All field constructor in Groovy

TupleConstructor annotation in Groovy generate constructors for class with each of its properties (eventually also fields). The class below@TupleConstructor(includeFields = true)class Person {   String firstName   String lastName&nb…

TupleConstructor annotation in Groovy generate constructors for class with each of its properties (eventually also fields). The class below

@TupleConstructor(includeFields = true)
class Person {
   String firstName
   String lastName
   private boolean male
}

will have constructors: Person(), Persion(String), Person(String, String) and Person(String, String, boolean). You could test it using code below.

class TupleConstructorTest extends GroovyTestCase{
    @Test
    void testSimpleTupleConstructorShouldGenerateConstructor() {
        assertScript '''
            import groovy.transform.TupleConstructor
            @TupleConstructor(includeFields = true)
            class Person {
                private final String firstName
                private final String lastName
                private final boolean male
                String toString(){ "$firstName $lastName $male" }
            }            
            assert Person.constructors.size() == 4
            assert new Person().toString() == 'null null false'
            assert new Person('John').toString() == 'John null false'
            assert new Person('John','Smith').toString() == 'John Smith false'
            assert new Person('John','Smith', true).toString() == 'John Smith true'
        '''
    }
}

I almost always create classes with all private final fields and generate constructior with all fields using my IDE.

So I have prepared new transformation AllFieldConstructor which bases on TupleConstructor and generates only constructor with all fields as parameters.

class AllFieldConstructorTest extends GroovyTestCase{
    @Test
    void testSimpleTupleConstructorShouldGenerateConstructor() {
        assertScript '''
            import com.blogspot.przybyszd.transformations.AllFieldConstructor
            @AllFieldConstructor
            class Person {
                private final String firstName
                private final String lastName
                private final boolean male
                String toString(){ "$firstName $lastName $male" }
            }
            assert Person.constructors.size() == 1
            assert new Person('John','Smith', true).toString() == 'John Smith true'
        '''
    }
}

The sources are available here

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Spock, Java and Maven

Few months ago I've came across Groovy - powerful language for JVM platform which combines the power of Java with abilities typical for scripting languages (dynamic typing, metaprogramming).

Together with Groovy I've discovered spock framework (https://code.google.com/p/spock/) - specification framework for Groovy (of course you can test Java classes too!). But spock is not only test/specification framework - it also contains powerful mocking tools.

Even though spock is dedicated for Groovy there is no problem with using it for Java classes tests. In this post I'm going to describe how to configure Maven project to build and run spock specifications together with traditional JUnit tests.


Firstly, we need to prepare pom.xml and add necessary dependencies and plugins.

Two obligatory libraries are:
<dependency>
<groupid>org.spockframework</groupId>
<artifactid>spock-core</artifactId>
<version>0.7-groovy-2.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupid>org.codehaus.groovy</groupId>
<artifactid>groovy-all</artifactId>
<version>${groovy.version}</version>
<scope>test</scope>
</dependency>
Where groovy.version is property defined in pom.xml for more convenient use and easy version change, just like this:
<properties>
<gmaven-plugin.version>1.4</gmaven-plugin.version>
<groovy.version>2.1.5</groovy.version>
</properties>

I've added property for gmaven-plugin version for the same reason ;)

Besides these two dependencies, we can use few additional ones providing extra functionality:
  • cglib - for class mocking
  • objenesis - enables mocking classes without default constructor
To add them to the project put these lines in <dependencies> section of pom.xml:
<dependency>
<groupid>cglib</groupId>
<artifactid>cglib-nodep</artifactId>
<version>3.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupid>org.objenesis</groupId>
<artifactid>objenesis</artifactId>
<version>1.3</version>
<scope>test</scope>
</dependency>

And that's all for dependencies section. Now we will focus on plugins necessary to compile Groovy classes. We need to add gmaven-plugin with gmaven-runtime-2.0 dependency in plugins section:
<plugin>
<groupid>org.codehaus.gmaven</groupId>
<artifactid>gmaven-plugin</artifactId>
<version>${gmaven-plugin.version}</version>
<configuration>
<providerselection>2.0</providerSelection>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupid>org.codehaus.gmaven.runtime</groupId>
<artifactid>gmaven-runtime-2.0</artifactId>
<version>${gmaven-plugin.version}</version>
<exclusions>
<exclusion>
<groupid>org.codehaus.groovy</groupId>
<artifactid>groovy-all</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupid>org.codehaus.groovy</groupId>
<artifactid>groovy-all</artifactId>
<version>${groovy.version}</version>
</dependency>
</dependencies>
</plugin>

With these configuration we can use spock and write our first specifications. But there is one issue: default settings for maven-surefire plugin demand that test classes must end with "..Test" postfix, which is ok when we want to use such naming scheme for our spock tests. But if we want to name them like CommentSpec.groovy or whatever with "..Spec" ending (what in my opinion is much more readable) we need to make little change in surefire plugin configuration:
<plugin>
<groupid>org.apache.maven.plugins</groupId>
<artifactid>maven-surefire-plugin</artifactId>
<version>2.15</version>
<configuration>
<includes>
<include>**/*Test.java</include>
<include>**/*Spec.java</include>
</includes>
</configuration>
</plugin>

As you can see there is a little trick ;) We add include directive for standard Java JUnit test ending with "..Test" postfix, but there is also an entry for spock test ending with "..Spec". And there is a trick: we must write "**/*Spec.java", not "**/*Spec.groovy", otherwise Maven will not run spock tests (which is strange and I've spent some time to figure out why Maven can't run my specs).

Little update: instead of "*.java" postfix for both types of tests we can write "*.class" what is in my opinion more readable and clean:
<include>**/*Test.class</include>
<include>**/*Spec.class</include>
(thanks to Tomek Pęksa for pointing this out!)

With such configuration, we can write either traditional JUnit test and put them in src/test/java directory or groovy spock specifications and place them in src/test/groovy. And both will work together just fine :) In one of my next posts I'll write something about using spock and its mocking abilities in practice, so stay in tune.

New HTTP Logger Grails plugin

I've wrote a new Grails plugin - httplogger. It logs:

  • request information (url, headers, cookies, method, body),
  • grails dispatch information (controller, action, parameters),
  • response information (elapsed time and body).

It is mostly useful for logging your REST traffic. Full HTTP web pages can be huge to log and generally waste your space. I suggest to map all of your REST controllers with the same path in UrlMappings, e.g. /rest/ and configure this plugin with this path.

Here is some simple output just to give you a taste of it.

17:16:00,331 INFO  filters.LogRawRequestInfoFilter  - 17:16:00,340 INFO  filters.LogRawRequestInfoFilter  - 17:16:00,342 INFO  filters.LogGrailsUrlsInfoFilter  - 17:16:00,731 INFO  filters.LogOutputResponseFilter  - >> #1 returned 200, took 405 ms.
17:16:00,745 INFO filters.LogOutputResponseFilter - >> #1 responded with '{count:0}'
17:18:55,799 INFO  filters.LogRawRequestInfoFilter  - 17:18:55,799 INFO  filters.LogRawRequestInfoFilter  - 17:18:55,800 INFO  filters.LogRawRequestInfoFilter  - 17:18:55,801 INFO  filters.LogOutputResponseFilter  - >> #2 returned 404, took 3 ms.
17:18:55,802 INFO filters.LogOutputResponseFilter - >> #2 responded with ''

Official plugin information can be found on Grails plugins website here: http://grails.org/plugins/httplogger or you can browse code on github: TouK/grails-httplogger.