Added in API level 1

MappedByteBuffer

abstract class MappedByteBuffer : ByteBuffer

kotlin.Any
↳	java.nio.Buffer
	↳	java.nio.ByteBuffer
		↳	java.nio.MappedByteBuffer

A direct byte buffer whose content is a memory-mapped region of a file.

Mapped byte buffers are created via the FileChannel.map method. This class extends the ByteBuffer class with operations that are specific to memory-mapped file regions.

A mapped byte buffer and the file mapping that it represents remain valid until the buffer itself is garbage-collected.

The content of a mapped byte buffer can change at any time, for example if the content of the corresponding region of the mapped file is changed by this program or another. Whether or not such changes occur, and when they occur, is operating-system dependent and therefore unspecified.

All or part of a mapped byte buffer may become inaccessible at any time, for example if the mapped file is truncated. An attempt to access an inaccessible region of a mapped byte buffer will not change the buffer's content and will cause an unspecified exception to be thrown either at the time of the access or at some later time. It is therefore strongly recommended that appropriate precautions be taken to avoid the manipulation of a mapped file by this program, or by a concurrently running program, except to read or write the file's content.

Mapped byte buffers otherwise behave no differently than ordinary direct byte buffers.

Summary

Public methods
Buffer	clear() Clears this buffer.
abstract ByteBuffer	compact() Compacts this buffer  (optional operation).
abstract ByteBuffer	duplicate() Creates a new byte buffer that shares this buffer's content.
Buffer	flip() Flips this buffer.
MappedByteBuffer!	force() Forces any changes made to this buffer's content to be written to the storage device containing the mapped file.
MappedByteBuffer!	force(index: Int, length: Int) Forces any changes made to a region of this buffer's content to be written to the storage device containing the mapped file.
Boolean	isLoaded() Tells whether or not this buffer's content is resident in physical memory.
Buffer	limit(newLimit: Int) Sets this buffer's limit.
MappedByteBuffer!	load() Loads this buffer's content into physical memory.
Buffer	mark() Sets this buffer's mark at its position.
Buffer	position(newPosition: Int) Sets this buffer's position.
Buffer	reset() Resets this buffer's position to the previously-marked position.
Buffer	rewind() Rewinds this buffer.
abstract ByteBuffer	slice() Creates a new byte buffer whose content is a shared subsequence of this buffer's content.
abstract MappedByteBuffer	slice(index: Int, length: Int) Creates a new byte buffer whose content is a shared subsequence of this buffer's content.

