public
abstract
class
ByteBuffer
extends Buffer
implements
Comparable<ByteBuffer>
java.lang.Object | ||
↳ | java.nio.Buffer | |
↳ | java.nio.ByteBuffer |
Known Direct Subclasses |
A byte buffer.
This class defines six categories of operations upon byte buffers:
Absolute and relative get
and
put
methods that read and write
single bytes;
Relative bulk get
methods that transfer contiguous sequences of bytes from this buffer
into an array;
Relative bulk put
methods that transfer contiguous sequences of bytes from a
byte array or some other byte
buffer into this buffer;
Absolute and relative get
and
put
methods that read and
write values of other primitive types, translating them to and from
sequences of bytes in a particular byte order;
Methods for creating view buffers, which allow a byte buffer to be viewed as a buffer containing values of some other primitive type; and
Methods for compacting
,
duplicating
, and
slicing
a byte buffer.
Byte buffers can be created either by A byte buffer is either direct or non-direct. Given a
direct byte buffer, the Java virtual machine will make a best effort to
perform native I/O operations directly upon it. That is, it will attempt to
avoid copying the buffer's content to (or from) an intermediate buffer
before (or after) each invocation of one of the underlying operating
system's native I/O operations.
A direct byte buffer may be created by invoking the allocation
, which allocates space for the buffer's
content, or by
wrapping
an
existing byte array into a buffer.
Direct vs. non-direct buffers
allocateDirect
factory method of this class. The
buffers returned by this method typically have somewhat higher allocation
and deallocation costs than non-direct buffers. The contents of direct
buffers may reside outside of the normal garbage-collected heap, and so
their impact upon the memory footprint of an application might not be
obvious. It is therefore recommended that direct buffers be allocated
primarily for large, long-lived buffers that are subject to the underlying
system's native I/O operations. In general it is best to allocate direct
buffers only when they yield a measureable gain in program performance.
Whether a byte buffer is direct or non-direct may be determined by
invoking its This class defines methods for reading and writing values of all other
primitive types, except boolean. Primitive values are translated
to (or from) sequences of bytes according to the buffer's current byte
order, which may be retrieved and modified via the For access to heterogeneous binary data, that is, sequences of values of
different types, this class defines a family of absolute and relative
get and put methods for each type. For 32-bit floating-point
values, for example, this class defines:
Corresponding methods are defined for the types char,
short, int, long, and double. The index
parameters of the absolute get and put methods are in terms of
bytes rather than of the type being read or written.
For access to homogeneous binary data, that is, sequences of values of
the same type, this class defines methods that can create views of a
given byte buffer. A view buffer is simply another buffer whose
content is backed by the byte buffer. Changes to the byte buffer's content
will be visible in the view buffer, and vice versa; the two buffers'
position, limit, and mark values are independent. The View buffers have three important advantages over the families of
type-specific get and put methods described above:
A view buffer is indexed not in terms of bytes but rather in terms
of the type-specific size of its values; A view buffer provides relative bulk get and put
methods that can transfer contiguous sequences of values between a buffer
and an array or some other buffer of the same type; and A view buffer is potentially much more efficient because it will
be direct if, and only if, its backing byte buffer is direct. The byte order of a view buffer is fixed to be that of its byte buffer
at the time that the view is created. 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.
The sequence of statements
isDirect
method. This method is provided so
that explicit buffer management can be done in performance-critical code.
Access to binary data
order
methods. Specific byte orders are represented by instances of the ByteOrder
class. The initial order of a byte buffer is always BIG_ENDIAN
.
float
getFloat()
float getFloat(int index)
void putFloat(float f)
void putFloat(int index, float f)
asFloatBuffer
method, for example, creates an instance of
the FloatBuffer
class that is backed by the byte buffer upon which
the method is invoked. Corresponding view-creation methods are defined for
the types char, short, int, long, and
double.
