uk.org.ogsadai.activity.sql
Class SQLQueryMultipleActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.sql.SQLQueryMultipleActivity

Direct Known Subclasses:

SQLBagActivity, SQLResilientQueryActivity

public abstract class SQLQueryMultipleActivity

extends Activity

This is abstract class for activities which query multiple relational resources e.g. SQLResilientQueryActivity and SQLBagActivity.

The activity's perform document is defined by schema/ogsadai/xsd/activities/sql_query_multiple.xsd.

The activity calls multiple data service resources each one being executed in its own thread.

Author:

The OGSA-DAI Project Team

Field Summary

private static java.lang.String	COPYRIGHT_NOTICE Copyright statement
private static DAILogger	LOG Logger object for logging in this class.
protected long	mClientTimeout Timeout in millisecond set by client: 0 for unlimited, -1 for n/a else a long.
protected DataServiceInfo[]	mMultipleDS Information about each data service and data service resource
protected BlockWriter	mOutput Activity output - WebRowSet containing result
protected java.lang.String	mOutputString The merged query result
protected java.lang.String	mSqlStatement SQL query statement from request
protected boolean	mTimeoutStatus Indicator of whether a thread has timed out or not
protected java.util.Timer	mTimer The timer that will be used by the threads to check the timout.

Fields inherited from class uk.org.ogsadai.activity.Activity

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

SQLQueryMultipleActivity(org.w3c.dom.Element element)

Method Summary

protected void	cleanUp() This method can be overridden by any Activity implementations that need to free up resources in the event of an error or intermediate termination of the activity processing.
void	initialise() This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin.
(package private) boolean	isTimeout() Check if the thread of each of the data service resources has timed out.
(package private) void	setTimeout(boolean status) Set the time out of each of the data service resources has timed out.

Methods inherited from class uk.org.ogsadai.activity.Activity

connectsTo, createOutputPipe, getActivityConfiguration, getActivityName, getCause, getName, getObservableStatus, getProperties, getSession, getStatus, hasActivityConfiguration, hasProperties, process, processBlock, processFirst, setActivityName, setCompleted, setError

Methods inherited from class java.lang.Object

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

Field Detail

COPYRIGHT_NOTICE

private static final java.lang.String COPYRIGHT_NOTICE

Copyright statement

See Also:

Constant Field Values

LOG

private static final DAILogger LOG

Logger object for logging in this class.

mOutput

protected BlockWriter mOutput

Activity output - WebRowSet containing result

mSqlStatement

protected java.lang.String mSqlStatement

SQL query statement from request

mOutputString

protected java.lang.String mOutputString

The merged query result

mMultipleDS

protected DataServiceInfo[] mMultipleDS

Information about each data service and data service resource

mClientTimeout

protected long mClientTimeout

Timeout in millisecond set by client: 0 for unlimited, -1 for n/a else a long.

mTimer

protected java.util.Timer mTimer

The timer that will be used by the threads to check the timout.

mTimeoutStatus

protected boolean mTimeoutStatus

Indicator of whether a thread has timed out or not

Constructor Detail

SQLQueryMultipleActivity

public SQLQueryMultipleActivity(org.w3c.dom.Element element)
                         throws ActivitySpecificationException,
                                ActivityCreationException

Method Detail

isTimeout

boolean isTimeout()

Check if the thread of each of the data service resources has timed out.

Returns:

true if so, false if not.

setTimeout

void setTimeout(boolean status)

Set the time out of each of the data service resources has timed out.

Parameters:

status - true if so, false if not.

initialise

public void initialise()
                throws ActivitySpecificationException,
                       ActivityExecutionException

Description copied from class: Activity

This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin. This might be used for setting up convenient fields to reference objects contained in the context. It shouldn't be used for opening resources. That should be done in processFirst.

Overrides:

initialise in class Activity

Throws:

ActivityExecutionException - If some system problem prevents the activity from initialising.

ActivitySpecificationException - If a problem with settings provided by a client prevents the activity from initialising.

cleanUp

protected void cleanUp()

Description copied from class: Activity

This method can be overridden by any Activity implementations that need to free up resources in the event of an error or intermediate termination of the activity processing.

Overrides:

cleanUp in class Activity