Inherited functions
From class ByteBuffer ByteBuffer alignedSlice(unitSize: Int) Creates a new byte buffer whose content is a shared and aligned subsequence of this buffer's content. The content of the new buffer will start at this buffer's current position rounded up to the index of the nearest aligned byte for the given unit size, and end at this buffer's limit rounded down to the index of the nearest aligned byte for the given unit size. If rounding results in out-of-bound values then the new buffer's capacity and limit will be zero. If rounding is within bounds the following expressions will be true for a new buffer nb and unit size unitSize: <code>nb.alignmentOffset(0, unitSize) == 0 nb.alignmentOffset(nb.limit(), unitSize) == 0 </code> 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 or fewer subject to alignment, its mark will be undefined, and its byte order will be BIG_ENDIAN. 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. Int alignmentOffset(index: Int, unitSize: Int) Returns the memory address, pointing to the byte at the given index, modulo the given unit size. The return value is non-negative in the range of 0 (inclusive) up to unitSize (exclusive), with zero indicating that the address of the byte at the index is aligned for the unit size, and a positive value that the address is misaligned for the unit size. If the address of the byte at the index is misaligned, the return value represents how much the index should be adjusted to locate a byte at an aligned address. Specifically, the index should either be decremented by the return value if the latter is not greater than index, or be incremented by the unit size minus the return value. Therefore given int value = alignmentOffset(index, unitSize) then the identities alignmentOffset(index - value, unitSize) == 0, value ≤ index and alignmentOffset(index + (unitSize - value), unitSize) == 0 must hold. ByteBuffer allocate(capacity: Int) Allocates a new byte 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 BIG_ENDIAN. It will have a backing array, and its array offset will be zero. ByteBuffer allocateDirect(capacity: Int) 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, each of its elements will be initialized to zero, and its byte order will be BIG_ENDIAN. Whether or not it has a backing array is unspecified. ByteArray 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. 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. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. 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, and its byte order will be BIG_ENDIAN. If this buffer is itself read-only then this method behaves in exactly the same way as the duplicate method. 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, its mark will be undefined, and its byte order will be that of the byte buffer at the moment the view is created. 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. Int compareTo(other: ByteBuffer) 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 Byte.compare(byte,byte). A byte buffer is not comparable to any other type of object. Boolean equals(other: Any?) 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. Byte get() Relative get method. Reads the byte at this buffer's current position, and then increments the position. ByteBuffer get(dst: ByteArray) 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) ByteBuffer get(dst: ByteArray, offset: Int, length: Int) 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 <code>for (int i = off; i &lt; off + len; i++) dst[i] = src.get(); </code> except that it first checks that there are sufficient bytes in this buffer and it is potentially much more efficient. Byte get(index: Int) Absolute get method. Reads the byte at the given index. ByteBuffer get(index: Int, dst: ByteArray) Absolute bulk get method. This method transfers bytes from this buffer into the given destination array. The position of this buffer is unchanged. An invocation of this method of the form src.get(index, dst) behaves in exactly the same way as the invocation: src.get(index, dst, 0, dst.length) ByteBuffer get(index: Int, dst: ByteArray, offset: Int, length: Int) Absolute bulk get method. This method transfers length bytes from this buffer into the given array, starting at the given index in this buffer and at the given offset in the array. The position of this buffer is unchanged. An invocation of this method of the form src.get(index, dst, offset, length) has exactly the same effect as the following loop except that it first checks the consistency of the supplied parameters and it is potentially much more efficient: <code>for (int i = offset, j = index; i &lt; offset + length; i++, j++) dst[i] = src.get(j); </code> 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. Char getChar(index: Int) 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. 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. Double getDouble(index: Int) 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. 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. Float getFloat(index: Int) 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. 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. Int getInt(index: Int) 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. 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. Long getLong(index: Int) 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. 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. Short getShort(index: Int) 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. 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. 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. Boolean isDirect() Tells whether or not this byte buffer is direct. Int mismatch(that: ByteBuffer) Finds and returns the relative index of the first mismatch between this buffer and a given buffer. The index is relative to the position of each buffer and will be in the range of 0 (inclusive) up to the smaller of the remaining elements in each buffer (exclusive). If the two buffers share a common prefix then the returned index is the length of the common prefix and it follows that there is a mismatch between the two buffers at that index within the respective buffers. If one buffer is a proper prefix of the other then the returned index is the smaller of the remaining elements in each buffer, and it follows that the index is only valid for the buffer with the larger number of remaining elements. Otherwise, there is no mismatch. 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. ByteBuffer order(bo: ByteOrder) Modifies this buffer's byte order. ByteBuffer put(b: Byte) Relative put method  (optional operation). Writes the given byte into this buffer at the current position, and then increments the position. ByteBuffer put(src: ByteArray) 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) ByteBuffer put(src: ByteArray, offset: Int, length: Int) 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 <code>for (int i = off; i &lt; off + len; i++) dst.put(src[i]); </code> except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient. ByteBuffer put(index: Int, b: Byte) Absolute put method  (optional operation). Writes the given byte into this buffer at the given index. ByteBuffer put(index: Int, src: ByteArray) Absolute bulk put method  (optional operation). This method copies bytes into this buffer from the given source array. The position of this buffer is unchanged. An invocation of this method of the form dst.put(index, src) behaves in exactly the same way as the invocation: dst.put(index, src, 0, src.length); ByteBuffer put(index: Int, src: ByteArray, offset: Int, length: Int) Absolute bulk put method  (optional operation). This method transfers length bytes from the given array, starting at the given offset in the array and at the given index in this buffer. The position of this buffer is unchanged. An invocation of this method of the form dst.put(index, src, offset, length) has exactly the same effect as the following loop except that it first checks the consistency of the supplied parameters and it is potentially much more efficient: <code>for (int i = offset, j = index; i &lt; offset + length; i++, j++) dst.put(j, src[i]); </code> ByteBuffer put(index: Int, src: ByteBuffer, offset: Int, length: Int) Absolute bulk put method  (optional operation). This method transfers length bytes into this buffer from the given source buffer, starting at the given offset in the source buffer and the given index in this buffer. The positions of both buffers are unchanged. In other words, an invocation of this method of the form dst.put(index, src, offset, length) has exactly the same effect as the loop <code>for (int i = offset, j = index; i &lt; offset + length; i++, j++) dst.put(j, src.get(i)); </code> except that it first checks the consistency of the supplied parameters and it is potentially much more efficient. If this buffer and the source buffer share the same backing array or memory, then the result will be as if the source elements were first copied to an intermediate location before being written into this buffer. ByteBuffer put(src: ByteBuffer) 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. If this buffer and the source buffer share the same backing array or memory, then the result will be as if the source elements were first copied to an intermediate location before being written into this buffer. ByteBuffer putChar(value: Char) 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. ByteBuffer putChar(index: Int, value: Char) 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. ByteBuffer putDouble(value: Double) 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. ByteBuffer putDouble(index: Int, value: Double) 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. ByteBuffer putFloat(value: Float) 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. ByteBuffer putFloat(index: Int, value: Float) 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. ByteBuffer putInt(value: Int) 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. ByteBuffer putInt(index: Int, value: Int) 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. ByteBuffer putLong(index: Int, value: Long) 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. ByteBuffer putLong(value: Long) 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. ByteBuffer putShort(index: Int, value: Short) 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. ByteBuffer putShort(value: Short) 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. String toString() Returns a string summarizing the state of this buffer. ByteBuffer wrap(array: ByteArray) 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, its mark will be undefined, and its byte order will be BIG_ENDIAN. Its backing array will be the given array, and its array offset will be zero. ByteBuffer wrap(array: ByteArray, offset: Int, length: Int) 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, its mark will be undefined, and its byte order will be BIG_ENDIAN. Its backing array will be the given array, and its array offset will be zero.
From class Buffer Int capacity() Returns this buffer's capacity. Boolean hasRemaining() Tells whether there are any elements between the current position and the limit. Boolean isReadOnly() Tells whether or not this buffer is read-only. Int limit() Returns this buffer's limit. Int position() Returns this buffer's position. Int remaining() Returns the number of elements between the current position and the limit.

