Package 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:
ClusterAwareConnectionProxy, 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.

  • Field Summary

    Fields 
    Modifier and Type Field Description
    protected boolean autoReconnect  
    protected boolean closedExplicitly  
    protected java.lang.String closedReason  
    protected ConnectionUrl connectionUrl  
    protected JdbcConnection currentConnection  
    protected java.util.List<HostInfo> hostsList  
    protected boolean isClosed  
    protected java.lang.Throwable lastExceptionDealtWith  
    protected JdbcConnection thisAsConnection  

  • Constructor Summary

    Constructors 
    Modifier Constructor Description
    protected MultiHostConnectionProxy​(ConnectionUrl connectionUrl)
    Constructs a MultiHostConnectionProxy instance for the given connection URL.

  • Method Summary

    Modifier and Type Method Description
    protected boolean allowedOnClosedConnection​(java.lang.reflect.Method method)
    Checks if the given method is allowed on closed connections.
    protected ConnectionImpl createConnectionForHost​(HostInfo hostInfo)
    Creates a new physical connection for the given HostInfo.
    protected void dealWithInvocationException​(java.lang.reflect.InvocationTargetException e)
    Deals with InvocationException from proxied objects.
    protected abstract void doAbort​(java.util.concurrent.Executor executor)
    Executes a abort() invocation;
    protected abstract void doAbortInternal()
    Executes a abortInternal() invocation;
    protected abstract void doClose()
    Executes a close() invocation;
    protected java.lang.reflect.InvocationHandler getNewJdbcInterfaceProxy​(java.lang.Object toProxy)
    Instantiates a new JdbcInterfaceProxy for the given object.
    protected JdbcConnection getParentProxy()
    Get this connection's parent proxy.
    protected JdbcConnection getProxy()
    Get this connection's proxy.
    protected void invalidateConnection​(JdbcConnection conn)
    Invalidates the specified connection by closing it.
    protected 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.
    protected 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.
    protected abstract boolean isSourceConnection()
    Checks if current connection is to a source host.
    protected 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.
    protected 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.
    protected abstract boolean shouldExceptionTriggerConnectionSwitch​(java.lang.Throwable t)
    Checks if the given throwable should trigger a connection switch.
    protected 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 Details

  • Constructor Details

    • MultiHostConnectionProxy

      protected 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 Details

    • 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.

    • proxyIfReturnTypeIsJdbcInterface

      protected 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

      protected 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

      protected 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

      protected 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

      protected abstract boolean isSourceConnection()
      Checks if current connection is to a source host.
      Returns:
      true if current connection is to a source host

    • invalidateCurrentConnection

      protected void invalidateCurrentConnection() throws java.sql.SQLException
      Invalidates the current connection.
      Throws:
      java.sql.SQLException - if an error occurs

    • invalidateConnection

      protected 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

      protected 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

      protected 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

      protected 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

      protected abstract void doClose() throws java.sql.SQLException
      Executes a close() invocation;
      Throws:
      java.sql.SQLException - if an error occurs

    • doAbortInternal

      protected abstract void doAbortInternal() throws java.sql.SQLException
      Executes a abortInternal() invocation;
      Throws:
      java.sql.SQLException - if an error occurs

    • doAbort

      protected 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

      protected 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