org.mmbase.storage.search.implementation.database
Class BasicQueryHandler

java.lang.Object
  org.mmbase.storage.search.implementation.database.BasicQueryHandler

All Implemented Interfaces:

CoreSearchQueryHandler, SearchQueryHandler

public class BasicQueryHandler
extends Object
implements CoreSearchQueryHandler

Basic implementation using a database. Uses a SqlHandler to create SQL string representations of search queries.

In order to execute search queries, these are represented as SQL strings by the handler, and in this form executed on the database.

Since:

MMBase-1.7

Version:

$Id: BasicQueryHandler.java 42909 2010-07-15 14:55:42Z michiel $

Author:

Rob van Maris

Field Summary

Fields inherited from interface org.mmbase.storage.search.SearchQueryHandler

FEATURE_MAX_NUMBER, FEATURE_OFFSET, FEATURE_REGEXP, SUPPORT_NONE, SUPPORT_NORMAL, SUPPORT_OPTIMAL, SUPPORT_WEAK

Constructor Summary

BasicQueryHandler(SqlHandler sqlHandler)
Default constructor.

Method Summary

String	createSqlString(SearchQuery query) Makes a String of a query, taking into consideration if the database supports offset and maxnumber features.
List<MMObjectNode>	getNodes(SearchQuery query, MMObjectBuilder builder) Processes a search query, returns the result as a list of nodes.
int	getSupportLevel(Constraint constraint, SearchQuery query) Gets the level at which a constraint is supported for a query by this handler.
int	getSupportLevel(int feature, SearchQuery query) Gets the level at which a feature is supported for a query by this handler.

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicQueryHandler

public BasicQueryHandler(SqlHandler sqlHandler)

Default constructor.

Parameters:

sqlHandler - The handler use to create SQL string representations of search queries.

Method Detail

getNodes

public List<MMObjectNode> getNodes(SearchQuery query,
                                   MMObjectBuilder builder)
                            throws SearchQueryException

Description copied from interface: CoreSearchQueryHandler

Processes a search query, returns the result as a list of nodes. Depending on the specified builder, the results will be:

• Resultnodes, with fields named according to the field aliases specified by the query.
• Clusternodes, with fields named <step alias>.<field name>, where the step alias is required to be of the form <step tablename><x>, and <x> is either empty or a single digit. Examples:
  images.number, images0.number, images1.number
• Real nodes, where all fields are required to be included in the query.

Specified by:

getNodes in interface CoreSearchQueryHandler

Parameters:

query - The search query.

builder - The builder for the result nodes. Specify a ResultBuilder to get resultnodes. ClusterBuilder to get clusternodes.

Returns:

The resulting nodes.

Throws:

SearchQueryException

See Also:

ResultNode, ClusterNode

createSqlString

public String createSqlString(SearchQuery query)
                       throws SearchQueryException

Makes a String of a query, taking into consideration if the database supports offset and maxnumber features. The resulting String is an SQL query which can be fed to the database.

Specified by:

createSqlString in interface SearchQueryHandler

Parameters:

query - the query to convert to sql

Returns:

the sql string

Throws:

SearchQueryException - when error occurs while making the string

getSupportLevel

public int getSupportLevel(int feature,
                           SearchQuery query)
                    throws SearchQueryException

Description copied from interface: SearchQueryHandler

Gets the level at which a feature is supported for a query by this handler. This is one of either:

• SUPPORT_NONE
• SUPPORT_WEAK
• SUPPORT_NORMAL
• SUPPORT_OPTIMAL

Given the choice, the query handler with the highest level of support is prefered.

Specified by:

getSupportLevel in interface SearchQueryHandler

Throws:

SearchQueryException

getSupportLevel

public int getSupportLevel(Constraint constraint,
                           SearchQuery query)
                    throws SearchQueryException

Description copied from interface: SearchQueryHandler

Gets the level at which a constraint is supported for a query by this handler. This is one of either:

• SUPPORT_NONE
• SUPPORT_WEAK
• SUPPORT_NORMAL
• SUPPORT_OPTIMAL

Given the choice, the query handler with the highest level of support is prefered.

Specified by:

getSupportLevel in interface SearchQueryHandler

Throws:

SearchQueryException