edu.ucsb.adl.bucket99
Class QueryThread

java.lang.Object
  |
  +--java.lang.Thread
        |
        +--edu.ucsb.adl.bucket99.QueryThread

All Implemented Interfaces:

QueryThread, java.lang.Runnable

public final class QueryThread

extends java.lang.Thread

implements QueryThread

A thread that executes an SQL query on behalf of the query driver for a collection. The thread reserves a database connection from the driver's connection pool, executes the query, requests standard ADL metadata views for each returned holding identifier, and adds the results to the query's result accumulator. Duplicate holding identifiers are discarded. Upon completion, the thread logs a record containing the following fields:

• The time the record was logged.
• The type of the record, which in this case is "query".
• The entity performing the logging, which in this case is the fully-qualified name of this class.
• The name of the collection, e.g., "adl_catalog".
• The time the thread was started.
• The time the query was submitted, or a negative value if an error occurred before the query was submitted.
• The time the first result was returned, or a negative value if the query returned zero results or an error occurred before the first result was returned.
• The total number of results returned by the query.
• The number of unique results.
• The exception that terminated the query, or the empty string if the query terminated successfully.
• The query in its original XML form.
• The query in SQL form.

All of the above times are in the semantics of System.currentTimeMillis.

Version:

$Header: /export/home/gjanee/bucket99/edu/ucsb/adl/bucket99/RCS/QueryThread.java,v 1.7 2006/06/23 02:25:01 gjanee Exp $

$Log: QueryThread.java,v $ Revision 1.7 2006/06/23 02:25:01 gjanee
Minor change to support metadata caching. Minor change to accomodate Java 1.5.

Revision 1.6 2004/09/14 00:08:22 gjanee
Minor change to better handle formatting of SQL exceptions.

Revision 1.5 2003/06/12 17:09:07 gjanee
Query results are now Result objects, i.e., triplets of standard metadata views. Added validation of query results.

Revision 1.4 2002/09/26 16:09:26 gjanee
Added the ability to preemptively cancel a running query.

Revision 1.3 2001/08/23 23:03:42 gjanee
Minor change to support string holding identifiers.

Revision 1.2 2000/10/26 13:12:06 gjanee
Disabled JDBC escape processing to avoid a syntax conflict with the MapInfo SpatialWare DataBlade over the use of curly braces ("{}").

Revision 1.1 2000/10/11 17:42:54 gjanee
Initial revision

Author:

Greg Janée
Alexandria Digital Library

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

QueryThread(java.lang.String collection, edu.ucsb.adl.middleware.Query query, java.lang.String sqlQuery, edu.ucsb.adl.middleware.ResultAccumulator accumulator, edu.ucsb.adl.bucket99.ConnectionPool pool, edu.ucsb.adl.bucket99.QueryDriver queryDriver, edu.ucsb.adl.middleware.MetadataDriver metadataDriver, boolean validateResults, edu.ucsb.adl.bucket99.Log log)
Creates a QueryThread.

Method Summary

java.lang.String	getCollection() Returns the name of the collection on whose behalf the thread is running.
java.lang.String	getProcessingState() Returns the thread's state.
edu.ucsb.adl.middleware.Query	getQuery() Returns the query the thread is executing.
java.lang.String	getSqlQuery() Returns the SQL query the thread is executing.
void	run()
void	stopASAP() Requests that the thread stop as soon as possible.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.ucsb.adl.middleware.QueryThread

start

Constructor Detail

QueryThread

public QueryThread(java.lang.String collection,
                   edu.ucsb.adl.middleware.Query query,
                   java.lang.String sqlQuery,
                   edu.ucsb.adl.middleware.ResultAccumulator accumulator,
                   edu.ucsb.adl.bucket99.ConnectionPool pool,
                   edu.ucsb.adl.bucket99.QueryDriver queryDriver,
                   edu.ucsb.adl.middleware.MetadataDriver metadataDriver,
                   boolean validateResults,
                   edu.ucsb.adl.bucket99.Log log)

Creates a QueryThread.

Parameters:

collection - The name of the collection, e.g., "adl_catalog".

query - The query to execute.

sqlQuery - The query to execute in SQL form.

accumulator - The accumulator to which results are to be sent.

pool - The connection pool.

queryDriver - The query driver creating the thread.

metadataDriver - The metadata driver to use to obtain metadata views.

validateResults - Indicates if query results should be validated.

log - The log file to log to, or null if logging is not desired.

Throws:

java.lang.NullPointerException - If any argument other than log is null.

Method Detail

stopASAP

public void stopASAP()

Requests that the thread stop as soon as possible.

Specified by:

stopASAP in interface QueryThread

getProcessingState

public java.lang.String getProcessingState()

Returns the thread's state.

Returns:

A description of the thread's state.

getCollection

public java.lang.String getCollection()

Returns the name of the collection on whose behalf the thread is running.

Specified by:

getCollection in interface QueryThread

Returns:

The collection name, e.g., "adl_catalog".

getQuery

public edu.ucsb.adl.middleware.Query getQuery()

Returns the query the thread is executing.

Returns:

The query.

getSqlQuery

public java.lang.String getSqlQuery()

Returns the SQL query the thread is executing.

Returns:

The query.

run

public void run()

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread