Overview

JavaScript in Etlworks is tightly integrated with the Java Virtual Machine.

This means your scripts can directly access all classes from:

• The Etlworks Java API

• Core Java packages (java.util, java.io, etc.)

• Any custom Java libraries you install

There are multiple ways to reference Java classes in JavaScript.

This article explains each method, when to use it, and provides examples and reference tables for the most commonly used Etlworks packages and classes.

Accessing Java Classes

There are four methods available:

Use a fully qualified Java class name

var list = new java.util.ArrayList();

Import packages using importPackage(package)

importPackage(java.util);

var list = new ArrayList();

Import classes using Java.type("class")

var ArrayList = Java.type("java.util.ArrayList");

var list = new ArrayList();

Import packages using JavaImporter

var javaImports = new JavaImporter(
    java.util,
    com.toolsverse.util
);

with (javaImports) {
  var list = new ArrayList();
  var ds = new DataSet();
}

Notes about JavaImporter

• Flexible

• Helpful when mixing many packages

• Slower than the other methods

• Not recommended for performance-critical code

Common Etlworks Packages

Below is a curated list of the most common Etlworks Java API packages and links to Javadoc (where applicable).

Purpose	Package
Utility classes	com.toolsverse.util
Logging	com.toolsverse.util.log
System configuration	com.toolsverse.config
Common ETL engine classes (DataSet, FieldDef, etc.)	com.toolsverse.etl.common
ETL engine configuration	com.toolsverse.etl.core.config
ETL engine core	com.toolsverse.etl.core.engine
Common ETL tasks	com.toolsverse.etl.core.task.common
Java collections and utilities	java.util

Commonly Used Classes and Example Usage

Below is a reference for frequently used Etlworks and Java classes you will likely use when writing scripts.

Utility Methods

com.toolsverse.util.Utils

Check for empty or null:

if (com.toolsverse.util.Utils.isNothing(value)) {
    // handle case
}

Working With File Names

com.toolsverse.util.FilenameUtils

var name = com.toolsverse.util.FilenameUtils.getName(path);

Working with Files

com.toolsverse.etl.core.task.common.FileManagerTask

Check if files exist

var found = com.toolsverse.etl.core.task.common.FileManagerTask.filesExist(
  etlConfig,
  "connectionName",
  "*.json"
);

List files

var list = com.toolsverse.etl.core.task.common.FileManagerTask.list(
  etlConfig,
  "connectionName",
  "*.json"
);

if (list != null) {
   for each (var file in list) {
     etlConfig.log("Name:" + file.getName() +
       ", Size:" + file.getSize() +
       ", Path:" + file.getPath() +
       ", Last modified:" + file.getLastModified());
   }
}

Write a file

com.toolsverse.etl.core.task.common.FileManagerTask.write(
   etlConfig,
   "connectionName",
   filename,
   payload
);

Read a file

var data = com.toolsverse.etl.core.task.common.FileManagerTask.read(
   etlConfig,
   "connectionName",
   filename
);

Execute HTTP call via a manually created Alias

var alias = new com.toolsverse.etl.common.Alias();
alias.setUrl("http://localhost:8080/health");
alias.setTransport("com.toolsverse.io.HttpProcessor");
alias.setParams("method=GET");

var response = com.toolsverse.etl.core.task.common.FileManagerTask.execute(
   alias, payload_or_null, true
);

Execute HTTP call using a named connection

var response = com.toolsverse.etl.core.task.common.FileManagerTask.execute(
   etlConfig,
   "connection_name",
   payload_or_null,
   true
);

Logging

com.toolsverse.util.log.Logger

com.toolsverse.util.log.Logger.log(
    com.toolsverse.util.log.Logger.SEVERE,
    null,
    "Error doing something"
);

System Configuration

com.toolsverse.config.SystemConfig

var props = com.toolsverse.config.SystemConfig.instance().getProperties();

Working with Data Sets

com.toolsverse.etl.common.DataSet

var fldValue = dataSet.getFieldValue(currentRow, "InvoiceNo");

com.toolsverse.etl.common.FieldDef

var fldName = dataSet.getFieldDef("InvoiceNo").getNameToUse();

com.toolsverse.etl.common.DataSetRecord

var record = dataSet.getRecord(0);

High-level Transformations

com.toolsverse.etl.common.CommonEtlUtils

var newDs = com.toolsverse.etl.common.CommonEtlUtils.intersect(
   dataSet,
   with,
   "id"
);

Connection Information

com.toolsverse.etl.common.Alias

var alias = etlConfig.getAliasesMap().get("Connection name");

ETL Engine Configuration

com.toolsverse.etl.core.config.EtlConfig

var alias = etlConfig.getAliasesMap().get("Connection name");

ETL Scenario

com.toolsverse.etl.core.engine.Scenario

var name = scenario.getName();

Summary

• You can access any Java class directly from JavaScript in Etlworks.

• The recommended method is to use fully qualified class names.

• JavaType("class"), importPackage and JavaImporter are available when you need shorter names or many imports.

• This guide provides a reference list of the most commonly used Etlworks packages and classes with examples.