Archive
Writing an Eclipse Plug-in: Upgrading to Eclipse 3.5
This is inconvenient, but only just so.
In moving from Eclipse 3.4 to 3.5 I found that the launch configurations created under Eclipse 3.4, but run under 3.5, decided not to work anymore. How to fix them? Sadly, the quickest way was to just delete the old ones and create new ones.
So here are instructions on how to create the launch configurations for the past and future examples of this ongoing project if you want to use Eclipse 3.5:
- Open the Run Configuration window.
- Delete the launch configuration named
customplugin. (If you have been slowly building this new project the you probably have a launch configuration namedcustomplugin. It is safe to delete it. If you have been slowly building your own application and including all of the things I have been describing for the last few months then I am not sure how to help except to recommend copying down all of your configuration information, deleting the launch configuration and creating a new one.) - In the list to the left right click on Eclipse Application and select New.
- Enter the following in the Main tab:
- Name: customplugin
- Location: ${workspace_loc}/../runtime-customplugin
- Clear: check. Leave Workspace selected
- Ask for Confirmation Before Clearing: uncheck, but if you want to be asked each time before clearing out your current runtime workbench environment you can certainly leave this checked.
- Run a Product: org.eclipse.platform.ide
- Runtime JRE: [whatever version of Java 6 you have been using]
- Enter the following in the Plug-ins tab:
- Launch With: Plug-ins Selected Below Only
- In the Workspace node put a checkmark next to the customplugin project. Uncheck the Target Platform node. This should unselect all of the default plug-ins.
- To the right click Add Required Plug-ins
- Click Apply.
Go to town.
Help! My Eclipse 3.5 Plug-in Editor has Stopped Working!
The other day I went back to work on a plug-in and found that the plug-in editor was misbehaving. I have multiple installs of Eclipse (3.4 and 3.5) installed on (K)ubuntu and I suspected that might be the problem even though I never had a problem with multiple installations of Eclipse before. Heavens! What’s a blogger to do?
In fact I did what most people would do: I went to Google. What I found was Saminda Wijeratne’s blog where the problem was the same, but the solution described was quite different than I eventually discovered. However, I discovered the solution because the blog encouraged me to go to the Eclipse Preferences window and look at the Plug-in Development –> Target Definitions.
At that point I realized that the ${eclipse_home} variable was pointing to my 3.4 installation instead of 3.5! A little bit more digging also led me to discover that I could not change ${eclipse_home} explicitly within Eclipse. The solution is probably specific to Kubuntu: when I added Eclipse 3.4 and 3.5 to KDE using the Menu Editor I did not set the Advanced –> Work Path. I thought Eclipse would be smart enough to get it right, but I turned out to be wrong (not a good habit to get into).
In the image below notice how the Work Path for the highlighted Eclipse 3.5 entry specifically references my 3.5 path.
.
Once that was done, saved and tested there was much joy in Wonderland.
The cat was alive (though it took a while to find it).
Watchmaker: A First and Second Example
Time to look at the framework that I was sure I was going to like more than JGAP and ECJ.
I do like it; more than JGAP, but not as much as ECJ. I’ll send flowers later.
Since both of the examples, Hello World (genetic algorithm) and Simple Math Test (a genetic program), are already done in Watchmaker all I will be doing is explaining how they were done using the Watchmaker framework.
Hello World – A Genetic Algorithm
This is straight out of the Watchmaker Framework example code. Only two classes are needed:
StringEvaluator, the fitness functionStringsExample, the class that starts the evolution
The StringEvaluator class does three things:
- hold onto the string the chromosomes are supposed to evolve into
- check every character of the candidate string to determine how close it is to the desired string
- return
falsewhen asked if a valid fitness value increases or decreases.
The StringsExample class creates the evolutionary environment in which the strings will evolve. The interesting stuff happens in here (reformatted to fit on this page).
This first section creates crossover and mutation objects specific to strings.
StringMutationmutates the evolving string using the alphabet as mutation values with a probability value of 0.02.StringCrossoverhandles the crossover of strings based on the defined number of crossover points. The default is 1 crossover point.
