Package org.apache.dubbo.remoting.buffer

Interface ChannelBuffer

All Superinterfaces:

Comparable<ChannelBuffer>

All Known Implementing Classes:

AbstractChannelBuffer, ByteBufferBackedChannelBuffer, DynamicChannelBuffer, HeapChannelBuffer

public interface ChannelBuffer
extends Comparable<ChannelBuffer>

A random and sequential accessible sequence of zero or more bytes (octets). This interface provides an abstract view for one or more primitive byte arrays (byte[]) and NIO buffers.

Creation of a buffer

It is recommended to create a new buffer using the helper methods in ChannelBuffers rather than calling an individual implementation's constructor.

Random Access Indexing

Just like an ordinary primitive byte array, ChannelBuffer uses zero-based indexing. It means the index of the first byte is always 0 and the index of the last byte is always capacity - 1. For example, to iterate all bytes of a buffer, you can do the following, regardless of its internal implementation:

 ChannelBuffer buffer = ...;
 for (int i = 0; i < buffer.capacity(); i ++) {
     byte b = buffer.getByte(i);
     System.out.println((char) b);
 }
 

Sequential Access Indexing

ChannelBuffer provides two pointer variables to support sequential read and write operations - readerIndex for a read operation and writerIndex for a write operation respectively. The following diagram shows how a buffer is segmented into three areas by the two pointers:

      +-------------------+------------------+------------------+
      | discardable bytes |  readable bytes  |  writable bytes  |
      |                   |     (CONTENT)    |                  |
      +-------------------+------------------+------------------+
      |                   |                  |                  |
      0      invalid input: '<'=      readerIndex   invalid input: '<'=   writerIndex    invalid input: '<'=    capacity
 

Readable bytes (the actual content)

This segment is where the actual data is stored. Any operation whose name starts with read or skip will get or skip the data at the current readerIndex and increase it by the number of read bytes. If the argument of the read operation is also a ChannelBuffer and no destination index is specified, the specified buffer's readerIndex is increased together.

If there's not enough content left, IndexOutOfBoundsException is raised. The default value of newly allocated, wrapped or copied buffer's readerIndex is 0.

 // Iterates the readable bytes of a buffer.
 ChannelBuffer buffer = ...;
 while (buffer.readable()) {
     System.out.println(buffer.readByte());
 }
 

Writable bytes

This segment is a undefined space which needs to be filled. Any operation whose name ends with write will write the data at the current writerIndex and increase it by the number of written bytes. If the argument of the write operation is also a ChannelBuffer, and no source index is specified, the specified buffer's readerIndex is increased together.

If there's not enough writable bytes left, IndexOutOfBoundsException is raised. The default value of newly allocated buffer's writerIndex is 0. The default value of wrapped or copied buffer's writerIndex is the capacity of the buffer.

 // Fills the writable bytes of a buffer with random integers.
 ChannelBuffer buffer = ...;
 while (buffer.writableBytes() >= 4) {
     buffer.writeInt(random.nextInt());
 }
 

Discardable bytes

This segment contains the bytes which were read already by a read operation. Initially, the size of this segment is 0, but its size increases up to the writerIndex as read operations are executed. The read bytes can be discarded by calling discardReadBytes() to reclaim unused area as depicted by the following diagram:

  BEFORE discardReadBytes()

      +-------------------+------------------+------------------+
      | discardable bytes |  readable bytes  |  writable bytes  |
      +-------------------+------------------+------------------+
      |                   |                  |                  |
      0      invalid input: '<'=      readerIndex   invalid input: '<'=   writerIndex    invalid input: '<'=    capacity


  AFTER discardReadBytes()

      +------------------+--------------------------------------+
      |  readable bytes  |    writable bytes (got more space)   |
      +------------------+--------------------------------------+
      |                  |                                      |
 readerIndex (0) invalid input: '<'= writerIndex (decreased)        invalid input: '<'=        capacity
 

Please note that there is no guarantee about the content of writable bytes after calling discardReadBytes(). The writable bytes will not be moved in most cases and could even be filled with completely different data depending on the underlying buffer implementation.

Clearing the buffer indexes

You can set both readerIndex and writerIndex to 0 by calling clear(). It does not clear the buffer content (e.g. filling with 0) but just clears the two pointers. Please also note that the semantic of this operation is different from ByteBuffer.clear().

