rdfschemarepository.java

这是外国一个开源推理机

	public StatementIterator getClasses() {
		return _queryOneColumnTable(CLASS_TABLE, "id", URIImpl.RDF_TYPE, URIImpl.RDFS_CLASS);
	}

	public boolean isClass(Resource resource) {
		return _isRowInOneColumnTable(CLASS_TABLE, "id", resource);
	}

	public StatementIterator getProperties() {
		return _queryOneColumnTable(PROPERTY_TABLE, "id", URIImpl.RDF_TYPE, URIImpl.RDF_PROPERTY);
	}

	public boolean isProperty(Resource resource) {
		return _isRowInOneColumnTable(PROPERTY_TABLE, "id", resource);
	}

	public StatementIterator getSubClassOf(Resource subClass, Resource superClass) {
		return _queryTwoColumnTable(
				SUBCLASSOF_TABLE, "sub", "super",
				subClass, URIImpl.RDFS_SUBCLASSOF, superClass);
	}

	public StatementIterator getDirectSubClassOf(Resource subClass, Resource superClass) {
		return _queryTwoColumnTable(
				DIRECT_SUBCLASSOF_TABLE, "sub", "super",
				subClass, URIImpl.RDFS_SUBCLASSOF, superClass);
	}

	public boolean isSubClassOf(Resource subClass, Resource superClass) {
		return _isRowInTwoColumnTable(
				SUBCLASSOF_TABLE, "sub", "super",
				subClass, superClass);
	}

	public boolean isDirectSubClassOf(Resource subClass, Resource superClass) {
		return _isRowInTwoColumnTable(
				DIRECT_SUBCLASSOF_TABLE, "sub", "super",
				subClass, superClass);
	}

	public StatementIterator getSubPropertyOf(Resource subProperty, Resource superProperty) {
		return _queryTwoColumnTable(
				SUBPROPERTYOF_TABLE, "sub", "super",
				subProperty, URIImpl.RDFS_SUBPROPERTYOF, superProperty);
	}

	public StatementIterator getDirectSubPropertyOf(Resource subProperty, Resource superProperty) {
		return _queryTwoColumnTable(
				DIRECT_SUBPROPERTYOF_TABLE, "sub", "super",
				subProperty, URIImpl.RDFS_SUBPROPERTYOF, superProperty);
	}

	public boolean isSubPropertyOf(Resource subProperty, Resource superProperty) {
		return _isRowInTwoColumnTable(
				SUBPROPERTYOF_TABLE, "sub", "super",
				subProperty, superProperty);
	}

	public boolean isDirectSubPropertyOf(Resource subProperty, Resource superProperty) {
		return _isRowInTwoColumnTable(
				DIRECT_SUBPROPERTYOF_TABLE, "sub", "super",
				subProperty, superProperty);
	}

	public StatementIterator getDomain(Resource prop, Resource domain) {
		return _queryTwoColumnTable(
				DOMAIN_TABLE, "property", "class",
				prop, URIImpl.RDFS_DOMAIN, domain);
	}

	public StatementIterator getRange(Resource prop, Resource domain) {
		return _queryTwoColumnTable(
				RANGE_TABLE, "property", "class",
				prop, URIImpl.RDFS_DOMAIN, domain);
	}

	public StatementIterator getType(Resource anInstance, Resource aClass) {
		return _queryTwoColumnTable(
				INSTANCEOF_TABLE, "inst", "class",
				anInstance, URIImpl.RDF_TYPE, aClass);
	}

	public StatementIterator getDirectType(Resource anInstance, Resource aClass) {
		return _queryTwoColumnTable(
				PROPER_INSTANCEOF_TABLE, "inst", "class",
				anInstance, URIImpl.RDF_TYPE, aClass);
	}

	public boolean isType(Resource anInstance, Resource aClass) {
		return _isRowInTwoColumnTable(
				INSTANCEOF_TABLE, "inst", "class",
				anInstance, aClass);
	}

	public boolean isDirectType(Resource anInstance, Resource aClass) {
		return _isRowInTwoColumnTable(
				PROPER_INSTANCEOF_TABLE, "inst", "class",
				anInstance, aClass);
	}

	public LiteralIterator getLiterals(String label, String language, URI datatype) {
		int datatypeId = 0;
		if (datatype != null) {
			datatypeId = _getURIId(datatype);

			if (datatypeId == 0) {
				// datatype URI not found
				return new EmptyLiteralIterator();
			}
		}

		String query =
				"SELECT l.id, dt.id, dt.namespace, dt.localname, l.language, l.label " +
				"FROM " + LITERALS_TABLE + " l, " + RESOURCES_TABLE + " dt " +
				"WHERE l.datatype = dt.id";

		boolean firstPartWritten = false;

		// label
		if (label != null) {
			// labelHash
			long labelHash = _getLabelHash(label);
			query += " l.labelHash = " + labelHash;

