Class ConnectionHandler (0.15.0)

public class ConnectionHandler extends Thread

Handles a connection from a client to Spanner. This ConnectionHandler uses WireMessage to receive and send all messages from and to the client, using the intermediate representation IntermediateStatement that servers as a middle layer between Postgres and Spanner.

Each ConnectionHandler is also a Thread. Although a TCP connection does not necessarily need to have its own thread, this makes the implementation more straightforward.

Inheritance

java.lang.Object > Thread > ConnectionHandler

Inherited Members

Object.equals(Object)

Object.finalize()

Object.getClass()

Object.hashCode()

Object.notify()

Object.notifyAll()

Object.wait()

Object.wait(long)

Object.wait(long,int)

Thread.activeCount()

Thread.checkAccess()

Thread.clone()

Thread.countStackFrames()

Thread.currentThread()

Thread.destroy()

Thread.dumpStack()

Thread.enumerate(Thread[])

Thread.getAllStackTraces()

Thread.getContextClassLoader()

Thread.getDefaultUncaughtExceptionHandler()

Thread.getId()

Thread.getName()

Thread.getPriority()

Thread.getStackTrace()

Thread.getState()

Thread.getThreadGroup()

Thread.getUncaughtExceptionHandler()

Thread.holdsLock(Object)

Thread.interrupt()

Thread.interrupted()

Thread.isAlive()

Thread.isDaemon()

Thread.isInterrupted()

Thread.join()

Thread.join(long)

Thread.join(long,int)

Thread.resume()

Thread.run()

Thread.setContextClassLoader(ClassLoader)

Thread.setDaemon(boolean)

Thread.setDefaultUncaughtExceptionHandler(Thread.UncaughtExceptionHandler)

Thread.setName(String)

Thread.setPriority(int)

Thread.setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler)

Thread.sleep(long)

Thread.sleep(long,int)

Thread.start()

Thread.stop()

Thread.stop(Throwable)

Thread.suspend()

Thread.toString()

Thread.yield()

Methods

cancelActiveStatement(int connectionId, int secret)

public boolean cancelActiveStatement(int connectionId, int secret)

To be used by a cancellation command to cancel a currently running statement, as contained in a specific connection identified by connectionId. Since cancellation is a flimsy contract at best, it is not imperative that the cancellation run, but it should be attempted nonetheless.

Parameters

Name	Description
`connectionId`	`int` The connection whose statement must be cancelled.
`secret`	`int` The secret value linked to the connection that is being cancelled. If it does not match, we cannot cancel.

Returns

Type	Description
`boolean`	true if the statement was cancelled.

cleanUp(IntermediateStatement statement)

public void cleanUp(IntermediateStatement statement)

Closes portals and statements if the result of an execute was the end of a transaction.

Parameter

Name	Description
`statement`	`IntermediateStatement`

Exceptions

Type	Description
`Exception`

clearActiveCopyStatement()

public void clearActiveCopyStatement()

clearInvalidMessageCount()

public void clearInvalidMessageCount()

Clears the number of invalid messages that was received. This is called whenever a valid message is encountered.

closeAllStatements()

public void closeAllStatements()

closePortal(String portalName)

public void closePortal(String portalName)

Parameter

Name	Description
`portalName`	`String`

Exceptions

Type	Description
`Exception`

closeStatement(String statementName)

public void closeStatement(String statementName)

Parameter

Name	Description
`statementName`	`String`

connectToSpanner(String database, Credentials credentials)

public void connectToSpanner(String database, Credentials credentials)

Parameters

Name	Description
`database`	`String`
`credentials`	`com.google.auth.Credentials`

getActiveCopyStatement()

public CopyStatement getActiveCopyStatement()

Returns

Type	Description
`CopyStatement`

getAutoDescribedStatement(String sql)

public Future<DescribeResult> getAutoDescribedStatement(String sql)

Returns the parameter types of a cached auto-described statement, or null if none is available in the cache.

Parameter

Name	Description
`sql`	`String`

Returns

Type	Description
`Future<DescribeResult>`

getConnectionId()

public int getConnectionId()

Returns

Type	Description
`int`

getConnectionMetadata()

public ConnectionMetadata getConnectionMetadata()

Returns

Type	Description
`ConnectionMetadata`

getDatabaseId()

public DatabaseId getDatabaseId()

Returns

Type	Description
`com.google.cloud.spanner.DatabaseId`

getExtendedQueryProtocolHandler()

public ExtendedQueryProtocolHandler getExtendedQueryProtocolHandler()

Returns

Type	Description
`ExtendedQueryProtocolHandler`

getInvalidMessageCount()

public int getInvalidMessageCount()

Returns the number of invalid messages that this connection has received in a row. This can for example happen if a client has initiated a COPY operation and the copy operation fails on the server. The server will then respond with an error response, but if the client fails to read that message and continues to send copy data messages, the server could get flooded. This value is used to detect such a situation and breaks the connection if too many invalid messages in a row are received.

