Class PGStream

  • All Implemented Interfaces:
    Closeable, Flushable, AutoCloseable

    public class PGStream
    extends Object
    implements Closeable, 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.

    • Constructor Detail

      • PGStream

        public PGStream​(SocketFactory socketFactory,
                        HostSpec hostSpec,
                        int timeout)
                 throws IOException
        Constructor: Connect to the PostgreSQL back end and return a stream connection.
        Parameters:
        socketFactory - socket factory to use when creating sockets
        hostSpec - the host and port to connect to
        timeout - timeout in milliseconds, or 0 if no timeout set
        Throws:
        IOException - if an IOException occurs below it.
    • Method Detail

      • isGssEncrypted

        public boolean isGssEncrypted()
      • setSecContext

        public void setSecContext​(GSSContext secContext)
      • getHostSpec

        public HostSpec getHostSpec()
      • getSocket

        public Socket getSocket()
      • hasMessagePending

        public boolean hasMessagePending()
                                  throws 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:
        IOException - if something wrong happens
      • setMinStreamAvailableCheckDelay

        public void setMinStreamAvailableCheckDelay​(int delay)
      • changeSocket

        public void changeSocket​(Socket socket)
                          throws 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:
        IOException - if something goes wrong
      • getEncoding

        public Encoding getEncoding()
      • setEncoding

        public void setEncoding​(Encoding encoding)
                         throws IOException
        Change the encoding used by this connection.
        Parameters:
        encoding - the new encoding to use
        Throws:
        IOException - if something goes wrong
      • getEncodingWriter

        public Writer getEncodingWriter()
                                 throws 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:
        IOException - if something goes wrong.
      • sendChar

        public void sendChar​(int val)
                      throws IOException
        Sends a single character to the back end.
        Parameters:
        val - the character to be sent
        Throws:
        IOException - if an I/O error occurs
      • sendInteger4

        public void sendInteger4​(int val)
                          throws IOException
        Sends a 4-byte integer to the back end.
        Parameters:
        val - the integer to be sent
        Throws:
        IOException - if an I/O error occurs
      • sendInteger2

        public void sendInteger2​(int val)
                          throws IOException
        Sends a 2-byte integer (short) to the back end.
        Parameters:
        val - the integer to be sent
        Throws:
        IOException - if an I/O error occurs or val cannot be encoded in 2 bytes
      • send

        public void send​(byte[] buf)
                  throws IOException
        Send an array of bytes to the backend.
        Parameters:
        buf - The array of bytes to be sent
        Throws:
        IOException - if an I/O error occurs
      • send

        public void send​(byte[] buf,
                         int siz)
                  throws IOException
        Send a fixed-size array of bytes to the backend. If buf.length < siz, pad with zeros. If buf.lengh > siz, truncate the array.
        Parameters:
        buf - the array of bytes to be sent
        siz - the number of bytes to be sent
        Throws:
        IOException - if an I/O error occurs
      • send

        public void send​(byte[] buf,
                         int off,
                         int siz)
                  throws IOException
        Send a fixed-size array of bytes to the backend. If length < siz, pad with zeros. If length > siz, truncate the array.
        Parameters:
        buf - the array of bytes to be sent
        off - offset in the array to start sending from
        siz - the number of bytes to be sent
        Throws:
        IOException - if an I/O error occurs
      • send

        public void send​(ByteStreamWriter writer)
                  throws IOException
        Send a fixed-size array of bytes to the backend. If length < siz, pad with zeros. If length > siz, truncate the array.
        Parameters:
        writer - the stream writer to invoke to send the bytes
        Throws:
        IOException - if an I/O error occurs
      • peekChar

        public int peekChar()
                     throws IOException
        Receives a single character from the backend, without advancing the current protocol stream position.
        Returns:
        the character received
        Throws:
        IOException - if an I/O Error occurs
      • receiveChar

        public int receiveChar()
                        throws IOException
        Receives a single character from the backend.
        Returns:
        the character received
        Throws:
        IOException - if an I/O Error occurs
      • receiveInteger4

        public int receiveInteger4()
                            throws IOException
        Receives a four byte integer from the backend.
        Returns:
        the integer received from the backend
        Throws:
        IOException - if an I/O error occurs
      • receiveInteger2

        public int receiveInteger2()
                            throws IOException
        Receives a two byte integer from the backend.
        Returns:
        the integer received from the backend
        Throws:
        IOException - if an I/O error occurs
      • receiveString

        public String receiveString​(int len)
                             throws 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:
        IOException - if something wrong happens
      • receiveErrorString

        public EncodingPredictor.DecodeResult receiveErrorString​(int len)
                                                          throws 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:
        IOException - if something wrong happens
      • receiveString

        public String receiveString()
                             throws 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:
        IOException - if an I/O error occurs, or end of file
      • receive

        public byte[] receive​(int siz)
                       throws IOException
        Reads in a given number of bytes from the backend.
        Parameters:
        siz - number of bytes to read
        Returns:
        array of bytes received
        Throws:
        IOException - if a data I/O error occurs
      • receive

        public void receive​(byte[] buf,
                            int off,
                            int siz)
                     throws IOException
        Reads in a given number of bytes from the backend.
        Parameters:
        buf - buffer to store result
        off - offset in buffer
        siz - number of bytes to read
        Throws:
        IOException - if a data I/O error occurs
      • sendStream

        public void sendStream​(InputStream inStream,
                               int remaining)
                        throws IOException
        Copy data from an input stream to the connection.
        Parameters:
        inStream - the stream to read data from
        remaining - the number of bytes to copy
        Throws:
        IOException - if a data I/O error occurs
      • setNetworkTimeout

        public void setNetworkTimeout​(int milliseconds)
                               throws IOException
        Throws:
        IOException
      • setMaxResultBuffer

        public void setMaxResultBuffer​(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.
      • clearResultBufferCount

        public void clearResultBufferCount()
        Method to clear count of byte buffer.
      • isClosed

        public boolean isClosed()