java.lang.Object
- org.apache.thrift.protocol.TProtocol
- - org.apache.thrift.protocol.TCompactProtocol

Direct Known Subclasses:

TTupleProtocol
```
public class TCompactProtocol
extends TProtocol
```
TCompactProtocol2 is the Java implementation of the compact protocol specified in THRIFT-110. The fundamental approach to reducing the overhead of structures is a) use variable-length integers all over the place and b) make use of unused bits wherever possible. Your savings will obviously vary based on the specific makeup of your structs, but in general, the more fields, nested structures, short strings and collections, and low-value i32 and i64 fields you have, the more benefit you'll see.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class TCompactProtocol.Factory
TProtocolFactory that produces TCompactProtocols.

Field Summary
- Fields inherited from class org.apache.thrift.protocol.TProtocol
  trans_

Constructor Summary

Constructors
Constructor	Description
`TCompactProtocol(TTransport transport)`	Create a TCompactProtocol.
`TCompactProtocol(TTransport transport, long stringLengthLimit)`	Deprecated. Use constructor specifying both string limit and container limit instead
`TCompactProtocol(TTransport transport, long stringLengthLimit, long containerLengthLimit)`	Create a TCompactProtocol.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.nio.ByteBuffer`	`readBinary()`	Read a byte[] from the wire.
`boolean`	`readBool()`	Read a boolean off the wire.
`byte`	`readByte()`	Read a single byte off the wire.
`double`	`readDouble()`	No magic here - just read a double off the wire.
`TField`	`readFieldBegin()`	Read a field header off the wire.
`void`	`readFieldEnd()`
`short`	`readI16()`	Read an i16 from the wire as a zigzag varint.
`int`	`readI32()`	Read an i32 from the wire as a zigzag varint.
`long`	`readI64()`	Read an i64 from the wire as a zigzag varint.
`TList`	`readListBegin()`	Read a list header off the wire.
`void`	`readListEnd()`
`TMap`	`readMapBegin()`	Read a map header off the wire.
`void`	`readMapEnd()`
`TMessage`	`readMessageBegin()`	Read a message header.
`void`	`readMessageEnd()`
`TSet`	`readSetBegin()`	Read a set header off the wire.
`void`	`readSetEnd()`
`java.lang.String`	`readString()`	Reads a byte[] (via readBinary), and then UTF-8 decodes it.
`TStruct`	`readStructBegin()`	Read a struct begin.
`void`	`readStructEnd()`	Doesn't actually consume any wire data, just removes the last field for this struct from the field stack.
`void`	`reset()`	Reset any internal state back to a blank slate.
`void`	`writeBinary(java.nio.ByteBuffer bin)`	Write a byte array, using a varint for the size.
`void`	`writeBool(boolean b)`	Write a boolean value.
`void`	`writeByte(byte b)`	Write a byte.
`protected void`	`writeCollectionBegin(byte elemType, int size)`	Abstract method for writing the start of lists and sets.
`void`	`writeDouble(double dub)`	Write a double to the wire as 8 bytes.
`void`	`writeFieldBegin(TField field)`	Write a field header containing the field id and field type.
`void`	`writeFieldEnd()`
`void`	`writeFieldStop()`	Write the STOP symbol so we know there are no more fields in this struct.
`void`	`writeI16(short i16)`	Write an I16 as a zigzag varint.
`void`	`writeI32(int i32)`	Write an i32 as a zigzag varint.
`void`	`writeI64(long i64)`	Write an i64 as a zigzag varint.
`void`	`writeListBegin(TList list)`	Write a list header.
`void`	`writeListEnd()`
`void`	`writeMapBegin(TMap map)`	Write a map header.
`void`	`writeMapEnd()`
`void`	`writeMessageBegin(TMessage message)`	Write a message header to the wire.
`void`	`writeMessageEnd()`
`void`	`writeSetBegin(TSet set)`	Write a set header.
`void`	`writeSetEnd()`
`void`	`writeString(java.lang.String str)`	Write a string to the wire with a varint size preceding.
`void`	`writeStructBegin(TStruct struct)`	Write a struct begin.
`void`	`writeStructEnd()`	Write a struct end.

