com.google.code.proto.streamio

Class AbstractPBWireByteMarkerHelper

java.lang.Object

com.google.code.proto.streamio.AbstractPBWireByteMarkerHelper

All Implemented Interfaces:

IPBWireByteMarkerHelper

Direct Known Subclasses:

PBWireSignedByteMarkerHelper, PBWireUnsignedByteMarkerHelper

public abstract class AbstractPBWireByteMarkerHelper
extends Object
implements IPBWireByteMarkerHelper

Abstract class to help write delimiting byte markers for Google protocol buffer generated messages used with PBStreamReader. The delimeter is a byte array holding the size of the generated message that will follow.

Author:

nichole

Constructor Summary

Constructors

Constructor and Description
AbstractPBWireByteMarkerHelper()

Method Summary

Modifier and Type	Method and Description
abstract int	bytesToInteger(byte[] marker) Convert the marker byte array to an integer
byte[]	createMessageDelimiter(com.google.protobuf.GeneratedMessage message) Create a delimiter for the given GeneratedMessage.
int	estimateTotalContentLength(List<? extends com.google.protobuf.GeneratedMessage> messages) Estimate the total number of bytes that will be used in a stream for a list of messages - this includes delimeters.
int	getByteMarkerSize() Get the number of bytes holding a message size, where these bytes are within the delimiter byte array and follow the byte marker.
int	getDelimiterSize() Get the total number of bytes of a delimeter for a generated message.
byte	getMarkerForStart() Get the byte marker used to identify the start of the delimiter.
abstract byte[]	integerToBytesBigEndian(int value) Convert the integer into a signed byte array composed of byte shifted parts of the integer.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractPBWireByteMarkerHelper

public AbstractPBWireByteMarkerHelper()

Method Detail

bytesToInteger

public abstract int bytesToInteger(byte[] marker)

Convert the marker byte array to an integer

Specified by:

bytesToInteger in interface IPBWireByteMarkerHelper

Parameters:

marker - big endian byte array

Returns:

value held by the marker

integerToBytesBigEndian

public abstract byte[] integerToBytesBigEndian(int value)

Convert the integer into a signed byte array composed of byte shifted parts of the integer.

Specified by:

integerToBytesBigEndian in interface IPBWireByteMarkerHelper

Parameters:

value - the integer to be represented by the returned byte array

Returns:

big endian byte array of the value

createMessageDelimiter

public byte[] createMessageDelimiter(com.google.protobuf.GeneratedMessage message)

Create a delimiter for the given GeneratedMessage.

Specified by:

createMessageDelimiter in interface IPBWireByteMarkerHelper

Parameters:

message - instance of GeneratedMessage

Returns:

byte array of size delimiterSize, to be used preceding serialized GeneratedMessages in a stream. The delimiter to separate serialized objects is a start byte of 0x80 followed by a 4-byte big-endian integer of the length of bytes.

estimateTotalContentLength

public int estimateTotalContentLength(List<? extends com.google.protobuf.GeneratedMessage> messages)

Estimate the total number of bytes that will be used in a stream for a list of messages - this includes delimeters. This is useful to set the content-length in an HTTP response.

Specified by:

estimateTotalContentLength in interface IPBWireByteMarkerHelper

Parameters:

messages - instances of GeneratedMessage

Returns:

total number of bytes needed for a list of generated messages. The total includes the delimiters too.

getByteMarkerSize

public int getByteMarkerSize()

Get the number of bytes holding a message size, where these bytes are within the delimiter byte array and follow the byte marker.

Specified by:

getByteMarkerSize in interface IPBWireByteMarkerHelper

Returns:

number of bytes holding a message size.

getDelimiterSize

public int getDelimiterSize()

Get the total number of bytes of a delimeter for a generated message.

Specified by:

getDelimiterSize in interface IPBWireByteMarkerHelper

Returns:

the number of bytes in a delimiter

getMarkerForStart

public byte getMarkerForStart()

Get the byte marker used to identify the start of the delimiter.

Specified by:

getMarkerForStart in interface IPBWireByteMarkerHelper

Returns:

byte marker used to identify the start of the delimiter