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Groovy example source code file (AnnotationTest.groovy)

This example Groovy source code file (AnnotationTest.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

annotation, annotation1, bar, class, elementtype, foo, foo, myannotation, myannotation, string, string, target, x, x

The Groovy AnnotationTest.groovy source code

/*
 * Copyright 2003-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gls.annotations

import gls.CompilableTestSupport

/**
 * Tests various properties of annotation definitions.
 *
 * @author Jochen Theodorou
 * @author Guillaume Laforge
 * @author Paul King
 */
class AnnotationTest extends CompilableTestSupport {

    /**
     * Check that it is possible to annotate an annotation definition with field and method target elements.
     */
    void testAnnotateAnnotationDefinitionWithMethodAndFieldTargetElementTypes() {
        shouldCompile """
            import java.lang.annotation.*
            import static java.lang.annotation.RetentionPolicy.*
            import static java.lang.annotation.ElementType.*

            @Retention(RUNTIME)
            @Target([METHOD, FIELD])
            @interface MyAnnotation { }
        """
    }

    void testCannotAnnotateAnotationDefinitionIfTargetIsNotOfType() {
        shouldNotCompile """
            import java.lang.annotation.*
            import static java.lang.annotation.ElementType.*

            // all target elements except ANNOTATION_TYPE
            @Target([CONSTRUCTOR, METHOD, FIELD, LOCAL_VARIABLE, PACKAGE, PARAMETER, TYPE])
            @interface MyAnnotation { }

            @MyAnnotation
            @interface AnotherAnnotation {}
        """
    }

    /**
     * The @OneToMany cascade parameter takes an array of CascadeType.
     * To use this annotation in Java with this parameter, you do <code>@OneToMany(cascade = { CascadeType.ALL })
     * In Groovy, you do <code>@OneToMany(cascade = [ CascadeType.ALL ]) (brackets instead of braces)
     * But when there's just one value in the array, the curly braces or brackets can be omitted:
     * <code>@OneToMany(cascade = [ CascadeType.ALL ])
     */
    void testOmittingBracketsForSingleValueArrayParameter() {
        shouldCompile """
            import gls.annotations.*

            class Book {}

            class Author {
                @OneToMany(cascade = CascadeType.ALL)
                Set<Book> books
            }

            def annotation = Author.class.getDeclaredField('books').annotations[0]

            assert annotation instanceof OneToMany
            assert annotation.cascade() == [CascadeType.ALL]
        """
    }

    void testPrimitiveDefault() {
        // NOTE: for int anything else than a plain number will fail.
        // For example 1l will fail too, even if it could be converted.
        // If this should be changed, then further discussion is needed.
        shouldNotCompile """
            @interface X {
                int x() default "1" // must be integer
            }
        """

        shouldCompile """
            @interface X {
                int x() default 1
            }
        """
    }

    void testConstant() {
        assertScript """
            class Baz {
                // static final int OTHER = 5
                // below we would like to but can't use:
                // constant field expressions, e.g. OTHER, or
                // constant property expressions, e.g. Short.MAX_VALUE
                @Foo(5) void run() {
                    assert Baz.class.getMethod('run').annotations[0].value() == 5
                }
            }

            import java.lang.annotation.*
            @Retention(RetentionPolicy.RUNTIME)
            @Target(ElementType.METHOD)
            @interface Foo {
                int value() default -3
            }

            new Baz().run()
        """
    }

    void testArrayDefault() {
        shouldNotCompile """
            @interface X {
                String[] x() default "1" // must be list
            }
        """

        shouldNotCompile """
            @interface X {
                String[] x() default ["1",2] // list must contain elements of correct type
            }
        """

        shouldCompile """
            @interface X {
                String[] x() default ["a","b"]
            }
        """
    }

    void testClassDefault() {
        shouldNotCompile """
            @interface X {
                Class x() default "1" // must be list
            }
        """

        shouldCompile """
            @interface X {
                Class x() default Number.class // class with .class
            }
        """

        shouldCompile """
            @interface X {
                Class x() default Number
            }
        """
    }

    void testEnumDefault() {
        shouldNotCompile """
            @interface X {
                ElementType x() default "1" // must be Enum
            }
        """

        shouldNotCompile """
            @interface X {
                ElementType x() default Target.TYPE // must be Enum of correct type
            }
        """

        shouldCompile """
            import java.lang.annotation.*

            @interface X {
                ElementType x() default ElementType.METHOD
            }
        """
    }

    void testAnnotationDefault() {
        shouldNotCompile """
            import java.lang.annotation.*
            @interface X {
                Target x() default "1" // must be Annotation
            }
        """

        shouldNotCompile """
            import java.lang.annotation.*

            @interface X {
                Target x() default @Retentention // must be correct type
            }
        """

        shouldCompile """
            import java.lang.annotation.*
            @interface X {
                Target x() default @Target([ElementType.TYPE])
            }
        """
    }

    void testSelfReference() {
        shouldNotCompile """
            @interface X {
                X x() default @X // self reference must not work
            }
        """
    }

    void testCyclicReference() {
        shouldNotCompile """
            @interface X {
                Y x() default @Y
            }