The pipeline contains the list of operators to be applied to the population; in this case just the two we just discussed.
StringsExample.java
...
public static String evolveString(String target)
{
List<EvolutionaryOperator> operators
= new ArrayList<EvolutionaryOperator>(2);
operators.add(new StringMutation(ALPHABET, new Probability(0.02d)));
operators.add(new StringCrossover());
EvolutionaryOperator pipeline
= new EvolutionPipeline(operators);
The EvolutionEngine is the petri dish where everything happens. The configuration objects are as follows:
- StringFactory, creates the initial chromosomes/individuals for the population
- pipeline, defined above
- StringEvaluator, the fitness function also discussed above
- RouletteWheelSelection, selects candidates at random where the probability is proportional to the candidates fitness score
- MersenneTwisterRNG, a faster more reliable random number generator
StringsExample.java
...
EvolutionEngine engine
= new ConcurrentEvolutionEngine(
new StringFactory(ALPHABET, target.length()),
pipeline,
new StringEvaluator(target),
new RouletteWheelSelection(),
new MersenneTwisterRNG());
The EvolutionObserver is an interesting construct. This visitor gives you a front row seat of things as they happen. It prints out a basic string, but has the potential for coolness.
StringsExample.java
...
engine.addEvolutionObserver(new EvolutionLogger());
Finally, turn on the engine for a population of 100 with a 5% elitism rate. Stop evolving when the fitness score equals 0.
StringsExample.java
...
return engine.evolve(100, // 100 individuals in the population.
5, // 5% elitism.
new TargetFitness(0, false));
}
The code for the above is part of the Watchmaker Framework so download and poke it to your heart’s content.
Simple Math Test – A Genetic Program
The Watchmaker documentation states that it is a framework for genetic algorithms. That made me quite concerned as Toby Segaran’s Simple Math Test is not an example of a genetic algorithm. However, a quick look at the examples in the WF download revealed a package named org.uncommons.watchmaker.example.geneticprogramming. In that package there is a file named GeneticProgrammingExample.java and it states:
GeneticProgrammingExample.java ... /** * Simple tree-based genetic programming application based on the first example * in Chapter 11 of Toby Segaran's Progamming Collective Intelligence. * @author Daniel Dyer */
Gotta love it. Less work for me and I don’t have to fight my way into the framework to figure out how to use WF in a genetic programming context. It seems unfair that both of the examples I chose are already done in WF, but that’s life. However, I will come up with a GP example that WF, JGAP, and ECJ have not done and see what it takes to implement them. One day. Soon.
[Perhaps Daniel Dyer will include the GP-related bits in an upcoming version of Watchmaker. Code reuse is a nice thing. I am hoping ECJ does that as well.]
The example geneticprogramming package contains the following files:
Node.java
BinaryNode.java
LeafNode.java
IfThenElse.java
IsGreater.java
Addition.java
Subtraction.java
Multiplication.java
Constant.java
Parameter.java
Simplification.java
TreeCrossover.java
TreeEvaluator.java
TreeFactory.java
TreeMutation.java
GeneticProgrammingExample.java
That’s a lot of files. Not having many of those classes in the framework shows.
In GP, the solution is an executable tree. During the evolution of the solution there will be trees that are not executable as well as trees that execute, but produce incorrect solutions.
In Watchmaker, the EvolutionEngine controls the process of creating a population, evolving them using various operators like crossover and mutation, checking their fitness and selecting the survivors for the next generation. This entails configuring it with:
- a
CandidateFactorywhich produces the population - an
EvolutionaryOperatorwhich contains otherEvolutionaryOperators such asTreeCrossoverandTreeMutation - a
FitnessEvaluator - a
SelectionStrategy - a random number generator that inherits from
Random
In this case, the EvolutionEngine, an instance of ConcurrentEvolutionEngine, is configured with:
- a
TreeFactorywhich produces a tree of Nodes - an
EvolutionPipelinewhich contains the crossover, mutation and simplification operators - a
TreeEvaluatorwhich will evaluate the fitness of the current tree/chromosome (given 2 input values does the tree produce the desired output value?) - a
RouletteWheelSelectionstrategy - a
MersenneTwisterRNGrandom number generator
You can read more about the RouletteWheelSelection in the Watchmaker Javadocs and at the Newcastle University Engineering Design Center, and about the MersenneTwisterRNG in the Uncommons Math Package Javadocs and at the university where it was developed. The Reader’s Digest version:
-
RouletteWheelSelection– selects candidates by giving them a higher chance of being randomly selected based on their fitness score. The higher the score the higher ther probability of their being chosen. They might be chosen more than once. -
MersenneTwisterRNG– a random number generator that is very random, very fast and very predictable. It is used by various pieces of Watchmaker to guarantee randomness where it is needed.
