924060929/impala-frontend

这个库是impala前端库，增加语法块位置信息的功能

impala-frontend

这个库是Impala前端库，增加语法块位置信息的功能

impala版本：cdh5.10.0-release

主要功能

1. 通过xx.startPosition和xx.endPosition得语法块的开始位置和结束位置
2. 通过xx.subBlocks去递归遍历子语法块

安装方法

把fe文件夹替换到Impala-cdhx.x.x-release目录中，运行./buildall.sh -fe_only，编译完成后复制fe/target/impala-frontend-0.1-SNAPSHOT.jar到工程中使用

Demo:

import java_cup.runtime.ExtendSymbolFactory;
import org.apache.impala.analysis.*;

import java.io.StringReader;

public class Test {
    public static void main(String[] args) throws Exception {
        String sql = "SELECT concat(o.order_id, '2') " +
            "FROM fact_order o " +
            "LEFT JOIN dim_business d " +
            "ON o.shop_id = d.shop_id " +
            "WHERE o.order_day_key=20170415";

        SqlScanner scanner = new SqlScanner(new StringReader(sql));
        SqlParser parser = new SqlParser(scanner, new ExtendSymbolFactory(sql));
        SelectStmt selectStmt = (SelectStmt) parser.parse().value;
        SelectList selectList = selectStmt.getSelectList();
        SelectListItem selectListItem = selectList.getItems().get(0);
        // expr相当于concat(o.order_id, '2')
        Expr expr = selectListItem.getExpr();

        // 输出结果：start: 7, end: 30
        System.out.println("start: " + expr.startPosition + ", end: " + expr.endPosition);

        // 0："concat"
        // 1: "("
        // 2: o.order_id, '2'
        // 3: ")"
        FunctionParams functionParams = (FunctionParams) expr.subBlocks.get(2);
        // 输出结果：start: 14, end: 29
        System.out.println("start: " + functionParams.startPosition + ", end: " + functionParams.endPosition);
    }
}

maven依赖：

<dependency>
    <groupId>org.apache.hive</groupId>
    <artifactId>hive-exec</artifactId>
    <version>0.14.0</version>
</dependency>

<dependency>
    <groupId>org.apache.sentry</groupId>
    <artifactId>sentry-core-model-db</artifactId>
    <version>1.5.1-cdh5.10.0</version>
    <exclusions>
        <exclusion>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>org.apache.impala</groupId>
    <artifactId>impala-frontend</artifactId>
    <version>cdh5.10.0-release</version>
    <scope>system</scope>
    <!-- 这里改成你的jar包存放的位置 -->
    <systemPath>${project.basedir}/src/main/lib/impala-frontend-0.1-SNAPSHOT.jar</systemPath>
</dependency>