Apache Presto - Aplikasi Fungsi Kustom

Buat proyek Maven untuk mengembangkan fungsi kustom Presto.

SimpleFunctionsFactory.java

Buat kelas SimpleFunctionsFactory untuk mengimplementasikan antarmuka FunctionFactory.

package com.tutorialspoint.simple.functions;  

import com.facebook.presto.metadata.FunctionFactory; 
import com.facebook.presto.metadata.FunctionListBuilder; 
import com.facebook.presto.metadata.SqlFunction; 
import com.facebook.presto.spi.type.TypeManager;  
import java.util.List;  

public class SimpleFunctionFactory implements FunctionFactory { 
   
   private final TypeManager typeManager;  
   public SimpleFunctionFactory(TypeManager typeManager) { 
      this.typeManager = typeManager; 
   }  
    @Override 
    
   public List<SqlFunction> listFunctions() { 
      return new FunctionListBuilder(typeManager) 
      .scalar(SimpleFunctions.class) 
      .getFunctions(); 
   } 
}

SimpleFunctionsPlugin.java

Buat kelas SimpleFunctionsPlugin untuk mengimplementasikan antarmuka Plugin.

package com.tutorialspoint.simple.functions;  

import com.facebook.presto.metadata.FunctionFactory; 
import com.facebook.presto.spi.Plugin; 
import com.facebook.presto.spi.type.TypeManager; 
import com.google.common.collect.ImmutableList;  
import javax.inject.Inject; 
import java.util.List; 
import static java.util.Objects.requireNonNull;  

public class SimpleFunctionsPlugin implements Plugin {  
   private TypeManager typeManager; 
   @Inject 
   
   public void setTypeManager(TypeManager typeManager) { 
      this.typeManager = requireNonNull(typeManager, "typeManager is null”); 
      //Inject TypeManager class here 
   }  
   @Override 
   
   public <T> List<T> getServices(Class<T> type){ 
      if (type == FunctionFactory.class) { 
         return ImmutableList.of(type.cast(new SimpleFunctionFactory(typeManager))); 
      } 
      return ImmutableList.of(); 
   } 
}

Tambahkan File Sumber Daya

Buat file sumber daya yang ditentukan dalam paket implementasi.

(com.tutorialspoint.simple.functions.SimpleFunctionsPlugin)

Sekarang pindah ke lokasi file sumber daya @ / path / ke / resource /

Kemudian tambahkan perubahannya,

com.facebook.presto.spi.Plugin

pom.xml

Tambahkan dependensi berikut ke file pom.xml.

<?xml version = "1.0"?> 
<project xmlns = "http://maven.apache.org/POM/4.0.0"  
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
 xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0  
    http://maven.apache.org/xsd/maven-4.0.0.xsd">  
   
   <modelVersion>4.0.0</modelVersion> 
   <groupId>com.tutorialspoint.simple.functions</groupId> 
   <artifactId>presto-simple-functions</artifactId>  
   <packaging>jar</packaging>  
   <version>1.0</version>
   <name>presto-simple-functions</name>
   <description>Simple test functions for Presto</description> 
   <properties> 
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>  
   <dependencies> 
      <dependency> 
         <groupId>com.facebook.presto</groupId> 
         <artifactId>presto-spi</artifactId>
         <version>0.149</version> 
      </dependency>  
      <dependency> 
         <groupId>com.facebook.presto</groupId> 
         <artifactId>presto-main</artifactId> 
         <version>0.149</version> 
      </dependency>  
      <dependency> 
         <groupId>javax.inject</groupId> 
         <artifactId>javax.inject</artifactId> 
         <version>1</version> 
      </dependency>  
      <dependency> 
         <groupId>com.google.guava</groupId> 
         <artifactId>guava</artifactId> 
         <version>19.0</version> 
      </dependency> 
   </dependencies>  
   <build> 
      <finalName>presto-simple-functions</finalName>  
      <plugins>  
      <!-- Make this jar executable --> 
         <plugin> 
            <groupId>org.apache.maven.plugins</groupId> 
            <artifactId>maven-jar-plugin</artifactId> 
            <version>2.3.2</version> 
         </plugin> 
      </plugins> 
   </build> 
</project>

SimpleFunctions.java

Buat kelas SimpleFunctions menggunakan atribut Presto.

package com.tutorialspoint.simple.functions;  

import com.facebook.presto.operator.Description; 
import com.facebook.presto.operator.scalar.ScalarFunction; 
import com.facebook.presto.operator.scalar.StringFunctions; 
import com.facebook.presto.spi.type.StandardTypes; 
import com.facebook.presto.type.LiteralParameters; 
import com.facebook.presto.type.SqlType;  

public final class SimpleFunctions { 
   private SimpleFunctions() { 
   }  
    
   @Description("Returns summation of two numbers") 
   @ScalarFunction(“mysum") 
   //function name 
   @SqlType(StandardTypes.BIGINT) 
    
   public static long sum(@SqlType(StandardTypes.BIGINT) long num1, 
   @SqlType(StandardTypes.BIGINT) long num2) { 
      return num1 + num2; 
   } 
}

Setelah aplikasi dibuat, kompilasi dan jalankan aplikasi. Ini akan menghasilkan file JAR. Salin file dan pindahkan file JAR ke direktori plugin server Presto target.

Kompilasi

mvn compile

Eksekusi

mvn package

Sekarang restart server Presto dan hubungkan klien Presto. Kemudian jalankan aplikasi fungsi kustom seperti yang dijelaskan di bawah ini,

$ ./presto --catalog mysql --schema default

Pertanyaan

presto:default> select mysum(10,10);

Hasil

_col0  
------- 
  20