Groovy example source code file (InterceptorTest.groovy)

This example Groovy source code file (InterceptorTest.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

groovytestcase, interceptable, interceptor, interceptortest, interceptortest, string, string, stringbuffer, stringbuffer, stringbufferwriter, stringbufferwriter, tracinginterceptor

The Groovy InterceptorTest.groovy source code

/*
 * Copyright 2003-2010 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

import org.codehaus.groovy.runtime.StringBufferWriter

/**
 * Test for the Interceptor Interface usage as implemented by the
 * TracingInterceptor. Makes also use of the ProxyMetaClass and
 * shows the collaboration.
 * As a side Effect, the ProxyMetaClass is also partly tested.
 *
 * @author Dierk Koenig
 * */
class InterceptorTest extends GroovyTestCase {

    def Interceptor logInterceptor
    def StringBuffer log
    def interceptable   // the object to intercept method calls on
    def proxy

    void setUp() {
        logInterceptor = new TracingInterceptor()
        log = new StringBuffer("\n")
        logInterceptor.writer = new StringBufferWriter(log)
        // we intercept calls from Groovy to the java.lang.String object
        interceptable = 'Interceptable String'
        proxy = ProxyMetaClass.getInstance(interceptable.class)
        proxy.setInterceptor(logInterceptor)
    }

    void testSimpleInterception() {
        proxy.use {
            assertEquals 20, interceptable.size()
            assertEquals 20, interceptable.length()
            assertTrue interceptable.startsWith('I', 0)
        }
        assertEquals("""
before java.lang.String.size()
after  java.lang.String.size()
before java.lang.String.length()
after  java.lang.String.length()
before java.lang.String.startsWith(java.lang.String, java.lang.Integer)
after  java.lang.String.startsWith(java.lang.String, java.lang.Integer)
""", log.toString())
    }

    void testNoInterceptionWithNullInterceptor() {
        proxy.setInterceptor(null)
        proxy.use {
            interceptable.size()
        }
    }

    void testConstructorInterception() {
        proxy.use {
            new String('some string')
        }
        assertEquals("""
before java.lang.String.ctor(java.lang.String)
after  java.lang.String.ctor(java.lang.String)
""", log.toString())
    }

    void testStaticMethodInterception() {
        proxy.use {
            assertEquals 'true', String.valueOf(true)
        }
        assertEquals("""
before java.lang.String.valueOf(java.lang.Boolean)
after  java.lang.String.valueOf(java.lang.Boolean)
""", log.toString())
    }

    void testInterceptionOfGroovyClasses() {
        def slicer = new groovy.mock.example.CheeseSlicer()
        def proxy = ProxyMetaClass.getInstance(slicer.class)
        proxy.setInterceptor(logInterceptor)
        proxy.use(slicer) {
            slicer.coffeeBreak('')
        }
        assertEquals("""
before groovy.mock.example.CheeseSlicer.coffeeBreak(java.lang.String)
after  groovy.mock.example.CheeseSlicer.coffeeBreak(java.lang.String)
""", log.toString())
    }

    void testProxyMetaClassUseMethodShouldReturnTheResultOfClosure() {
        assertEquals true, proxy.use { true }
    }
}