# Class ConnectionState

java.lang.Object
org.apache.tomcat.jdbc.pool.JdbcInterceptor
org.apache.tomcat.jdbc.pool.interceptor.ConnectionState

All Implemented Interfaces:
  `InvocationHandler`

public class ConnectionState extends JdbcInterceptor
Interceptor that keep track of connection state to avoid roundtrips to the database. The `ConnectionPool` is optimized to do as little work as possible. The pool itself doesn't remember settings like `Connection.setAutoCommit(boolean)`, `Connection.setReadOnly(boolean)`, `Connection.setCatalog(String)` or `Connection.setTransactionIsolation(int)`. It relies on the application to remember how and when these settings have been applied. In the cases where the application code doesn't know or want to keep track of the state, this interceptor helps cache the state, and it also avoids roundtrips to the database asking for it.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected Boolean`
  `autoCommit`
  Cached auto-commit state of the connection.
  `protected String`
  `catalog`
  Cached catalog (database) name of the connection.
  `protected Boolean`
  `readOnly`
  Cached read-only state of the connection.
  `protected final String[]`
  `readState`
  Method names for reading connection state.
  `protected Integer`
  `transactionIsolation`
  Cached transaction isolation level of the connection.
  `protected final String[]`
  `writeState`
  Method names for writing connection state.

  ### Fields inherited from class JdbcInterceptor

  `CLOSE_VAL, EQUALS_VAL, GETCONNECTION_VAL, HASHCODE_VAL, ISCLOSED_VAL, ISVALID_VAL, ISWRAPPERFOR_VAL, properties, TOSTRING_VAL, UNWRAP_VAL`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `ConnectionState()`
  Creates a new ConnectionState interceptor instance.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `disconnected(ConnectionPool parent, PooledConnection con, boolean finalizing)`
  Called when `Connection.close()` is called on the underlying connection.
  `Object`
  `invoke(Object proxy, Method method, Object[] args)`
  Gets invoked each time an operation on `Connection` is invoked.
  `void`
  `reset(ConnectionPool parent, PooledConnection con)`
  Gets called each time the connection is borrowed from the pool This means that if an interceptor holds a reference to the connection the interceptor can be reused for another connection.

  ### Methods inherited from class JdbcInterceptor

  `compare, compare, getNext, getProperties, isUseEquals, poolClosed, poolStarted, setNext, setProperties, setUseEquals`

  ### Methods inherited from class Object

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

- ## Field Details

  - ### readState

    protected final String[] readState
    Method names for reading connection state.

  - ### writeState

    protected final String[] writeState
    Method names for writing connection state.

  - ### autoCommit

    protected Boolean autoCommit
    Cached auto-commit state of the connection.

  - ### transactionIsolation

    protected Integer transactionIsolation
    Cached transaction isolation level of the connection.

  - ### readOnly

    protected Boolean readOnly
    Cached read-only state of the connection.

  - ### catalog

    protected String catalog
    Cached catalog (database) name of the connection.

- ## Constructor Details

  - ### ConnectionState

    public ConnectionState()
    Creates a new ConnectionState interceptor instance.

- ## Method Details

  - ### reset

    public void reset(ConnectionPool parent, PooledConnection con)
    Description copied from class: `JdbcInterceptor`
    Gets called each time the connection is borrowed from the pool This means that if an interceptor holds a reference to the connection the interceptor can be reused for another connection.
    This method may be called with null as both arguments when we are closing down the connection.
    Specified by:
      `reset` in class `JdbcInterceptor`
    Parameters:
      `parent` - - the connection pool owning the connection
      `con` - - the pooled connection

  - ### disconnected

    public void disconnected(ConnectionPool parent, PooledConnection con, boolean finalizing)
    Description copied from class: `JdbcInterceptor`
    Called when `Connection.close()` is called on the underlying connection. This is to notify the interceptors, that the physical connection has been released. Implementation of this method should be thought through with care, as no actions should trigger an exception.
    Overrides:
      `disconnected` in class `JdbcInterceptor`
    Parameters:
      `parent` - - the connection pool that this connection belongs to
      `con` - - the pooled connection that holds this connection
      `finalizing` - - if this connection is finalizing. True means that the pooled connection will not reconnect the underlying connection

  - ### invoke

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
    Description copied from class: `JdbcInterceptor`
    Gets invoked each time an operation on `Connection` is invoked.
    Specified by:
      `invoke` in interface `InvocationHandler`
    Overrides:
      `invoke` in class `JdbcInterceptor`
    Throws:
      `Throwable`