dubbo ChannelBuffer 源码
dubbo ChannelBuffer 代码
文件路径：/dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/buffer/ChannelBuffer.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.dubbo.remoting.buffer;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
/**
* 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 ({@code byte[]}) and {@linkplain ByteBuffer NIO buffers}.
* <p/>
* <h3>Creation of a buffer</h3>
* <p/>
* It is recommended to create a new buffer using the helper methods in {@link
* ChannelBuffers} rather than calling an individual implementation's
* constructor.
* <p/>
* <h3>Random Access Indexing</h3>
* <p/>
* Just like an ordinary primitive byte array, {@link ChannelBuffer} uses <a
* href="http://en.wikipedia.org/wiki/Index_(information_technology)#Array_element_identifier">zero-based
* indexing</a>. It means the index of the first byte is always {@code 0} and
* the index of the last byte is always {@link #capacity() capacity - 1}. For
* example, to iterate all bytes of a buffer, you can do the following,
* regardless of its internal implementation:
* <p/>
* <pre>
* {@link ChannelBuffer} buffer = ...;
* for (int i = 0; i < buffer.capacity(); i ++</strong>) {
* byte b = buffer.getByte(i);
* System.out.println((char) b);
* }
* </pre>
* <p/>
* <h3>Sequential Access Indexing</h3>
* <p/>
* {@link ChannelBuffer} provides two pointer variables to support sequential
* read and write operations - {@link #readerIndex() readerIndex} for a read
* operation and {@link #writerIndex() writerIndex} for a write operation
* respectively. The following diagram shows how a buffer is segmented into
* three areas by the two pointers:
* <p/>
* <pre>
* +-------------------+------------------+------------------+
* | discardable bytes | readable bytes | writable bytes |
* | | (CONTENT) | |
* +-------------------+------------------+------------------+
* | | | |
* 0 <= readerIndex <= writerIndex <= capacity
* </pre>
* <p/>
* <h4>Readable bytes (the actual content)</h4>
* <p/>
* This segment is where the actual data is stored. Any operation whose name
* starts with {@code read} or {@code skip} will get or skip the data at the
* current {@link #readerIndex() readerIndex} and increase it by the number of
* read bytes. If the argument of the read operation is also a {@link
* ChannelBuffer} and no destination index is specified, the specified buffer's
* {@link #readerIndex() readerIndex} is increased together.
* <p/>
* If there's not enough content left, {@link IndexOutOfBoundsException} is
* raised. The default value of newly allocated, wrapped or copied buffer's
* {@link #readerIndex() readerIndex} is {@code 0}.
* <p/>
* <pre>
* // Iterates the readable bytes of a buffer.
* {@link ChannelBuffer} buffer = ...;
* while (buffer.readable()) {
* System.out.println(buffer.readByte());
* }
* </pre>
* <p/>
* <h4>Writable bytes</h4>
* <p/>
* This segment is a undefined space which needs to be filled. Any operation
* whose name ends with {@code write} will write the data at the current {@link
* #writerIndex() writerIndex} and increase it by the number of written bytes.
* If the argument of the write operation is also a {@link ChannelBuffer}, and
* no source index is specified, the specified buffer's {@link #readerIndex()
* readerIndex} is increased together.
* <p/>
* If there's not enough writable bytes left, {@link IndexOutOfBoundsException}
* is raised. The default value of newly allocated buffer's {@link
* #writerIndex() writerIndex} is {@code 0}. The default value of wrapped or
* copied buffer's {@link #writerIndex() writerIndex} is the {@link #capacity()
* capacity} of the buffer.
* <p/>
* <pre>
* // Fills the writable bytes of a buffer with random integers.
* {@link ChannelBuffer} buffer = ...;
* while (buffer.writableBytes() >= 4) {
* buffer.writeInt(random.nextInt());
* }
* </pre>
* <p/>
* <h4>Discardable bytes</h4>
* <p/>
* This segment contains the bytes which were read already by a read operation.