Let’s look at the fitness function next. The TreeEvaluator is initialized with an array of two input values and an output value. The code, while different than that found in Collective Intelligence, heads for the same target: if the difference between the result from the evolved formula and the supplied output value is zero then we have a winner.
TreeEvaluator.java ... double actualValue = candidate.evaluate(entry.getKey()); double diff = actualValue - entry.getValue(); error += (diff * diff);
The Watchmaker code takes the difference between the actual and the expected values, squares it and adds it to the error value for each iteration of the input values. When error equals zero then the formula works. Same goal, different path.
The EvolutionPipeline contains three operators that are executed in the order in which they are given:
GeneticProgrammingExample.java
...
List<EvolutionaryOperator<Node>> operators = new ArrayList<EvolutionaryOperator<Node>>(3);
operators.add(new TreeMutation(factory, new Probability(0.4d)));
operators.add(new TreeCrossover());
operators.add(new Simplification());
...
EvolutionEngine<Node> engine
= new ConcurrentEvolutionEngine<Node>(...
new EvolutionPipeline<Node>(operators),
...);
When a new population is created the EvolutionaryOperators are called in order:
TreeMutation, with a mutation probability of 40%TreeCrossover, which is a single-point crossoverSimplification, which asks each Node to simplify itself; for example, if the Node contains 3 + 5 then simplify it to 8, but if the Node contains x + 5 (a variable and a constant), then leave it alone.
All that is left is the TreeFactory. The TreeFactory needs to know 4 things to do its job:
- the parameter count for the nodes that are not constants (for example,
Additiongets 2 parameters) - the maximum depth of any given tree (too shallow doesn’t allow for a rich enough execution tree, too deep might generate a bunch of useless code)
- the probability to use in the creation of functions
- the probability to use in the creation of parameters
The EvolutionEngine will call TreeFactory.generateRandomCandidate(), which will call TreeFactory.makeNode(), to randomly create Nodes of functions, parameters or constants:
TreeFactory.java
...
private Node makeNode(Random rng, int maxDepth)
{
if (functionProbability.nextEvent(rng) && maxDepth > 1)
{
// Max depth for sub-trees is one less than max depth for this node.
int depth = maxDepth - 1;
switch (rng.nextInt(5))
{
case 0: return new Addition(makeNode(rng, depth), makeNode(rng, depth));
case 1: return new Subtraction(makeNode(rng, depth), makeNode(rng, depth));
case 2: return new Multiplication(makeNode(rng, depth), makeNode(rng, depth));
case 3: return new IfThenElse(makeNode(rng, depth), makeNode(rng, depth), makeNode(rng, depth));
default: return new IsGreater(makeNode(rng, depth), makeNode(rng, depth));
}
}
...
When the TreeFactory creates a function it is only creating one of five possibilities. Adding additional baseline functions is pretty trivial once you see it presented like this. Daniel Dyer really has done a great job.
The last thing the TreeFactory does is either create a parameter with a parameter count of 1 or 0, or return a constant with a value of 0-10. All too easy.
TreeFactory.java
...
else if (parameterProbability.nextEvent(rng))
{
return new Parameter(rng.nextInt(parameterCount));
}
else
{
return new Constant(rng.nextInt(11));
}
}
Just for fun I have included an example of the code from two of the Nodes: Addition and IfThenElse.
