WSCallHelper (IBM WebSphere Application Server [adapter])

com.ibm.websphere.rsadapter
Class WSCallHelper
java.lang.Object
  |
  +--com.ibm.websphere.rsadapter.WSCallHelper
public class WSCallHelper
extends java.lang.Object

Provides static methods for invoking non-standard methods on objects wrapped by WebSphere. For example, the jdbcCall method can be used to invoke vendor specific non-JDBC methods on the underlying JDBC objects wrapped by WebSphere.

Field Summary

static int CALLABLE_STATEMENT
          Constant indicating a java.sql.CallableStatement parameter.

static int CONNECTION
          Constant indicating a java.sql.Connection parameter.

static java.lang.String CONSTRUCTOR
          Constant indicating the jdbcPass method is invoking a constructor.

static int DATA_SOURCE
          Constant indicating a javax.sql.DataSource parameter.

static int DATABASE_META_DATA
          Constant indicating a java.sql.DatabaseMetaData parameter.

static int IGNORE
          Constant indicating the corresponding parameter should be ignored.

static int PREPARED_STATEMENT
          Constant indicating a java.sql.PreparedStatement parameter.

static int RESULT_SET
          Constant indicating a java.sql.ResultSet parameter.

static int STATEMENT
          Constant indicating a java.sql.Statement parameter.

Method Summary

static java.lang.Object call(java.lang.Object target, java.lang.String methName, java.lang.Object[] params, java.lang.Class[] types)
          A shortcut method for reflection.

static DataStoreHelper createDataStoreHelper(java.lang.String dsClassName)
          Deprecated. - please use getDataStoreHelper instead of this method

static DataStoreHelper getDataStoreHelper(javax.sql.DataSource ds)
          Retrieves the DataStoreHelper associated with the specified WebSphere DataSource.

static boolean isShareable(java.sql.Connection conn)
          Determines whether a WebSphere Connection is shareable or not.

static java.lang.Object jdbcCall(java.lang.Class underlyingObjectType, java.lang.Object caller, java.lang.String methName, java.lang.Object[] args, java.lang.Class[] argTypes)
          Calls a non-standard-JDBC method, specific to the JDBC provider implementation class, on the underlying JDBC object corresponding to a WebSphere JDBC wrapper.

static java.lang.Object jdbcPass(java.lang.Class targetClass, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] types, int[] unwrap)
          Invokes a static method for which one or more of the method parameters must be a native JDBC object.

static java.lang.Object jdbcPass(java.lang.Object targetObject, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] types, int[] unwrap)
          Invokes a method for which one or more of the method parameters must be a native JDBC object.

static void setConnectionError(java.lang.Object connHandle)
          Signals WebSphere that an application-detected fatal error has occured on the specified Connection handle so that WebSphere may remove it from the pool, or purge the entire pool, as determined by the purge policy.

Methods inherited from class java.lang.Object

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

Field Detail

CONSTRUCTOR
public static final java.lang.String CONSTRUCTOR
Constant indicating the jdbcPass method is invoking a constructor.

See Also:
Constant Field Values

IGNORE
public static final int IGNORE
Constant indicating the corresponding parameter should be ignored.

Since:

WAS 5.1

See Also:
Constant Field Values

DATA_SOURCE
public static final int DATA_SOURCE
Constant indicating a javax.sql.DataSource parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

CONNECTION
public static final int CONNECTION
Constant indicating a java.sql.Connection parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

STATEMENT
public static final int STATEMENT
Constant indicating a java.sql.Statement parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

PREPARED_STATEMENT
public static final int PREPARED_STATEMENT
Constant indicating a java.sql.PreparedStatement parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

CALLABLE_STATEMENT
public static final int CALLABLE_STATEMENT
Constant indicating a java.sql.CallableStatement parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

RESULT_SET
public static final int RESULT_SET
Constant indicating a java.sql.ResultSet parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

DATABASE_META_DATA
public static final int DATABASE_META_DATA
Constant indicating a java.sql.DatabaseMetaData parameter.

Since:

WAS 5.1

See Also:
Constant Field Values

Method Detail

call
public static java.lang.Object call(java.lang.Object target,
                                    java.lang.String methName,
                                    java.lang.Object[] params,
                                    java.lang.Class[] types)
                             throws java.lang.NoSuchMethodException,
                                    java.lang.SecurityException,
                                    java.lang.IllegalAccessException,
                                    java.lang.IllegalArgumentException,
                                    java.lang.reflect.InvocationTargetException
A shortcut method for reflection.

Parameters:
target - the object to invoke a method on.
methName - the name of the method.
params - an ordered list of the parameters passed to the method.
types - an ordered list of the parameter types on the method signature.
Returns:
The Object returned by the specified method, or null if it returns nothing. In the case where the value normally returned is a primitive, it is returned in its corresponding wrapper class.
Throws:
java.lang.NoSuchMethodException - if a matching method is not found or if the name is ""or "".
java.lang.SecurityException - if access to the information is denied.
java.lang.IllegalAccessException - if the underlying method is inaccessible.
java.lang.IllegalArgumentException - if the number of actual and formal parameters differ, or if an unwrapping conversion fails.
java.lang.reflect.InvocationTargetException - if the underlying method throws an exception.
java.lang.NullPointerException - if the specified object is null and the method is an instance method.
java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.
See Also:
java.lang.Class.getMethod, java.lang.reflect.Method.invoke

createDataStoreHelper
public static DataStoreHelper createDataStoreHelper(java.lang.String dsClassName)
                                             throws javax.resource.ResourceException
Deprecated. - please use getDataStoreHelper instead of this method

DEPRECATED Create a new instance of the DataStoreHelper for the specified DataSource class.

Parameters:
dsClassName - the name of the DataSource class.
Returns:
the DataStoreStoreHelper or null if none is found.
Throws:
ResourceException - if an error occurs creating the DataStoreHelper.

getDataStoreHelper
public static final DataStoreHelper getDataStoreHelper(javax.sql.DataSource ds)
Retrieves the DataStoreHelper associated with the specified WebSphere DataSource.

Parameters:
ds - a WebSphere DataSource.
Returns:
the DataStoreHelper

isShareable
public static final boolean isShareable(java.sql.Connection conn)
                                 throws java.sql.SQLException
Determines whether a WebSphere Connection is shareable or not.

Parameters:
conn - the Connection.
Returns:
true if this Connection is shareable; false if it is non-shareable.
Throws:
SQLException - if the Connection is closed.
java.lang.ClassCastException - if the Connection is not a WebSphere Connection wrapper.

jdbcCall
public static final java.lang.Object jdbcCall(java.lang.Class underlyingObjectType,
                                              java.lang.Object caller,
                                              java.lang.String methName,
                                              java.lang.Object[] args,
                                              java.lang.Class[] argTypes)
                                       throws java.sql.SQLException
Calls a non-standard-JDBC method, specific to the JDBC provider implementation class, on the underlying JDBC object corresponding to a WebSphere JDBC wrapper. This method should be used for non-JDBC methods only.

For example, if JDBC provider X provided a non-standard method on its implementation of java.sql.Connection called countOpenStatements() taking two int parameters, and if a WebSphere DataSource was configured for JDBC provider X and used to get a Connection, conn, the following could be used to call the method and read the value returned,
 Object result = WSCallHelper.jdbcCall(
     null,
     conn,
     "countOpenStatements",
     new Object[] { new Integer(ResultSet.TYPE_FORWARD_ONLY),
                    new Integer(ResultSet.CONCUR_READ_ONLY) },
     new Class[] { int.class, int.class });

 int numOpenStatements = ((Integer) result).intValue();
When to use the 'underlyingObjectType' Parameter

Some WebSphere JDBC wrappers wrap multiple JDBC classes. For example, the WebSphere Connection wrapper contains a java.sql.Connection and either a javax.sql.PooledConnection or a javax.sql.XAConnection. The underlyingObjectType parameter allows for distinguishing between the multiple wrapped objects according to their interface class.

