I'm attempting to run this script. If I pull it all out of the class, it runs fine. When I wrap it in my "Test" class, I get this error:
Apparent variable 'json_users' was found in a static scope but doesn't
refer to a local variable, static field or class
class Test{
def testProc(JsonBuilder json_List) {
println json_List.prettyPrint
}
public static void main(String[] args){
def query = 'Select * from mytable'
def resultset = sql.rows(query)
json_users = new JsonBuilder(users:resultset)
testProc(json_users)
}
}
Any idea why I'm receiving this error?
There are multiple things wrong. One is that you cannot invoke an instance method from a static method. Another is that you can't refer to json_users without declaring it (you can in a script, but not in a class).
Instead of this:
class Test {
def testProc(JsonBuilder json_List) {
println json_List.prettyPrint
}
public static void main(String[] args){
def query = 'Select * from mytable'
def resultset = sql.rows(query)
json_users = new JsonBuilder(users:resultset)
testProc(json_users)
}
}
Try this:
class Test {
static testProc(JsonBuilder json_List) {
println json_List.prettyPrint
}
static void main(args){
def query = 'Select * from mytable'
// you will have to declare and initialize
// the sql variable.
def resultset = sql.rows(query)
def json_users = new JsonBuilder(users:resultset)
testProc(json_users)
}
}
Related
I have a piece of code below where Employee class creates object of AppraisalCalculator using reflection. I want to mock this AppraisalCalculator object using PowerMockito.
class AppraisalCalculator {
public int appraisal() {
return 300;
}
}
class Employee {
public int updateSalary() {
// line 1
AppraisalCalculator ac =
AppraisalCalculator.class.getConstructor().newInstance();
return ac.appraisal();
}
}
class TestRunner {
#Test
public void test() {
AppraisalCalulator acMock=PowerMockito.mock(AppraisalCalculator.class);
PowerMockito
.whenNew(AppraisalCalculator.class)
.withNoArguments()
.thenReturn(600);
Employee emp = new Employee();
int actualValue = emp.updateSalary();
int expectedValue=600;
Assert.equals(expectedValue,actualValue);
}
}
Here, even though I have mocked the Appraisal calculator object, it still calls the real appraisal() method from AppraisalCalculator. If the actual AppraisalCalculator at line 1 is created using new Operator instead of newInstance() then this mocking works.
Can anyone explain why this is not working if the actual object is created using reflection? What can I do to mock this Object in such scenario?
Let me first start by rephrasing your question will fully working code.
#RunWith(PowerMockRunner.class)
#PrepareForTest(Employee.class)
public class TestRunner {
#Test
public void test() throws Exception {
AppraisalCalculator acMock = PowerMockito.mock(AppraisalCalculator.class);
PowerMockito
.whenNew(AppraisalCalculator.class)
.withNoArguments()
.thenReturn(acMock);
when(acMock.appraisal()).thenReturn(600);
Employee emp = new Employee();
int actualValue = emp.updateSalary();
int expectedValue = 600;
assertEquals(expectedValue, actualValue);
}
}
Then, the way PowerMock works is that the PowerMockRunner will look at each class that needs to be prepared (here Employee), then look for a call to the constructor we want to replace and do it. This is done at class loading. The real class bytecode calling the constructor is replaced by the one returning the mock.
The thing is that if you are using reflection, PowerMock can't know by reading the bytecode that this constructor will be called. It will only be known dynamically afterwards. So no mocking done.
If you really do need to create the class to be mocked by reflection, I would actually refactor the code a bit.
In Employee I would add something like
protected AppraisalCalculator getCalculator() {
try {
return AppraisalCalculator.class.newInstance();
} catch (InstantiationException | IllegalAccessException e) {
throw new RuntimeException(e);
}
}
while is a method dedicated to isolate the calculator construction.