Addition.java
...
public Addition(Node left, Node right)
{
super(left, right, '+');
}
...
public double evaluate(double[] programParameters)
{
return left.evaluate(programParameters) + right.evaluate(programParameters);
}
...
The constructor for Addition takes in two Nodes and a printable version of the operation. There is no check to see if the Nodes can evaluate to something useable by the Addition object; this is part of the evolution process. The trees that don’t work will be disposed of.
The evaluate() method calls evaluate() on the left and right Nodes and adds them together. ‘Nuff said.
The next example is the IfThenElse Node. It contains three nodes: a condition, code to execute if the condition is true, or code to execute if the condition is false.
IfThenElse.java
...
public IfThenElse(Node condition, Node then, Node otherwise)
{
this.condition = condition;
this.then = then;
this.otherwise = otherwise;
}
...
Again, notice no check on the actual capabilities of each Node.
IfThenElse.java
...
public double evaluate(double[] programParameters)
{
return condition.evaluate(programParameters) > 0 // If...
? then.evaluate(programParameters) // Then...
: otherwise.evaluate(programParameters); // Else...
}
...
The evaluate() method resolves to the Java ternary operator and returns the result of either the then Node or otherwise Node. Yes, there is more code in the IfThenElse class (about 200 lines including comments), but the concepts are approachable and the code is quite clean/clear.
There. The Watchmaker framework and the Hello World and Simple Math Test examples.
I feel better now.
The Output
... Generation 28: 493.0 Generation 29: 233.0 Generation 30: 233.0 Generation 31: 45.0 Generation 32: 5.0 Generation 33: 0.0 (((arg0 + 4.0) * arg0) + ((arg1 + -5.0) + (((6.0 + arg1) + 4.0) - arg0)))
The above simplified becomes:
(((arg0 + 4.0) * arg0) + ((arg1 + -5.0) + (((6.0 + arg1) + 4.0) - arg0))) arg0^2 + 4*arg0 + arg1 - 5 + 6 + arg1 + 4 - arg0 arg0^2 + 3*arg0 + 2*arg1 + 5
If we make arg0 –> x and arg1 –> y then the above becomes x^2 + 3*x + 2*y + 5 which matches Toby Segaran’s formula. Go team!
And finally, in my never ending attempt to compare apples-to-apples, and failing miserably I might add, I present the same problem run by each of the three frameworks:
JGAP: 25 generations @ 1000 individuals/generation;
ECJ: 7 generations @ 1024 individuals/generation;
Watchmaker: 33 generations @ 1000 individuals/generation;
ECJ wins again.
The Bad
I was kinda disappointed when I realized that GP was not supported out of the box; the example above was an easy way to discover how to implement GP in Watchmaker, but it felt strange that such a good framework would leave it out. However, Watchmaker is at version 0.6.2 so I have high hopes for the future. Keep going!
The Good
Watchmaker is so easy to use! It uses all kinds of great design ideas, naming conventions, examples, etc. C’mon! You’re using generics! You rock!
The Code
Download the Watchmaker framework and go to town.
DBUnit in Eclipse
Just the other day I was wondering how DBUnit was doing. As a former consultant I used to use DBUnit along with various JUnit extensions on a regular basis.
Given that Eclipse has moved on, JUnit has moved on and DBUnit has moved on I thought I would present a straightforward example of how to use DBUnit with JUnit 4.0 and Eclipse.
Not that much has changed therefore there is not going to be a lot of hand holding here.
Assumptions
Eclipse 3.5
JUnit 4.0 – included with Eclipse
DBUnit 2.4.5
SLF4J 1.5.8 – DBUnit needs this
HSQL DB 1.8.0
I implemented this example on Kubuntu 9.10, if that makes any difference.
If you are new to Eclipse then just download any version that seems reasonable as long as it includes a Java development environment.
The Easy Part
Make sure all of the above software is available somewhere on your machine. If not, install all the software in your favorite places.
Start Eclipse.