Public methods

clear

Added in API level 1

fun clear(): Buffer

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.

Return
Buffer	This buffer

compact

Added in API level 1

abstract fun compact(): ByteBuffer

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:

<code>buf.clear();          // Prepare buffer for use
    while (in.read(buf) &gt;= 0 || buf.position != 0) {
        buf.flip();
        out.write(buf);
        buf.compact();    // In case of partial write
    }
  </code>

Return
ByteBuffer	This buffer

Exceptions
java.nio.ReadOnlyBufferException	If this buffer is read-only

duplicate

Added in API level 1

abstract fun duplicate(): ByteBuffer

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, and its byte order will be BIG_ENDIAN. 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.

Return
ByteBuffer	The new byte buffer

flip

Added in API level 1

fun flip(): Buffer

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.

Return
Buffer	This buffer

force

Added in API level 1

fun force(): MappedByteBuffer!

Forces any changes made to this buffer's content to be written to the storage device containing the mapped file. The region starts at index zero in this buffer and is capacity() bytes.

If the file mapped into this buffer resides on a local storage device then when this method returns it is guaranteed that all changes made to the buffer since it was created, or since this method was last invoked, will have been written to that device.

If the file does not reside on a local device then no such guarantee is made.

If this buffer was not mapped in read/write mode (java.nio.channels.FileChannel.MapMode#READ_WRITE) then invoking this method may have no effect. In particular, the method has no effect for buffers mapped in read-only or private mapping modes. This method may or may not have an effect for implementation-specific mapping modes.

Return
MappedByteBuffer!	This buffer

Exceptions
java.io.UncheckedIOException	If an I/O error occurs writing the buffer's content to the storage device containing the mapped file

force

Added in API level 35

fun force(
    index: Int, 
    length: Int
): MappedByteBuffer!