Methods inherited from class org.apache.thrift.protocol.TProtocol
getScheme, getTransport

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - TCompactProtocol
```
public TCompactProtocol(TTransport transport,
                        long stringLengthLimit,
                        long containerLengthLimit)
```
    Create a TCompactProtocol.
    
    Parameters:
    
    transport - the TTransport object to read from or write to.
    
    stringLengthLimit - the maximum number of bytes to read for variable-length fields.
    
    containerLengthLimit - the maximum number of elements to read for containers.
  - TCompactProtocol
```
@Deprecated
public TCompactProtocol(TTransport transport,
                        long stringLengthLimit)
```
    Deprecated.
    Use constructor specifying both string limit and container limit instead
    
    Create a TCompactProtocol.
    
    Parameters:
    
    transport - the TTransport object to read from or write to.
    
    stringLengthLimit - the maximum number of bytes to read for variable-length fields.
  - TCompactProtocol
```
public TCompactProtocol(TTransport transport)
```
    Create a TCompactProtocol.
    
    Parameters:
    
    transport - the TTransport object to read from or write to.
- Method Detail
  - reset
```
public void reset()
```
    Description copied from class: TProtocol
    
    Reset any internal state back to a blank slate. This method only needs to be implemented for stateful protocols.
    
    Overrides:
    
    reset in class TProtocol
  - writeMessageBegin
```
public void writeMessageBegin(TMessage message)
                       throws TException
```
    Write a message header to the wire. Compact Protocol messages contain the protocol version so we can migrate forwards in the future if need be.
    
    Specified by:
    
    writeMessageBegin in class TProtocol
    
    Throws:
    
    TException
  - writeStructBegin
```
public void writeStructBegin(TStruct struct)
                      throws TException
```
    Write a struct begin. This doesn't actually put anything on the wire. We use it as an opportunity to put special placeholder markers on the field stack so we can get the field id deltas correct.
    
    Specified by:
    
    writeStructBegin in class TProtocol
    
    Throws:
    
    TException
  - writeStructEnd
```
public void writeStructEnd()
                    throws TException
```
    Write a struct end. This doesn't actually put anything on the wire. We use this as an opportunity to pop the last field from the current struct off of the field stack.
    
    Specified by:
    
    writeStructEnd in class TProtocol
    
    Throws:
    
    TException
  - writeFieldBegin
```
public void writeFieldBegin(TField field)
                     throws TException
```
    Write a field header containing the field id and field type. If the difference between the current field id and the last one is small (< 15), then the field id will be encoded in the 4 MSB as a delta. Otherwise, the field id will follow the type header as a zigzag varint.
    
    Specified by:
    
    writeFieldBegin in class TProtocol
    
    Throws:
    
    TException
  - writeFieldStop
```
public void writeFieldStop()
                    throws TException
```
    Write the STOP symbol so we know there are no more fields in this struct.
    
    Specified by:
    
    writeFieldStop in class TProtocol
    
    Throws:
    
    TException
  - writeMapBegin
```
public void writeMapBegin(TMap map)
                   throws TException
```
    Write a map header. If the map is empty, omit the key and value type headers, as we don't need any additional information to skip it.
    
    Specified by:
    
    writeMapBegin in class TProtocol
    
    Throws:
    
    TException
  - writeListBegin
```
public void writeListBegin(TList list)
                    throws TException
```
    Write a list header.
    
    Specified by:
    
    writeListBegin in class TProtocol
    
    Throws:
    
    TException
  - writeSetBegin
```
public void writeSetBegin(TSet set)
                   throws TException
```
    Write a set header.
    
    Specified by:
    
    writeSetBegin in class TProtocol
    
    Throws:
    
    TException
  - writeBool
```
public void writeBool(boolean b)
               throws TException
```
    Write a boolean value. Potentially, this could be a boolean field, in which case the field header info isn't written yet. If so, decide what the right type header is for the value and then write the field header. Otherwise, write a single byte.
    
    Specified by:
    
    writeBool in class TProtocol
    
    Throws:
    
    TException
  - writeByte
```
public void writeByte(byte b)
               throws TException
```
    Write a byte. Nothing to see here!
    