  BEFORE clear()

      +-------------------+------------------+------------------+
      | discardable bytes |  readable bytes  |  writable bytes  |
      +-------------------+------------------+------------------+
      |                   |                  |                  |
      0      invalid input: '<'=      readerIndex   invalid input: '<'=   writerIndex    invalid input: '<'=    capacity


  AFTER clear()

      +---------------------------------------------------------+
      |             writable bytes (got more space)             |
      +---------------------------------------------------------+
      |                                                         |
      0 = readerIndex = writerIndex            invalid input: '<'=            capacity
 

Mark and reset

There are two marker indexes in every buffer. One is for storing readerIndex and the other is for storing writerIndex. You can always reposition one of the two indexes by calling a reset method. It works in a similar fashion to the mark and reset methods in InputStream except that there's no readlimit.

Conversion to existing JDK types

Byte array

If a ChannelBuffer is backed by a byte array (i.e. byte[]), you can access it directly via the array() method. To determine if a buffer is backed by a byte array, hasArray() should be used.

NIO Buffers

Various toByteBuffer() methods convert a ChannelBuffer into one or more NIO buffers. These methods avoid buffer allocation and memory copy whenever possible, but there's no guarantee that memory copy will not be involved.

I/O Streams

Please refer to ChannelBufferInputStream and ChannelBufferOutputStream.

