/* * Copyright 1999-2017 Alibaba Group Holding Ltd. * * Licensed 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 com.alibaba.druid.sql.visitor.functions; import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE; import com.alibaba.druid.sql.ast.SQLExpr; import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr; import com.alibaba.druid.sql.visitor.SQLEvalVisitor; public class Elt implements Function { public final static Elt instance = new Elt(); public Object eval(SQLEvalVisitor visitor, SQLMethodInvokeExpr x) { if (x.getParameters().size() <= 1) { return SQLEvalVisitor.EVAL_ERROR; } SQLExpr param0 = x.getParameters().get(0); param0.accept(visitor); Object param0Value = param0.getAttributes().get(EVAL_VALUE); int param0IntValue; if (!(param0Value instanceof Number)) { return SQLEvalVisitor.EVAL_ERROR; } param0IntValue = ((Number) param0Value).intValue(); if (param0IntValue >= x.getParameters().size()) { return null; } SQLExpr item = x.getParameters().get(param0IntValue); item.accept(visitor); Object itemValue = item.getAttributes().get(EVAL_VALUE); return itemValue; } }