com.mysql.cj.jdbc.ha

Class MultiHostConnectionProxy

java.lang.Object

com.mysql.cj.jdbc.ha.MultiHostConnectionProxy

All Implemented Interfaces:

java.lang.reflect.InvocationHandler

Direct Known Subclasses:

FailoverConnectionProxy, LoadBalancedConnectionProxy, ReplicationConnectionProxy

public abstract class MultiHostConnectionProxy
extends java.lang.Object
implements java.lang.reflect.InvocationHandler

An abstract class that processes generic multi-host configurations. This class has to be sub-classed by specific multi-host implementations, such as load-balancing and failover.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) class	MultiHostConnectionProxy.JdbcInterfaceProxy Proxy class to intercept and deal with errors that may occur in any object bound to the current connection.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) boolean	autoReconnect
(package private) boolean	closedExplicitly
(package private) java.lang.String	closedReason
protected ConnectionUrl	connectionUrl
(package private) JdbcConnection	currentConnection
(package private) java.util.List<HostInfo>	hostsList
(package private) boolean	isClosed
protected java.lang.Throwable	lastExceptionDealtWith
private static java.lang.String	METHOD_ABORT
private static java.lang.String	METHOD_ABORT_INTERNAL
private static java.lang.String	METHOD_CLOSE
private static java.lang.String	METHOD_EQUALS
private static java.lang.String	METHOD_GET_AUTO_COMMIT
private static java.lang.String	METHOD_GET_CATALOG
private static java.lang.String	METHOD_GET_DATABASE
private static java.lang.String	METHOD_GET_MULTI_HOST_SAFE_PROXY
private static java.lang.String	METHOD_GET_SCHEMA
private static java.lang.String	METHOD_GET_SESSION_MAX_ROWS
private static java.lang.String	METHOD_GET_TRANSACTION_ISOLATION
private static java.lang.String	METHOD_IS_CLOSED
(package private) JdbcConnection	parentProxyConnection
(package private) JdbcConnection	thisAsConnection
(package private) JdbcConnection	topProxyConnection

Constructor Summary

Constructors

Constructor and Description
MultiHostConnectionProxy() Initializes a connection wrapper for this MultiHostConnectionProxy instance.
MultiHostConnectionProxy(ConnectionUrl connectionUrl) Constructs a MultiHostConnectionProxy instance for the given connection URL.

