| /* |
| * Buffer.java February 2001 |
| * |
| * Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net> |
| * |
| * 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.simpleframework.common.buffer; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * The <code>Buffer</code> interface represents a collection of bytes |
| * that can be written to and later read. This is used to provide a |
| * region of memory is such a way that the underlying representation |
| * of that memory is independent of its use. Typically buffers are |
| * implemented as either allocated byte arrays or files. |
| * |
| * @author Niall Gallagher |
| * |
| * @see org.simpleframework.common.buffer.Allocator |
| */ |
| public interface Buffer { |
| |
| /** |
| * This method is used to allocate a segment of this buffer as a |
| * separate buffer object. This allows the buffer to be sliced in |
| * to several smaller independent buffers, while still allowing the |
| * parent buffer to manage a single buffer. This is useful if the |
| * parent is split in to logically smaller segments. |
| * |
| * @return this returns a buffer which is a segment of this buffer |
| */ |
| Buffer allocate() throws IOException; |
| |
| /** |
| * This method is used so that a buffer can be represented as a |
| * stream of bytes. This provides a quick means to access the data |
| * that has been written to the buffer. It wraps the buffer within |
| * an input stream so that it can be read directly. |
| * |
| * @return a stream that can be used to read the buffered bytes |
| */ |
| InputStream open() throws IOException; |
| |
| /** |
| * This method is used to acquire the buffered bytes as a string. |
| * This is useful if the contents need to be manipulated as a |
| * string or transferred into another encoding. If the UTF-8 |
| * content encoding is not supported the platform default is |
| * used, however this is unlikely as UTF-8 should be supported. |
| * |
| * @return this returns a UTF-8 encoding of the buffer contents |
| */ |
| String encode() throws IOException; |
| |
| /** |
| * This method is used to acquire the buffered bytes as a string. |
| * This is useful if the contents need to be manipulated as a |
| * string or transferred into another encoding. This will convert |
| * the bytes using the specified character encoding format. |
| * |
| * @param charset this is the charset to encode the data with |
| * |
| * @return this returns the encoding of the buffer contents |
| */ |
| String encode(String charset) throws IOException; |
| |
| /** |
| * This method is used to append bytes to the end of the buffer. |
| * This will expand the capacity of the buffer if there is not |
| * enough space to accommodate the extra bytes. |
| * |
| * @param array this is the byte array to append to this buffer |
| * |
| * @return this returns this buffer for another operation |
| */ |
| Buffer append(byte[] array) throws IOException; |
| |
| /** |
| * This method is used to append bytes to the end of the buffer. |
| * This will expand the capacity of the buffer if there is not |
| * enough space to accommodate the extra bytes. |
| * |
| * @param array this is the byte array to append to this buffer |
| * @param len the number of bytes to be read from the array |
| * @param off this is the offset to begin reading the bytes from |
| * |
| * @return this returns this buffer for another operation |
| */ |
| Buffer append(byte[] array, int off, int len) throws IOException; |
| |
| /** |
| * This will clear all data from the buffer. This simply sets the |
| * count to be zero, it will not clear the memory occupied by the |
| * instance as the internal buffer will remain. This allows the |
| * memory occupied to be reused as many times as is required. |
| */ |
| void clear() throws IOException; |
| |
| /** |
| * This method is used to ensure the buffer can be closed. Once |
| * the buffer is closed it is an immutable collection of bytes and |
| * can not longer be modified. This ensures that it can be passed |
| * by value without the risk of modification of the bytes. |
| */ |
| void close() throws IOException; |
| |
| /** |
| * This is used to provide the number of bytes that have been |
| * written to the buffer. This increases as bytes are appended |
| * to the buffer. if the buffer is cleared this resets to zero. |
| * |
| * @return this returns the number of bytes within the buffer |
| */ |
| long length(); |
| } |