* Initially, the size of this segment is {@code 0}, but its size increases up
* to the {@link #writerIndex() writerIndex} as read operations are executed.
* The read bytes can be discarded by calling {@link #discardReadBytes()} to
* reclaim unused area as depicted by the following diagram:
* <p/>
* <pre>
* BEFORE discardReadBytes()
*
* +-------------------+------------------+------------------+
* | discardable bytes | readable bytes | writable bytes |
* +-------------------+------------------+------------------+
* | | | |
* 0 <= readerIndex <= writerIndex <= capacity
*
*
* AFTER discardReadBytes()
*
* +------------------+--------------------------------------+
* | readable bytes | writable bytes (got more space) |
* +------------------+--------------------------------------+
* | | |
* readerIndex (0) <= writerIndex (decreased) <= capacity
* </pre>
* <p/>
* Please note that there is no guarantee about the content of writable bytes
* after calling {@link #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.
* <p/>
* <h4>Clearing the buffer indexes</h4>
* <p/>
* You can set both {@link #readerIndex() readerIndex} and {@link #writerIndex()
* writerIndex} to {@code 0} by calling {@link #clear()}. It does not clear the
* buffer content (e.g. filling with {@code 0}) but just clears the two
* pointers. Please also note that the semantic of this operation is different
* from {@link ByteBuffer#clear()}.
* <p/>
* <pre>
* BEFORE clear()
*
* +-------------------+------------------+------------------+
* | discardable bytes | readable bytes | writable bytes |
* +-------------------+------------------+------------------+
* | | | |
* 0 <= readerIndex <= writerIndex <= capacity
*
*
* AFTER clear()
*
* +---------------------------------------------------------+
* | writable bytes (got more space) |
* +---------------------------------------------------------+
* | |
* 0 = readerIndex = writerIndex <= capacity
* </pre>
* <p/>
* <h3>Mark and reset</h3>
* <p/>
* There are two marker indexes in every buffer. One is for storing {@link
* #readerIndex() readerIndex} and the other is for storing {@link
* #writerIndex() 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 {@link InputStream} except that there's no {@code
* readlimit}.
* <p/>
* <h3>Conversion to existing JDK types</h3>
* <p/>
* <h4>Byte array</h4>
* <p/>
* If a {@link ChannelBuffer} is backed by a byte array (i.e. {@code byte[]}),
* you can access it directly via the {@link #array()} method. To determine if
* a buffer is backed by a byte array, {@link #hasArray()} should be used.
* <p/>
* <h4>NIO Buffers</h4>
* <p/>
* Various {@link #toByteBuffer()} methods convert a {@link 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.
* <p/>
* <h4>I/O Streams</h4>
* <p/>
* Please refer to {@link ChannelBufferInputStream} and {@link
* ChannelBufferOutputStream}.
*
*
*/
public interface ChannelBuffer extends Comparable<ChannelBuffer> {
/**
* Returns the number of bytes (octets) this buffer can contain.
*/
int capacity();
/**
* Sets the {@code readerIndex} and {@code writerIndex} of this buffer to
* {@code 0}. This method is identical to {@link #setIndex(int, int)
* setIndex(0, 0)}.
* <p/>
* Please note that the behavior of this method is different from that of
* NIO buffer, which sets the {@code limit} to the {@code capacity} of the
* buffer.
*/
void clear();
/**
* 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 {@code buf.copy(buf.readerIndex(),
* buf.readableBytes())}. This method does not modify {@code readerIndex} or
* {@code writerIndex} of this buffer.
*/
ChannelBuffer copy();
/**
* 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 {@code readerIndex} or {@code writerIndex} of this
* buffer.
*/
ChannelBuffer copy(int index, int length);
/**
* Discards the bytes between the 0th index and {@code readerIndex}. It
* moves the bytes between {@code readerIndex} and {@code writerIndex} to
* the 0th index, and sets {@code readerIndex} and {@code writerIndex} to
* {@code 0} and {@code oldWriterIndex - oldReaderIndex} respectively.
