org.apache.lucene.queryparser.flexible.core.builders

Class QueryTreeBuilder

java.lang.Object

org.apache.lucene.queryparser.flexible.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

Fields

Modifier and Type	Field and Description
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

Constructors

Constructor and Description
QueryTreeBuilder() QueryTreeBuilder constructor.

Method Summary

Methods

Modifier and Type	Method and Description
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