org.openrdf.sesame.sailimpl.rdbms.iterators
Class RdbmsStatementIterator

java.lang.Object
  org.openrdf.sesame.sailimpl.rdbms.iterators.RdbmsStatementIterator

All Implemented Interfaces:

StatementIterator

public class RdbmsStatementIterator

extends Object

implements StatementIterator

A StatementIterator that executes an SQL query. The ResultSet should contain 3 columns for each resource or literal that is not fixed. For a resource this is: id, namespace and localname. For a literal this is: id, language and value. The total number of columns expected depends on the number of values/positions that have been specified by the caller. E.g. if the caller asks for all statements with a specific subject, the subject is 'fixed', and doesn't have to be queried from the database. In this case, the query is expected to have six columns: three for the predicate and three for the object.

Author:

Peter van 't Hof, Arjohn Kampman

Constructor Summary

RdbmsStatementIterator(RdfSource source, String[] namespaceNames, Connection databaseCon, String queryResources, String queryLiterals, Resource subject, URI predicate, Value object)
Constructor.

Method Summary

void	close() Closes the iterator and frees any resources that it uses (e.g.
boolean	hasNext() Checks whether there are any more statements available.
Statement	next() Gets the next statement.

Methods inherited from class java.lang.Object

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

Constructor Detail

RdbmsStatementIterator

public RdbmsStatementIterator(RdfSource source,
                              String[] namespaceNames,
                              Connection databaseCon,
                              String queryResources,
                              String queryLiterals,
                              Resource subject,
                              URI predicate,
                              Value object)

Constructor.

Parameters:

source - the object to supply as 'creator' to created IdValues.

namespaceNames - an array of namespace names that are index using their IDs.

databaseCon - connection to the repository

queryResources - query specified for the resources table, or null if statements with resources as object do not need to be queried.

queryLiterals - query specified for the literals table, or null if statements with literals as object do not need to be queried.

subject - A (fixed) subject, or null if the subject should be queried from the database.

predicate - A (fixed) predicate, or null if the predicate should be queried from the database.

object - A (fixed) object, or null if the object should be queried from the database.

Method Detail

hasNext

public boolean hasNext()

Description copied from interface: StatementIterator

Checks whether there are any more statements available.

Specified by:

hasNext in interface StatementIterator

Returns:

true if there are more statements available, false otherwise.

next

public Statement next()

Description copied from interface: StatementIterator

Gets the next statement.

Specified by:

next in interface StatementIterator

Returns:

the next statement.

close

public void close()

Description copied from interface: StatementIterator

Closes the iterator and frees any resources that it uses (e.g. connections to databases). Every StatementIterator should be properly closed when it has returned all of its statements, or when it is no longer needed.

Specified by:

close in interface StatementIterator