Method Summary

Modifier and Type	Method and Description
protected boolean	allowedOnClosedConnection(java.lang.reflect.Method method) Checks if the given method is allowed on closed connections.
(package private) ConnectionImpl	createConnectionForHost(HostInfo hostInfo) Creates a new physical connection for the given HostInfo.
(package private) void	dealWithInvocationException(java.lang.reflect.InvocationTargetException e) Deals with InvocationException from proxied objects.
(package private) abstract void	doAbort(java.util.concurrent.Executor executor) Executes a abort() invocation;
(package private) abstract void	doAbortInternal() Executes a abortInternal() invocation;
(package private) abstract void	doClose() Executes a close() invocation;
(package private) java.lang.reflect.InvocationHandler	getNewJdbcInterfaceProxy(java.lang.Object toProxy) Instantiates a new JdbcInterfaceProxy for the given object.
(package private) JdbcConnection	getNewWrapperForThisAsConnection() Wraps this object with a new multi-host Connection instance.
protected JdbcConnection	getParentProxy() Get this connection's parent proxy.
protected JdbcConnection	getProxy() Get this connection's proxy.
(package private) int	initializeHostsSpecs(ConnectionUrl connUrl, java.util.List<HostInfo> hosts) Initializes the hosts lists and makes a "clean" local copy of the given connection properties so that it can be later used to create standard connections.
(package private) void	invalidateConnection(JdbcConnection conn) Invalidates the specified connection by closing it.
(package private) void	invalidateCurrentConnection() Invalidates the current connection.
java.lang.Object	invoke(java.lang.Object proxy, java.lang.reflect.Method method, java.lang.Object[] args) Proxies method invocation on the java.sql.Connection interface, trapping multi-host specific methods and generic methods.
(package private) abstract java.lang.Object	invokeMore(java.lang.Object proxy, java.lang.reflect.Method method, java.lang.Object[] args) Continuation of the method invocation process, to be implemented within each subclass.
(package private) boolean	isMasterConnection() Deprecated.
(package private) abstract boolean	isSourceConnection() Checks if current connection is to a source host.
(package private) abstract void	pickNewConnection() Picks the "best" connection to use from now on.
protected void	propagateProxyDown(JdbcConnection proxyConn) Propagates the connection proxy down through the multi-host connections chain.
(package private) java.lang.Object	proxyIfReturnTypeIsJdbcInterface(java.lang.Class<?> returnType, java.lang.Object toProxy) If the given return type is or implements a JDBC interface, proxies the given object so that we can catch SQL errors and fire a connection switch.
protected void	setProxy(JdbcConnection proxyConn) Sets this connection's proxy.
(package private) abstract boolean	shouldExceptionTriggerConnectionSwitch(java.lang.Throwable t) Checks if the given throwable should trigger a connection switch.
(package private) void	syncSessionState(JdbcConnection source, JdbcConnection target) Synchronizes session state between two connections.
(package private) void	syncSessionState(JdbcConnection source, JdbcConnection target, boolean readOnly) Synchronizes session state between two connections, allowing to override the read-only status.

Methods inherited from class java.lang.Object

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

Field Detail

METHOD_GET_MULTI_HOST_SAFE_PROXY

private static final java.lang.String METHOD_GET_MULTI_HOST_SAFE_PROXY

See Also:

Constant Field Values

METHOD_EQUALS

private static final java.lang.String METHOD_EQUALS

See Also:

Constant Field Values

METHOD_CLOSE

private static final java.lang.String METHOD_CLOSE

See Also:

Constant Field Values

METHOD_ABORT_INTERNAL

private static final java.lang.String METHOD_ABORT_INTERNAL

See Also:

Constant Field Values

METHOD_ABORT

private static final java.lang.String METHOD_ABORT

See Also:

Constant Field Values

METHOD_IS_CLOSED

private static final java.lang.String METHOD_IS_CLOSED

See Also:

Constant Field Values

METHOD_GET_AUTO_COMMIT

private static final java.lang.String METHOD_GET_AUTO_COMMIT

See Also:

Constant Field Values

METHOD_GET_CATALOG

private static final java.lang.String METHOD_GET_CATALOG

See Also:

Constant Field Values

METHOD_GET_SCHEMA

private static final java.lang.String METHOD_GET_SCHEMA

See Also:

Constant Field Values

METHOD_GET_DATABASE

private static final java.lang.String METHOD_GET_DATABASE

See Also:

Constant Field Values

METHOD_GET_TRANSACTION_ISOLATION

private static final java.lang.String METHOD_GET_TRANSACTION_ISOLATION

See Also:

Constant Field Values

METHOD_GET_SESSION_MAX_ROWS

private static final java.lang.String METHOD_GET_SESSION_MAX_ROWS

See Also:

Constant Field Values

hostsList

java.util.List<HostInfo> hostsList

connectionUrl

protected ConnectionUrl connectionUrl

autoReconnect

boolean autoReconnect

thisAsConnection

JdbcConnection thisAsConnection

parentProxyConnection

JdbcConnection parentProxyConnection

topProxyConnection

JdbcConnection topProxyConnection

currentConnection

JdbcConnection currentConnection

isClosed

boolean isClosed

closedExplicitly

boolean closedExplicitly

closedReason

java.lang.String closedReason

lastExceptionDealtWith

protected java.lang.Throwable lastExceptionDealtWith

Constructor Detail

MultiHostConnectionProxy

MultiHostConnectionProxy()
                  throws java.sql.SQLException

Initializes a connection wrapper for this MultiHostConnectionProxy instance.