This parameter is only required when invoking a method on WebSphere wrappers containing multiple JDBC objects and requesting to invoke a method on a JDBC interface other than that of the wrapper class. In all other cases a value of null may be used, as in the above example. A second example, where the underlyingObjectType parameter is required follows,

Assume JDBC provider X provides a non-standard method on its implementation of javax.sql.XAConnection called getTransactionStatus(), and a WebSphere DataSource was configured for JDBC provider X and used to get a Connection, conn. Then the following can be used to call the method and read the value returned,
 String status = (String) WSCallHelper.jdbcCall(
     javax.sql.XAConnection.class,
     conn,
     "getTransactionStatus",
     new Object[] {},
     new Class[] {});
Determining what Properties are Settable on a DataSource

As a general rule, properties which are settable on the GUI during DataSource creation are not settable through the WSCallHelper. The WSCallHelper support is intended for providing the ability to set additional properties, which are not representable on the GUI configuration.

WebSphere will allow you to set, through the GUI, any property type meeting the following criteria,

is a primitive type or is a wrapper for a primitive type (int, long, char, Integer)
has a single-parameter String constructor (java.math.BigInteger, java.math.BigDecimal)
is java.util.Properties

All remaining setters should be available through the WSCallHelper.
Parameters:
underlyingObjectType - The interface class of the underlying JDBC object to use. This value may be null if WebSphere wrapper wraps only one type of JDBC object or the JDBC interface is the same as that of the WebSphere wrapper class.
caller - The WebSphere JDBC wrapper on which to call the method.
methName - name of the method to call.
args - list of method parameters.
argTypes - list of method parameter types.
Returns:
The Object returned by the specified method, or null if it returns nothing. In the case where the value normally returned is a primitive, it is returned in its corresponding wrapper class.
Throws:
SQLException - if the method call is invalid or throws a SQLException itself during execution. SQLException may also be thrown when the method name supplied is a standard JDBC method.
jdbcPass
public static java.lang.Object jdbcPass(java.lang.Class targetClass,
                                        java.lang.String methodName,
                                        java.lang.Object[] args,
                                        java.lang.Class[] types,
                                        int[] unwrap)
                                 throws java.sql.SQLException
Invokes a static method for which one or more of the method parameters must be a native JDBC object. This method substitutes any WebSphere JDBC wrappers with the corresponding native JDBC object and invokes the static method. The jdbcPass method should be used only when native JDBC objects are required.

For example, assume JDBC provider XYZ provides a class, ResultSetFormatter, which contains a static method, format, taking two parameters of types com.xyz.jdbc.XYZResultSet and int. Also, assume the internal implementation of the format method requires access to special proprietary methods or fields defined on the com.xyz.jdbc.XYZResultSet class. If WebSphere is configured to use JDBC provider XYZ and a ResultSet object, rset, is obtained, the following code could be used to invoke the ResultSetFormatter.format method:
 Object result = WSCallHelper.jdbcPass(
     ResultSetFormatter.class,
     "format",
     new Object[] { rset, new Integer(2) },
     new Class[] { com.xyz.jdbc.XYZResultSet.class, int.class }
     new int[] { WSCallHelper.RESULT_SET, WSCallHelper.IGNORE });
 
WARNING:

Usage of jdbcPass bypasses WebSphere's JDBC wrappers and may result in unpredictable, unstable behavior. WebSphere does not claim to support the jdbcPass methods and neither IBM nor WebSphere are responsible for any damage incurred by usage of the jdbcPass methods. Any customer choosing to use the jdbcPass methods does so at their own risk.