The, just create a child class
#Test
public void testWithChildClass() {
// Note that you don't need PowerMock anymore
AppraisalCalculator acMock = Mockito.mock(AppraisalCalculator.class);
when(acMock.appraisal()).thenReturn(600);
Employee emp = new Employee() {
#Override
protected AppraisalCalculator getCalculator() {
return acMock;
}
};
int actualValue = emp.updateSalary();
int expectedValue = 600;
assertEquals(expectedValue, actualValue);
}
or a partial mock (spy)
#Test
public void test2() {
// No PowerMock either here
AppraisalCalculator acMock = Mockito.mock(AppraisalCalculator.class);
when(acMock.appraisal()).thenReturn(600);
Employee emp = spy(new Employee());
doReturn(acMock).when(emp).getCalculator();
int actualValue = emp.updateSalary();
int expectedValue = 600;
assertEquals(expectedValue, actualValue);
}
I have a groovy script that defines a method which throws an exception.
Using AST Transformations I generate at compile time a new class.
Then I copy this method from the script to this new class and make the class available at runtime.
When at runtime I create a new object of the new class and call the method in stack trace I can see references to Script1 class instead of the new generated class.
Exception in thread "main" java.lang.RuntimeException
at MyGeneratedClass.myMethod(Script1.groovy:4)
at MyGeneratedClass$myMethod.call(Unknown Source)
at scripttest.ExTest.main(ExTest.groovy:35)
Is there anything I can do to change it so I don't see this Script1.groovy class in stack trace but the new class and line number within it?
My code:
class ExTest {
public static void main(String[] a) {
String script = '''
def myMethod() {
throw new RuntimeException()
}
'''
def config = new CompilerConfiguration()
config.addCompilationCustomizers(new MyCompilerConfiguration())
ClassLoader classLoaderToUse = new GroovyClassLoader()
GroovyShell shell = new GroovyShell(classLoaderToUse, new Binding(), config)
Script parsedScript = shell.parse(script)
def generatedClass = parsedScript.class.fields.find {it.name == 'myGeneratedClassField'}.type
def generated = generatedClass.newInstance()
generated.myMethod()
}
}
class MyCompilerConfiguration extends CompilationCustomizer {
MyCompilerConfiguration() {
super(CompilePhase.CONVERSION)
}
#Override
void call(SourceUnit source, GeneratorContext context, ClassNode currentClassNode) throws CompilationFailedException {
def newClassAst = new AstBuilder().buildFromSpec {
classNode('MyGeneratedClass', ClassNode.ACC_PUBLIC) {
classNode java.lang.Object
interfaces { classNode GroovyObject }
mixins { }
}
}
ClassNode myGeneratedClassNode = newClassAst[0]
source.getAST().addClass(myGeneratedClassNode)
currentClassNode.addField('myGeneratedClassField', Opcodes.ACC_PUBLIC, myGeneratedClassNode, new EmptyExpression())
MethodNode myMethodNode = source.getAST().methods.find {it.name == 'myMethod'}
myGeneratedClassNode.addMethod(myMethodNode.name, Opcodes.ACC_PUBLIC, myMethodNode.returnType, myMethodNode.parameters, myMethodNode.exceptions, myMethodNode.code)
}
}
Your stacktrace is correct, the Script1.groovy:4 you see is not the name of a class, but the name of the file which has generated this class, which is, in your case, a Groovy File.
This name come from the CodeSource instance present in the CompilationUnit associated with the ClassNode. You can change it by using a GroovyCodeSource in methods like GroovyShell.parse or GroovyClassLoader.parseClass, but I think it's a really bad idea ! (security, debugging and other thinks are related to this object)
I want to create a groovy class og script like this:
//...
def slurper = new ConfigSlurper().parse(someFile)
//...
//The exact method declaration
def methodCall(def arg){
//Whatever i want to do
}
//Maybe it is easier with methodMissing
def methodMissing(def args) {
//Whatever i want to do
}
The file to slurp could look like this:
some {
property = methodCall("with arg")
}
The question is how i can delegate the "methodCall" to the class or script that parses with the configslurper? At the moment it will give you a methodMissing.
I thik that this blog post have an example of what are you trying to do. It's more complicated than a methodMissing but can be done.