* <p/>
* Please refer to the class documentation for more detailed explanation.
*/
void discardReadBytes();
/**
* Makes sure the number of {@linkplain #writableBytes() 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: <ul> <li>a non-dynamic buffer will throw an {@link
* IndexOutOfBoundsException}.</li> <li>a dynamic buffer will expand its
* capacity so that the number of the {@link #writableBytes() writable
* bytes} becomes equal to or greater than the specified value. The
* expansion involves the reallocation of the internal buffer and
* consequently memory copy.</li> </ul>
*
* @param writableBytes the expected minimum number of writable bytes
* @throws IndexOutOfBoundsException if {@linkplain #writableBytes() the
* writable bytes} of this buffer is less
* than the specified value and if this
* buffer is not a dynamic buffer
*/
void ensureWritableBytes(int writableBytes);
/**
* Determines if the content of the specified buffer is identical to the
* content of this array. 'Identical' here means: <ul> <li>the size of the
* contents of the two buffers are same and</li> <li>every single byte of
* the content of the two buffers are same.</li> </ul> Please note that it
* does not compare {@link #readerIndex()} nor {@link #writerIndex()}. This
* method also returns {@code false} for {@code null} and an object which is
* not an instance of {@link ChannelBuffer} type.
*/
@Override
boolean equals(Object o);
/**
* Returns the factory which creates a {@link ChannelBuffer} whose type and
* default {@link java.nio.ByteOrder} are same with this buffer.
*/
ChannelBufferFactory factory();
/**
* Gets a byte at the specified absolute {@code index} in this buffer. This
* method does not modify {@code readerIndex} or {@code writerIndex} of this
* buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or {@code index + 1} is
* greater than {@code this.capacity}
*/
byte getByte(int index);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of this buffer
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* dst.length} is greater than {@code
* this.capacity}
*/
void getBytes(int index, byte[] dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of this buffer.
*
* @param dstIndex the first index of the destination
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if the specified {@code
* dstIndex} is less than {@code 0}, if
* {@code index + length} is greater than
* {@code this.capacity}, or if {@code
* dstIndex + length} is greater than
* {@code dst.length}
*/
void getBytes(int index, byte[] dst, int dstIndex, int length);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index} until the destination's position reaches
* its limit. This method does not modify {@code readerIndex} or {@code
* writerIndex} of this buffer while the destination's {@code position} will
* be increased.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* dst.remaining()} is greater than {@code
* this.capacity}
*/
void getBytes(int index, ByteBuffer dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index} until the destination becomes
* non-writable. This method is basically same with {@link #getBytes(int,
* ChannelBuffer, int, int)}, except that this method increases the {@code
* writerIndex} of the destination by the number of the transferred bytes
* while {@link #getBytes(int, ChannelBuffer, int, int)} does not. This
* method does not modify {@code readerIndex} or {@code writerIndex} of the
* source buffer (i.e. {@code this}).
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* dst.writableBytes} is greater than
* {@code this.capacity}
*/
void getBytes(int index, ChannelBuffer dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index}. This method is basically same with
* {@link #getBytes(int, ChannelBuffer, int, int)}, except that this method
* increases the {@code writerIndex} of the destination by the number of the
* transferred bytes while {@link #getBytes(int, ChannelBuffer, int, int)}
* does not. This method does not modify {@code readerIndex} or {@code
* writerIndex} of the source buffer (i.e. {@code this}).
*
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if {@code index +
* length} is greater than {@code
* this.capacity}, or if {@code length} is
* greater than {@code dst.writableBytes}
*/
void getBytes(int index, ChannelBuffer dst, int length);
/**
* Transfers this buffer's data to the specified destination starting at the
* specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of both the source (i.e. {@code
* this}) and the destination.
