Groovy example source code file (MetaClassPropertyTest.groovy)

This example Groovy source code file (MetaClassPropertyTest.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

expandometaclass, expandometaclass, expandometaproperty, expandometaproperty, groovytestcase, mcptest1, mcptest1, metaclassimpl, metaclassimpl, metaclasspropertytest

The Groovy MetaClassPropertyTest.groovy source code

/*
 * Copyright 2003-2009 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 groovy.lang

class MetaClassPropertyTest extends GroovyTestCase {

    void testForJavaClass() {
        checkMetaClassBehavior("hello world")
    }

    void testForGroovyClass() {
        checkMetaClassBehavior(new MCPTest1())
    }

    private checkMetaClassBehavior(Object foo) {
        // check metaclass points to correct class
        assertEquals foo.class, foo.metaClass.theClass

        // check defaults
        assert foo.metaClass.adaptee instanceof MetaClassImpl
        assert foo.class.metaClass.adaptee instanceof MetaClassImpl

        // use metaclass builder on instance
        foo.metaClass.dummy = {}
        assert foo.metaClass.adaptee instanceof ExpandoMetaClass
        assert foo.class.metaClass.adaptee instanceof MetaClassImpl

        // use metaclass builder on class
        foo.class.metaClass.dummy = {}
        assert foo.metaClass.adaptee instanceof ExpandoMetaClass
        // a little fragile but ExpandoMetaProperty is not public
        assert foo.class.metaClass.adaptee.getClass().name.contains('ExpandoMetaClass$ExpandoMetaProperty')

        // remove class-based metaclass
        GroovySystem.metaClassRegistry.removeMetaClass(foo.class)
        assert foo.metaClass.adaptee instanceof ExpandoMetaClass
        assert foo.class.metaClass.adaptee instanceof MetaClassImpl
    }
}

class MCPTest1 {
}