			// label
			query += " AND l.label ";
			if (_rdbms.emptyStringIsNull() && label.length() == 0) {
				query += "IS NULL";
			}
			else {
				query += "= '" + _rdbms.escapeString(label) + "'";
			}

			firstPartWritten = true;
		}

		//  language
		if (language != null && datatype == null) {
			if (firstPartWritten) {
				query += " AND";
			}
			query += " l.language = '" + _rdbms.escapeString(language) + "'";

			firstPartWritten = true;
		}

		// datatype
		if (datatype != null) {
			if (firstPartWritten) {
				query += " AND";
			}
			query += "dt.id = " + datatypeId;
		}

		try {
			Connection con = _rdbms.getConnection();
			return new RdbmsLiteralIterator(this, _namespaceNames, con, query);
		}
		catch (SQLException e) {
			throw new SailInternalException(e);
		}
	}

	/**
	 * Queries a one-column table like <tt>CLASS_TABLE</tt> or <tt>PROPER_INSTANCEOF_TABLE</tt>.
	 *
	 * @param tableName The name of the table to query.
	 * @param colName The name of the column in the table.
	 * @param prop The property that should be returned by the resulting StatementIterator.
	 * @param obj The object that should be returned by the resulting StatementIterator.
	 * @return A StatementIterator containing the requested statements.
	 **/
	protected StatementIterator _queryOneColumnTable(String tableName, String colName, URI prop, Resource obj) {
		String query =
				"SELECT r.id, r.namespace, r.localname FROM " +
					tableName + " t, " + 
					RESOURCES_TABLE + " r " +
				"WHERE t."+colName + " = r.id";
		try {
			Connection con = _rdbms.getConnection();
			return new RdbmsStatementIterator(
					this, _namespaceNames, con,
					query, null, null, prop, obj);
		}
		catch (SQLException e) {
			throw new SailInternalException(e);
		}
	}

	/**
	 * Checks whether a resource is present in a one-column table like
	 * <tt>CLASS_TABLE</tt> or <tt>PROPERTY_TABLE</tt>.
	 *
	 * @param tableName The name of the table to query.
	 * @param colName The name of the column in the table.
	 * @param val The value that the column should have.
	 **/
	protected boolean _isRowInOneColumnTable(String tableName, String colName, Resource val) {
		int id = _getResourceId(val);

		if (id == 0) {
			// unknown resource
			return false;
		}

		String query =
				"SELECT * FROM " + tableName +
				" WHERE " + colName + " = " + id;

		try {
			return _rdbms.queryHasResults(query);
		}
		catch (SQLException e) {
			throw new SailInternalException(e);
		}
	}

	/**
	 * Queries a two-column table like
	 * <tt>SUBCLASSOF_TABLE</tt>, <tt>DIRECT_SUBCLASSOF_TABLE</tt>,
	 * <tt>SUBPROPERTYOF_TABLE</tt>, <tt>DIRECT_SUBPROPERTYOF_TABLE</tt>,
	 * <tt>INSTANCEOF_TABLE</tt>, <tt>PROPER_INSTANCEOF_TABLE</tt>,
	 * <tt>DOMAIN_TABLE</tt> or <tt>RANGE_TABLE</tt>.
	 *
	 * @param tableName The name of the table to query.
	 * @param col1Name The name of the first column in the table.
	 * @param col2Name The name of the second column in the table.
	 * @param val1 The value that the first column should have, or
	 * <tt>null</tt> for a wildcard.
	 * @param prop The property that should be returned by the
	 * resulting StatementIterator.
	 * @param val2 The value that the second column should have, or
	 * <tt>null</tt> for a wildcard.
	 * @return A StatementIterator containing the requested statements.
	 **/
	protected StatementIterator _queryTwoColumnTable(
			String tableName, String col1Name, String col2Name,
			Resource val1, URI prop, Resource val2)
	{
		int id1 = 0, id2 = 0;

		if (val1 != null) {
			id1 = _getResourceId(val1);
			if (id1 == 0) {
				// unknown resource
				return new EmptyStatementIterator();
			}
		}

		if (val2 != null) {
			id2 = _getResourceId(val2);
			if (id2 == 0) {
				// unknown resource
				return new EmptyStatementIterator();
			}
		}

		String select = "SELECT ";
		String from = " FROM " + tableName + " t";
		String where = " WHERE ";

		// val1
		if (id1 != 0) {
			// val1 is specified
			where += "t."+col1Name + " = " + id1;
		}
		else {
			// val1 is a wildcard
			select += "r1.id, r1.namespace, r1.localname";
			from += ", " + RESOURCES_TABLE + " r1";
			where += "t."+col1Name + " = r1.id";
		}

		// val2
		if (id2 != 0) {
			// val2 is specified
			where += " AND t."+col2Name + " = " + id2;
		}
		else {
			// val2 is a wildcard
			if (id1 == 0) {
				select += ", ";
			}

			select += "r2.id, r2.namespace, r2.localname";
			from += ", " + RESOURCES_TABLE + " r2";
			where += " AND t."+col2Name + " = r2.id";
		}

		if (id1 != 0 && id2 != 0) {
			select += "*";
		}

		String query = select + from + where;

		try {
			Connection con = _rdbms.getConnection();
			return new RdbmsStatementIterator(
					this, _namespaceNames, con,
					query, null, val1, prop, val2);
		}
		catch (SQLException e) {
			throw new SailInternalException(e);
		}
	}