The Short Version
- Start your database
- Create a Java Project
- Add DBUnit to your classpath
- Write and run a database test
- Create initial and expected dataset files
- Extend DBTestCase (inheritance) or use a JUnit class (composition)
- Implement your test methods
The Longer Version
Start your database
I don’t have a database to run so I downloaded and installed HSQL. To run the HSQL server, which I prefer in examples, open a command window, go to the HSQL folder and run:
java -cp lib/hsqldb.jar org.hsqldb.Server -database.0 file:hiddenclause -dbname.0 xdb
In this case the database name is xdb with the database files named hiddenclause.*. Call your files whatever. I will add test data later.
My Eclipse default configuration includes:
Source folder name: src
Output folder name: classes
Default execution environment: JavaSE-1.6
Create a Java Project
Create a Java Project named DBUnitExample. ‘Nuff said.
Add DBUnit to your classpath
Once the project appears in the Package Explorer, right click on the project name and select Properties –> Java Build Path –> Libraries. Click Add External JARs and add the DBUnit JAR file, in this case dbunit-2.4.5.jar, to the list of libraries in the classpath. Yes, you could also have done this when you first created the project.
Add:
- slf4j-api-1.5.8.jar
- slf4j-simple-1.5.8.jar
- hsqldb.jar
to the classpath as well.
Click OK to close the Properties window.
Write and run a database test
Add Test Data
As running a test on a fresh database is a little difficult start the HSQL Database Manager from another shell (in the HSQL directory):
java -cp lib/hsqldb.jar org.hsqldb.util.DatabaseManager
In the Connect window enter:
Setting Name: hiddenclause example
Type: HSQL Database Engine Server
Driver: org.hsqldb.jdbcDriver
URL: jdbc:hsqldb:hsql://localhost/xdb
User: sa
Password: [leave blank]
Click OK.
Almost done. Select Options –> Insert Test Data. Now we have 4 tables worth of data to test with. Run a delete on the CUSTOMER table so that is is empty.
Close the Database Manager.
Write a Database Test
The steps for writing a DBUnit test are:
1. Create initial and expected dataset files
2. Extend DBTestCase (inheritance) or use a JUnit class (composition)
3. Implement your test methods
Once you get comfortable with that the additional steps are:
1. Create initial and expected dataset files
2. Extend DBTestCase (inheritance) or use a JUnit class (composition)
3. Implement getSetUpOperation() and getTearDownOperation() (optional)
4. Override setUpDatabaseConfig() (optional)
5. Implement your test methods
We’ll just do the first one using the test data created by HSQL.
Create initial and expected dataset files
The DBUnit dataset can come from anywhere (files, databases, spreadsheets, etc.). Where the data comes from is hidden behind the class that implements IDataSet. For this example, we will use XML datasets.
Here is the initial dataset file:
customer-init.xml
<?xml version="1.0" encoding="UTF-8"?> <dataset. <CUSTOMER /> </dataset>
Here is the expected dataset (what we expect to find in the database after executing some code):
<?xml version="1.0" encoding="UTF-8"?> <dataset> <CUSTOMER ID="1" FIRSTNAME="John" LASTNAME="Smith" STREET="1 Main Street" CITY="Anycity" /> </dataset>
Extend DBTestCase (inheritance) or use a JUnit class (composition)
The first version of CustomerTest will inherit from the DBUnit class DBTestCase. That is the recommended way of creating a DBUnit test. It uses the JUnit 3.8.2 classes which still works even with the JUnit 4.0 JAR file.
public class CustomerTest extends DBTestCase {
...
@Override
protected IDataSet getDataSet() throws Exception {
...
}
}
The getDataSet() method is called to initialize the database before the test. Consider it part of your setup logic. Let’s load the initialization dataset.
@Override
protected IDataSet getDataSet() throws Exception {
return new FlatXmlDataSet(
new FileInputStream("customer-init.xml"));
}
There are a number of properties that need to be set prior to DBUnit doing its magic. You can set those properties in the constructor:
public CustomerTest(String name) {
super(name);
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_DRIVER_CLASS,
"org.hsqldb.jdbcDriver");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_CONNECTION_URL,
"jdbc:hsqldb:hsql://localhost/xdb");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_USERNAME,
"sa");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_PASSWORD,
"");
_customerFactory = CustomerFactory.getInstance();
}
In real life you would set the driver name, connection URL and username and password to their appropriate values.
