A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer
  Throws:
    `ClassCastException` - If the argument is not a float buffer

### order

    public abstract ByteOrder order()

  Retrieves this buffer's byte order.

  The byte order of a float buffer created by allocation or by wrapping an existing `float` array is the ``native order`` of the underlying hardware. The byte order of a float buffer created as a view of a byte buffer is that of the byte buffer at the moment that the view is created.

  Returns:
    This buffer's byte order

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