Invocation chaining
can, for example, be replaced by the single statement
bb.putInt(0xCAFEBABE);
bb.putShort(3);
bb.putShort(45);
bb.putInt(0xCAFEBABE).putShort(3).putShort(45);
Summary
Public methods | |
---|---|
static
ByteBuffer
|
allocate(int capacity)
Allocates a new byte buffer. |
static
ByteBuffer
|
allocateDirect(int capacity)
Allocates a new direct byte buffer. |
final
byte[]
|
array()
Returns the byte array that backs this buffer (optional operation). |
final
int
|
arrayOffset()
Returns the offset within this buffer's backing array of the first element of the buffer (optional operation). |
abstract
CharBuffer
|
asCharBuffer()
Creates a view of this byte buffer as a char buffer. |
abstract
DoubleBuffer
|
asDoubleBuffer()
Creates a view of this byte buffer as a double buffer. |
abstract
FloatBuffer
|
asFloatBuffer()
Creates a view of this byte buffer as a float buffer. |
abstract
IntBuffer
|
asIntBuffer()
Creates a view of this byte buffer as an int buffer. |
abstract
LongBuffer
|
asLongBuffer()
Creates a view of this byte buffer as a long buffer. |
abstract
ByteBuffer
|
asReadOnlyBuffer()
Creates a new, read-only byte buffer that shares this buffer's content. |
abstract
ShortBuffer
|
asShortBuffer()
Creates a view of this byte buffer as a short buffer. |
abstract
ByteBuffer
|
compact()
Compacts this buffer (optional operation). |
int
|
compareTo(ByteBuffer that)
Compares this buffer to another. |
abstract
ByteBuffer
|
duplicate()
Creates a new byte buffer that shares this buffer's content. |
boolean
|
equals(Object ob)
Tells whether or not this buffer is equal to another object. |
abstract
byte
|
get()
Relative get method. |
ByteBuffer
|
get(byte[] dst, int offset, int length)
Relative bulk get method. |
abstract
byte
|
get(int index)
Absolute get method. |
ByteBuffer
|
get(byte[] dst)
Relative bulk get method. |
abstract
char
|
getChar()
Relative get method for reading a char value. |
abstract
char
|
getChar(int index)
Absolute get method for reading a char value. |
abstract
double
|
getDouble(int index)
Absolute get method for reading a double value. |
abstract
double
|
getDouble()
Relative get method for reading a double value. |
abstract
float
|
getFloat()
Relative get method for reading a float value. |
abstract
float
|
getFloat(int index)
Absolute get method for reading a float value. |
abstract
int
|
getInt(int index)
Absolute get method for reading an int value. |
abstract
int
|
getInt()
Relative get method for reading an int value. |
abstract
long
|
getLong(int index)
Absolute get method for reading a long value. |
abstract
long
|
getLong()
Relative get method for reading a long value. |
abstract
short
|
getShort(int index)
Absolute get method for reading a short value. |
abstract
short
|
getShort()
Relative get method for reading a short value. |
final
boolean
|
hasArray()
Tells whether or not this buffer is backed by an accessible byte array. |
int
|
hashCode()
Returns the current hash code of this buffer. |
abstract
boolean
|
isDirect()
Tells whether or not this byte buffer is direct. |
final
ByteOrder
|
order()
Retrieves this buffer's byte order. |
final
ByteBuffer
|
order(ByteOrder bo)
Modifies this buffer's byte order. |
final
ByteBuffer
|
put(byte[] src)
Relative bulk put method (optional operation). |
abstract
ByteBuffer
|
put(byte b)
Relative put method (optional operation). |
ByteBuffer
|
put(byte[] src, int offset, int length)
Relative bulk put method (optional operation). |
abstract
ByteBuffer
|
put(int index, byte b)
Absolute put method (optional operation). |
ByteBuffer
|
put(ByteBuffer src)
Relative bulk put method (optional operation). |
abstract
ByteBuffer
|
putChar(int index, char value)
Absolute put method for writing a char value (optional operation). |
abstract
ByteBuffer
|
putChar(char value)
Relative put method for writing a char value (optional operation). |
abstract
ByteBuffer
|
putDouble(double value)
Relative put method for writing a double value (optional operation). |
abstract
ByteBuffer
|
putDouble(int index, double value)
Absolute put method for writing a double value (optional operation). |
abstract
ByteBuffer
|
putFloat(int index, float value)
Absolute put method for writing a float value (optional operation). |
abstract
ByteBuffer
|
