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Groovy example source code file (FormalParameterTest.groovy)

This example Groovy source code file (FormalParameterTest.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

barclay, barclay, compilabletestsupport, compilabletestsupport, formalparametertest, formalparametertest, ken, ken, string

The Groovy FormalParameterTest.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,
 * See the License for the specific language governing permissions and
 * limitations under the License.
package gls.ch08.s04

import gls.CompilableTestSupport

 * a formal parameter is a parameter to a method, this parameter must work
 * as any local variable. But we generally do boxing on local variables, which
 * is not possible for formal parameters. The type is given through the
 * method signature.
class FormalParameterTest extends CompilableTestSupport {

    void testPrimitiveParameterAssignment() {
        // test int and long as they have different lengths on in the bytecode
        assert intMethod(1i, 2i) == 2i
        assert longMethod(1l, 2l) == 2l


    int intMethod(int i, int j) {
        i = j
        return i

    long longMethod(long i, long j) {
        i = j
        return i

     * Chapter 8:    Classes
     * Section 8.4:  Method Declarations
     * Author:       Ken Barclay
     * File:         arity.method.declaration.classes.8.4.groovy
     * A class declaration may include any number of method declarations including
     *   abstract method declarations.
     * A method is given a name and an optional list of formal parameter declarations
     *   enclosed in parentheses ( and ). A parameter declaration at its simplest is
     *   simply a parameter name. It may be prefixed with a combination of optional
     *   parameter modifiers (def or final), a type, or a type followed by the varargs
     *   symbol (...). Two formal parameters with the same name is disallowed.
     * A formal parameter may be optionally initialized with an expression, referred
     *   to as a default parameter. If the number of actual parameters is fewer than
     *   the number of formal parameters, then each actual is used to initialize, in
     *   order, the non-default formal parameters. When all the actual parameters are
     *   used in this manner, all subsequent formal parameters require default values.
     * If the last formal parameter is a variable arity parameter, it is considered
     *   to define a method that is referred to as a variable arity method. Invocations
     *   of a variable arity method may contain more actual argument expressions than
     *   formal parameters. All the actual argument expressions that do not correspond
     *   to the formal parameters preceding the variable arity parameter will be evaluated
     *   and the results stored into an array that will be passed to the method invocation.
    def dump(age, String... names) {
        names.collect { name ->
            "name: $name age: $age"

    void testVariableArity() {
        def l1 = dump(22, 'Ken', 'Barclay')
        def l2 = ["name: Ken age: 22", "name: Barclay age: 22"]
        l1.eachWithIndex { it, i ->
            assert it == l2[i]


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