| /* |
| |
| Derby - Class org.apache.derby.impl.sql.compile.ReferencedTablesVisitor |
| |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to you under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| |
| */ |
| |
| |
| package org.apache.derby.impl.sql.compile; |
| |
| import org.apache.derby.iapi.error.StandardException; |
| import org.apache.derby.iapi.sql.compile.Visitable; |
| import org.apache.derby.iapi.sql.compile.Visitor; |
| import org.apache.derby.iapi.util.JBitSet; |
| |
| /** |
| * Build a JBitSet of all of the referenced tables in the tree. |
| * |
| */ |
| class ReferencedTablesVisitor implements Visitor |
| { |
| private JBitSet tableMap; |
| |
| ReferencedTablesVisitor(JBitSet tableMap) |
| { |
| this.tableMap = tableMap; |
| } |
| |
| |
| //////////////////////////////////////////////// |
| // |
| // VISITOR INTERFACE |
| // |
| //////////////////////////////////////////////// |
| |
| /** |
| * Don't do anything unless we have a ColumnReference, |
| * Predicate or ResultSetNode node. |
| * |
| * @param node the node to process |
| * |
| * @return me |
| * |
| * @exception StandardException on error |
| */ |
| public Visitable visit(Visitable node) |
| throws StandardException |
| { |
| if (node instanceof ColumnReference) |
| { |
| ((ColumnReference)node).getTablesReferenced(tableMap); |
| } |
| else if (node instanceof Predicate) |
| { |
| Predicate pred = (Predicate) node; |
| tableMap.or(pred.getReferencedSet()); |
| } |
| else if (node instanceof ResultSetNode) |
| { |
| ResultSetNode rs = (ResultSetNode) node; |
| tableMap.or(rs.getReferencedTableMap()); |
| } |
| |
| return node; |
| } |
| |
| /** |
| * No need to go below a Predicate or ResultSet. |
| * |
| * @return Whether or not to go below the node. |
| */ |
| public boolean skipChildren(Visitable node) |
| { |
| return (node instanceof Predicate || |
| node instanceof ResultSetNode); |
| } |
| |
| public boolean visitChildrenFirst(Visitable node) |
| { |
| return false; |
| } |
| |
| public boolean stopTraversal() |
| { |
| return false; |
| } |
| //////////////////////////////////////////////// |
| // |
| // CLASS INTERFACE |
| // |
| //////////////////////////////////////////////// |
| JBitSet getTableMap() |
| { |
| return tableMap; |
| } |
| } |