Method Summary

Modifier and Type	Method	Description
byte[]	array()	Returns the backing byte array of this buffer.
int	arrayOffset()	Returns the offset of the first byte within the backing byte array of this buffer.
int	capacity()	Returns the number of bytes (octets) this buffer can contain.
void	clear()	Sets the readerIndex and writerIndex of this buffer to 0.
ChannelBuffer	copy()	Returns a copy of this buffer's readable bytes.
ChannelBuffer	copy(int index, int length)	Returns a copy of this buffer's sub-region.
void	discardReadBytes()	Discards the bytes between the 0th index and readerIndex.
void	ensureWritableBytes(int writableBytes)	Makes sure the number of the writable bytes is equal to or greater than the specified value.
boolean	equals(Object o)	Determines if the content of the specified buffer is identical to the content of this array.
ChannelBufferFactory	factory()	Returns the factory which creates a ChannelBuffer whose type and default ByteOrder are same with this buffer.
byte	getByte(int index)	Gets a byte at the specified absolute index in this buffer.
void	getBytes(int index, byte[] dst)	Transfers this buffer's data to the specified destination starting at the specified absolute index.
void	getBytes(int index, byte[] dst, int dstIndex, int length)	Transfers this buffer's data to the specified destination starting at the specified absolute index.
void	getBytes(int index, OutputStream dst, int length)	Transfers this buffer's data to the specified stream starting at the specified absolute index.
void	getBytes(int index, ByteBuffer dst)	Transfers this buffer's data to the specified destination starting at the specified absolute index until the destination's position reaches its limit.
void	getBytes(int index, ChannelBuffer dst)	Transfers this buffer's data to the specified destination starting at the specified absolute index until the destination becomes non-writable.
void	getBytes(int index, ChannelBuffer dst, int length)	Transfers this buffer's data to the specified destination starting at the specified absolute index.
void	getBytes(int index, ChannelBuffer dst, int dstIndex, int length)	Transfers this buffer's data to the specified destination starting at the specified absolute index.
boolean	hasArray()	Returns true if and only if this buffer has a backing byte array.
boolean	isDirect()	Returns true if and only if this buffer is backed by an NIO direct buffer.
void	markReaderIndex()	Marks the current readerIndex in this buffer.
void	markWriterIndex()	Marks the current writerIndex in this buffer.
boolean	readable()	Returns true if and only if (this.writerIndex - this.readerIndex) is greater than 0.
int	readableBytes()	Returns the number of readable bytes which is equal to (this.writerIndex - this.readerIndex).
byte	readByte()	Gets a byte at the current readerIndex and increases the readerIndex by 1 in this buffer.
void	readBytes(byte[] dst)	Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= dst.length).
void	readBytes(byte[] dst, int dstIndex, int length)	Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).
ChannelBuffer	readBytes(int length)	Transfers this buffer's data to a newly created buffer starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).
void	readBytes(OutputStream dst, int length)	Transfers this buffer's data to the specified stream starting at the current readerIndex.
void	readBytes(ByteBuffer dst)	Transfers this buffer's data to the specified destination starting at the current readerIndex until the destination's position reaches its limit, and increases the readerIndex by the number of the transferred bytes.
void	readBytes(ChannelBuffer dst)	Transfers this buffer's data to the specified destination starting at the current readerIndex until the destination becomes non-writable, and increases the readerIndex by the number of the transferred bytes.
void	readBytes(ChannelBuffer dst, int length)	Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).
void	readBytes(ChannelBuffer dst, int dstIndex, int length)	Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).
int	readerIndex()	Returns the readerIndex of this buffer.
void	readerIndex(int readerIndex)	Sets the readerIndex of this buffer.
default void	release()	If this buffer is backed by an NIO direct buffer, in some scenarios it may be necessary to manually release.
void	resetReaderIndex()	Repositions the current readerIndex to the marked readerIndex in this buffer.
void	resetWriterIndex()	Marks the current writerIndex in this buffer.
void	setByte(int index, int value)	Sets the specified byte at the specified absolute index in this buffer.
void	setBytes(int index, byte[] src)	Transfers the specified source array's data to this buffer starting at the specified absolute index.
void	setBytes(int index, byte[] src, int srcIndex, int length)	Transfers the specified source array's data to this buffer starting at the specified absolute index.
int	setBytes(int index, InputStream src, int length)	Transfers the content of the specified source stream to this buffer starting at the specified absolute index.
void	setBytes(int index, ByteBuffer src)	Transfers the specified source buffer's data to this buffer starting at the specified absolute index until the source buffer's position reaches its limit.
void	setBytes(int index, ChannelBuffer src)	Transfers the specified source buffer's data to this buffer starting at the specified absolute index until the source buffer becomes unreadable.
void	setBytes(int index, ChannelBuffer src, int length)	Transfers the specified source buffer's data to this buffer starting at the specified absolute index.
void	setBytes(int index, ChannelBuffer src, int srcIndex, int length)	Transfers the specified source buffer's data to this buffer starting at the specified absolute index.
void	setIndex(int readerIndex, int writerIndex)	Sets the readerIndex and writerIndex of this buffer in one shot.
void	skipBytes(int length)	Increases the current readerIndex by the specified length in this buffer.
ByteBuffer	toByteBuffer()	Converts this buffer's readable bytes into a NIO buffer.
ByteBuffer	toByteBuffer(int index, int length)	Converts this buffer's sub-region into a NIO buffer.
boolean	writable()	Returns true if and only if (this.capacity - this.writerIndex) is greater than 0.
int	writableBytes()	Returns the number of writable bytes which is equal to (this.capacity - this.writerIndex).
void	writeByte(int value)	Sets the specified byte at the current writerIndex and increases the writerIndex by 1 in this buffer.
void	writeBytes(byte[] src)	Transfers the specified source array's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= src.length).
void	writeBytes(byte[] src, int index, int length)	Transfers the specified source array's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length).
int	writeBytes(InputStream src, int length)	Transfers the content of the specified stream to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes.
void	writeBytes(ByteBuffer src)	Transfers the specified source buffer's data to this buffer starting at the current writerIndex until the source buffer's position reaches its limit, and increases the writerIndex by the number of the transferred bytes.
void	writeBytes(ChannelBuffer src)	Transfers the specified source buffer's data to this buffer starting at the current writerIndex until the source buffer becomes unreadable, and increases the writerIndex by the number of the transferred bytes.
void	writeBytes(ChannelBuffer src, int length)	Transfers the specified source buffer's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length).
void	writeBytes(ChannelBuffer src, int srcIndex, int length)	Transfers the specified source buffer's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length).
int	writerIndex()	Returns the writerIndex of this buffer.
void	writerIndex(int writerIndex)	Sets the writerIndex of this buffer.

Methods inherited from interface java.lang.Comparable

compareTo

Method Details

capacity

int capacity()

Returns the number of bytes (octets) this buffer can contain.

clear

void clear()

Sets the readerIndex and writerIndex of this buffer to 0. This method is identical to setIndex(0, 0).

Please note that the behavior of this method is different from that of NIO buffer, which sets the limit to the capacity of the buffer.

copy

ChannelBuffer copy()

Returns a copy of this buffer's readable bytes. Modifying the content of the returned buffer or this buffer does not affect each other at all. This method is identical to buf.copy(buf.readerIndex(), buf.readableBytes()). This method does not modify readerIndex or writerIndex of this buffer.

copy

ChannelBuffer copy(int index,
 int length)

Returns a copy of this buffer's sub-region. Modifying the content of the returned buffer or this buffer does not affect each other at all. This method does not modify readerIndex or writerIndex of this buffer.

discardReadBytes

void discardReadBytes()

Discards the bytes between the 0th index and readerIndex. It moves the bytes between readerIndex and writerIndex to the 0th index, and sets readerIndex and writerIndex to 0 and oldWriterIndex - oldReaderIndex respectively.

