java.nio

Class FloatBuffer

java.lang.Object

java.nio.Buffer

java.nio.FloatBuffer

All Implemented Interfaces:

Comparable<FloatBuffer>

public abstract class FloatBuffer
extends Buffer
implements Comparable<FloatBuffer>

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

Modifier and Type	Method and Description
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.
FloatBuffer	clear() Clears this buffer.
abstract FloatBuffer	compact() Compacts this buffer (optional operation).
int	compareTo(FloatBuffer that) Compares this buffer to another.
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.
FloatBuffer	flip() Flips this buffer.
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.
FloatBuffer	limit(int newLimit) Sets this buffer's limit.
FloatBuffer	mark() Sets this buffer's mark at its position.
abstract ByteOrder	order() Retrieves this buffer's byte order.
FloatBuffer	position(int newPosition) Sets this buffer's position.
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).
FloatBuffer	reset() Resets this buffer's position to the previously-marked position.
FloatBuffer	rewind() Rewinds this buffer.
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, hasRemaining, isReadOnly, limit, position, remaining

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, its mark will be undefined, each of its elements will be initialized to zero, and its byte order will be the native order of the underlying hardware. 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

Throws:

IllegalArgumentException - If the capacity is a negative integer

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 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, its mark will be undefined, and its byte order will be the native order of the underlying hardware. 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 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, its mark will be undefined, and its byte order will be the native order of the underlying hardware. 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, its mark will be undefined, and its byte order will be identical to that 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

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, mark values, and byte order 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, mark values, and byte order 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) 

Parameters:

dst - The destination array

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:

src - The array from which floats are to be read

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) 

Parameters:

src - The source array

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.

Specified by:

hasArray in class Buffer

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.

Specified by:

array in class Buffer

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.

Specified by:

arrayOffset in class Buffer

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

position

public final FloatBuffer position(int newPosition)

Sets this buffer's position. If the mark is defined and larger than the new position then it is discarded.

Overrides:

position in class Buffer

Parameters:

newPosition - The new position value; must be non-negative and no larger than the current limit

Returns:

This buffer

Since:

1.9

limit

public final FloatBuffer limit(int newLimit)

Sets this buffer's limit. If the position is larger than the new limit then it is set to the new limit. If the mark is defined and larger than the new limit then it is discarded.

Overrides:

limit in class Buffer

Parameters:

newLimit - The new limit value; must be non-negative and no larger than this buffer's capacity

Returns:

This buffer

Since:

1.9

mark

public final FloatBuffer mark()

Sets this buffer's mark at its position.

Overrides:

mark in class Buffer

Returns:

This buffer

Since:

1.9

reset

public final FloatBuffer reset()

Resets this buffer's position to the previously-marked position.

Invoking this method neither changes nor discards the mark's value.

Overrides:

reset in class Buffer

Returns:

This buffer

Since:

1.9

clear

public final FloatBuffer clear()

Clears this buffer. The position is set to zero, the limit is set to the capacity, and the mark is discarded.

Invoke this method before using a sequence of channel-read or put operations to fill this buffer. For example:

 buf.clear();     // Prepare buffer for reading
 in.read(buf);    // Read data

This method does not actually erase the data in the buffer, but it is named as if it did because it will most often be used in situations in which that might as well be the case.

Overrides:

clear in class Buffer

Returns:

This buffer

Since:

1.9

flip

public final FloatBuffer flip()

Flips this buffer. The limit is set to the current position and then the position is set to zero. If the mark is defined then it is discarded.

After a sequence of channel-read or put operations, invoke this method to prepare for a sequence of channel-write or relative get operations. For example:

 buf.put(magic);    // Prepend header
 in.read(buf);      // Read data into rest of buffer
 buf.flip();        // Flip buffer
 out.write(buf);    // Write header + data to channel

This method is often used in conjunction with the compact method when transferring data from one place to another.

Overrides:

flip in class Buffer

Returns:

This buffer

Since:

1.9

rewind

public final FloatBuffer rewind()

Rewinds this buffer. The position is set to zero and the mark is discarded.

Invoke this method before a sequence of channel-write or get operations, assuming that the limit has already been set appropriately. For example:

 out.write(buf);    // Write remaining data
 buf.rewind();      // Rewind buffer
 buf.get(array);    // Copy data into array

Overrides:

rewind in class Buffer

Returns:

This buffer

Since:

1.9

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.

Specified by:

isDirect in class Buffer

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), System.identityHashCode(java.lang.Object)

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. This method considers two float elements a and b to be equal if (a == b) || (Float.isNaN(a) && Float.isNaN(b)). The values -0.0 and +0.0 are considered to be equal, unlike Float.equals(Object).

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(), HashMap

compareTo

public int compareTo(FloatBuffer that)

Compares this buffer to another.

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. Pairs of float elements are compared as if by invoking Float.compare(float,float), except that -0.0 and 0.0 are considered to be equal. Float.NaN is considered by this method to be equal to itself and greater than all other float values (including Float.POSITIVE_INFINITY).

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

Specified by:

compareTo in interface Comparable<FloatBuffer>

Parameters:

that - 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

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