org.mmbase.storage.search

Interface SearchQueryHandler

All Known Implementing Classes:

BasicQueryHandler

public interface SearchQueryHandler

Defines methods for an object that handles search query requests.

Since:

MMBase-1.7

Version:

$Id$

Author:

Rob van Maris

Field Summary

Fields

Modifier and Type	Field and Description
static int	FEATURE_MAX_NUMBER Feature that allows specifying the maximum number of results to be returned.
static int	FEATURE_OFFSET Feature that allows specifying an index in the list of results, as a starting popublic final static int for results to be returned.
static int	FEATURE_REGEXP Feature that allows to search on string by a regular expression.
static int	SUPPORT_NONE Support level for features that are not supported.
static int	SUPPORT_NORMAL Support level for features that are available for use under normal circumstances.
static int	SUPPORT_OPTIMAL Support level for features that are optimally supported.
static int	SUPPORT_WEAK Support level for features that are supported, but not recommended when performance is critical.

Method Summary

Modifier and Type	Method and Description
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.

Field Detail

SUPPORT_NONE

static final int SUPPORT_NONE

Support level for features that are not supported.

See Also:

Constant Field Values

SUPPORT_WEAK

static final int SUPPORT_WEAK

Support level for features that are supported, but not recommended when performance is critical.

See Also:

Constant Field Values

SUPPORT_NORMAL

static final int SUPPORT_NORMAL

Support level for features that are available for use under normal circumstances.

See Also:

Constant Field Values

SUPPORT_OPTIMAL

static final int SUPPORT_OPTIMAL

Support level for features that are optimally supported. This applies also to features that are supported without a significant impact on performance penalty.

See Also:

Constant Field Values

FEATURE_MAX_NUMBER

static final int FEATURE_MAX_NUMBER

Feature that allows specifying the maximum number of results to be returned.

See Also:

SearchQuery.getMaxNumber(), Constant Field Values

FEATURE_OFFSET

static final int FEATURE_OFFSET

Feature that allows specifying an index in the list of results, as a starting popublic final static int for results to be returned.

See Also:

SearchQuery.getOffset(), Constant Field Values

FEATURE_REGEXP

static final int FEATURE_REGEXP

Feature that allows to search on string by a regular expression.

See Also:

SearchQuery.getOffset(), Constant Field Values

Method Detail

getSupportLevel

int getSupportLevel(int feature,
                    SearchQuery query)
             throws SearchQueryException

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.

Throws:

SearchQueryException

getSupportLevel

int getSupportLevel(Constraint constraint,
                    SearchQuery query)
             throws SearchQueryException

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.

Throws:

SearchQueryException

getNodes

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

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.

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

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.

Parameters:

query - the query to convert to sql

Returns:

the sql string

Throws:

SearchQueryException - when error occurs while making the string

Since:

MMBase-1.8.5