Forces any changes made to a region of this buffer's content to be written to the storage device containing the mapped file. The region starts at the given index in this buffer and is length bytes.

If the file mapped into this buffer resides on a local storage device then when this method returns it is guaranteed that all changes made to the selected region buffer since it was created, or since this method was last invoked, will have been written to that device. The force operation is free to write bytes that lie outside the specified region, for example to ensure that data blocks of some device-specific granularity are transferred in their entirety.

If the file does not reside on a local device then no such guarantee is made.

If this buffer was not mapped in read/write mode (java.nio.channels.FileChannel.MapMode#READ_WRITE) then invoking this method may have no effect. In particular, the method has no effect for buffers mapped in read-only or private mapping modes. This method may or may not have an effect for implementation-specific mapping modes.

Parameters
index	Int: The index of the first byte in the buffer region that is to be written back to storage; must be non-negative and less than capacity()
length	Int: The length of the region in bytes; must be non-negative and no larger than capacity() - index

Return
MappedByteBuffer!	This buffer

Exceptions
java.lang.IndexOutOfBoundsException	if the preconditions on the index and length do not hold.
java.io.UncheckedIOException	If an I/O error occurs writing the buffer's content to the storage device containing the mapped file

isLoaded

Added in API level 1

fun isLoaded(): Boolean

Tells whether or not this buffer's content is resident in physical memory.

A return value of true implies that it is highly likely that all of the data in this buffer is resident in physical memory and may therefore be accessed without incurring any virtual-memory page faults or I/O operations. A return value of false does not necessarily imply that the buffer's content is not resident in physical memory.

The returned value is a hint, rather than a guarantee, because the underlying operating system may have paged out some of the buffer's data by the time that an invocation of this method returns.

Return
Boolean	true if it is likely that this buffer's content is resident in physical memory

limit

Added in API level 1

fun limit(newLimit: Int): Buffer

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.

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

Return
Buffer	This buffer

Exceptions
java.lang.IllegalArgumentException	If the preconditions on newLimit do not hold

load

Added in API level 1

fun load(): MappedByteBuffer!

Loads this buffer's content into physical memory.

This method makes a best effort to ensure that, when it returns, this buffer's content is resident in physical memory. Invoking this method may cause some number of page faults and I/O operations to occur.

Return
MappedByteBuffer!	This buffer

mark

Added in API level 1

fun mark(): Buffer

Sets this buffer's mark at its position.

Return
Buffer	This buffer

position

Added in API level 1

fun position(newPosition: Int): Buffer

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

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

Return
Buffer	This buffer

Exceptions
java.lang.IllegalArgumentException	If the preconditions on newPosition do not hold

reset

Added in API level 1

fun reset(): Buffer

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

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

Return
Buffer	This buffer

Exceptions
java.nio.InvalidMarkException	If the mark has not been set

rewind

Added in API level 1

fun rewind(): Buffer

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

Return
Buffer	This buffer

slice

Added in API level 1

abstract fun slice(): ByteBuffer

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, its mark will be undefined, and its byte order will be BIG_ENDIAN. 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.

Reading bytes into physical memory by invoking load() on the returned buffer, or writing bytes to the storage device by invoking force() on the returned buffer, will only act on the sub-range of this buffer that the returned buffer represents, namely [position(),limit()).

Return
ByteBuffer	The new byte buffer

slice

Added in API level 34

abstract fun slice(
    index: Int, 
    length: Int
): MappedByteBuffer

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 position index in this buffer, and will contain length elements. 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 length, its mark will be undefined, and its byte order will be BIG_ENDIAN. 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.

Reading bytes into physical memory by invoking load() on the returned buffer, or writing bytes to the storage device by invoking force() on the returned buffer, will only act on the sub-range of this buffer that the returned buffer represents, namely [index,index+length), where index and length are assumed to satisfy the preconditions.

Parameters
index	Int: The position in this buffer at which the content of the new buffer will start; must be non-negative and no larger than limit()
length	Int: The number of elements the new buffer will contain; must be non-negative and no larger than limit() - index

Return
MappedByteBuffer	The new buffer

Exceptions
java.lang.IndexOutOfBoundsException	If index is negative or greater than limit(), length is negative, or length > limit() - index