	/**
	 * Checks whether a combination of two resources is present in
	 * a two-column table like
	 * <tt>SUBCLASSOF_TABLE</tt>, <tt>DIRECT_SUBCLASSOF_TABLE</tt>,
	 * <tt>SUBPROPERTYOF_TABLE</tt>, <tt>DIRECT_SUBPROPERTYOF_TABLE</tt>,
	 * <tt>INSTANCEOF_TABLE</tt>, <tt>PROPER_INSTANCEOF_TABLE</tt>,
	 * <tt>DOMAIN_TABLE</tt> or <tt>RANGE_TABLE</tt>
	 *
	 * @param tableName The name of the table to query.
	 * @param col1Name The name of the first column in the table.
	 * @param col2Name The name of the second column in the table.
	 * @param val1 The value that the first column should have.
	 * @param val2 The value that the second column should have.
	 **/
	protected boolean _isRowInTwoColumnTable(
			String tableName, String col1Name, String col2Name,
			Resource val1, Resource val2)
	{
		int id1 = _getResourceId(val1);
		if (id1 == 0) {
			return false;
		}

		int id2 = _getResourceId(val2);
		if (id2 == 0) {
			return false;
		}

		String query = 
				"SELECT * FROM " + tableName +
				" WHERE " + col1Name + " = " + id1 +
				" AND " + col2Name + " = " + id2;

		try {
			return _rdbms.queryHasResults(query);
		}
		catch (SQLException e) {
			throw new SailInternalException(e);
		}
	}

	// Overrides RdfSource._convertPathExpressionToSQL(...)
	protected PathExpression _convertPathExpressionToSQL(
			PathExpression pathExpr, String peId,
			StringBuffer from, StringBuffer where, Map varToSqlIdMapping)
	{
		if (pathExpr instanceof DirectType) {
			DirectType dt = (DirectType)pathExpr;

			from.append(", " + PROPER_INSTANCEOF_TABLE + " " + peId);

			_processPathExpressionVar(dt.getSubjectVar(), peId+".inst", where, varToSqlIdMapping);
			_processPathExpressionVar(dt.getObjectVar(), peId+".class", where, varToSqlIdMapping);

			return null;
		}
		else if (pathExpr instanceof DirectSubClassOf) {
			DirectSubClassOf dsco = (DirectSubClassOf)pathExpr;

			from.append(", " + DIRECT_SUBCLASSOF_TABLE + " " + peId);

			_processPathExpressionVar(dsco.getSubjectVar(), peId+".sub", where, varToSqlIdMapping);
			_processPathExpressionVar(dsco.getObjectVar(), peId+".super", where, varToSqlIdMapping);

			return null;
		}
		else if (pathExpr instanceof DirectSubPropertyOf) {
			DirectSubPropertyOf dspo = (DirectSubPropertyOf)pathExpr;

			from.append(", " + DIRECT_SUBPROPERTYOF_TABLE + " " + peId);

			_processPathExpressionVar(dspo.getSubjectVar(), peId+".sub", where, varToSqlIdMapping);
			_processPathExpressionVar(dspo.getObjectVar(), peId+".super", where, varToSqlIdMapping);

			return null;
		}
		else {
			if (pathExpr instanceof TriplePattern) {
				TriplePattern tp = (TriplePattern)pathExpr;
				Value predicate = tp.getPredicateVar().getValue();

				if (URIImpl.RDF_TYPE.equals(predicate)) {
					// Use INSTANCEOF_TABLE
					from.append(", " + INSTANCEOF_TABLE + " " + peId);

					_processPathExpressionVar(tp.getSubjectVar(), peId+".inst", where, varToSqlIdMapping);
					_processPathExpressionVar(tp.getObjectVar(), peId+".class", where, varToSqlIdMapping);

					return null;
				}
				else if (URIImpl.RDFS_SUBCLASSOF.equals(predicate)) {
					// Use SUBCLASSOF_TABLE
					from.append(", " + SUBCLASSOF_TABLE + " " + peId);

					_processPathExpressionVar(tp.getSubjectVar(), peId+".sub", where, varToSqlIdMapping);
					_processPathExpressionVar(tp.getObjectVar(), peId+".super", where, varToSqlIdMapping);

					return null;
				}
				else if (URIImpl.RDFS_SUBPROPERTYOF.equals(predicate)) {
					// Use SUBPROPERTYOF_TABLE
					from.append(", " + SUBPROPERTYOF_TABLE + " " + peId);

					_processPathExpressionVar(tp.getSubjectVar(), peId+".sub", where, varToSqlIdMapping);
					_processPathExpressionVar(tp.getObjectVar(), peId+".super", where, varToSqlIdMapping);

					return null;
				}
			}

			return super._convertPathExpressionToSQL(pathExpr, peId, from, where, varToSqlIdMapping);
		}
	}

	public RDBMS getRDBMS() {
		return _rdbms;
	}
}