Package org.postgresql.core
Class PGStream
- java.lang.Object
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- org.postgresql.core.PGStream
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- All Implemented Interfaces:
java.io.Closeable
,java.io.Flushable
,java.lang.AutoCloseable
public class PGStream extends java.lang.Object implements java.io.Closeable, java.io.Flushable
Wrapper around the raw connection to the server that implements some basic primitives (reading/writing formatted data, doing string encoding, etc).
In general, instances of PGStream are not threadsafe; the caller must ensure that only one thread at a time is accessing a particular PGStream instance.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
changeSocket(java.net.Socket socket)
Switch this stream to using a new socket.void
clearResultBufferCount()
Method to clear count of byte buffer.void
close()
Closes the connection.void
flush()
Flush any pending output to the backend.Encoding
getEncoding()
java.io.Writer
getEncodingWriter()
Get a Writer instance that encodes directly onto the underlying stream.HostSpec
getHostSpec()
int
getNetworkTimeout()
java.net.Socket
getSocket()
javax.net.SocketFactory
getSocketFactory()
boolean
hasMessagePending()
Check for pending backend messages without blocking.boolean
isClosed()
int
peekChar()
Receives a single character from the backend, without advancing the current protocol stream position.void
receive(byte[] buf, int off, int siz)
Reads in a given number of bytes from the backend.byte[]
receive(int siz)
Reads in a given number of bytes from the backend.int
receiveChar()
Receives a single character from the backend.void
receiveEOF()
Consume an expected EOF from the backend.EncodingPredictor.DecodeResult
receiveErrorString(int len)
Receives a fixed-size string from the backend, and tries to avoid "UTF-8 decode failed" errors.int
receiveInteger2()
Receives a two byte integer from the backend.int
receiveInteger4()
Receives a four byte integer from the backend.java.lang.String
receiveString()
Receives a null-terminated string from the backend.java.lang.String
receiveString(int len)
Receives a fixed-size string from the backend.Tuple
receiveTupleV3()
Read a tuple from the back end.void
send(byte[] buf)
Send an array of bytes to the backend.void
send(byte[] buf, int siz)
Send a fixed-size array of bytes to the backend.void
send(byte[] buf, int off, int siz)
Send a fixed-size array of bytes to the backend.void
send(ByteStreamWriter writer)
Send a fixed-size array of bytes to the backend.void
sendChar(int val)
Sends a single character to the back end.void
sendInteger2(int val)
Sends a 2-byte integer (short) to the back end.void
sendInteger4(int val)
Sends a 4-byte integer to the back end.void
sendStream(java.io.InputStream inStream, int remaining)
Copy data from an input stream to the connection.void
setEncoding(Encoding encoding)
Change the encoding used by this connection.void
setMaxResultBuffer(java.lang.String value)
Method to set MaxResultBuffer inside PGStream.void
setMinStreamAvailableCheckDelay(int delay)
void
setNetworkTimeout(int milliseconds)
void
skip(int size)
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Constructor Detail
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PGStream
public PGStream(javax.net.SocketFactory socketFactory, HostSpec hostSpec, int timeout) throws java.io.IOException
Constructor: Connect to the PostgreSQL back end and return a stream connection.- Parameters:
socketFactory
- socket factory to use when creating socketshostSpec
- the host and port to connect totimeout
- timeout in milliseconds, or 0 if no timeout set- Throws:
java.io.IOException
- if an IOException occurs below it.
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PGStream
@Deprecated public PGStream(javax.net.SocketFactory socketFactory, HostSpec hostSpec) throws java.io.IOException
Deprecated.Constructor: Connect to the PostgreSQL back end and return a stream connection.- Parameters:
socketFactory
- socket factoryhostSpec
- the host and port to connect to- Throws:
java.io.IOException
- if an IOException occurs below it.