Throws:

java.sql.SQLException - if an error occurs

MultiHostConnectionProxy

MultiHostConnectionProxy(ConnectionUrl connectionUrl)
                  throws java.sql.SQLException

Constructs a MultiHostConnectionProxy instance for the given connection URL.

Parameters:

connectionUrl - The connection URL.

Throws:

java.sql.SQLException - if an error occurs

Method Detail

initializeHostsSpecs

int initializeHostsSpecs(ConnectionUrl connUrl,
                         java.util.List<HostInfo> hosts)

Initializes the hosts lists and makes a "clean" local copy of the given connection properties so that it can be later used to create standard connections.

Parameters:

connUrl - The connection URL that initialized this multi-host connection.

hosts - The list of hosts for this multi-host connection.

Returns:

The number of hosts found in the hosts list.

getProxy

protected JdbcConnection getProxy()

Get this connection's proxy. A multi-host connection may not be at top level in the multi-host connections chain. In such case the first connection in the chain is available as a proxy.

Returns:

Returns this connection's proxy if there is one or itself if this is the first one.

getParentProxy

protected JdbcConnection getParentProxy()

Get this connection's parent proxy.

Returns:

Returns this connection's proxy if there is one.

setProxy

protected final void setProxy(JdbcConnection proxyConn)

Sets this connection's proxy. This proxy should be the first connection in the multi-host connections chain. After setting the connection proxy locally, propagates it through the dependent connections.

Parameters:

proxyConn - The top level connection in the multi-host connections chain.

propagateProxyDown

protected void propagateProxyDown(JdbcConnection proxyConn)

Propagates the connection proxy down through the multi-host connections chain. This method is intended to be overridden in subclasses that manage more than one active connection at same time.

Parameters:

proxyConn - The top level connection in the multi-host connections chain.

getNewWrapperForThisAsConnection

JdbcConnection getNewWrapperForThisAsConnection()
                                         throws java.sql.SQLException

Wraps this object with a new multi-host Connection instance.

Returns:

The connection object instance that wraps 'this'.

Throws:

java.sql.SQLException - if an error occurs

proxyIfReturnTypeIsJdbcInterface

java.lang.Object proxyIfReturnTypeIsJdbcInterface(java.lang.Class<?> returnType,
                                                  java.lang.Object toProxy)

If the given return type is or implements a JDBC interface, proxies the given object so that we can catch SQL errors and fire a connection switch.

Parameters:

returnType - The type the object instance to proxy is supposed to be.

toProxy - The object instance to proxy.

Returns:

The proxied object or the original one if it does not implement a JDBC interface.

getNewJdbcInterfaceProxy

java.lang.reflect.InvocationHandler getNewJdbcInterfaceProxy(java.lang.Object toProxy)

Instantiates a new JdbcInterfaceProxy for the given object. Subclasses can override this to return instances of JdbcInterfaceProxy subclasses.

Parameters:

toProxy - The object instance to be proxied.

Returns:

The new InvocationHandler instance.

dealWithInvocationException

void dealWithInvocationException(java.lang.reflect.InvocationTargetException e)
                          throws java.sql.SQLException,
                                 java.lang.Throwable,
                                 java.lang.reflect.InvocationTargetException

Deals with InvocationException from proxied objects.

Parameters:

e - The Exception instance to check.

Throws:

java.sql.SQLException - if an error occurs

java.lang.Throwable - if an error occurs

java.lang.reflect.InvocationTargetException - if an error occurs

shouldExceptionTriggerConnectionSwitch

abstract boolean shouldExceptionTriggerConnectionSwitch(java.lang.Throwable t)

Checks if the given throwable should trigger a connection switch.

Parameters:

t - The Throwable instance to analyze.