            @interface Y {
                X x() default @X
            }
        """
    }

    void testParameter() {
        shouldNotCompile """
            @interface X {
                String x(int x) default "" // annotation members can't have parameters
            }
        """
    }

    void testThrowsClause() {
        shouldNotCompile """
            @interface X {
                String x() throws IOException // annotation members can't have exceptions
            }
        """
    }

    void testExtends() {
        shouldNotCompile """
            @interface X extends Serializable{}
            // annotation members can't extend
        """
    }

    void testInvalidMemberType() {
        shouldNotCompile """
            @interface X {
                Object x() // Object is no type for constants
            }
        """
    }

    void testNull() {
        shouldNotCompile """
            @interface X {
                String x() default null // null is no constant for annotations
            }
        """
    }

    void testUsage() {
        assertScript """
            import java.lang.annotation.*

            // a random annnotation type
            @Retention(RetentionPolicy.RUNTIME)
            @interface MyAnnotation {
                String stringValue()
                int intValue()
                int defaultInt() default 1
                String defaultString() default ""
                Class defaultClass() default Integer.class
                ElementType defaultEnum() default ElementType.TYPE
                Target defaultAnnotation() default @Target([ElementType.TYPE])
            }


            @MyAnnotation(stringValue = "for class", intValue = 100)
            class Foo {}

            Annotation[] annotations = Foo.class.annotations
            assert annotations.size() == 1
            MyAnnotation my = annotations[0]
            assert my.stringValue() == "for class"
            assert my.intValue() == 100
            assert my.defaultInt() == 1
            assert my.defaultString() == ""
            assert my.defaultClass() == Integer

            assert my.defaultEnum() == ElementType.TYPE
            assert my.defaultAnnotation() instanceof Target
        """
    }

    void testJavaAnnotationUsageWithGroovyKeyword() {
        assertScript """
            package gls.annotations
            import java.lang.annotation.*
            @JavaAnnotation(in = 3)
            class Foo {}

            Annotation[] annotations = Foo.class.annotations
            assert annotations.size() == 1
            JavaAnnotation my = annotations[0]
            assert my.in() == 3
        """
    }

    void testUsageOnClass() {
        assertScript """
            import java.lang.annotation.*

            @Deprecated
            class Foo{}

            assert Foo.class.annotations.size() == 1
        """
    }

    void testFieldAndPropertyRuntimeRetention() {
        assertScript """
            import org.codehaus.groovy.ast.ClassNode
            import java.lang.annotation.*

            @Retention(RetentionPolicy.RUNTIME)
            @interface Annotation1 {}

            @Annotation1 class A {
                @Annotation1 method1(){}
                @Annotation1 public field1
                @Annotation1 prop1
            }

            new ClassNode(A).with {
                assert annotations: "ClassNode for class 'A' has an annotation as it should"
                getMethod('method1').with {
                    assert annotations: "Annotation on 'method1' not found"
                }
                getField('field1').with {
                    assert annotations: "Annotation on 'field1' not found"
                }
                getField('prop1').with {
                    assert annotations: "Annotation on 'property1' not found"
                }
            }
        """
    }

    void testSingletonArrayUsage() {
        assertScript """
            import java.lang.annotation.*

            // a random annnotation type
            @Retention(RetentionPolicy.RUNTIME)
            @interface MyAnnotation {
                String[] things()
            }

            @MyAnnotation(things = "x")
            class Foo {}

            Annotation[] annotations = Foo.class.annotations
            assert annotations.size() == 1
            MyAnnotation my = annotations[0]
            assert my.things().size() == 1
            assert my.things()[0] == "x"
        """
    }

    void testSettingAnnotationMemberTwice() {
        shouldNotCompile """
        package gls.annotations

        @JavaAnnotation(in = 1, in = 2)
        class Foo {}
    """
    }

    void testGetterCallWithSingletonAnnotation() {
        assertScript """
            @Singleton class MyService3410{}
            assert MyService3410.instance != null
            assert MyService3410.getInstance() != null
      """
    }

    void testAttributePropertyConstants() {
        assertScript """
            import java.lang.annotation.*
            import static Constants.*

            @Retention(RetentionPolicy.RUNTIME)
            @Target(ElementType.FIELD)
            @interface Anno {
                double value() default 0.0d
                String[] array() default []
            }

            class Constants {
                public static final String BAR = "bar"
                public static final APPROX_PI = 3.14d
            }

            interface IConstants {
                String FOO = "foo"
            }

            class ClassWithAnnotationUsingConstant {
                @Anno(array = [IConstants.FOO, BAR, groovy.inspect.Inspector.GROOVY])
                public annotatedStrings