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Method Detail
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getHostSpec
public HostSpec getHostSpec()
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getSocket
public java.net.Socket getSocket()
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getSocketFactory
public javax.net.SocketFactory getSocketFactory()
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hasMessagePending
public boolean hasMessagePending() throws java.io.IOException
Check for pending backend messages without blocking. Might return false when there actually are messages waiting, depending on the characteristics of the underlying socket. This is used to detect asynchronous notifies from the backend, when available.- Returns:
- true if there is a pending backend message
- Throws:
java.io.IOException
- if something wrong happens
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setMinStreamAvailableCheckDelay
public void setMinStreamAvailableCheckDelay(int delay)
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changeSocket
public void changeSocket(java.net.Socket socket) throws java.io.IOException
Switch this stream to using a new socket. Any existing socket is not closed; it's assumed that we are changing to a new socket that delegates to the original socket (e.g. SSL).- Parameters:
socket
- the new socket to change to- Throws:
java.io.IOException
- if something goes wrong
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getEncoding
public Encoding getEncoding()
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setEncoding
public void setEncoding(Encoding encoding) throws java.io.IOException
Change the encoding used by this connection.- Parameters:
encoding
- the new encoding to use- Throws:
java.io.IOException
- if something goes wrong
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getEncodingWriter
public java.io.Writer getEncodingWriter() throws java.io.IOException
Get a Writer instance that encodes directly onto the underlying stream.
The returned Writer should not be closed, as it's a shared object. Writer.flush needs to be called when switching between use of the Writer and use of the PGStream write methods, but it won't actually flush output all the way out -- call
flush()
to actually ensure all output has been pushed to the server.- Returns:
- the shared Writer instance
- Throws:
java.io.IOException
- if something goes wrong.
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sendChar
public void sendChar(int val) throws java.io.IOException
Sends a single character to the back end.- Parameters:
val
- the character to be sent- Throws:
java.io.IOException
- if an I/O error occurs
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sendInteger4
public void sendInteger4(int val) throws java.io.IOException
Sends a 4-byte integer to the back end.- Parameters:
val
- the integer to be sent- Throws:
java.io.IOException
- if an I/O error occurs
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sendInteger2
public void sendInteger2(int val) throws java.io.IOException
Sends a 2-byte integer (short) to the back end.- Parameters:
val
- the integer to be sent- Throws:
java.io.IOException
- if an I/O error occurs orval
cannot be encoded in 2 bytes
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send
public void send(byte[] buf) throws java.io.IOException
Send an array of bytes to the backend.- Parameters:
buf
- The array of bytes to be sent- Throws:
java.io.IOException
- if an I/O error occurs
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send
public void send(byte[] buf, int siz) throws java.io.IOException
Send a fixed-size array of bytes to the backend. Ifbuf.length < siz
, pad with zeros. Ifbuf.lengh > siz
, truncate the array.- Parameters:
buf
- the array of bytes to be sentsiz
- the number of bytes to be sent- Throws:
java.io.IOException
- if an I/O error occurs
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send
public void send(byte[] buf, int off, int siz) throws java.io.IOException
Send a fixed-size array of bytes to the backend. Iflength < siz
, pad with zeros. Iflength > siz
, truncate the array.- Parameters:
buf
- the array of bytes to be sentoff
- offset in the array to start sending fromsiz
- the number of bytes to be sent- Throws:
java.io.IOException
- if an I/O error occurs
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send
public void send(ByteStreamWriter writer) throws java.io.IOException
Send a fixed-size array of bytes to the backend. Iflength < siz
, pad with zeros. Iflength > siz
, truncate the array.- Parameters:
writer
- the stream writer to invoke to send the bytes- Throws:
java.io.IOException
- if an I/O error occurs
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peekChar
public int peekChar() throws java.io.IOException
Receives a single character from the backend, without advancing the current protocol stream position.- Returns:
- the character received
- Throws:
java.io.IOException
- if an I/O Error occurs
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receiveChar
public int receiveChar() throws java.io.IOException
Receives a single character from the backend.- Returns:
- the character received
- Throws:
java.io.IOException
- if an I/O Error occurs
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receiveInteger4
public int receiveInteger4() throws java.io.IOException
Receives a four byte integer from the backend.- Returns:
- the integer received from the backend
- Throws:
java.io.IOException
- if an I/O error occurs
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receiveInteger2
public int receiveInteger2() throws java.io.IOException
Receives a two byte integer from the backend.- Returns:
- the integer received from the backend
- Throws:
java.io.IOException
- if an I/O error occurs
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receiveString
public java.lang.String receiveString(int len) throws java.io.IOException
Receives a fixed-size string from the backend.- Parameters:
len
- the length of the string to receive, in bytes.- Returns:
- the decoded string
- Throws:
java.io.IOException
- if something wrong happens
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receiveErrorString
public EncodingPredictor.DecodeResult receiveErrorString(int len) throws java.io.IOException
Receives a fixed-size string from the backend, and tries to avoid "UTF-8 decode failed" errors.- Parameters:
len
- the length of the string to receive, in bytes.- Returns:
- the decoded string
- Throws:
java.io.IOException
- if something wrong happens
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receiveString
public java.lang.String receiveString() throws java.io.IOException
Receives a null-terminated string from the backend. If we don't see a null, then we assume something has gone wrong.- Returns:
- string from back end
- Throws:
java.io.IOException
- if an I/O error occurs, or end of file
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receiveTupleV3
public Tuple receiveTupleV3() throws java.io.IOException, java.lang.OutOfMemoryError, java.sql.SQLException
Read a tuple from the back end. A tuple is a two dimensional array of bytes. This variant reads the V3 protocol's tuple representation.- Returns:
- tuple from the back end
- Throws:
java.io.IOException
- if a data I/O error occursjava.sql.SQLException
- if read more bytes than set maxResultBufferjava.lang.OutOfMemoryError
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receive
public byte[] receive(int siz) throws java.io.IOException
Reads in a given number of bytes from the backend.- Parameters:
siz
- number of bytes to read- Returns:
- array of bytes received
- Throws:
java.io.IOException
- if a data I/O error occurs
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receive
public void receive(byte[] buf, int off, int siz) throws java.io.IOException
Reads in a given number of bytes from the backend.- Parameters:
buf
- buffer to store resultoff
- offset in buffersiz
- number of bytes to read- Throws:
java.io.IOException
- if a data I/O error occurs
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skip
public void skip(int size) throws java.io.IOException
- Throws:
java.io.IOException
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sendStream
public void sendStream(java.io.InputStream inStream, int remaining) throws java.io.IOException
Copy data from an input stream to the connection.- Parameters:
inStream
- the stream to read data fromremaining
- the number of bytes to copy- Throws:
java.io.IOException
- if a data I/O error occurs
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flush
public void flush() throws java.io.IOException
Flush any pending output to the backend.- Specified by:
flush
in interfacejava.io.Flushable
- Throws:
java.io.IOException
- if an I/O error occurs
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receiveEOF
public void receiveEOF() throws java.sql.SQLException, java.io.IOException
Consume an expected EOF from the backend.- Throws:
java.io.IOException
- if an I/O error occursjava.sql.SQLException
- if we get something other than an EOF
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close
public void close() throws java.io.IOException
Closes the connection.- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Throws:
java.io.IOException
- if an I/O Error occurs
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setNetworkTimeout
public void setNetworkTimeout(int milliseconds) throws java.io.IOException
- Throws:
java.io.IOException
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getNetworkTimeout
public int getNetworkTimeout() throws java.io.IOException
- Throws:
java.io.IOException
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setMaxResultBuffer
public void setMaxResultBuffer(java.lang.String value) throws PSQLException
Method to set MaxResultBuffer inside PGStream.- Parameters:
value
- value of new max result buffer as string (cause we can expect % or chars to use multiplier)- Throws:
PSQLException
- exception returned when occurred parsing problem.
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clearResultBufferCount
public void clearResultBufferCount()
Method to clear count of byte buffer.
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isClosed
public boolean isClosed()
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