org.mycore.backend.jdom
Class MCRJDOMSearcher

java.lang.Object
  org.mycore.common.events.MCREventHandlerBase
      org.mycore.services.fieldquery.MCRSearcher
          org.mycore.backend.jdom.MCRJDOMSearcher

All Implemented Interfaces:

MCREventHandler

public class MCRJDOMSearcher
extends MCRSearcher

Implements a searcher and indexer for MCRObject metadata using only data in memory without any persistent structures. When data is indexed, the values are stored as XML document in memory. When data is searched, the query is transformed to a XSL condition and run against the XML in memory. Before first use of instances of this class, all MCRObject metadata is loaded from persistent store and indexed in memory. This class may also be useful for learning how to implement MCRSearchers and indexers.

Author:

Frank Lützenkirchen

Field Summary

Fields inherited from class org.mycore.services.fieldquery.MCRSearcher

ID, index, prefix, RETURN_ID_CACHE

Constructor Summary

MCRJDOMSearcher()

Method Summary

void	addSortData(Iterator<MCRHit> hits, List<MCRSortBy> sortBy) Adds field values needed for sorting for those hits that do not have sort data set already.
void	addToIndex(String entryID, String returnID, List fields) Adds field values to the search index.
static boolean	compare(String valueA, String valueB, String operator) Implements a string compare operator as Xalan function extension
static boolean	contains(String value, String words) Implements the contains operator as Xalan function extension
void	init(String ID) Initializes the searcher and sets its unique ID.
static boolean	like(String value, String pattern) Implements the like operator as Xalan function extension
void	removeFromIndex(String entryID) Removes the values of the given entry from the backend index.
MCRResults	search(MCRCondition condition, int maxResults, List sortBy, boolean addSortData) Executes a query on this searcher.

Methods inherited from class org.mycore.services.fieldquery.MCRSearcher

clearIndex, clearIndex, getID, getIndex, getReturnID, handleFileCreated, handleFileDeleted, handleFileRepaired, handleFileUpdated, handleObjectCreated, handleObjectDeleted, handleObjectRepaired, handleObjectUpdated, notifySearcher, undoObjectCreated, undoObjectDeleted

Methods inherited from class org.mycore.common.events.MCREventHandlerBase

doHandleEvent, doNothing, handleClassificationCreated, handleClassificationDeleted, handleClassificationRepaired, handleClassificationUpdated, handleDerivateCreated, handleDerivateDeleted, handleDerivateRepaired, handleDerivateUpdated, undoClassificationCreated, undoClassificationDeleted, undoClassificationRepaired, undoClassificationUpdated, undoDerivateCreated, undoDerivateDeleted, undoDerivateRepaired, undoDerivateUpdated, undoFileCreated, undoFileDeleted, undoFileRepaired, undoFileUpdated, undoHandleEvent, undoObjectRepaired, undoObjectUpdated

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.mycore.common.events.MCREventHandler

doHandleEvent, undoHandleEvent

Constructor Detail

MCRJDOMSearcher

public MCRJDOMSearcher()

Method Detail

init

public void init(String ID)

Description copied from class: MCRSearcher

Initializes the searcher and sets its unique ID.

Overrides:

init in class MCRSearcher

Parameters:

ID - the non-null unique ID of this searcher instance

addToIndex

public void addToIndex(String entryID,
                       String returnID,
                       List fields)

Description copied from class: MCRSearcher

Adds field values to the search index. Searchers that need an indexer must overwrite this method to store the values in their backend index. If this class is configured as event handler, this method is automatically called when objects are created or updated. The field values have been extracted from the object's data as defined by searchfields.xml

Overrides:

addToIndex in class MCRSearcher

Parameters:

entryID - the unique ID of this entry in the index

returnID - the ID to return as result of a search (MCRHit ID)

fields - a List of MCRFieldValue objects

removeFromIndex

public void removeFromIndex(String entryID)

Description copied from class: MCRSearcher

Removes the values of the given entry from the backend index. Searchers that need an indexer must overwrite this method to delete the values in their backend index. If this class is configured as event handler, this method is automatically called when objects are deleted or updated.

Overrides:

removeFromIndex in class MCRSearcher

Parameters:

entryID - the unique ID of this entry in the index

search

public MCRResults search(MCRCondition condition,
                         int maxResults,
                         List sortBy,
                         boolean addSortData)

Description copied from class: MCRSearcher

Executes a query on this searcher. The query MUST only refer to fields that are managed by this searcher.

Specified by:

search in class MCRSearcher

maxResults - the maximum number of results to return, 0 means all results

sortBy - a not-null list of MCRSortBy sort criteria. The list is empty if the results should not be sorted

addSortData - if false, backend should sort results itself while executing the query. If this is not possible or the parameter is true, backend should not sort the results itself, but only store the data of the fields in the sortBy list which are needed to sort later

Returns:

the query results

contains

public static boolean contains(String value,
                               String words)

Implements the contains operator as Xalan function extension

like

public static boolean like(String value,
                           String pattern)

Implements the like operator as Xalan function extension

compare

public static boolean compare(String valueA,
                              String valueB,
                              String operator)

Implements a string compare operator as Xalan function extension

addSortData

public void addSortData(Iterator<MCRHit> hits,
                        List<MCRSortBy> sortBy)

Description copied from class: MCRSearcher

Adds field values needed for sorting for those hits that do not have sort data set already. Subclasses must overwrite this method, otherwise sorting results will not always work correctly. The default implementation in this class does nothing.

Overrides:

addSortData in class MCRSearcher

Parameters:

hits - the MCRHit objects that do not have sort data set

sortBy - the MCRFieldDef fields that are sort criteria