*
* @param dstIndex the first index of the destination
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if the specified {@code
* dstIndex} is less than {@code 0}, if
* {@code index + length} is greater than
* {@code this.capacity}, or if {@code
* dstIndex + length} is greater than
* {@code dst.capacity}
*/
void getBytes(int index, ChannelBuffer dst, int dstIndex, int length);
/**
* Transfers this buffer's data to the specified stream starting at the
* specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of this buffer.
*
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* length} is greater than {@code
* this.capacity}
* @throws IOException if the specified stream threw an
* exception during I/O
*/
void getBytes(int index, OutputStream dst, int length) throws IOException;
/**
* Returns {@code true} if and only if this buffer is backed by an NIO
* direct buffer.
*/
boolean isDirect();
/**
* Marks the current {@code readerIndex} in this buffer. You can reposition
* the current {@code readerIndex} to the marked {@code readerIndex} by
* calling {@link #resetReaderIndex()}. The initial value of the marked
* {@code readerIndex} is {@code 0}.
*/
void markReaderIndex();
/**
* Marks the current {@code writerIndex} in this buffer. You can reposition
* the current {@code writerIndex} to the marked {@code writerIndex} by
* calling {@link #resetWriterIndex()}. The initial value of the marked
* {@code writerIndex} is {@code 0}.
*/
void markWriterIndex();
/**
* Returns {@code true} if and only if {@code (this.writerIndex -
* this.readerIndex)} is greater than {@code 0}.
*/
boolean readable();
/**
* Returns the number of readable bytes which is equal to {@code
* (this.writerIndex - this.readerIndex)}.
*/
int readableBytes();
/**
* Gets a byte at the current {@code readerIndex} and increases the {@code
* readerIndex} by {@code 1} in this buffer.
*
* @throws IndexOutOfBoundsException if {@code this.readableBytes} is less
* than {@code 1}
*/
byte readByte();
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} and increases the {@code readerIndex} by the
* number of the transferred bytes (= {@code dst.length}).
*
* @throws IndexOutOfBoundsException if {@code dst.length} is greater than
* {@code this.readableBytes}
*/
void readBytes(byte[] dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} and increases the {@code readerIndex} by the
* number of the transferred bytes (= {@code length}).
*
* @param dstIndex the first index of the destination
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code dstIndex} is
* less than {@code 0}, if {@code length}
* is greater than {@code this.readableBytes},
* or if {@code dstIndex + length} is
* greater than {@code dst.length}
*/
void readBytes(byte[] dst, int dstIndex, int length);
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} until the destination's position reaches its
* limit, and increases the {@code readerIndex} by the number of the
* transferred bytes.
*
* @throws IndexOutOfBoundsException if {@code dst.remaining()} is greater
* than {@code this.readableBytes}
*/
void readBytes(ByteBuffer dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} until the destination becomes non-writable,
* and increases the {@code readerIndex} by the number of the transferred
* bytes. This method is basically same with {@link
* #readBytes(ChannelBuffer, int, int)}, except that this method increases
* the {@code writerIndex} of the destination by the number of the
* transferred bytes while {@link #readBytes(ChannelBuffer, int, int)} does
* not.
*
* @throws IndexOutOfBoundsException if {@code dst.writableBytes} is greater
* than {@code this.readableBytes}
*/
void readBytes(ChannelBuffer dst);
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} and increases the {@code readerIndex} by the
* number of the transferred bytes (= {@code length}). This method is
* basically same with {@link #readBytes(ChannelBuffer, int, int)}, except
* that this method increases the {@code writerIndex} of the destination by
* the number of the transferred bytes (= {@code length}) while {@link
* #readBytes(ChannelBuffer, int, int)} does not.
*
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.readableBytes} or if {@code
* length} is greater than {@code
* dst.writableBytes}
*/
void readBytes(ChannelBuffer dst, int length);
/**
* Transfers this buffer's data to the specified destination starting at the
* current {@code readerIndex} and increases the {@code readerIndex} by the
* number of the transferred bytes (= {@code length}).
