Use JAR library collections in Python app

This article provides an introduction to cross-technology handling of collections. Data structures are one of the essential aspects of every piece of software. Any application constantly process various information, that very often require specific grouping and access strategies. This aspect is addressed by arrays and more advanced collection types. By using the Javonet framework, users gain ability to easily and effectively work with data structures originating from JAR library. Every collection from JAR library is treated as reference.

Javonet allows you to reference and use modules or packages written in (Java/Kotlin/Groovy/Clojure, C#/VB.NET, Ruby, Perl, Python, JavaScript/TypeScript) like they were created in your technology. If have not yet created your first project check Javonet overview and quick start guides for your technology.

With Javonet you can interact with collections from JAR library like they were available in Python but invocation must be performed through Javonet SDK API.

Work with JAR library lists in Python application

Javonet SDK contains various methods to interact with lists and consume the results in Python:

I code in:
# use activate only once in your app
Javonet.activate("your-license-key")

# create called runtime context
called_runtime = Javonet.in_memory().jvm()

# get type from the runtime
list_type = called_runtime.get_type("java.util.ArrayList").execute()

# create instance of generic class
list_instance = list_type.create_instance().execute()

# invoke instance's method
list_instance.invoke_generic_method("add", "one").execute()
list_instance.invoke_generic_method("add", "two").execute()
list_instance.invoke_generic_method("add", "three").execute()
list_instance.invoke_generic_method("add", "four").execute()
list_instance.invoke_generic_method("add", "five").execute()
list_instance.invoke_generic_method("add", "six").execute()

# get elements from list
response1 = list_instance.get_index(2).execute()
response2 = list_instance[3].execute()

# get value from response
result1 = response1.get_value()
result2 = response2.get_value()

# write result to console
print(result1)
print(result2)

In the snippet above, list specific to called technology framework is created.
Then, some elements are added to the list. Finally, this list can be handled through Javonet SDK, f.e. with getIndex method.

Work with JAR library dictionaries in Python application

Javonet SDK contains various methods to interact with dictionaries and consume the results in Python:

I code in:
# use activate only once in your app
Javonet.activate("your-license-key")

# create called runtime context
called_runtime = Javonet.in_memory().jvm()

# get type from the runtime
dictionary_type = called_runtime.get_type("java.util.HashMap").execute()

# create instance of generic class
dictionary = dictionary_type.create_instance().execute()

# invoke instance's method
dictionary.invoke_generic_method("put", "pi", math.pi).execute()
dictionary.invoke_generic_method("put", "e", math.e).execute()
dictionary.invoke_generic_method("put", "c", 299792458.0).execute()

# get elements from dictionary
response1 = dictionary.get_index("pi").execute()
response2 = dictionary["c"].execute()

# get value from response
result1 = response1.get_value()
result2 = response2.get_value()

# write result to console
print(result1)
print(result2)

In the snippet above, list specific to called technology framework is created.
Then, some elements are added to the list. Finally, this list can be handled through Javonet SDK, f.e. with getIndex method.

The same operation can be performed remotely by just changing the new Runtime Context invocation from in memory to tcp that will create and interact with your JAR library objects on any remote node, container or service that hosts Javonet Code Gateway. This way you can preserve the same logic in your application and instantly switch between monolithic and microservices architecture without the need to implement the integration layer based on web services or other remote invocation methods.

Read more about use cases and software architecture scenarios where Javonet runtime bridging technology can support your development process.

Additional references