Please refer to the class documentation for more detailed explanation.

ensureWritableBytes

void ensureWritableBytes(int writableBytes)

Makes sure the number of the writable bytes is equal to or greater than the specified value. If there is enough writable bytes in this buffer, this method returns with no side effect. Otherwise:

• a non-dynamic buffer will throw an IndexOutOfBoundsException.
• a dynamic buffer will expand its capacity so that the number of the writable bytes becomes equal to or greater than the specified value. The expansion involves the reallocation of the internal buffer and consequently memory copy.

Parameters:

writableBytes - the expected minimum number of writable bytes

Throws:

IndexOutOfBoundsException - if the writable bytes of this buffer is less than the specified value and if this buffer is not a dynamic buffer

equals

boolean equals(Object o)

Determines if the content of the specified buffer is identical to the content of this array. 'Identical' here means:

• the size of the contents of the two buffers are same and
• every single byte of the content of the two buffers are same.

Please note that it does not compare readerIndex() nor writerIndex(). This method also returns false for null and an object which is not an instance of ChannelBuffer type.

Overrides:

equals in class Object

factory

ChannelBufferFactory factory()

Returns the factory which creates a ChannelBuffer whose type and default ByteOrder are same with this buffer.

getByte

byte getByte(int index)

Gets a byte at the specified absolute index in this buffer. This method does not modify readerIndex or writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or index + 1 is greater than this.capacity

getBytes

void getBytes(int index,
 byte[] dst)

Transfers this buffer's data to the specified destination starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + dst.length is greater than this.capacity

getBytes

void getBytes(int index,
 byte[] dst,
 int dstIndex,
 int length)

Transfers this buffer's data to the specified destination starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer.

Parameters:

dstIndex - the first index of the destination

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if the specified dstIndex is less than 0, if index + length is greater than this.capacity, or if dstIndex + length is greater than dst.length

getBytes

void getBytes(int index,
 ByteBuffer dst)

Transfers this buffer's data to the specified destination starting at the specified absolute index until the destination's position reaches its limit. This method does not modify readerIndex or writerIndex of this buffer while the destination's position will be increased.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + dst.remaining() is greater than this.capacity

getBytes

void getBytes(int index,
 ChannelBuffer dst)

Transfers this buffer's data to the specified destination starting at the specified absolute index until the destination becomes non-writable. This method is basically same with getBytes(int, ChannelBuffer, int, int), except that this method increases the writerIndex of the destination by the number of the transferred bytes while getBytes(int, ChannelBuffer, int, int) does not. This method does not modify readerIndex or writerIndex of the source buffer (i.e. this).

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + dst.writableBytes is greater than this.capacity

getBytes

void getBytes(int index,
 ChannelBuffer dst,
 int length)

Transfers this buffer's data to the specified destination starting at the specified absolute index. This method is basically same with getBytes(int, ChannelBuffer, int, int), except that this method increases the writerIndex of the destination by the number of the transferred bytes while getBytes(int, ChannelBuffer, int, int) does not. This method does not modify readerIndex or writerIndex of the source buffer (i.e. this).

Parameters:

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if index + length is greater than this.capacity, or if length is greater than dst.writableBytes

getBytes

void getBytes(int index,
 ChannelBuffer dst,
 int dstIndex,
 int length)

Transfers this buffer's data to the specified destination starting at the specified absolute index. This method does not modify readerIndex or writerIndex of both the source (i.e. this) and the destination.

Parameters:

dstIndex - the first index of the destination

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if the specified dstIndex is less than 0, if index + length is greater than this.capacity, or if dstIndex + length is greater than dst.capacity

getBytes

void getBytes(int index,
 OutputStream dst,
 int length)
       throws IOException

Transfers this buffer's data to the specified stream starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer.