Restrictions:

Permitted Methods. Due to the high degree of unpredictability and instability possible as side effects of using jdbcPass, WebSphere permits the invocation of only a select list of methods via the jdbcPass interface. These methods guarantee they will not alter the state of native JDBC objects in any way that might adversely effect the behavior of the WebSphere JDBC wrappers. Any customer requiring access to additional methods via jdbcPass should contact WebSphere support.

Exception Mapping. Because multiple native JDBC objects--possibly all from different DataSources--might be involved in a single jdbcPass invocation, it is not possible for WebSphere to handle connection error detection, stale statement detection, or any other type of exception mapping. It is left to the application to implement any exception mapping and handling which might be necessary. Applications may use the setConnectionError method to notify WebSphere of any such connection error situations detected by the application.
Parameters:
targetClass - the class on which to invoke the static method.
methodName - the name of the method to invoke. The WSCallHelper.CONSTRUCTOR constant may be used to signal the method is a constructor.
args - list of method parameters, of which at least one is a WebSphere JDBC wrapper.
types - list of method parameter types.
unwrap - list of constants specifying which method parameters are WebSphere JDBC wrappers needing to be unwrapped and replaced with the corresponding native JDBC objects.
Returns:
The Object returned by the specified method, or null if it returns nothing. In the case where the value normally returned is a primitive, it is returned in its corresponding wrapper class.
Throws:
SQLException - if the method call is invalid or throws a SQLException itself during execution. SQLException may also be thrown if the method requested is not permitted by WebSphere.
Since:

WAS 5.1
jdbcPass
public static java.lang.Object jdbcPass(java.lang.Object targetObject,
                                        java.lang.String methodName,
                                        java.lang.Object[] args,
                                        java.lang.Class[] types,
                                        int[] unwrap)
                                 throws java.sql.SQLException
Invokes a method for which one or more of the method parameters must be a native JDBC object. The jdbcPass method should be used only when native JDBC objects are required.

For example, assume JDBC provider XYZ provides a class, com.x.jdbc.CustomTable, which contains a proprietary method, populate, taking two parameters of types com.xyz.jdbc.XYZConnection and String. Also, assume the internal implementation of the populate method requires access to special proprietary methods or fields defined on the com.xyz.jdbc.XYZConnection class. If WebSphere is configured to use JDBC provider XYZ and a java.sql.Connection object, conn, is obtained, the following code could be used to invoke the customTable.populate method:
 Object result = WSCallHelper.jdbcPass(
     customTable
     "populate",
     new Object[] { conn, "select zebras, elephants, alligators, from zooStats" },
     new Class[] { com.xyz.jdbc.XYZConnection.class, String.class }
     new int[] { WSCallHelper.CONNECTION, WSCallHelper.IGNORE });
 
WARNING:

Usage of jdbcPass bypasses WebSphere's JDBC wrappers and may result in unpredictable, unstable behavior. WebSphere does not claim to support the jdbcPass methods and neither IBM nor WebSphere are responsible for any damage incurred by usage of the jdbcPass methods. Any customer choosing to use the jdbcPass methods does so at their own risk.

Restrictions:

Permitted Methods. Due to the high degree of unpredictability and instability possible as side effects of using jdbcPass, WebSphere permits the invocation of only a select list of methods via the jdbcPass interface. These methods guarantee they will not alter the state of native JDBC objects in any way that might adversely effect the behavior of the WebSphere JDBC wrappers. Any customer requiring access to additional methods via jdbcPass should contact WebSphere support.