Thanks to Sérgio Michels link I found a solution:
public class ScriptWithMethods extends Script {
String scriptText;
public ScriptWithMethods(File file) {
scriptText = file.text
}
public void run() {
GroovyShell shell = new GroovyShell();
Closure closure = shell.evaluate("{it->$string}");
closure.resolveStrategy = Closure.DELEGATE_FIRST
closure.delegate = this
closure.call()
}
def methodCall(def arg){
//Whatever i want to do
}
}
//...
def script = new ScriptWithMethods(scriptText:someFile)
def slurper = new ConfigSlurper().parse(script)
Of cause you could also use "method missing", but this works in my usecase
I have a set of groovy scripts in package hierarchy. I have 1 main script, from which I want to call others. For example I have these scripts (with public classes/interfaces of the same name in them):
package.MainScript
package.MyInterface;
package.utils.MyInterfaceImpl1 //implements MyInterface
package.utils.MyInterfaceImpl2 //implements MyInterface
Is there a way to call one script from the other without knowing called class name at compile time? I mean to do something like dynamic class loading like:
class MainScript {
public static void main (String[] args) {
MyInterface instance = Class.forName("package.utils.Util1");
}
}
Yeah! Groovy is a dynamic language. You can create class instance dynamically.
package.MyInterface
class MyInterfaceImpl1 {
def greet() {
"Hello"
}
}
package.MyInterface
class MyInterfaceImpl2 {
def greet() {
"Hi!"
}
}
def name = 'MyInterfaceImpl1' // Choose whatever you want at runtime
def className = Class.forName("MyInterface.$name")
def instance = className.newInstance()
assert instance.greet() == 'Hello'
I'd like to create a simple wrapper, which would allow calling objects methods as a fluent interface. I've been thinking about rewriting methods of a class upon creation, but this doesn't seem to work. Is this possible in some way with groovy metaprograming?
I have this kind of code snippet so far:
class FluentWrapper {
def delegate
FluentWrapper(wrapped) {
delegate = wrapped
delegate.class.getMethods().each { method ->
def name = method.getName()
FluentWrapper.metaClass."$name" = { Object[] varArgs ->
method.invoke(wrapped, name, varArgs)
return this
}
}
}
def methodMissing(String name, args) {
def method = delegate.getClass().getDeclaredMethods().find { it.match(name) }
if(method) {
method.invoke(delegate,name, args)
return FluentWrapper(delegate)
}
else throw new MissingMethodException(name, delegate, args)
}
}
Assuming example Java class:
class Person {
void setAge()
void setName()
}
I'd like to be able to execute the following piece of code:
def wrappedPerson = new FluentWrapper(new Person())
wrappedPerson.setAge().setName()
I'm using Groovy 1.6.7 for this.
This is all Groovy, and I'm using 1.8.6 (the current latest), but given this Person Class:
class Person {
int age
String name
public void setAge( int age ) { this.age = age }
public void setName( String name ) { this.name = name }
public String toString() { "$name $age" }
}
And this FluentWrapper class:
class FluentWrapper {
def delegate
FluentWrapper(wrapped) {
delegate = wrapped
}
def methodMissing(String name, args) {
def method = delegate.getClass().declaredMethods.find { it.name == name }
if(method) {
method.invoke( delegate, args )
return this
}
else throw new MissingMethodException(name, delegate, args)
}
}
Then, you should be able to do:
def wrappedPerson = new FluentWrapper(new Person())
Person person = wrappedPerson.setAge( 85 ).setName( 'tim' ).delegate
And person should have the age and name specified
I find #tim_yates' answer nice, but you couldn't access delegate methods' return values (something one usually likes doing, even for Builders in the case of build() :)
Moreover, if this wasn't intended for a Builder but for an object with a chainable interface (like that of jQuery wrapped objects in JS), it would be a serious issue.
So I'd put the wrapper like this:
class FluentWrapper {
def delegate
FluentWrapper(wrapped) {
delegate = wrapped
}
def methodMissing(String name, args) {
def method = delegate.getClass().declaredMethods.find { it.name == name }
if(method) {
def result = method.invoke(delegate, args)
return result != null ? result : this
}
else throw new MissingMethodException(name, delegate, args)
}
}
Note the elvis operator is unsuitable since a falsy value would never get returned.
Of course, it's up to the invoker to know wether a method is chainable or not, but that could be overcome with method annotations if neccesary.