    Specified by:
    
    writeByte in class TProtocol
    
    Throws:
    
    TException
  - writeI16
```
public void writeI16(short i16)
              throws TException
```
    Write an I16 as a zigzag varint.
    
    Specified by:
    
    writeI16 in class TProtocol
    
    Throws:
    
    TException
  - writeI32
```
public void writeI32(int i32)
              throws TException
```
    Write an i32 as a zigzag varint.
    
    Specified by:
    
    writeI32 in class TProtocol
    
    Throws:
    
    TException
  - writeI64
```
public void writeI64(long i64)
              throws TException
```
    Write an i64 as a zigzag varint.
    
    Specified by:
    
    writeI64 in class TProtocol
    
    Throws:
    
    TException
  - writeDouble
```
public void writeDouble(double dub)
                 throws TException
```
    Write a double to the wire as 8 bytes.
    
    Specified by:
    
    writeDouble in class TProtocol
    
    Throws:
    
    TException
  - writeString
```
public void writeString(java.lang.String str)
                 throws TException
```
    Write a string to the wire with a varint size preceding.
    
    Specified by:
    
    writeString in class TProtocol
    
    Throws:
    
    TException
  - writeBinary
```
public void writeBinary(java.nio.ByteBuffer bin)
                 throws TException
```
    Write a byte array, using a varint for the size.
    
    Specified by:
    
    writeBinary in class TProtocol
    
    Throws:
    
    TException
  - writeMessageEnd
```
public void writeMessageEnd()
                     throws TException
```
    Specified by:
    
    writeMessageEnd in class TProtocol
    
    Throws:
    
    TException
  - writeMapEnd
```
public void writeMapEnd()
                 throws TException
```
    Specified by:
    
    writeMapEnd in class TProtocol
    
    Throws:
    
    TException
  - writeListEnd
```
public void writeListEnd()
                  throws TException
```
    Specified by:
    
    writeListEnd in class TProtocol
    
    Throws:
    
    TException
  - writeSetEnd
```
public void writeSetEnd()
                 throws TException
```
    Specified by:
    
    writeSetEnd in class TProtocol
    
    Throws:
    
    TException
  - writeFieldEnd
```
public void writeFieldEnd()
                   throws TException
```
    Specified by:
    
    writeFieldEnd in class TProtocol
    
    Throws:
    
    TException
  - writeCollectionBegin
```
protected void writeCollectionBegin(byte elemType,
                                    int size)
                             throws TException
```
    Abstract method for writing the start of lists and sets. List and sets on the wire differ only by the type indicator.
    
    Throws:
    
    TException
  - readMessageBegin
```
public TMessage readMessageBegin()
                          throws TException
```
    Read a message header.
    
    Specified by:
    
    readMessageBegin in class TProtocol
    
    Throws:
    
    TException
  - readStructBegin
```
public TStruct readStructBegin()
                        throws TException
```
    Read a struct begin. There's nothing on the wire for this, but it is our opportunity to push a new struct begin marker onto the field stack.
    
    Specified by:
    
    readStructBegin in class TProtocol
    
    Throws:
    
    TException
  - readStructEnd
```
public void readStructEnd()
                   throws TException
```
    Doesn't actually consume any wire data, just removes the last field for this struct from the field stack.
    
    Specified by:
    
    readStructEnd in class TProtocol
    
    Throws:
    
    TException
  - readFieldBegin
```
public TField readFieldBegin()
                      throws TException
```
    Read a field header off the wire.
    
    Specified by:
    
    readFieldBegin in class TProtocol
    
    Throws:
    
    TException
  - readMapBegin
```
public TMap readMapBegin()
                  throws TException
```
    Read a map header off the wire. If the size is zero, skip reading the key and value type. This means that 0-length maps will yield TMaps without the "correct" types.
    
    Specified by:
    
    readMapBegin in class TProtocol
    
    Throws:
    
    TException
  - readListBegin
```
public TList readListBegin()
                    throws TException
```
    Read a list header off the wire. If the list size is 0-14, the size will be packed into the element type header. If it's a longer list, the 4 MSB of the element type header will be 0xF, and a varint will follow with the true size.
    
