| /* |
| * 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.asterix.lang.sqlpp.visitor; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.asterix.common.functions.FunctionConstants; |
| import org.apache.asterix.common.functions.FunctionSignature; |
| import org.apache.asterix.lang.common.base.Expression; |
| import org.apache.asterix.lang.common.clause.WhereClause; |
| import org.apache.asterix.lang.common.expression.CallExpr; |
| import org.apache.asterix.lang.common.expression.LiteralExpr; |
| import org.apache.asterix.lang.common.expression.VariableExpr; |
| import org.apache.asterix.lang.common.literal.StringLiteral; |
| import org.apache.asterix.lang.common.statement.DeleteStatement; |
| import org.apache.asterix.lang.common.statement.Query; |
| import org.apache.asterix.lang.common.struct.Identifier; |
| import org.apache.asterix.lang.sqlpp.clause.FromClause; |
| import org.apache.asterix.lang.sqlpp.clause.FromTerm; |
| import org.apache.asterix.lang.sqlpp.clause.SelectBlock; |
| import org.apache.asterix.lang.sqlpp.clause.SelectClause; |
| import org.apache.asterix.lang.sqlpp.clause.SelectElement; |
| import org.apache.asterix.lang.sqlpp.clause.SelectSetOperation; |
| import org.apache.asterix.lang.sqlpp.expression.SelectExpression; |
| import org.apache.asterix.lang.sqlpp.struct.SetOperationInput; |
| import org.apache.asterix.lang.sqlpp.visitor.base.AbstractSqlppAstVisitor; |
| import org.mortbay.util.SingletonList; |
| |
| /** |
| * This class rewrites delete statement to contain a query that specifying |
| * what to delete. |
| */ |
| public class SqlppDeleteRewriteVisitor extends AbstractSqlppAstVisitor<Void, Void> { |
| |
| @Override |
| public Void visit(DeleteStatement deleteStmt, Void visitArg) { |
| List<Expression> arguments = new ArrayList<>(); |
| Identifier dataverseName = deleteStmt.getDataverseName(); |
| Identifier datasetName = deleteStmt.getDatasetName(); |
| String arg = dataverseName == null ? datasetName.getValue() |
| : dataverseName.getValue() + "." + datasetName.getValue(); |
| LiteralExpr argumentLiteral = new LiteralExpr(new StringLiteral(arg)); |
| arguments.add(argumentLiteral); |
| CallExpr callExpression = new CallExpr(new FunctionSignature(FunctionConstants.ASTERIX_NS, "dataset", 1), |
| arguments); |
| |
| // From clause. |
| VariableExpr var = deleteStmt.getVariableExpr(); |
| FromTerm fromTerm = new FromTerm(callExpression, var, null, null); |
| @SuppressWarnings("unchecked") |
| FromClause fromClause = new FromClause(SingletonList.newSingletonList(fromTerm)); |
| |
| // Where clause. |
| WhereClause whereClause = null; |
| Expression condition = deleteStmt.getCondition(); |
| if (condition != null) { |
| whereClause = new WhereClause(condition); |
| } |
| |
| // Select clause. |
| VariableExpr returnExpr = new VariableExpr(var.getVar()); |
| returnExpr.setIsNewVar(false); |
| SelectElement selectElement = new SelectElement(returnExpr); |
| SelectClause selectClause = new SelectClause(selectElement, null, false); |
| |
| // Construct the select expression. |
| SelectBlock selectBlock = new SelectBlock(selectClause, fromClause, null, whereClause, null, null, null); |
| SelectSetOperation selectSetOperation = new SelectSetOperation(new SetOperationInput(selectBlock, null), null); |
| SelectExpression selectExpression = new SelectExpression(null, selectSetOperation, null, null, false); |
| Query query = new Query(false, false, selectExpression, 0, new ArrayList<>(), new ArrayList<>()); |
| query.setBody(selectExpression); |
| |
| // return the delete statement. |
| deleteStmt.setQuery(query); |
| return null; |
| } |
| |
| } |