Returns:

true if the given throwable should trigger a connection switch

isSourceConnection

abstract boolean isSourceConnection()

Checks if current connection is to a source host.

Returns:

true if current connection is to a source host

isMasterConnection

@Deprecated
boolean isMasterConnection()

Deprecated.

Use isSourceConnection() instead.

Returns:

boolean

invalidateCurrentConnection

void invalidateCurrentConnection()
                          throws java.sql.SQLException

Invalidates the current connection.

Throws:

java.sql.SQLException - if an error occurs

invalidateConnection

void invalidateConnection(JdbcConnection conn)
                   throws java.sql.SQLException

Invalidates the specified connection by closing it.

Parameters:

conn - The connection instance to invalidate.

Throws:

java.sql.SQLException - if an error occurs

pickNewConnection

abstract void pickNewConnection()
                         throws java.sql.SQLException

Picks the "best" connection to use from now on. Each subclass needs to implement its connection switch strategy on it.

Throws:

java.sql.SQLException - if an error occurs

createConnectionForHost

ConnectionImpl createConnectionForHost(HostInfo hostInfo)
                                throws java.sql.SQLException

Creates a new physical connection for the given HostInfo.

Parameters:

hostInfo - The host info instance.

Returns:

The new Connection instance.

Throws:

java.sql.SQLException - if an error occurs

syncSessionState

void syncSessionState(JdbcConnection source,
                      JdbcConnection target)
               throws java.sql.SQLException

Synchronizes session state between two connections.

Parameters:

source - The connection where to get state from.

target - The connection where to set state.

Throws:

java.sql.SQLException - if an error occurs

syncSessionState

void syncSessionState(JdbcConnection source,
                      JdbcConnection target,
                      boolean readOnly)
               throws java.sql.SQLException

Synchronizes session state between two connections, allowing to override the read-only status.

Parameters:

source - The connection where to get state from.

target - The connection where to set state.

readOnly - The new read-only status.

Throws:

java.sql.SQLException - if an error occurs

doClose

abstract void doClose()
               throws java.sql.SQLException

Executes a close() invocation;

Throws:

java.sql.SQLException - if an error occurs

doAbortInternal

abstract void doAbortInternal()
                       throws java.sql.SQLException

Executes a abortInternal() invocation;

Throws:

java.sql.SQLException - if an error occurs

doAbort

abstract void doAbort(java.util.concurrent.Executor executor)
               throws java.sql.SQLException

Executes a abort() invocation;

Parameters:

executor - executor

Throws:

java.sql.SQLException - if an error occurs

invoke

public java.lang.Object invoke(java.lang.Object proxy,
                               java.lang.reflect.Method method,
                               java.lang.Object[] args)
                        throws java.lang.Throwable

Proxies method invocation on the java.sql.Connection interface, trapping multi-host specific methods and generic methods. Subclasses have to override this to complete the method invocation process, deal with exceptions and decide when to switch connection. To avoid unnecessary additional exception handling overriders should consult #canDealWith(Method) before chaining here.

Specified by:

invoke in interface java.lang.reflect.InvocationHandler

Parameters:

proxy - proxy object

method - method to invoke

args - method parameters

Returns:

method result

Throws:

java.lang.Throwable - if an error occurs

invokeMore

abstract java.lang.Object invokeMore(java.lang.Object proxy,
                                     java.lang.reflect.Method method,
                                     java.lang.Object[] args)
                              throws java.lang.Throwable

Continuation of the method invocation process, to be implemented within each subclass.

Parameters:

proxy - proxy object

method - method to invoke

args - method parameters

Returns:

method result

Throws:

java.lang.Throwable - if an error occurs

allowedOnClosedConnection

protected boolean allowedOnClosedConnection(java.lang.reflect.Method method)

Checks if the given method is allowed on closed connections.

Parameters:

method - method

Returns:

true if the given method is allowed on closed connections