putFloat(float value)
Relative put method for writing a float value (optional operation). |
abstract
ByteBuffer
|
putInt(int index, int value)
Absolute put method for writing an int value (optional operation). |
abstract
ByteBuffer
|
putInt(int value)
Relative put method for writing an int value (optional operation). |
abstract
ByteBuffer
|
putLong(long value)
Relative put method for writing a long value (optional operation). |
abstract
ByteBuffer
|
putLong(int index, long value)
Absolute put method for writing a long value (optional operation). |
abstract
ByteBuffer
|
putShort(short value)
Relative put method for writing a short value (optional operation). |
abstract
ByteBuffer
|
putShort(int index, short value)
Absolute put method for writing a short value (optional operation). |
abstract
ByteBuffer
|
slice()
Creates a new byte buffer whose content is a shared subsequence of this buffer's content. |
String
|
toString()
Returns a string summarizing the state of this buffer. |
static
ByteBuffer
|
wrap(byte[] array)
Wraps a byte array into a buffer. |
static
ByteBuffer
|
wrap(byte[] array, int offset, int length)
Wraps a byte array into a buffer. |
Inherited methods | |
---|---|
From
class
java.nio.Buffer
| |
From
class
java.lang.Object
| |
From
interface
java.lang.Comparable
|
ByteBuffer allocate (int capacity)
Allocates a new byte buffer.
The new buffer's position will be zero, its limit will be its
capacity, its mark will be undefined, and each of its elements will be
initialized to zero. It will have a backing array
, and its
array
offset
will be zero.
Parameters | |
---|---|
capacity |
int :
The new buffer's capacity, in bytes |
Returns | |
---|---|
ByteBuffer |
The new byte buffer |
Throws | |
---|---|
IllegalArgumentException |
If the capacity is a negative integer |
ByteBuffer allocateDirect (int capacity)
Allocates a new direct byte buffer.
The new buffer's position will be zero, its limit will be its
capacity, its mark will be undefined, and each of its elements will be
initialized to zero. Whether or not it has a
backing array
is unspecified.
Parameters | |
---|---|
capacity |
int :
The new buffer's capacity, in bytes |
Returns | |
---|---|
ByteBuffer |
The new byte buffer |
Throws | |
---|---|
IllegalArgumentException |
If the capacity is a negative integer |
byte[] array ()
Returns the byte 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 | |
---|---|
byte[] |
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 |
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 | |
---|---|
int |
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 |
CharBuffer asCharBuffer ()
Creates a view of this byte buffer as a char buffer.
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 bytes remaining in this buffer divided by two, 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 | |
---|---|
CharBuffer |
A new char buffer |
DoubleBuffer asDoubleBuffer ()
Creates a view of this byte buffer as a double buffer.
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 bytes remaining in this buffer divided by eight, 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 | |
---|---|
DoubleBuffer |
A new double buffer |
FloatBuffer asFloatBuffer ()
Creates a view of this byte buffer as a float buffer.
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 bytes remaining in this buffer divided by four, 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 | |
---|---|
FloatBuffer |
A new float buffer |
IntBuffer asIntBuffer ()
Creates a view of this byte buffer as an int buffer.
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 bytes remaining in this buffer divided by four, 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 | |
---|---|
IntBuffer |
A new int buffer |
LongBuffer asLongBuffer ()
Creates a view of this byte buffer as a long buffer.
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 bytes remaining in this buffer divided by eight, 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 | |
---|---|
LongBuffer |
A new long buffer |
ByteBuffer asReadOnlyBuffer ()
Creates a new, read-only byte 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 | |
---|---|
ByteBuffer |
The new, read-only byte buffer |
ShortBuffer asShortBuffer ()
Creates a view of this byte buffer as a short buffer.