Implement your test methods
For this example, we are going to test an insert into the db.
public void testInsert() throws Exception {
// insert a customer into the database
Customer customer = _customerFactory.create("John", "Smith");
customer.setStreet("1 Main Street");
customer.setCity("Anycity");
_customerFactory.update(customer);
...
The code for the CustomerFactory and Customer are at the end of this post.
The data that has just been entered into the database becomes your actual assertable values. Go get them.
// get the actual table values
IDatabaseConnection connection = getConnection();
IDataSet databaseDataSet = connection.createDataSet();
ITable actualTable = databaseDataSet.getTable("CUSTOMER");
The values defined in customer-expected.xml are what you expect the values to be. Go get them.
// get the expected table values
IDataSet expectedDataSet = new FlatXmlDataSet(
new FileInputStream("customer-expected.xml"));
ITable expectedTable = expectedDataSet.getTable("CUSTOMER");
Check the actual against the expected and complain or not as the case may be.
Assertion.assertEquals(expectedTable, actualTable);
}[/sourcecode]
A version that uses a JUnit class as a wrapper around the DBUnit code looks like this:
/**
* This is an example only! Use it for anything else at your own risk!
* You have been warned! Coder/user beware!
*
* copyright 2009 Carlos Valcarcel
*/
package hiddenclause.example.dbunit;
import java.io.FileInputStream;
import org.dbunit.Assertion;
import org.dbunit.IDatabaseTester;
import org.dbunit.JdbcDatabaseTester;
import org.dbunit.database.IDatabaseConnection;
import org.dbunit.dataset.IDataSet;
import org.dbunit.dataset.ITable;
import org.dbunit.dataset.xml.FlatXmlDataSet;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
/**
* @author carlos
*/
public class CustomerJunitTest {
private CustomerFactory _customerFactory;
private IDatabaseTester databaseTester;
@Before
public void setUp() throws Exception {
databaseTester = new JdbcDatabaseTester("org.hsqldb.jdbcDriver",
"jdbc:hsqldb:hsql://localhost/xdb",
"sa", "");
// initialize your dataset here
IDataSet dataSet = new FlatXmlDataSet(new FileInputStream("customer-init.xml"));
databaseTester.setDataSet(dataSet);
// will call default setUpOperation
databaseTester.onSetup();
_customerFactory = CustomerFactory.getInstance();
}
@Test
public void testInsert() throws Exception {
// insert a customer into the database
Customer customer = _customerFactory.create("John", "Smith");
customer.setStreet("1 Main Street");
customer.setCity("Anycity");
_customerFactory.update(customer);
// get the actual table values
IDatabaseConnection connection = databaseTester.getConnection();
IDataSet databaseDataSet = connection.createDataSet();
ITable actualTable = databaseDataSet.getTable("CUSTOMER");
// get the expected table values
IDataSet expectedDataSet = new FlatXmlDataSet(
new FileInputStream("customer-expected.xml"));
ITable expectedTable = expectedDataSet.getTable("CUSTOMER");
Assertion.assertEquals(expectedTable, actualTable);
}
@After
public void tearDown() throws Exception {
databaseTester.onTearDown();
}
}
Things to notice:
- less configuration (the System.setProperty() calls are gone)
- explicit creation of a IDatabaseTester object
- explicit call to databaseTester.onSetup()
- explicit call to databaseTester.onTearDown()
Run the Database Test
With all the pieces in place it is now safe to run the CustomerTest DBUnit class. You will probably see some warning messages in the Console view about the data type factory being incorrect. You can safely ignore that error for this example. In real life you probably want to instantiate a new DataTypeFactory based on the database you are using.
If any of the above does not quite work as described let me know and I will update the above explanation.
The Code
customer-init.xml
<?xml version="1.0" encoding="UTF-8"?>
<dataset>
<CUSTOMER />
</dataset>
customer-expected.xml
<?xml version="1.0" encoding="UTF-8"?>
<dataset>
<CUSTOMER ID="1"
FIRSTNAME="John"
LASTNAME="Smith"
STREET="1 Main Street"
CITY="Anycity" />
</dataset>
CustomerTest.java
/**
* This is an example only! Use it for anything else at your own risk!