Parameters:

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + length is greater than this.capacity

IOException - if the specified stream threw an exception during I/O

isDirect

boolean isDirect()

Returns true if and only if this buffer is backed by an NIO direct buffer.

markReaderIndex

void markReaderIndex()

Marks the current readerIndex in this buffer. You can reposition the current readerIndex to the marked readerIndex by calling resetReaderIndex(). The initial value of the marked readerIndex is 0.

markWriterIndex

void markWriterIndex()

Marks the current writerIndex in this buffer. You can reposition the current writerIndex to the marked writerIndex by calling resetWriterIndex(). The initial value of the marked writerIndex is 0.

readable

boolean readable()

Returns true if and only if (this.writerIndex - this.readerIndex) is greater than 0.

readableBytes

int readableBytes()

Returns the number of readable bytes which is equal to (this.writerIndex - this.readerIndex).

readByte

byte readByte()

Gets a byte at the current readerIndex and increases the readerIndex by 1 in this buffer.

Throws:

IndexOutOfBoundsException - if this.readableBytes is less than 1

readBytes

void readBytes(byte[] dst)

Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= dst.length).

Throws:

IndexOutOfBoundsException - if dst.length is greater than this.readableBytes

readBytes

void readBytes(byte[] dst,
 int dstIndex,
 int length)

Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).

Parameters:

dstIndex - the first index of the destination

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified dstIndex is less than 0, if length is greater than this.readableBytes, or if dstIndex + length is greater than dst.length

readBytes

void readBytes(ByteBuffer dst)

Transfers this buffer's data to the specified destination starting at the current readerIndex until the destination's position reaches its limit, and increases the readerIndex by the number of the transferred bytes.

Throws:

IndexOutOfBoundsException - if dst.remaining() is greater than this.readableBytes

readBytes

void readBytes(ChannelBuffer dst)

Transfers this buffer's data to the specified destination starting at the current readerIndex until the destination becomes non-writable, and increases the readerIndex by the number of the transferred bytes. This method is basically same with readBytes(ChannelBuffer, int, int), except that this method increases the writerIndex of the destination by the number of the transferred bytes while readBytes(ChannelBuffer, int, int) does not.

Throws:

IndexOutOfBoundsException - if dst.writableBytes is greater than this.readableBytes

readBytes

void readBytes(ChannelBuffer dst,
 int length)

Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length). This method is basically same with readBytes(ChannelBuffer, int, int), except that this method increases the writerIndex of the destination by the number of the transferred bytes (= length) while readBytes(ChannelBuffer, int, int) does not.

Throws:

IndexOutOfBoundsException - if length is greater than this.readableBytes or if length is greater than dst.writableBytes

readBytes

void readBytes(ChannelBuffer dst,
 int dstIndex,
 int length)

Transfers this buffer's data to the specified destination starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length).

Parameters:

dstIndex - the first index of the destination

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified dstIndex is less than 0, if length is greater than this.readableBytes, or if dstIndex + length is greater than dst.capacity

readBytes

ChannelBuffer readBytes(int length)

Transfers this buffer's data to a newly created buffer starting at the current readerIndex and increases the readerIndex by the number of the transferred bytes (= length). The returned buffer's readerIndex and writerIndex are 0 and length respectively.

Parameters:

length - the number of bytes to transfer

Returns:

the newly created buffer which contains the transferred bytes

Throws:

IndexOutOfBoundsException - if length is greater than this.readableBytes

resetReaderIndex

void resetReaderIndex()

Repositions the current readerIndex to the marked readerIndex in this buffer.

Throws:

IndexOutOfBoundsException - if the current writerIndex is less than the marked readerIndex

resetWriterIndex

void resetWriterIndex()

Marks the current writerIndex in this buffer. You can reposition the current writerIndex to the marked writerIndex by calling resetWriterIndex(). The initial value of the marked writerIndex is 0.

readerIndex

int readerIndex()

Returns the readerIndex of this buffer.

readerIndex

void readerIndex(int readerIndex)

Sets the readerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified readerIndex is less than 0 or greater than this.writerIndex

readBytes

void readBytes(OutputStream dst,
 int length)
        throws IOException

Transfers this buffer's data to the specified stream starting at the current readerIndex.