*
* @param dstIndex the first index of the destination
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code dstIndex} is
* less than {@code 0}, if {@code length}
* is greater than {@code this.readableBytes},
* or if {@code dstIndex + length} is
* greater than {@code dst.capacity}
*/
void readBytes(ChannelBuffer dst, int dstIndex, int length);
/**
* Transfers this buffer's data to a newly created buffer starting at the
* current {@code readerIndex} and increases the {@code readerIndex} by the
* number of the transferred bytes (= {@code length}). The returned buffer's
* {@code readerIndex} and {@code writerIndex} are {@code 0} and {@code
* length} respectively.
*
* @param length the number of bytes to transfer
* @return the newly created buffer which contains the transferred bytes
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.readableBytes}
*/
ChannelBuffer readBytes(int length);
/**
* Repositions the current {@code readerIndex} to the marked {@code
* readerIndex} in this buffer.
*
* @throws IndexOutOfBoundsException if the current {@code writerIndex} is
* less than the marked {@code
* readerIndex}
*/
void resetReaderIndex();
/**
* Marks the current {@code writerIndex} in this buffer. You can reposition
* the current {@code writerIndex} to the marked {@code writerIndex} by
* calling {@link #resetWriterIndex()}. The initial value of the marked
* {@code writerIndex} is {@code 0}.
*/
void resetWriterIndex();
/**
* Returns the {@code readerIndex} of this buffer.
*/
int readerIndex();
/**
* Sets the {@code readerIndex} of this buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code readerIndex} is
* less than {@code 0} or greater than
* {@code this.writerIndex}
*/
void readerIndex(int readerIndex);
/**
* Transfers this buffer's data to the specified stream starting at the
* current {@code readerIndex}.
*
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.readableBytes}
* @throws IOException if the specified stream threw an
* exception during I/O
*/
void readBytes(OutputStream dst, int length) throws IOException;
/**
* Sets the specified byte at the specified absolute {@code index} in this
* buffer. The 24 high-order bits of the specified value are ignored. This
* method does not modify {@code readerIndex} or {@code writerIndex} of this
* buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or {@code index + 1} is
* greater than {@code this.capacity}
*/
void setByte(int index, int value);
/**
* Transfers the specified source array's data to this buffer starting at
* the specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of this buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* src.length} is greater than {@code
* this.capacity}
*/
void setBytes(int index, byte[] src);
/**
* Transfers the specified source array's data to this buffer starting at
* the specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of this buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if the specified {@code
* srcIndex} is less than {@code 0}, if
* {@code index + length} is greater than
* {@code this.capacity}, or if {@code
* srcIndex + length} is greater than
* {@code src.length}
*/
void setBytes(int index, byte[] src, int srcIndex, int length);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the specified absolute {@code index} until the source buffer's position
* reaches its limit. This method does not modify {@code readerIndex} or
* {@code writerIndex} of this buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* src.remaining()} is greater than {@code
* this.capacity}
*/
void setBytes(int index, ByteBuffer src);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the specified absolute {@code index} until the source buffer becomes
* unreadable. This method is basically same with {@link #setBytes(int,
* ChannelBuffer, int, int)}, except that this method increases the {@code
* readerIndex} of the source buffer by the number of the transferred bytes
* while {@link #setBytes(int, ChannelBuffer, int, int)} does not. This
* method does not modify {@code readerIndex} or {@code writerIndex} of the
* source buffer (i.e. {@code this}).
*
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* src.readableBytes} is greater than
* {@code this.capacity}
*/
void setBytes(int index, ChannelBuffer src);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the specified absolute {@code index}. This method is basically same with
* {@link #setBytes(int, ChannelBuffer, int, int)}, except that this method
* increases the {@code readerIndex} of the source buffer by the number of
* the transferred bytes while {@link #setBytes(int, ChannelBuffer, int,
* int)} does not. This method does not modify {@code readerIndex} or {@code
* writerIndex} of the source buffer (i.e. {@code this}).
