computer science

Umple

Umple is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Umple rather than just read about it. In short: Umple is a language for both object-oriented programming and modelling with class diagrams and state diagrams. The name Umple is a portmanteau of "UML", "ample" and "Simple", indicating that it is designed to provide ample features to extend programming languages with UML capabilities.

Key takeaways

Umple belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Umple to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Umple from memory before moving on to harder problems.

Reference excerpt

Umple is a language for both object-oriented programming and modelling with class diagrams and state diagrams. The name Umple is a portmanteau of "UML", "ample" and "Simple", indicating that it is designed to provide ample features to extend programming languages with UML capabilities.

History and philosophy The design of Umple started in 2008 at the University of Ottawa. Umple was open-sourced and its development was moved to Google Code in early 2011 and to GitHub in 2015. Umple was developed, in part, to address certain problems observed in the modelling community. Most specifically, it was designed to bring modelling and programming into alignment, It was intended to help overcome inhibitions against modelling common in the programmer community. It was also intended to reduce some of the difficulties of model-driven development that arise from the need to use large, expensive or incomplete tools. One design objective is to enable programmers to model in a way they see as natural, by adding modelling constructs to programming languages.

Features and capabilities

Umple can be used to represent in a textual manner many UML modelling entities found in class diagrams and state diagrams. Umple can generate code for these in various programming languages. Currently Umple fully supports Java, C++ and PHP as target programming languages and has functional, but somewhat incomplete support for Ruby. Umple also incorporates various features not related to UML, such as the singleton pattern, keys, immutability, mixins and aspect-oriented code injection. The class diagram notations Umple supports includes classes, interfaces, attributes, associations, generalizations and operations. The code Umple generates for attributes include code in the constructor, 'get' methods and 'set' methods. The generated code differs considerably depending on whether the attribute has properties such as immutability, has a default value, or is part of a key. Umple generates many methods for manipulating, querying and navigating associations. It supports all combinations of UML multiplicity and enforces referential integrity. Umple supports the vast majority of UML state machine notation, including arbitrarily deep nested states, concurrent regions, actions on entry, exit and transition, plus long-lasting activities while in a state. A state machine is treated as an enumerated attribute where the value is controlled by events. Events encoded in the state machine can be methods written by the user, or else generated by the Umple compiler. Events are triggered by calling the method. An event can trigger transitions (subject to guards) in several different state machines. Since a program can be entirely written around one or more state machines, Umple enables automata-based programming. The bodies of methods are written in one of the target programming languages. The same is true for other imperative code such as state machine actions and guards, and code to be injected in an aspect-oriented manner. Such code can be injected before many of the methods in the code Umple generates, for example before or after setting or getting attributes and associations. The Umple notation for UML constructs can be embedded in any of its supported target programming languages. When this is done, Umple can be seen as a pre-processor: The Umple compiler expands the UML constructs into code of the target language. Code in a target language can be passed to the Umple compiler directly; if no Umple-specific notation is found, then the target-language code is emitted unchanged by the Umple compiler. Umple, combined with one of its target languages for imperative code, can be seen and used as a complete programming language. Umple plus Java can therefore be seen as an extension of Java. Alternatively, if imperative code and Umple-specific concepts are left out, Umple can be seen as a way of expressing a large subset of UML in a purely textual manner. Code in one of the supported programming languages can be added in the same manner as UML envisions adding action language code.

License Umple is licensed under an MIT-style license.

Examples Here is the classic Hello world program written in Umple (extending Java):

This example looks just like Java, because Umple extends other programming languages. With the program saved in a file named HelloWorld.ump, it can be compiled from the command line:

$ java -jar umple.jar HelloWorld.ump

To run it:

$ java HelloWorld

The following is a fully executable example showing embedded Java methods and declaration of an association.

The following example describes a state machine called status, with states Open, Closing, Closed, Opening and HalfOpen, and with various events that cause transitions from one state to another.

class GarageDoor { status { Open { buttonOrObstacle -> Closing; } Closing { buttonOrObstacle -> Opening; reachBottom -> Closed; } Closed { buttonOrObstacle -> Opening; } Opening { buttonOrObstacle -> HalfOpen; reachTop -> Open; } HalfOpen { buttonOrObstacle -> Opening; } } }

Umple use in practice The first version of the Umple compiler was written in Java, Antlr and Jet (Java Emitter Templates), but in a bootstrapping process, the Java code was converted to Umple following a technique called Umplification. The Antlr and Jet were also later converted to native Umple. Umple is therefore now written entirely in itself, in other words it is self-hosted and serves as its own largest test case. Umple and UmpleOnline have been used in the classroom by several instructors to teach UML and modelling. In one study it was found to help speed up the process of teaching UML, and was also found to improve the grades of students.

Tools Umple is available as a Jar file so it can be run from the command line, and as an Eclipse plugin. There is also an online tool for Umple called UmpleOnline

, which allows a developer to create an Umple system by drawing a UML class diagram, editing Umple code or both. Umple models created with UmpleOnline are stored in the cloud. Currently UmpleOnline only supports Umple programs consisting of a single input file. In addition to code, Umple's tools can generate a variety of other types of output, including user interfaces based on the Umple model.

See also Model Driven Engineering Executable UML Unified Modeling Language

References

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Umple

Start with the simplest possible case. Write down what Umple claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Umple before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Umple ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Umple

In research: Umple appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Umple in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Umple is common in secondary-school and first-year university syllabi. It links to neighbouring topics Concurrent programming languages, Free UML tools, JVM programming languages, so understanding it makes those chapters shorter.
In everyday life: Look for Umple outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Umple in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Umple means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Umple out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Umple in simple terms?

Why does Umple matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Umple?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Umple.