Returns

Type	Description
`int`

getPortal(String portalName)

public IntermediatePortalStatement getPortal(String portalName)

Parameter

Name	Description
`portalName`	`String`

Returns

Type	Description
`IntermediatePortalStatement`

getSecret()

public int getSecret()

Returns

Type	Description
`int`

getServer()

public ProxyServer getServer()

Returns

Type	Description
`ProxyServer`

getSpannerConnection()

public Connection getSpannerConnection()

Returns

Type	Description
`Connection`

getStatement(String statementName)

public IntermediatePreparedStatement getStatement(String statementName)

Parameter

Name	Description
`statementName`	`String`

Returns

Type	Description
`IntermediatePreparedStatement`

getStatus()

public synchronized ConnectionHandler.ConnectionStatus getStatus()

Returns

Type	Description
`ConnectionHandler.ConnectionStatus`

getWellKnownClient()

public ClientAutoDetector.WellKnownClient getWellKnownClient()

Returns

Type	Description
`ClientAutoDetector.WellKnownClient`

handleMessages()

public void handleMessages()

Reads and handles wire-protocol messages. This method is normally only called from this ConnectionHandler, but certain sub-protocols such as the COPY protocol also need to process messages in line.

Exceptions

Type	Description
`Exception`

handleTerminate()

public void handleTerminate()

Called when a Terminate message is received. This closes this ConnectionHandler.

hasPortal(String portalName)

public boolean hasPortal(String portalName)

Parameter

Name	Description
`portalName`	`String`

Returns

Type	Description
`boolean`

hasStatement(String statementName)

public boolean hasStatement(String statementName)

Parameter

Name	Description
`statementName`	`String`

Returns

Type	Description
`boolean`

increaseInvalidMessageCount()

public void increaseInvalidMessageCount()

Increases the number of invalid messages that was received in a row by 1.

maybeDetermineWellKnownClient(Statement statement)

public void maybeDetermineWellKnownClient(Statement statement)

This is called by the simple com.google.cloud.spanner.pgadapter.wireprotocol.QueryMessage to give the connection the opportunity to determine the client that is connected based on the SQL string that is being executed.

Parameter

Name	Description
`statement`	`com.google.cloud.spanner.Statement`

registerAutoDescribedStatement(String sql, Future<DescribeResult> describeResult)

public void registerAutoDescribedStatement(String sql, Future<DescribeResult> describeResult)

Stores the parameter types of an auto-described statement in the cache.

Parameters

Name	Description
`sql`	`String`
`describeResult`	`Future<DescribeResult>`

registerPortal(String portalName, IntermediatePortalStatement portal)

public void registerPortal(String portalName, IntermediatePortalStatement portal)

Parameters

Name	Description
`portalName`	`String`
`portal`	`IntermediatePortalStatement`

registerStatement(String statementName, IntermediatePreparedStatement statement)

public void registerStatement(String statementName, IntermediatePreparedStatement statement)

Parameters

Name	Description
`statementName`	`String`
`statement`	`IntermediatePreparedStatement`

run()

public void run()

Simple runner starts a loop which keeps taking inbound messages, processing them, sending them to Spanner, getting a result, processing that result, and replying to the client (in that order). Also instantiates input and output streams from the client and handles auth.

Overrides

Thread.run()

setActiveCopyStatement(CopyStatement copyStatement)

public void setActiveCopyStatement(CopyStatement copyStatement)

Parameter

Name	Description
`copyStatement`	`CopyStatement`

setMessageState(WireMessage message)

public void setMessageState(WireMessage message)

Parameter

Name	Description
`message`	`WireMessage`

setStatus(ConnectionHandler.ConnectionStatus status)

public synchronized void setStatus(ConnectionHandler.ConnectionStatus status)

Parameter

Name	Description
`status`	`ConnectionHandler.ConnectionStatus`

setWellKnownClient(ClientAutoDetector.WellKnownClient wellKnownClient)

public void setWellKnownClient(ClientAutoDetector.WellKnownClient wellKnownClient)

Parameter

Name	Description
`wellKnownClient`	`ClientAutoDetector.WellKnownClient`