net.cnri.repository.search

Class BooleanQuery

java.lang.Object

net.cnri.repository.search.BooleanQuery

All Implemented Interfaces:

Query

public class BooleanQuery
extends java.lang.Object
implements Query

A query reflecting a boolean expression. Modeled on the Lucene style of Boolean query. Comprises a list of subqueries with occurence marker, which are either MUST, SHOULD, or MUST_NOT.

A BooleanQuery will match an object if and only if:

• it matches every MUST subquery;
• it matches at least one SHOULD subquery (or there is no such subquery); and
• it matches no MUST_NOT subquery.

"AND" expressions map to MUST; "OR" to SHOULD; "NOT" to MUST_NOT.

See Also:

BooleanClause, BooleanClause.Occur

Constructor Summary

Constructors

Constructor and Description
BooleanQuery(java.util.Collection<BooleanClause> clauses) Constructs an instance.
BooleanQuery(java.lang.Object... objects) Constructs an instance from parameters which are each either BooleanClause, Query, or BooleanClause.Occur.

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	accept(QueryVisitor<T> visitor) Returns the result of applying a QueryVisitor to this query.
java.util.List<BooleanClause>	clauses()
boolean	containsNoMustClauses()
boolean	onlyContainsMustNotClauses()
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

BooleanQuery

public BooleanQuery(java.util.Collection<BooleanClause> clauses)

Constructs an instance.

Parameters:

clauses - the clauses of the instance

BooleanQuery

public BooleanQuery(java.lang.Object... objects)

Constructs an instance from parameters which are each either BooleanClause, Query, or BooleanClause.Occur.

Example: new BooleanQuery(q1,MUST,q2,SHOULD,q3,SHOULD,q4,MUST_NOT) models q1 /\ (q2 \/ q3) /\ ~q4.

Parameters:

objects - the objects used to construct the instance. Each object must be a BooleanClause, a Query, or a BooleanClause.Occur. Each Query will be converted into a BooleanClause with its Occur set to the next BooleanClause.Occur in the arguments. All the BooleanClauses become the clauses of the constructed instance.

Method Detail

clauses

public java.util.List<BooleanClause> clauses()

Returns:

the clauses of this instance

onlyContainsMustNotClauses

public boolean onlyContainsMustNotClauses()

containsNoMustClauses

public boolean containsNoMustClauses()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

accept

public <T> T accept(QueryVisitor<T> visitor)
         throws RepositoryException

Description copied from interface: Query

Returns the result of applying a QueryVisitor to this query. A QueryVisitor implementation will return different results based on the runtime type of the query. This allows the emulation of structural pattern matching over possible Query types.

Specified by:

accept in interface Query

Parameters:

visitor - the visitor

Returns:

the result of the visit

Throws:

RepositoryException