                @Anno(Math.PI)
                public annotatedMath1
                @Anno(APPROX_PI)
                public annotatedMath2
            }

            assert ClassWithAnnotationUsingConstant.getDeclaredField('annotatedStrings').annotations[0].array() == ['foo', 'bar', "GROOVY"]
            assert ClassWithAnnotationUsingConstant.getDeclaredField('annotatedMath1').annotations[0].value() == Math.PI
            assert ClassWithAnnotationUsingConstant.getDeclaredField('annotatedMath2').annotations[0].value() == Constants.APPROX_PI
        """
    }

    void testNestedAttributePropertyConstants() {
        assertScript """
            import java.lang.annotation.*
            import static Constants.*

            @Retention(RetentionPolicy.RUNTIME)
            @Target(ElementType.FIELD)
            @interface Outer {
                Inner value()
                String[] array() default []
            }

            @Retention(RetentionPolicy.RUNTIME)
            @Target(ElementType.FIELD)
            @interface Inner {
                String[] value() default []
            }

            class Constants {
                public static final String BAR = "bar"
                public static final String BAZ = "baz"
            }

            interface IConstants {
                String FOO = "foo"
                String FOOBAR = "foobar"
            }

            class ClassWithNestedAnnotationUsingConstant {
                @Outer(value = @Inner([IConstants.FOOBAR, BAR, groovy.inspect.Inspector.GROOVY]),
                       array = [IConstants.FOO, groovy.inspect.Inspector.GROOVY, BAZ])
                public outer
            }

            assert ClassWithNestedAnnotationUsingConstant.getDeclaredField('outer').annotations[0].array() == ['foo', 'GROOVY', 'baz']
            assert ClassWithNestedAnnotationUsingConstant.getDeclaredField('outer').annotations[0].value().value() == ['foobar', 'bar', 'GROOVY']
        """
    }

    void testRuntimeRetentionAtAllLevels() {
        assertScript """
            import java.lang.annotation.*

            @Retention(RetentionPolicy.RUNTIME)
            @Target([ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER, ElementType.CONSTRUCTOR, ElementType.FIELD])
            @interface MyAnnotation {
                String value() default ""
            }

            @MyAnnotation('class')
            class MyClass {
                @MyAnnotation('field')
                public myField

                @MyAnnotation('constructor')
                MyClass(@MyAnnotation('constructor param') arg){}

                @MyAnnotation('method')
                def myMethod(@MyAnnotation('method param') arg) {}
            }

            def c1 = new MyClass()
            assert c1.class.annotations[0].value() == 'class'

            def field = c1.class.fields.find{ it.name == 'myField' }
            assert field.annotations[0].value() == 'field'

            def method = c1.class.methods.find{ it.name == 'myMethod' }
            assert method.annotations[0].value() == 'method'
            assert method.parameterAnnotations[0][0].value() == 'method param'

            def constructor = c1.class.constructors[0]
            assert constructor.annotations[0].value() == 'constructor'
            assert constructor.parameterAnnotations[0][0].value() == 'constructor param'
        """
    }

    void testAnnotationWithValuesNotGivenForAttributesWithoutDefaults() {
        def scriptStr
        scriptStr = """
            import java.lang.annotation.Retention
            import java.lang.annotation.RetentionPolicy

            @Retention(RetentionPolicy.RUNTIME)
            @interface Annot3454V1 {
                String x()
            }

            @Annot3454V1
            class Bar {}
        """

        // compiler should not allow this, because there is no default value for x
        shouldNotCompile(scriptStr)

        scriptStr = """
            import java.lang.annotation.Retention
            import java.lang.annotation.RetentionPolicy
            
            @Retention(RetentionPolicy.RUNTIME)
            @interface Annot3454V2 {
                String x() default 'xxx'
                String y()
            }
            
            @Annot3454V2
            class Bar {}
        """

        // compiler should not allow this, because there is no default value for y
        shouldNotCompile(scriptStr)

        scriptStr = """
            import java.lang.annotation.Retention
            import java.lang.annotation.RetentionPolicy
            
            @Retention(RetentionPolicy.RUNTIME)
            @interface Annot3454V3 {
                String x() default 'xxx'
                String y()
            }
            
            @Annot3454V3(y = 'yyy')
            class Bar {}
            
            def anno = Bar.class.getAnnotation(Annot3454V3)
            assert anno.x() == 'xxx'
            assert anno.y() == 'yyy'
        """
        // compiler should allow this, because there is default value for x and value provided for y
        assertScript(scriptStr)
    }

    void testAllowedTargetsCheckAlsoWorksForAnnotationTypesDefinedOutsideThisCompilationUnit() {
        shouldCompile """
            @java.lang.annotation.Documented
            @interface Foo {}
        """

        shouldNotCompile """
            @java.lang.annotation.Documented
            class Foo {
                def bar
            }
        """

        shouldNotCompile """
            class Foo {
                @java.lang.annotation.Documented
                def bar
            }
        """

        shouldCompile """
            import org.junit.*

            class Foo {
                @Test
                void foo() {}
            }
        """

        shouldNotCompile """
            import org.junit.*

            @Test
            class Foo {
                void foo() {}
            }
        """
    }
}

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