In this Java AIML tutorial, we will learn to create simple chatbot program in Java. A Chatbot is an application designed to simulate the conversation with human users, especially over the Internet. Internally it uses any NLP (Natural Language Processing) system to interpret the human interactions and reply back with meaningful information.

AIML (Artificial Intelligence Markup Language) is an XML dialect for creating natural language software agents. It contains the basic rules which Natural Language Understanding (NLU) unit uses internally. It can be think of as a heart of the engine. The more rules we add in AIML – the more intelligent our Chatbot will be.

It’s important to know the difference between NLP and NLU. NLP refers to all systems that work together to handle end-to-end interactions between machines and humans in the preferred language of the human. In other words, NLP lets people and machines talk to each other “naturally”. NLU is actually a subset of the wider world of NLP. It helps in parsing unstructured inputs e.g. mispronunciations, swapped words, contractions, colloquialisms, and other quirks.

Table of Contents

1. Prerequisite
2. Java AIML Chatbot Example
3. Add Custom Patterns in Chatbot
4. Summary

1. Prerequisite

  • Reference AIML Implementation – To get started, we shall use an already working reference application. There is one such java based implementation called program-ab hosted on google-code repository. Download the program-ab latest distribution from google code repository.
  • Eclipse and Maven – for coding and development.

2. Java AIML Chatbot Example

Follow these simple steps for building your first Chatbot application.

2.1. Download Unzip the program-ab distribution

We need to first unzip the program-ab distribution to a convenient folder. We will need to take Ab.jar and existing AIML rules from it.

2.2. Create eclipse project

Create eclipse maven project to start the development. So let’s create a maven project with .

2.3. Create project and import AIML library

Create eclipse maven project to start the development. Choose packaging as jar and GAV coordinate as your choice and import to eclipse. Now create a folder lib in the base folder and copy the Ab.jar from the program-ab distribution to this folder.

2.4. Add AIML to classpath

To add AIML to classpath, add Ab.jar to deployment assembly in eclipse. Alternatively you can install this jar into your local maven repository and then use it.

Add below AIML maven dependency to pom.xml. Now build the maven project by command mvn clean install.

 <dependencies>
	<dependency>
		<artifactId>com.google</artifactId>
		<groupId>Ab</groupId>
		<version>0.0.4.3</version>
		<scope>system</scope>
		<systemPath>${basedir}/lib/Ab.jar</systemPath>
	</dependency>
</dependencies>

2.5. Copy default AIML rules

Copy the bots folder from program-ab directory into the resources folder of your maven project. This folder contains default AIML sets that we will use initially. Later we will see how we can add our custom rules into our Chatbot.

Project Structure with bots added to resources folder

2.6. Create Hello World Chatbot Program

Now create a simple java program i.e. Chatbot.java. It’s main() method will invoke the chat program which will run on the command prompt. Basic structure of this program will be to introduce a infinite loop and in each loop take a user input from command prompt and then we will ask program-ab API to give the answer of the input provided by user.

More details about the program-ab API interaction is mentioned in the wiki link.

package com.howtodoinjava.ai;

import java.io.File;
import org.alicebot.ab.Bot;
import org.alicebot.ab.Chat;
import org.alicebot.ab.History;
import org.alicebot.ab.MagicBooleans;
import org.alicebot.ab.MagicStrings;
import org.alicebot.ab.utils.IOUtils;

public class Chatbot {
	private static final boolean TRACE_MODE = false;
	static String botName = "super";

	public static void main(String[] args) {
		try {

			String resourcesPath = getResourcesPath();
			System.out.println(resourcesPath);
			MagicBooleans.trace_mode = TRACE_MODE;
			Bot bot = new Bot("super", resourcesPath);
			Chat chatSession = new Chat(bot);
			bot.brain.nodeStats();
			String textLine = "";

			while(true) {
				System.out.print("Human : ");
				textLine = IOUtils.readInputTextLine();
				if ((textLine == null) || (textLine.length() < 1))
					textLine = MagicStrings.null_input;
				if (textLine.equals("q")) {
					System.exit(0);
				} else if (textLine.equals("wq")) {
					bot.writeQuit();
					System.exit(0);
				} else {
					String request = textLine;
					if (MagicBooleans.trace_mode)
						System.out.println("STATE=" + request + ":THAT=" + ((History) chatSession.thatHistory.get(0)).get(0) + ":TOPIC=" + chatSession.predicates.get("topic"));
					String response = chatSession.multisentenceRespond(request);
					while (response.contains("&lt;"))
						response = response.replace("&lt;", "<");
					while (response.contains("&gt;"))
						response = response.replace("&gt;", ">");
					System.out.println("Robot : " + response);
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	private static String getResourcesPath() {
		File currDir = new File(".");
		String path = currDir.getAbsolutePath();
		path = path.substring(0, path.length() - 2);
		System.out.println(path);
		String resourcesPath = path + File.separator + "src" + File.separator + "main" + File.separator + "resources";
		return resourcesPath;
	}
}

