org.apache.lucene.queryParser.core.builders
Class QueryTreeBuilder

java.lang.Object
  org.apache.lucene.queryParser.core.builders.QueryTreeBuilder

All Implemented Interfaces:

QueryBuilder

Direct Known Subclasses:

StandardQueryTreeBuilder

public class QueryTreeBuilder
extends Object
implements QueryBuilder

This class should be used when there is a builder for each type of node. The type of node may be defined in 2 different ways: - by the field name, when the node implements the FieldableNode interface - by its class, it keeps checking the class and all the interfaces and classes this class implements/extends until it finds a builder for that class/interface This class always check if there is a builder for the field name before it checks for the node class. So, field name builders have precedence over class builders. When a builder is found for a node, it's called and the node is passed to the builder. If the returned built object is not null, it's tagged on the node using the tag QUERY_TREE_BUILDER_TAGID. The children are usually built before the parent node. However, if a builder associated to a node is an instance of QueryTreeBuilder, the node is delegated to this builder and it's responsible to build the node and its children.

See Also:

QueryBuilder

Field Summary

static String

QUERY_TREE_BUILDER_TAGID This tag is used to tag the nodes in a query tree with the built objects produced from their own associated builder.

Constructor Summary

QueryTreeBuilder()
QueryTreeBuilder constructor.

Method Summary

Object	build(QueryNode queryNode) Builds some kind of object from a query tree.
void	setBuilder(CharSequence fieldName, QueryBuilder builder) Associates a field name with a builder.
void	setBuilder(Class<? extends QueryNode> queryNodeClass, QueryBuilder builder) Associates a class with a builder

Methods inherited from class java.lang.Object

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

Field Detail

QUERY_TREE_BUILDER_TAGID

public static final String QUERY_TREE_BUILDER_TAGID

This tag is used to tag the nodes in a query tree with the built objects produced from their own associated builder.

Constructor Detail

QueryTreeBuilder

public QueryTreeBuilder()

QueryTreeBuilder constructor.

Method Detail

setBuilder

public void setBuilder(CharSequence fieldName,
                       QueryBuilder builder)

Associates a field name with a builder.

Parameters:

fieldName - the field name

builder - the builder to be associated

setBuilder

public void setBuilder(Class<? extends QueryNode> queryNodeClass,
                       QueryBuilder builder)

Associates a class with a builder

Parameters:

queryNodeClass - the class

builder - the builder to be associated

build

public Object build(QueryNode queryNode)
             throws QueryNodeException

Builds some kind of object from a query tree. Each node in the query tree is built using an specific builder associated to it.

Specified by:

build in interface QueryBuilder

Parameters:

queryNode - the query tree root node

Returns:

the built object

Throws:

QueryNodeException - if some node builder throws a QueryNodeException or if there is a node which had no builder associated to it