Exception Mapping. Because multiple native JDBC objects--possibly all from different DataSources--might be involved in a single jdbcPass invocation, it is not possible for WebSphere to handle connection error detection, stale statement detection, or any other type of exception mapping. It is left to the application to implement any exception mapping and handling which might be necessary. Applications may use the setConnectionError method to notify WebSphere of any such connection error situations detected by the application.
Parameters:
targetObject - the object on which to invoke the method.
methodName - the name of the method to invoke. The WSCallHelper.CONSTRUCTOR constant may be used to signal the method is a constructor.
args - list of method parameters, of which at least one is a WebSphere JDBC wrapper.
types - list of method parameter types.
unwrap - list of constants specifying which method parameters are WebSphere JDBC wrappers needing to be unwrapped and replaced with the corresponding native JDBC objects.
Returns:
The Object returned by the specified method, or null if it returns nothing. In the case where the value normally returned is a primitive, it is returned in its corresponding wrapper class.
Throws:
java.sql.SQLException - if the method call is invalid or throws a SQLException itself during execution. SQLException may also be thrown if the method requested is not permitted by WebSphere.
Since:

WAS 5.1
setConnectionError
public static final void setConnectionError(java.lang.Object connHandle)
Signals WebSphere that an application-detected fatal error has occured on the specified Connection handle so that WebSphere may remove it from the pool, or purge the entire pool, as determined by the purge policy.

Parameters:
connHandle - the Connection handle on which the error occurred.

WebSphere is a trademark of the IBM Corporation in the United States, other countries, or both.

IBM is a trademark of the IBM Corporation in the United States, other countries, or both.

Field Summary
static int	CALLABLE_STATEMENT Constant indicating a java.sql.CallableStatement parameter.
static int	CONNECTION Constant indicating a java.sql.Connection parameter.
static java.lang.String	CONSTRUCTOR Constant indicating the jdbcPass method is invoking a constructor.
static int	DATA_SOURCE Constant indicating a javax.sql.DataSource parameter.
static int	DATABASE_META_DATA Constant indicating a java.sql.DatabaseMetaData parameter.
static int	IGNORE Constant indicating the corresponding parameter should be ignored.
static int	PREPARED_STATEMENT Constant indicating a java.sql.PreparedStatement parameter.
static int	RESULT_SET Constant indicating a java.sql.ResultSet parameter.
static int	STATEMENT Constant indicating a java.sql.Statement parameter.

Method Summary
static java.lang.Object	call(java.lang.Object target, java.lang.String methName, java.lang.Object[] params, java.lang.Class[] types) A shortcut method for reflection.
static DataStoreHelper	createDataStoreHelper(java.lang.String dsClassName) Deprecated. - please use getDataStoreHelper instead of this method
static DataStoreHelper	getDataStoreHelper(javax.sql.DataSource ds) Retrieves the DataStoreHelper associated with the specified WebSphere DataSource.
static boolean	isShareable(java.sql.Connection conn) Determines whether a WebSphere Connection is shareable or not.
static java.lang.Object	jdbcCall(java.lang.Class underlyingObjectType, java.lang.Object caller, java.lang.String methName, java.lang.Object[] args, java.lang.Class[] argTypes) Calls a non-standard-JDBC method, specific to the JDBC provider implementation class, on the underlying JDBC object corresponding to a WebSphere JDBC wrapper.
static java.lang.Object	jdbcPass(java.lang.Class targetClass, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] types, int[] unwrap) Invokes a static method for which one or more of the method parameters must be a native JDBC object.
static java.lang.Object	jdbcPass(java.lang.Object targetObject, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] types, int[] unwrap) Invokes a method for which one or more of the method parameters must be a native JDBC object.
static void	setConnectionError(java.lang.Object connHandle) Signals WebSphere that an application-detected fatal error has occured on the specified Connection handle so that WebSphere may remove it from the pool, or purge the entire pool, as determined by the purge policy.

com.ibm.websphere.rsadapter Class WSCallHelper

CONSTRUCTOR

IGNORE

DATA_SOURCE

CONNECTION

STATEMENT

PREPARED_STATEMENT

CALLABLE_STATEMENT

RESULT_SET

DATABASE_META_DATA

call

createDataStoreHelper

getDataStoreHelper

isShareable

jdbcCall

When to use the 'underlyingObjectType' Parameter

Determining what Properties are Settable on a DataSource

jdbcPass

jdbcPass

setConnectionError

com.ibm.websphere.rsadapter
Class WSCallHelper