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 bytes remaining in this buffer divided by two, 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 | |
---|---|
ShortBuffer |
A new short buffer |
ByteBuffer compact ()
Compacts this buffer (optional operation).
The bytes between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the byte at index p = position() is copied to index zero, the byte at index p + 1 is copied to index one, and so forth until the byte 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 bytes copied, rather than to zero, so that an invocation of this method can be followed immediately by an invocation of another relative put method.
Invoke this method after writing data from a buffer in case the write was incomplete. The following loop, for example, copies bytes from one channel to another via the buffer buf:
buf.clear(); // Prepare buffer for use while (in.read(buf) >= 0 || buf.position != 0) { buf.flip(); out.write(buf); buf.compact(); // In case of partial write }
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
ReadOnlyBufferException |
If this buffer is read-only |
int compareTo (ByteBuffer that)
Compares this buffer to another.
Two byte 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 byte
elements are compared as if by invoking
compare(byte, byte)
.
A byte buffer is not comparable to any other type of object.
Parameters | |
---|---|
that |
ByteBuffer
|
Returns | |
---|---|
int |
A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer |
ByteBuffer duplicate ()
Creates a new byte 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 | |
---|---|
ByteBuffer |
The new byte buffer |
boolean equals (Object ob)
Tells whether or not this buffer is equal to another object.
Two byte buffers are equal if, and only if,
They have the same element type,
They have the same number of remaining elements, and
The two sequences of remaining elements, considered independently of their starting positions, are pointwise equal.
A byte buffer is not equal to any other type of object.
Parameters | |
---|---|
ob |
Object :
The object to which this buffer is to be compared |
Returns | |
---|---|
boolean |
true if, and only if, this buffer is equal to the given object |
byte get ()
Relative get method. Reads the byte at this buffer's current position, and then increments the position.
Returns | |
---|---|
byte |
The byte at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If the buffer's current position is not smaller than its limit |
ByteBuffer get (byte[] dst, int offset, int length)
Relative bulk get method.
This method transfers bytes from this buffer into the given
destination array. If there are fewer bytes remaining in the
buffer than are required to satisfy the request, that is, if
length > remaining(), then no
bytes are transferred and a BufferUnderflowException
is
thrown.
Otherwise, this method copies length bytes 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 bytes in this buffer and it is potentially much more efficient.
Parameters | |
---|---|
dst |
byte :
The array into which bytes are to be written |
offset |
int :
The offset within the array of the first byte to be
written; must be non-negative and no larger than
dst.length |
length |
int :
The maximum number of bytes to be written to the given
array; must be non-negative and no larger than
dst.length - offset |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than length bytes remaining in this buffer |
IndexOutOfBoundsException |
If the preconditions on the offset and length parameters do not hold |
byte get (int index)
Absolute get method. Reads the byte at the given index.
Parameters | |
---|---|
index |
int :
The index from which the byte will be read |
Returns | |
---|---|
byte |
The byte at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit |
ByteBuffer get (byte[] dst)
Relative bulk get method.
This method transfers bytes 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 |
byte
|
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than length bytes remaining in this buffer |
char getChar ()
Relative get method for reading a char value.
Reads the next two bytes at this buffer's current position, composing them into a char value according to the current byte order, and then increments the position by two.
Returns | |
---|---|
char |
The char value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than two bytes remaining in this buffer |
char getChar (int index)
Absolute get method for reading a char value.
Reads two bytes at the given index, composing them into a char value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
char |
The char value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus one |
double getDouble (int index)
Absolute get method for reading a double value.
Reads eight bytes at the given index, composing them into a double value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
double |
The double value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus seven |
double getDouble ()
Relative get method for reading a double value.
Reads the next eight bytes at this buffer's current position, composing them into a double value according to the current byte order, and then increments the position by eight.
Returns | |
---|---|
double |
The double value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than eight bytes remaining in this buffer |
float getFloat ()
Relative get method for reading a float value.
Reads the next four bytes at this buffer's current position, composing them into a float value according to the current byte order, and then increments the position by four.