Parameters:

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if length is greater than this.readableBytes

IOException - if the specified stream threw an exception during I/O

setByte

void setByte(int index,
 int value)

Sets the specified byte at the specified absolute index in this buffer. The 24 high-order bits of the specified value are ignored. This method does not modify readerIndex or writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or index + 1 is greater than this.capacity

setBytes

void setBytes(int index,
 byte[] src)

Transfers the specified source array's data to this buffer starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + src.length is greater than this.capacity

setBytes

void setBytes(int index,
 byte[] src,
 int srcIndex,
 int length)

Transfers the specified source array's data to this buffer starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if the specified srcIndex is less than 0, if index + length is greater than this.capacity, or if srcIndex + length is greater than src.length

setBytes

void setBytes(int index,
 ByteBuffer src)

Transfers the specified source buffer's data to this buffer starting at the specified absolute index until the source buffer's position reaches its limit. This method does not modify readerIndex or writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + src.remaining() is greater than this.capacity

setBytes

void setBytes(int index,
 ChannelBuffer src)

Transfers the specified source buffer's data to this buffer starting at the specified absolute index until the source buffer becomes unreadable. This method is basically same with setBytes(int, ChannelBuffer, int, int), except that this method increases the readerIndex of the source buffer by the number of the transferred bytes while setBytes(int, ChannelBuffer, int, int) does not. This method does not modify readerIndex or writerIndex of the source buffer (i.e. this).

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + src.readableBytes is greater than this.capacity

setBytes

void setBytes(int index,
 ChannelBuffer src,
 int length)

Transfers the specified source buffer's data to this buffer starting at the specified absolute index. This method is basically same with setBytes(int, ChannelBuffer, int, int), except that this method increases the readerIndex of the source buffer by the number of the transferred bytes while setBytes(int, ChannelBuffer, int, int) does not. This method does not modify readerIndex or writerIndex of the source buffer (i.e. this).

Parameters:

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if index + length is greater than this.capacity, or if length is greater than src.readableBytes

setBytes

void setBytes(int index,
 ChannelBuffer src,
 int srcIndex,
 int length)

Transfers the specified source buffer's data to this buffer starting at the specified absolute index. This method does not modify readerIndex or writerIndex of both the source (i.e. this) and the destination.

Parameters:

srcIndex - the first index of the source

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified index is less than 0, if the specified srcIndex is less than 0, if index + length is greater than this.capacity, or if srcIndex + length is greater than src.capacity

setBytes

int setBytes(int index,
 InputStream src,
 int length)
      throws IOException

Transfers the content of the specified source stream to this buffer starting at the specified absolute index. This method does not modify readerIndex or writerIndex of this buffer.

Parameters:

length - the number of bytes to transfer

Returns:

the actual number of bytes read in from the specified channel. -1 if the specified channel is closed.

Throws:

IndexOutOfBoundsException - if the specified index is less than 0 or if index + length is greater than this.capacity

IOException - if the specified stream threw an exception during I/O

setIndex

void setIndex(int readerIndex,
 int writerIndex)

Sets the readerIndex and writerIndex of this buffer in one shot. This method is useful when you have to worry about the invocation order of readerIndex(int) and writerIndex(int) methods. For example, the following code will fail:

 // Create a buffer whose readerIndex, writerIndex and capacity are
 // 0, 0 and 8 respectively.
 ChannelBuffer buf = ChannelBuffers.buffer(8);

 // IndexOutOfBoundsException is thrown because the specified
 // readerIndex (2) cannot be greater than the current writerIndex (0).
 buf.readerIndex(2);
 buf.writerIndex(4);
 

The following code will also fail:

 // Create a buffer whose readerIndex, writerIndex and capacity are
 // 0, 8 and 8 respectively.
 ChannelBuffer buf = ChannelBuffers.wrappedBuffer(new
 byte[8]);

 // readerIndex becomes 8.
 buf.readLong();

 // IndexOutOfBoundsException is thrown because the specified
 // writerIndex (4) cannot be less than the current readerIndex (8).
 buf.writerIndex(4);
 buf.readerIndex(2);
 

By contrast, setIndex(int, int) guarantees that it never throws an IndexOutOfBoundsException as long as the specified indexes meet basic constraints, regardless what the current index values of the buffer are:

 // No matter what the current state of the buffer is, the following
 // call always succeeds as long as the capacity of the buffer is not
 // less than 4.
 buf.setIndex(2, 4);
 

Throws:

IndexOutOfBoundsException - if the specified readerIndex is less than 0, if the specified writerIndex is less than the specified readerIndex or if the specified writerIndex is greater than this.capacity

skipBytes

void skipBytes(int length)

Increases the current readerIndex by the specified length in this buffer.