*
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if {@code index +
* length} is greater than {@code
* this.capacity}, or if {@code length} is
* greater than {@code src.readableBytes}
*/
void setBytes(int index, ChannelBuffer src, int length);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the specified absolute {@code index}. This method does not modify {@code
* readerIndex} or {@code writerIndex} of both the source (i.e. {@code
* this}) and the destination.
*
* @param srcIndex the first index of the source
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0}, if the specified {@code
* srcIndex} is less than {@code 0}, if
* {@code index + length} is greater than
* {@code this.capacity}, or if {@code
* srcIndex + length} is greater than
* {@code src.capacity}
*/
void setBytes(int index, ChannelBuffer src, int srcIndex, int length);
/**
* Transfers the content of the specified source stream to this buffer
* starting at the specified absolute {@code index}. This method does not
* modify {@code readerIndex} or {@code writerIndex} of this buffer.
*
* @param length the number of bytes to transfer
* @return the actual number of bytes read in from the specified channel.
* {@code -1} if the specified channel is closed.
* @throws IndexOutOfBoundsException if the specified {@code index} is less
* than {@code 0} or if {@code index +
* length} is greater than {@code
* this.capacity}
* @throws IOException if the specified stream threw an
* exception during I/O
*/
int setBytes(int index, InputStream src, int length) throws IOException;
/**
* Sets the {@code readerIndex} and {@code writerIndex} of this buffer in
* one shot. This method is useful when you have to worry about the
* invocation order of {@link #readerIndex(int)} and {@link
* #writerIndex(int)} methods. For example, the following code will fail:
* <p/>
* <pre>
* // Create a buffer whose readerIndex, writerIndex and capacity are
* // 0, 0 and 8 respectively.
* {@link ChannelBuffer} buf = {@link 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);
* </pre>
* <p/>
* The following code will also fail:
* <p/>
* <pre>
* // Create a buffer whose readerIndex, writerIndex and capacity are
* // 0, 8 and 8 respectively.
* {@link ChannelBuffer} buf = {@link 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);
* </pre>
* <p/>
* By contrast, {@link #setIndex(int, int)} guarantees that it never throws
* an {@link IndexOutOfBoundsException} as long as the specified indexes
* meet basic constraints, regardless what the current index values of the
* buffer are:
* <p/>
* <pre>
* // 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);
* </pre>
*
* @throws IndexOutOfBoundsException if the specified {@code readerIndex} is
* less than 0, if the specified {@code
* writerIndex} is less than the specified
* {@code readerIndex} or if the specified
* {@code writerIndex} is greater than
* {@code this.capacity}
*/
void setIndex(int readerIndex, int writerIndex);
/**
* Increases the current {@code readerIndex} by the specified {@code length}
* in this buffer.
*
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.readableBytes}
*/
void skipBytes(int length);
/**
* 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 {@code
* buf.toByteBuffer(buf.readerIndex(), buf.readableBytes())}. This method
* does not modify {@code readerIndex} or {@code writerIndex} of this
* buffer.
*/
ByteBuffer toByteBuffer();
/**
* 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 {@code
* readerIndex} or {@code writerIndex} of this buffer.
*/
ByteBuffer toByteBuffer(int index, int length);
/**
* Returns {@code true} if and only if {@code (this.capacity -
* this.writerIndex)} is greater than {@code 0}.
*/
boolean writable();
/**
* Returns the number of writable bytes which is equal to {@code
* (this.capacity - this.writerIndex)}.
*/
int writableBytes();
/**
* Sets the specified byte at the current {@code writerIndex} and increases
* the {@code writerIndex} by {@code 1} in this buffer. The 24 high-order
* bits of the specified value are ignored.
*
* @throws IndexOutOfBoundsException if {@code this.writableBytes} is less
* than {@code 1}
*/
void writeByte(int value);
/**
* Transfers the specified source array's data to this buffer starting at
* the current {@code writerIndex} and increases the {@code writerIndex} by
* the number of the transferred bytes (= {@code src.length}).