Returns | |
---|---|
float |
The float value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than four bytes remaining in this buffer |
float getFloat (int index)
Absolute get method for reading a float value.
Reads four bytes at the given index, composing them into a float value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
float |
The float value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus three |
int getInt (int index)
Absolute get method for reading an int value.
Reads four bytes at the given index, composing them into a int value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
int |
The int value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus three |
int getInt ()
Relative get method for reading an int value.
Reads the next four bytes at this buffer's current position, composing them into an int value according to the current byte order, and then increments the position by four.
Returns | |
---|---|
int |
The int value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than four bytes remaining in this buffer |
long getLong (int index)
Absolute get method for reading a long value.
Reads eight bytes at the given index, composing them into a long value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
long |
The long value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus seven |
long getLong ()
Relative get method for reading a long value.
Reads the next eight bytes at this buffer's current position, composing them into a long value according to the current byte order, and then increments the position by eight.
Returns | |
---|---|
long |
The long value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than eight bytes remaining in this buffer |
short getShort (int index)
Absolute get method for reading a short value.
Reads two bytes at the given index, composing them into a short value according to the current byte order.
Parameters | |
---|---|
index |
int :
The index from which the bytes will be read |
Returns | |
---|---|
short |
The short value at the given index |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus one |
short getShort ()
Relative get method for reading a short value.
Reads the next two bytes at this buffer's current position, composing them into a short value according to the current byte order, and then increments the position by two.
Returns | |
---|---|
short |
The short value at the buffer's current position |
Throws | |
---|---|
BufferUnderflowException |
If there are fewer than two bytes remaining in this buffer |
boolean hasArray ()
Tells whether or not this buffer is backed by an accessible byte array.
If this method returns true then the array
and arrayOffset
methods may safely be invoked.
Returns | |
---|---|
boolean |
true if, and only if, this buffer is backed by an array and is not read-only |
int hashCode ()
Returns the current hash code of this buffer.
The hash code of a byte 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.
Returns | |
---|---|
int |
The current hash code of this buffer |
boolean isDirect ()
Tells whether or not this byte buffer is direct.
Returns | |
---|---|
boolean |
true if, and only if, this buffer is direct |
ByteOrder order ()
Retrieves this buffer's byte order.
The byte order is used when reading or writing multibyte values, and
when creating buffers that are views of this byte buffer. The order of
a newly-created byte buffer is always BIG_ENDIAN
.
Returns | |
---|---|
ByteOrder |
This buffer's byte order |
ByteBuffer order (ByteOrder bo)
Modifies this buffer's byte order.
Parameters | |
---|---|
bo |
ByteOrder :
The new byte order,
either BIG_ENDIAN
or LITTLE_ENDIAN |
Returns | |
---|---|
ByteBuffer |
This buffer |
ByteBuffer put (byte[] src)
Relative bulk put method (optional operation).
This method transfers the entire content of the given source byte 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 |
byte
|
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there is insufficient space in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer put (byte b)
Relative put method (optional operation).
Writes the given byte into this buffer at the current position, and then increments the position.
Parameters | |
---|---|
b |
byte :
The byte to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If this buffer's current position is not smaller than its limit |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer put (byte[] src, int offset, int length)
Relative bulk put method (optional operation).
This method transfers bytes into this buffer from the given
source array. If there are more bytes to be copied from the array
than remain in this buffer, that is, if
length > remaining(), then no
bytes are transferred and a BufferOverflowException
is
thrown.
Otherwise, this method copies length bytes 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 |
byte :
The array from which bytes are to be read |
offset |
int :
The offset within the array of the first byte to be read;
must be non-negative and no larger than array.length |
length |
int :
The number of bytes to be read from the given array;
must be non-negative and no larger than
array.length - offset |
Returns | |
---|---|
ByteBuffer |
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 |
ByteBuffer put (int index, byte b)
Absolute put method (optional operation).
Writes the given byte into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the byte will be written |
b |
byte :
The byte value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer put (ByteBuffer src)
Relative bulk put method (optional operation).
