/**
* 创建新的buffer，保存老的buffer。
*
* @throws IllegalStateException 如果不在buffer模式，或<code>getWriter</code> 方法曾被调用，或<code>
* getOutputStream</code>方法从未被调用
*/
public void pushBuffer() {
if (!buffering) {
throw new IllegalStateException("Buffering mode is required to pushBuffer");
}
if (stream == null && writer == null) {
throw new IllegalStateException(
"getOutputStream() or getWriter() method has not been called yet");
}
flushBufferAdapter();
// 向stream或writer stack中压入新的buffer。
if (stream != null) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
bytesStack.push(bytes);
((BufferedServletOutputStream) stream).updateOutputStream(bytesStack.peek());
logger.logMessage(
LogLevel.DEBUG, "Pushed new byte buffer (stack size is " + bytesStack.size() + ")");
} else {
StringWriter chars = new StringWriter();
charsStack.push(chars);
((BufferedServletWriter) writer).updateWriter(charsStack.peek());
logger.logMessage(
LogLevel.DEBUG, "Pushed new character buffer (stack size is " + charsStack.size() + ")");
}
}
/**
* 弹出最近的buffer，如果堆栈中只有一个buffer，则弹出后再创建一个新的。
*
* @return 最近的buffer内容，如果<code>getOutputStream</code>方法从未被调用，则返回空的byte array
* @throws IllegalStateException 如果不在buffer模式，或<code>getWriter</code>方法曾被调用
*/
public ByteArray popByteBuffer() {
if (!buffering) {
throw new IllegalStateException("Buffering mode is required to popByteBuffer");
}
if (writer != null) {
throw new IllegalStateException(
"Unable to popByteBuffer() since the getWriter() method has been called");
}
if (stream == null) {
return new ByteArray(EMPTY_BYTE_ARRAY, 0, 0);
} else {
flushBufferAdapter();
ByteArrayOutputStream block = bytesStack.pop();
if (bytesStack.size() == 0) {
bytesStack.push(new ByteArrayOutputStream());
}
((BufferedServletOutputStream) stream).updateOutputStream(bytesStack.peek());
logger.logMessage(
LogLevel.DEBUG, "Popped the last byte buffer (stack size is " + bytesStack.size() + ")");
return block.toByteArray();
}
}
/**
* 清除所有buffers，常用于显示出错信息。
*
* @throws IllegalStateException 如果response已经commit
*/
public void resetBuffer() {
if (buffering) {
flushBufferAdapter();
if (stream != null) {
bytesStack.clear();
bytesStack.add(new ByteArrayOutputStream());
((BufferedServletOutputStream) stream).updateOutputStream(bytesStack.peek());
}
if (writer != null) {
charsStack.clear();
charsStack.add(new StringWriter());
((BufferedServletWriter) writer).updateWriter(charsStack.peek());
}
}
super.resetBuffer();
}