* You have been warned! Coder/user beware!
*
* copyright 2009 Carlos Valcarcel
*/
package hiddenclause.example.dbunit;
import java.io.FileInputStream;
import org.dbunit.Assertion;
import org.dbunit.DBTestCase;
import org.dbunit.PropertiesBasedJdbcDatabaseTester;
import org.dbunit.database.IDatabaseConnection;
import org.dbunit.dataset.IDataSet;
import org.dbunit.dataset.ITable;
import org.dbunit.dataset.xml.FlatXmlDataSet;
/**
* @author carlos
*/
public class CustomerTest extends DBTestCase {
private CustomerFactory _customerFactory;
public CustomerTest(String name) {
super(name);
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_DRIVER_CLASS,
"org.hsqldb.jdbcDriver");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_CONNECTION_URL,
"jdbc:hsqldb:hsql://localhost/xdb");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_USERNAME,
"sa");
System.setProperty(
PropertiesBasedJdbcDatabaseTester.DBUNIT_PASSWORD,
"");
_customerFactory = CustomerFactory.getInstance();
}
public void testInsert() throws Exception {
// insert a customer into the database
Customer customer = _customerFactory.create("John", "Smith");
customer.setStreet("1 Main Street");
customer.setCity("Anycity");
_customerFactory.update(customer);
// get the actual table values
IDatabaseConnection connection = getConnection();
IDataSet databaseDataSet = connection.createDataSet();
ITable actualTable = databaseDataSet.getTable("CUSTOMER");
// get the expected table values
IDataSet expectedDataSet = new FlatXmlDataSet(
new FileInputStream("customer-expected.xml"));
ITable expectedTable = expectedDataSet.getTable("CUSTOMER");
Assertion.assertEquals(expectedTable, actualTable);
}
/*
* (non-Javadoc)
* @see org.dbunit.DatabaseTestCase#getDataSet()
*/
@Override
protected IDataSet getDataSet() throws Exception {
return new FlatXmlDataSet(
new FileInputStream("customer-init.xml"));
}
}
CustomerFactory.java
/**
* This is an example only! Use it for anything else at your own risk!
* You have been warned! Coder/user beware!
*
* copyright 2009 Carlos Valcarcel
*/
package hiddenclause.example.dbunit;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
/**
* @author carlos
*
*/
public class CustomerFactory {
static {
try {
Class.forName("org.hsqldb.jdbcDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static CustomerFactory getInstance()
{
return new CustomerFactory();
}
public Customer create(String firstName, String lastName) {
return new Customer(1, firstName, lastName);
}
public void update(Customer customer) throws SQLException {
Connection connection = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/xdb");
String sql = "insert into customer (id, firstname, lastname, street, city) values ("
+ customer.getId() + ", "
+ "'" + customer.getFirstName() + "', "
+ "'" + customer.getLastName() + "', "
+ "'" + customer.getStreet() + "', "
+ "'" + customer.getCity() + "'"
+ ")";
Statement stmt = connection.createStatement();
stmt.execute(sql);
if (stmt.getUpdateCount() != 1) {
throw new SQLException("Insert failed!");
}
}
}
Customer.java
/**
* This is an example only! Use it for anything else at your own risk!
* You have been warned! Coder/user beware!
*
* copyright 2009 Carlos Valcarcel
*/
package hiddenclause.example.dbunit;
/**
* @author carlos
*
*/
public class Customer {
private int _id;
private String _firstName;
private String _lastName;
private String _street;
private String _city;
public Customer(int id, String firstName, String lastName) {
_id = id;
_firstName = firstName;
_lastName = lastName;
}
public int getId() {
return _id;
}
public String getFirstName() {
return _firstName;
}
public String getLastName() {
return _lastName;
}
public String getStreet() {
return _street;
}
public String getCity() {
return _city;
}
public void setStreet(String street) {
_street = street;
}
public void setCity(String city) {
_city = city;
}
}
