IvyScript-Java Integration

Call Java methods and fields

You can easily write own Java classes and use them directly in IvyScript. You can call static methods and fields from Java classes (e.g. java.lang.Math). You have to address the class with the qualified name or use import statements. If a Java method has no return parameter (void) then the called object of the method is returned (e.g. a call to user.setName(...) returns object user).

import java.lang.Math;

Number r = Math.random();
Number pi = Math.PI;

out.n= r*pi;

Working with different Date, Time and DateTime implementations

When working with Databases and Web Services in Axon.ivy, then different implementations of Date, Time and combined Date-Time information are encountered (e.g. java.util.Date, java.sql.Date, Axis Time, etc). To further complicate matters, some of those implementations are - for historical reasons - mutable (e.g. java.util.Date) which is from todays’ perspective an unwelcomed behavior. This has been remedied by some other implementations.

To facilitate working with values of those different types, IvyScript will always convert them to the corresponding, immutable IvyScript base types whenever such values are encountered, according to the following table:

Automatic conversion of foreign Date / Time values

Java type	Ivy type
Axis1 Time	Ivy Time
Axis2 Time	Ivy Time
Axis1 Duration	Ivy Duration
Axis2 Duration	Ivy Duration
JDBC (SQL) Timestamp	Ivy DateTime
JDBC (SQL) Date	Ivy Date
JDBC (SQL) Time	Ivy Time
Java Date	Ivy DateTime

The automatic conversion into IvyScript types takes place transparently. The developer should therefore only think in terms of the IvyScript Date / Time types. No explicit conversion has to be made, neither when reading nor when writing those types.

Warning

As a general rule, do not create any variables or objects of foreign (i.e. Java) Date / Time types inside IvyScript . Although a statement such as

java.util.Date myDate = new java.util.Date();

is valid and permitted in IvyScript, the actual type of the myDate object will aways be IvyScript DateTime, due to the auto-conversion. This can lead to confusion.

When trying to find out if date or time values are null or not initialized, developers should always use the is initialized operator rather than testing against null:

// recommended style
if (person.birthday is initialized) ...
if (in.lunchTime is initialized) ...
if (schedule.appointment is initialized) ...

// unsafe style, not recommended
if (person.birthday != null) ...
if (in.lunchTime != null) ...
if (schedule.appointment != null) ...

Auto casting rules

IvyScript supports auto casting between the most important Java types and IvyScript types. This means, that you no longer have to use the toXyz() methods on your IvyScript values. Instead you can directly assign IvyScript types to Java types and vice versa. This also holds for lists (IvyScript) and arrays (Java).

The following auto-casting rules are supported by IvyScript (bidirectional):

Auto casting rules

Java type		Ivy type
Axis1 Time	<->	Ivy Time
Axis2 Time	<->	Ivy Time
Axis1 Duration	<->	Ivy Duration
Axis2 Duration	<->	Ivy Duration
JDBC (SQL) Timestamp	<->	Ivy DateTime
JDBC (SQL) Date	<->	Ivy Date
JDBC (SQL) Time	<->	Ivy Time
Java Date	<->	Ivy DateTime
Java Date	<->	Ivy Date
Java Date	<->	Ivy Time
byte[]	<->	Ivy Binary
aType[]	<->	Ivy List<aType>>