This method transfers the bytes remaining in the given source
buffer into this buffer. If there are more bytes remaining in the
source buffer than in this buffer, that is, if
src.remaining() > remaining(),
then no bytes are transferred and a BufferOverflowException
is thrown.
Otherwise, this method copies n = src.remaining() bytes 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 |
ByteBuffer :
The source buffer from which bytes are to be read;
must not be this buffer |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there is insufficient space in this buffer for the remaining bytes in the source buffer |
IllegalArgumentException |
If the source buffer is this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putChar (int index, char value)
Absolute put method for writing a char value (optional operation).
Writes two bytes containing the given char value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
char :
The char value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus one |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putChar (char value)
Relative put method for writing a char value (optional operation).
Writes two bytes containing the given char value, in the current byte order, into this buffer at the current position, and then increments the position by two.
Parameters | |
---|---|
value |
char :
The char value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than two bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putDouble (double value)
Relative put method for writing a double value (optional operation).
Writes eight bytes containing the given double value, in the current byte order, into this buffer at the current position, and then increments the position by eight.
Parameters | |
---|---|
value |
double :
The double value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than eight bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putDouble (int index, double value)
Absolute put method for writing a double value (optional operation).
Writes eight bytes containing the given double value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
double :
The double value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus seven |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putFloat (int index, float value)
Absolute put method for writing a float value (optional operation).
Writes four bytes containing the given float value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
float :
The float value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus three |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putFloat (float value)
Relative put method for writing a float value (optional operation).
Writes four bytes containing the given float value, in the current byte order, into this buffer at the current position, and then increments the position by four.
Parameters | |
---|---|
value |
float :
The float value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than four bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putInt (int index, int value)
Absolute put method for writing an int value (optional operation).
Writes four bytes containing the given int value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
int :
The int value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus three |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putInt (int value)
Relative put method for writing an int value (optional operation).
Writes four bytes containing the given int value, in the current byte order, into this buffer at the current position, and then increments the position by four.
Parameters | |
---|---|
value |
int :
The int value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than four bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putLong (long value)
Relative put method for writing a long value (optional operation).
Writes eight bytes containing the given long value, in the current byte order, into this buffer at the current position, and then increments the position by eight.
Parameters | |
---|---|
value |
long :
The long value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than eight bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putLong (int index, long value)
Absolute put method for writing a long value (optional operation).
Writes eight bytes containing the given long value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
long :
The long value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus seven |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putShort (short value)
Relative put method for writing a short value (optional operation).
Writes two bytes containing the given short value, in the current byte order, into this buffer at the current position, and then increments the position by two.
Parameters | |
---|---|
value |
short :
The short value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
BufferOverflowException |
If there are fewer than two bytes remaining in this buffer |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer putShort (int index, short value)
Absolute put method for writing a short value (optional operation).
Writes two bytes containing the given short value, in the current byte order, into this buffer at the given index.
Parameters | |
---|---|
index |
int :
The index at which the bytes will be written |
value |
short :
The short value to be written |
Returns | |
---|---|
ByteBuffer |
This buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If index is negative or not smaller than the buffer's limit, minus one |
ReadOnlyBufferException |
If this buffer is read-only |
ByteBuffer slice ()
Creates a new byte 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 bytes 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 | |
---|---|
ByteBuffer |
The new byte buffer |
String toString ()
Returns a string summarizing the state of this buffer.
Returns | |
---|---|
String |
A summary string |
ByteBuffer wrap (byte[] array)
Wraps a byte array into a buffer.
The new buffer will be backed by the given byte 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 |
byte :
The array that will back this buffer |
Returns | |
---|---|
ByteBuffer |
The new byte buffer |
ByteBuffer wrap (byte[] array, int offset, int length)
Wraps a byte array into a buffer.
The new buffer will be backed by the given byte 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 |
byte :
The array that will back the new buffer |
offset |
int :
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 |
int :
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 | |
---|---|
ByteBuffer |
The new byte buffer |
Throws | |
---|---|
IndexOutOfBoundsException |
If the preconditions on the offset and length parameters do not hold |