Throws:

IndexOutOfBoundsException - if length is greater than this.readableBytes

toByteBuffer

ByteBuffer toByteBuffer()

Converts this buffer's readable bytes into a NIO buffer. The returned buffer might or might not share the content with this buffer, while they have separate indexes and marks. This method is identical to buf.toByteBuffer(buf.readerIndex(), buf.readableBytes()). This method does not modify readerIndex or writerIndex of this buffer.

toByteBuffer

ByteBuffer toByteBuffer(int index,
 int length)

Converts this buffer's sub-region into a NIO buffer. The returned buffer might or might not share the content with this buffer, while they have separate indexes and marks. This method does not modify readerIndex or writerIndex of this buffer.

writable

boolean writable()

Returns true if and only if (this.capacity - this.writerIndex) is greater than 0.

writableBytes

int writableBytes()

Returns the number of writable bytes which is equal to (this.capacity - this.writerIndex).

writeByte

void writeByte(int value)

Sets the specified byte at the current writerIndex and increases the writerIndex by 1 in this buffer. The 24 high-order bits of the specified value are ignored.

Throws:

IndexOutOfBoundsException - if this.writableBytes is less than 1

writeBytes

void writeBytes(byte[] src)

Transfers the specified source array's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= src.length).

Throws:

IndexOutOfBoundsException - if src.length is greater than this.writableBytes

writeBytes

void writeBytes(byte[] src,
 int index,
 int length)

Transfers the specified source array's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length).

Parameters:

index - the first index of the source

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified srcIndex is less than 0, if srcIndex + length is greater than src.length, or if length is greater than this.writableBytes

writeBytes

void writeBytes(ByteBuffer src)

Transfers the specified source buffer's data to this buffer starting at the current writerIndex until the source buffer's position reaches its limit, and increases the writerIndex by the number of the transferred bytes.

Throws:

IndexOutOfBoundsException - if src.remaining() is greater than this.writableBytes

writeBytes

void writeBytes(ChannelBuffer src)

Transfers the specified source buffer's data to this buffer starting at the current writerIndex until the source buffer becomes unreadable, and increases the writerIndex by the number of the transferred bytes. This method is basically same with writeBytes(ChannelBuffer, int, int), except that this method increases the readerIndex of the source buffer by the number of the transferred bytes while writeBytes(ChannelBuffer, int, int) does not.

Throws:

IndexOutOfBoundsException - if src.readableBytes is greater than this.writableBytes

writeBytes

void writeBytes(ChannelBuffer src,
 int length)

Transfers the specified source buffer's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length). This method is basically same with writeBytes(ChannelBuffer, int, int), except that this method increases the readerIndex of the source buffer by the number of the transferred bytes (= length) while writeBytes(ChannelBuffer, int, int) does not.

Parameters:

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if length is greater than this.writableBytes or if length is greater then src.readableBytes

writeBytes

void writeBytes(ChannelBuffer src,
 int srcIndex,
 int length)

Transfers the specified source buffer's data to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes (= length).

Parameters:

srcIndex - the first index of the source

length - the number of bytes to transfer

Throws:

IndexOutOfBoundsException - if the specified srcIndex is less than 0, if srcIndex + length is greater than src.capacity, or if length is greater than this.writableBytes

writeBytes

int writeBytes(InputStream src,
 int length)
        throws IOException

Transfers the content of the specified stream to this buffer starting at the current writerIndex and increases the writerIndex by the number of the transferred bytes.

Parameters:

length - the number of bytes to transfer

Returns:

the actual number of bytes read in from the specified stream

Throws:

IndexOutOfBoundsException - if length is greater than this.writableBytes

IOException - if the specified stream threw an exception during I/O

writerIndex

int writerIndex()

Returns the writerIndex of this buffer.

writerIndex

void writerIndex(int writerIndex)

Sets the writerIndex of this buffer.

Throws:

IndexOutOfBoundsException - if the specified writerIndex is less than this.readerIndex or greater than this.capacity

array

byte[] array()

Returns the backing byte array of this buffer.

Throws:

UnsupportedOperationException - if there is no accessible backing byte array

hasArray

boolean hasArray()

Returns true if and only if this buffer has a backing byte array. If this method returns true, you can safely call array() and arrayOffset().

arrayOffset

int arrayOffset()

Returns the offset of the first byte within the backing byte array of this buffer.

Throws:

UnsupportedOperationException - if there is no accessible backing byte array

release

default void release()

If this buffer is backed by an NIO direct buffer, in some scenarios it may be necessary to manually release.