org.apache.ratis.thirdparty.io.grpc.internal.ReadableBuffer Maven / Gradle / Ivy
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/*
* Copyright 2014 The gRPC Authors
*
* Licensed 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.ratis.thirdparty.io.grpc.internal;
import java.io.Closeable;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import javax.annotation.Nullable;
/**
* Interface for an abstract byte buffer. Buffers are intended to be a read-only, except for the
* read position which is incremented after each read call.
*
* Buffers may optionally expose a backing array for optimization purposes, similar to what is
* done in {@link ByteBuffer}. It is not expected that callers will attempt to modify the backing
* array.
*/
public interface ReadableBuffer extends Closeable {
/**
* Gets the current number of readable bytes remaining in this buffer.
*/
int readableBytes();
/**
* Reads the next unsigned byte from this buffer and increments the read position by 1.
*
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
int readUnsignedByte();
/**
* Reads a 4-byte signed integer from this buffer using big-endian byte ordering. Increments the
* read position by 4.
*
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
int readInt();
/**
* Increments the read position by the given length.
*
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
void skipBytes(int length);
/**
* Reads {@code length} bytes from this buffer and writes them to the destination array.
* Increments the read position by {@code length}.
*
* @param dest the destination array to receive the bytes.
* @param destOffset the starting offset in the destination array.
* @param length the number of bytes to be copied.
* @throws IndexOutOfBoundsException if required bytes are not readable or {@code dest} is too
* small.
*/
void readBytes(byte[] dest, int destOffset, int length);
/**
* Reads from this buffer until the destination's position reaches its limit, and increases the
* read position by the number of the transferred bytes.
*
* @param dest the destination buffer to receive the bytes.
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
void readBytes(ByteBuffer dest);
/**
* Reads {@code length} bytes from this buffer and writes them to the destination stream.
* Increments the read position by {@code length}. If the required bytes are not readable, throws
* {@link IndexOutOfBoundsException}.
*
* @param dest the destination stream to receive the bytes.
* @param length the number of bytes to be copied.
* @throws IOException thrown if any error was encountered while writing to the stream.
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
void readBytes(OutputStream dest, int length) throws IOException;
/**
* Reads {@code length} bytes from this buffer and returns a new Buffer containing them. Some
* implementations may return a Buffer sharing the backing memory with this buffer to prevent
* copying. However, that means that the returned buffer may keep the (possibly much larger)
* backing memory in use even after this buffer is closed.
*
* @param length the number of bytes to contain in returned Buffer.
* @throws IndexOutOfBoundsException if required bytes are not readable
*/
ReadableBuffer readBytes(int length);
/**
* Indicates whether or not this buffer exposes a backing array.
*/
boolean hasArray();
/**
* Gets the backing array for this buffer. This is an optional method, so callers should first
* check {@link #hasArray}.
*
* @throws UnsupportedOperationException the buffer does not support this method
*/
byte[] array();
/**
* Gets the offset in the backing array of the current read position. This is an optional method,
* so callers should first check {@link #hasArray}
*
* @throws UnsupportedOperationException the buffer does not support this method
*/
int arrayOffset();
/**
* Indicates whether or not {@link #mark} operation is supported for this buffer.
*/
boolean markSupported();
/**
* Marks the current position in this buffer. A subsequent call to the {@link #reset} method
* repositions this stream at the last marked position so that subsequent reads re-read the same
* bytes.
*/
void mark();
/**
* Repositions this buffer to the position at the time {@link #mark} was last called on this
* buffer.
*/
void reset();
/**
* Indicates whether or not {@link #getByteBuffer} operation is supported for this buffer.
*/
boolean byteBufferSupported();
/**
* Gets a {@link ByteBuffer} that contains some bytes of the content next to be read, or {@code
* null} if this buffer has been exhausted. The number of bytes contained in the returned buffer
* is implementation specific. The position of this buffer is unchanged after calling this
* method. The returned buffer's content should not be modified, but the position, limit, and
* mark may be changed. Operations for changing the position, limit, and mark of the returned
* buffer does not affect the position, limit, and mark of this buffer. Buffers returned by this
* method have independent position, limit and mark. This is an optional method, so callers
* should first check {@link #byteBufferSupported}.
*
* @throws UnsupportedOperationException the buffer does not support this method.
*/
@Nullable
ByteBuffer getByteBuffer();
/**
* Closes this buffer and releases any resources.
*/
@Override
void close();
}