org.apache.lucene.queryParser.standard.processors
Class MultiFieldQueryNodeProcessor

java.lang.Object
  org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl
      org.apache.lucene.queryParser.standard.processors.MultiFieldQueryNodeProcessor

All Implemented Interfaces:

QueryNodeProcessor

public class MultiFieldQueryNodeProcessor
extends QueryNodeProcessorImpl

This processor is used to expand terms so the query looks for the same term in different fields. It also boosts a query based on its field.

This processor looks for every FieldableNode contained in the query node tree. If a FieldableNode is found, it checks if there is a StandardQueryConfigHandler.ConfigurationKeys.MULTI_FIELDS defined in the QueryConfigHandler. If there is, the FieldableNode is cloned N times and the clones are added to a BooleanQueryNode together with the original node. N is defined by the number of fields that it will be expanded to. The BooleanQueryNode is returned.

See Also:

StandardQueryConfigHandler.ConfigurationKeys.MULTI_FIELDS

Constructor Summary

MultiFieldQueryNodeProcessor()

Method Summary

protected QueryNode	postProcessNode(QueryNode node) This method is invoked for every node when walking up the tree.
protected QueryNode	preProcessNode(QueryNode node) This method is invoked for every node when walking down the tree.
protected void	processChildren(QueryNode queryTree) This method is called every time a child is processed.
protected List<QueryNode>	setChildrenOrder(List<QueryNode> children) This method is invoked for every node that has at least on child.

Methods inherited from class org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl

getQueryConfigHandler, process, setQueryConfigHandler

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiFieldQueryNodeProcessor

public MultiFieldQueryNodeProcessor()

Method Detail

postProcessNode

protected QueryNode postProcessNode(QueryNode node)
                             throws QueryNodeException

Description copied from class: QueryNodeProcessorImpl

This method is invoked for every node when walking up the tree.

Specified by:

postProcessNode in class QueryNodeProcessorImpl

Parameters:

node - node the query node to be post-processed

Returns:

a query node

Throws:

QueryNodeException - if something goes wrong during the query node processing

processChildren

protected void processChildren(QueryNode queryTree)
                        throws QueryNodeException

Description copied from class: QueryNodeProcessorImpl

This method is called every time a child is processed.

Overrides:

processChildren in class QueryNodeProcessorImpl

Parameters:

queryTree - the query node child to be processed

Throws:

QueryNodeException - if something goes wrong during the query node processing

preProcessNode

protected QueryNode preProcessNode(QueryNode node)
                            throws QueryNodeException

Description copied from class: QueryNodeProcessorImpl

This method is invoked for every node when walking down the tree.

Specified by:

preProcessNode in class QueryNodeProcessorImpl

Parameters:

node - the query node to be pre-processed

Returns:

a query node

Throws:

QueryNodeException - if something goes wrong during the query node processing

setChildrenOrder

protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
                                    throws QueryNodeException

Description copied from class: QueryNodeProcessorImpl

This method is invoked for every node that has at least on child. It's invoked right before QueryNodeProcessorImpl.postProcessNode(QueryNode) is invoked.

Specified by:

setChildrenOrder in class QueryNodeProcessorImpl

Parameters:

children - the list containing all current node's children

Returns:

a new list containing all children that should be set to the current node

Throws:

QueryNodeException - if something goes wrong during the query node processing