*
* @throws IndexOutOfBoundsException if {@code src.length} is greater than
* {@code this.writableBytes}
*/
void writeBytes(byte[] src);
/**
* Transfers the specified source array's data to this buffer starting at
* the current {@code writerIndex} and increases the {@code writerIndex} by
* the number of the transferred bytes (= {@code length}).
*
* @param index the first index of the source
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code srcIndex} is
* less than {@code 0}, if {@code srcIndex
* + length} is greater than {@code
* src.length}, or if {@code length} is
* greater than {@code this.writableBytes}
*/
void writeBytes(byte[] src, int index, int length);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the current {@code writerIndex} until the source buffer's position
* reaches its limit, and increases the {@code writerIndex} by the number of
* the transferred bytes.
*
* @throws IndexOutOfBoundsException if {@code src.remaining()} is greater
* than {@code this.writableBytes}
*/
void writeBytes(ByteBuffer src);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the current {@code writerIndex} until the source buffer becomes
* unreadable, and increases the {@code writerIndex} by the number of the
* transferred bytes. This method is basically same with {@link
* #writeBytes(ChannelBuffer, int, int)}, except that this method increases
* the {@code readerIndex} of the source buffer by the number of the
* transferred bytes while {@link #writeBytes(ChannelBuffer, int, int)} does
* not.
*
* @throws IndexOutOfBoundsException if {@code src.readableBytes} is greater
* than {@code this.writableBytes}
*/
void writeBytes(ChannelBuffer src);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the current {@code writerIndex} and increases the {@code writerIndex} by
* the number of the transferred bytes (= {@code length}). This method is
* basically same with {@link #writeBytes(ChannelBuffer, int, int)}, except
* that this method increases the {@code readerIndex} of the source buffer
* by the number of the transferred bytes (= {@code length}) while {@link
* #writeBytes(ChannelBuffer, int, int)} does not.
*
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.writableBytes} or if {@code
* length} is greater then {@code
* src.readableBytes}
*/
void writeBytes(ChannelBuffer src, int length);
/**
* Transfers the specified source buffer's data to this buffer starting at
* the current {@code writerIndex} and increases the {@code writerIndex} by
* the number of the transferred bytes (= {@code length}).
*
* @param srcIndex the first index of the source
* @param length the number of bytes to transfer
* @throws IndexOutOfBoundsException if the specified {@code srcIndex} is
* less than {@code 0}, if {@code srcIndex
* + length} is greater than {@code
* src.capacity}, or if {@code length} is
* greater than {@code this.writableBytes}
*/
void writeBytes(ChannelBuffer src, int srcIndex, int length);
/**
* Transfers the content of the specified stream to this buffer starting at
* the current {@code writerIndex} and increases the {@code writerIndex} by
* the number of the transferred bytes.
*
* @param length the number of bytes to transfer
* @return the actual number of bytes read in from the specified stream
* @throws IndexOutOfBoundsException if {@code length} is greater than
* {@code this.writableBytes}
* @throws IOException if the specified stream threw an
* exception during I/O
*/
int writeBytes(InputStream src, int length) throws IOException;
/**
* Returns the {@code writerIndex} of this buffer.
*/
int writerIndex();
/**
* Sets the {@code writerIndex} of this buffer.
*
* @throws IndexOutOfBoundsException if the specified {@code writerIndex} is
* less than {@code this.readerIndex} or
* greater than {@code this.capacity}
*/
void writerIndex(int writerIndex);
/**
* Returns the backing byte array of this buffer.
*
* @throws UnsupportedOperationException if there is no accessible backing byte
* array
*/
byte[] array();
/**
* Returns {@code true} if and only if this buffer has a backing byte array.
* If this method returns true, you can safely call {@link #array()} and
* {@link #arrayOffset()}.
*/
boolean hasArray();
/**
* 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
*/
int arrayOffset();
}
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