    Specified by:
    
    readListBegin in class TProtocol
    
    Throws:
    
    TException
  - readSetBegin
```
public TSet readSetBegin()
                  throws TException
```
    Read a set header off the wire. If the set size is 0-14, the size will be packed into the element type header. If it's a longer set, the 4 MSB of the element type header will be 0xF, and a varint will follow with the true size.
    
    Specified by:
    
    readSetBegin in class TProtocol
    
    Throws:
    
    TException
  - readBool
```
public boolean readBool()
                 throws TException
```
    Read a boolean off the wire. If this is a boolean field, the value should already have been read during readFieldBegin, so we'll just consume the pre-stored value. Otherwise, read a byte.
    
    Specified by:
    
    readBool in class TProtocol
    
    Throws:
    
    TException
  - readByte
```
public byte readByte()
              throws TException
```
    Read a single byte off the wire. Nothing interesting here.
    
    Specified by:
    
    readByte in class TProtocol
    
    Throws:
    
    TException
  - readI16
```
public short readI16()
              throws TException
```
    Read an i16 from the wire as a zigzag varint.
    
    Specified by:
    
    readI16 in class TProtocol
    
    Throws:
    
    TException
  - readI32
```
public int readI32()
            throws TException
```
    Read an i32 from the wire as a zigzag varint.
    
    Specified by:
    
    readI32 in class TProtocol
    
    Throws:
    
    TException
  - readI64
```
public long readI64()
             throws TException
```
    Read an i64 from the wire as a zigzag varint.
    
    Specified by:
    
    readI64 in class TProtocol
    
    Throws:
    
    TException
  - readDouble
```
public double readDouble()
                  throws TException
```
    No magic here - just read a double off the wire.
    
    Specified by:
    
    readDouble in class TProtocol
    
    Throws:
    
    TException
  - readString
```
public java.lang.String readString()
                            throws TException
```
    Reads a byte[] (via readBinary), and then UTF-8 decodes it.
    
    Specified by:
    
    readString in class TProtocol
    
    Throws:
    
    TException
  - readBinary
```
public java.nio.ByteBuffer readBinary()
                               throws TException
```
    Read a byte[] from the wire.
    
    Specified by:
    
    readBinary in class TProtocol
    
    Throws:
    
    TException
  - readMessageEnd
```
public void readMessageEnd()
                    throws TException
```
    Specified by:
    
    readMessageEnd in class TProtocol
    
    Throws:
    
    TException
  - readFieldEnd
```
public void readFieldEnd()
                  throws TException
```
    Specified by:
    
    readFieldEnd in class TProtocol
    
    Throws:
    
    TException
  - readMapEnd
```
public void readMapEnd()
                throws TException
```
    Specified by:
    
    readMapEnd in class TProtocol
    
    Throws:
    
    TException
  - readListEnd
```
public void readListEnd()
                 throws TException
```
    Specified by:
    
    readListEnd in class TProtocol
    
    Throws:
    
    TException
  - readSetEnd
```
public void readSetEnd()
                throws TException
```
    Specified by:
    
    readSetEnd in class TProtocol
    
    Throws:
    
    TException

Class TCompactProtocol

Nested Class Summary

Field Summary

Fields inherited from class org.apache.thrift.protocol.TProtocol

Constructor Summary

Method Summary

Methods inherited from class org.apache.thrift.protocol.TProtocol

Methods inherited from class java.lang.Object

Constructor Detail

TCompactProtocol

TCompactProtocol

TCompactProtocol

Method Detail

reset

writeMessageBegin

writeStructBegin

writeStructEnd

writeFieldBegin

writeFieldStop

writeMapBegin

writeListBegin

writeSetBegin

writeBool

writeByte

writeI16

writeI32

writeI64

writeDouble

writeString

writeBinary

writeMessageEnd

writeMapEnd

writeListEnd

writeSetEnd

writeFieldEnd

writeCollectionBegin

readMessageBegin

readStructBegin

readStructEnd

readFieldBegin

readMapBegin

readListBegin

readSetBegin

readBool

readByte

readI16

readI32

readI64

readDouble

readString

readBinary

readMessageEnd

readFieldEnd

readMapEnd

readListEnd

readSetEnd