2.7. Test Chatbot Interactions

Now our program is ready and we can now start conversation with chat. To do that just run the program as java application. To exit, you shall type q or wq.

Human : Hi
Robot : Hi! It's delightful to see you.
Human : How are you
Robot : Feeling really joyful today.
Human : My name is sajal
Robot : Glad to see you, Sajal
Human : what is my name
Robot : Sajal
Human : tell me my name
Robot : Sajal

Like this, you can do basic talk with the chat bot.

3. Add Custom Patterns in Chatbot

Now we can add our custom patterns in the bot to add more intelligence in the interactions. To do that create a new .aiml file in the aiml directory of your bot (src\main\resources\bots\super\aiml) . Add as many categories in that file as you wish. Here category refer to the human questions and template refers to chat bot’s response. I have created a file called a-custom-entry.aiml and added three questions as below.

<?xml version="1.0" encoding="UTF-8"?>
<aiml>
	<category><pattern>WHAT IS JAVA</pattern>
		<template>Java is a programming language.</template>
	</category>
	<category><pattern>WHAT IS CHAT BOT</pattern>
		<template>Chatbot is a computer program designed to simulate 
		conversation with human users, especially over the Internet.</template>
	</category>
	<category><pattern>WHAT IS INDIA</pattern>
		<template>wonderful country.</template>
	</category>
</aiml>

Now we can ask bot these three questions as well.

Once our custom aiml file is ready, we need to do generate corresponding entries for other folders parallel to aiml. To do it, we need to invoke the bot.writeAIMLFiles(). I have created another java program called AddAiml.java for this purpose. Once you are done with the aiml editing, just run this program once before starting the bot. It will add these custom entries to the bot’s brain.

package com.howtodoinjava.ai;

import java.io.File;
import org.alicebot.ab.Bot;
import org.alicebot.ab.MagicBooleans;

public class AddAiml {

	private static final boolean TRACE_MODE = false;
	static String botName = "super";

	public static void main(String[] args) {
		try {

			String resourcesPath = getResourcesPath();
			System.out.println(resourcesPath);
			MagicBooleans.trace_mode = TRACE_MODE;
			Bot bot = new Bot("super", resourcesPath);
			
			bot.writeAIMLFiles();

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	private static String getResourcesPath() {
		File currDir = new File(".");
		String path = currDir.getAbsolutePath();
		path = path.substring(0, path.length() - 2);
		System.out.println(path);
		String resourcesPath = path + File.separator + "src" + File.separator + "main" + File.separator + "resources";
		return resourcesPath;
	}
}

3.1. Test custom chat patterns

After running the AddAiml, once you have added the new entries into the AIML, run the chat bot program again and ask the new questions. It should give proper response.

In my case, here is the output.

Human : What is java
Robot : Java is a programming language.
Human : what is chat bot
Robot : Chatbot is a computer program designed to simulate 
		conversation with human users, especially over the Internet.
Human : what is india
Robot : wonderful country.

4. Summary

In this AIML Java tutorial, we have learn to create simple command line based chatbot program with program-ab reference application. Next time, when you have any such requirement, you can think of AIML based chat bot. It is capable to doing moderate stuffs easily.

To enhance your knowledge, you may try to –

  • Play with AIML and create more interesting conversations. AIML has many tags which you can use, it also give some option to configure Sraix to invoke external REST based web services.
  • Add your own custom placeholder in the template section and parse that from the AIML response and do more based on your identifier in the response, like You can able to invoke your own web service to get some more information.
  • Convert this command line chat program to web based chat, I am currently working on that and will publish a followup post on that.
  • You can add your custom rule engine on top of your AIML response to do more.

AIML can do lots of things, but now a days much more sophisticated techniques are available specially in the Machine Learning space, try to learn those as well.

I have deleted the Ab.jar file from this source code distribution due to the size restriction. Please add the jar file from program-ab distribution that you have downloaded initially.

Happy Learning !!