uk.ac.ic.doc.automed.qproc.cache
Interface IQueryCache

All Superinterfaces:

Cacheable, java.util.Iterator, QueryRewritable

All Known Implementing Classes:

DefaultQueryCache, QueryCache

public interface IQueryCache
extends Cacheable, QueryRewritable

IQueryCache.java A public interface for query cache. It serves as the actual interface to query cache implementation by other projects.

Author:

Duc M Le dmle@doc.ic.ac.uk Created on 20 April 2006 Department of Computing, Imperial College

Method Summary

java.lang.String	addQuery(java.lang.String query, java.lang.Object metadata) Store reference to the AbstractQueryProcessor object that processes this query so that we can in a later stage use the query analysis with query result to build a semantic cache entry for the query .
void	addQueryResult(java.lang.String queryID, java.lang.Object resultObj) Add a new query to cache.
int	addSubQueryResult(java.lang.String queryID, java.lang.String subQuery, java.lang.Object resultObj) Add result of a sub-query of a query in the cache.
java.util.List	getCachedQueries() Return external queries of all cached items
ASG	getExactQuery(java.lang.String query) Check in the cache for an exact query match.
ASG	getExactSubQuery(java.lang.String subQuery) Check sub-query existence in the whole cache.
ASG	getExactSubQuery(java.lang.String queryID, java.lang.String subQuery) Check if result of the sub-query of a query already exists in the cache.
ASG[]	getQuery(java.lang.String query) Check in the cache for a similar query match.
java.lang.Object[]	getQueryMetadataObjects() Return an array of metadata objects associated to the query objects

Methods inherited from interface uk.ac.ic.doc.automed.util.cache.Cacheable

addListener, clear, getContentObject, notifyListeners, refresh

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Methods inherited from interface uk.ac.ic.doc.rodex.qproc.QueryRewritable

rewrite

Method Detail

addQueryResult

void addQueryResult(java.lang.String queryID,
                    java.lang.Object resultObj)
                    throws CacheIntegrityException

Add a new query to cache. The query is used as the key and result object
is the value. Often a query was pre-processed in query rewriting phase by an
instance of AbstractQueryProcessor whose result was added to this cache. Query result is often retrieved and later added to the cache at the execution phase
Hence, what we are doing here is to find the cache-item corresponding to the query and update it with

Parameters:

queryID - the unique query identifier (generated by #addQuery(String query, String fQuery, String sQuery, String iQuery, Object metadata, Object qproc) method

resultObj - the result object from query execution

Throws:

CacheIntegrityException

addSubQueryResult

int addSubQueryResult(java.lang.String queryID,
                      java.lang.String subQuery,
                      java.lang.Object resultObj)
                      throws CacheIntegrityException

Add result of a sub-query of a query in the cache. A query might have one or more intermediate results each of which is added as a sub_result item (List object) of the query cache item.

Each query's sub result is represented as a two-dimensional array as follows:
Object[] subResult = new Object[] {subQuery, subQueryResult}

Parameters:

queryID - the id of the parent query

subQuery - sub-query string

resultObj - sub-query result object

Returns:

int the sub-result id of the query identified by queryID

Throws:

CacheIntegrityException

addQuery

java.lang.String addQuery(java.lang.String query,
                          java.lang.Object metadata)
                          throws CacheIntegrityException

Store reference to the AbstractQueryProcessor object that processes this query
so that we can in a later stage use the query analysis with query result
to build a semantic cache entry for the query
.
A query processor object is constructed for each query in query rewriting phase carried out by the query mediator component.

Parameters:

query - the original (external) IQL query posed by user

fQuery - the formulated query

sQuery - the executional representation of the query

iQuery - the internal representation of the query. This is the primary query id.

metadata - the metadata object of the query (e.g. QueryAnalyser)

qproc - the AbstractQueryProcessor object

Returns:

String the unique query identifier

Throws:

CacheIntegrityException

getExactQuery

ASG getExactQuery(java.lang.String query)

Check in the cache for an exact query match. Note that this method operates on the internal IQL representation of the query which must only result in at most one matched entry. In any case, this method returns an array of the possible query results as ASGs.

Parameters:

query - the query string must be in internal format

Returns:

ASG[] array of possible query results found in the cache

getExactSubQuery

ASG getExactSubQuery(java.lang.String queryID,
                     java.lang.String subQuery)
                     throws CacheIntegrityException

Check if result of the sub-query of a query already exists in the cache. This method only checks sub-query existence among sub-queries of a given query instead of all queries in the cache

Parameters:

queryID - the ID of query to which the sub-query is associated

subQuery - sub-query to search for

Returns:

ASG sub-query result (or null if sub-query is not found

Throws:

CacheIntegrityException

getExactSubQuery

ASG getExactSubQuery(java.lang.String subQuery)

Check sub-query existence in the whole cache. This method is preferred to throws CacheIntegrityException

Parameters:

subQuery - sub-query to search for

Returns:

ASG sub-query result (or null if sub-query is not found

getQuery

ASG[] getQuery(java.lang.String query)

Check in the cache for a similar query match. Note that this method operates on the external IQL representation of the query which could result in more than one exact matches in the cache. In any case, this method returns an array of the possible query results as ASGs.

Parameters:

query - the query string must be in external format

Returns:

ASG[] array of possible query results found in the cache

getCachedQueries

java.util.List getCachedQueries()

Return external queries of all cached items

Returns:

List a list of all metadata objects in the cache OR null
if no queries are found

getQueryMetadataObjects

java.lang.Object[] getQueryMetadataObjects()

Return an array of metadata objects associated to the query objects