Groovy example source code file (SwitchTest.groovy)

This example Groovy source code file (SwitchTest.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

a, a, b, default, groovytestcase, integer, integer, list, list, listinterface, number, number, switchtest, unknown

The Groovy SwitchTest.groovy source code

package groovy

class SwitchTest extends GroovyTestCase {

    void testSwitch() {
        callSwitch("foo", "foo")
        callSwitch("bar", "barfoo")
        callSwitch("barbar", "barfoo")
        callSwitch("dummy", "d*")
        callSwitch("xyz", "xyzDefault")
        callSwitch("zzz", "Default")
        callSwitch(4, "List")
        callSwitch(5, "List")
        callSwitch(6, "List")
        callSwitch("inList", "List")
        callSwitch(1, "Integer")
        callSwitch(1.2, "Number")
        callSwitch(null, "null")
        callSwitch([1, 2, 3], "ListInterface")
    }

    def callSwitch(x, expected) {
        def result = ""
        switch (x) {
            case null:
                result = "null"
                break

            case ~/d.*/:
                result = "d*"
                break

            case "barbar":
            case "bar":
                result = result + "bar"

            case "foo":
                result = result + "foo"
                break

            case [4, 5, 6, 'inList']:
                result = "List"
                break

            case Integer:
                result = "Integer"
                break

            case Number:
                result = "Number"
                break

            case List:
                result = "ListInterface"
                break

            case "xyz":
                result = result + "xyz"

            default:
                result = result + "Default"
                // unnecessary just testing compiler
                break
        }
        assert result == expected, "Expected $expected but found $result when calling switch with $x"
    }

    // test the continue in switch, which should jump to the the while start
    void testSwitchScope() {
        def i = 0
        def j = 0
        while (true) {
            ++i;
            switch (i) {
                case 4:
                    continue
                case 5:
                    break;
                default:
                    j += i;
                    break;
            }
            if (i == 5) break;
        }
        assert j == 6
    }

    void testSwitchWithClosure() {
        switch (0) {
            case {true}: break
            default: assert false
        }
        switch (0) {
            case {false}: assert false
        }
        switch (0) {
            case {it == 0}: break
            default: assert false
        }
        switch (0) {
            case {candidate -> candidate == 0}: break
            default: assert false
        }
    }

    /** older versions of groovy produced a ListExpression for a
        fall through. the result was that it worked in some cases
        and in other cases not. For example not for patterns */
    void testFallthroughToOtherCaseWithNoCode() {
        def a = ['FileName.java', 'AnotherFileName.groovy', 'foo']
        def i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                case ~/.*groovy$/:
                    i++
                    break
                default:
                    i += 10
            }
        }
        assertEquals 12, i
    }

    void testFallthroughToOtherCaseWithCode() {
        def a = ['FileName.java', 'AnotherFileName.groovy', 'foo']
        def i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                    i += 5
                case ~/.*groovy$/:
                    i++
                    break
                default:
                    i += 10
            }
        }
        assertEquals 17, i
    }

    void testFallthroughToDefaultWithNoCode() {
        def a = ['FileName.java', 'AnotherFileName.groovy', 'foo']
        def i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                    i++
                    break
                case ~/.*groovy$/:
                default:
                    i += 10
            }
        }
        assertEquals 21, i
    }

    void testFallthroughToDefaultWithCode() {
        def a = ['FileName.java', 'AnotherFileName.groovy', 'foo']
        def i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                    i++
                    break
                case ~/.*groovy$/:
                    i += 5
                default:
                    i += 10
            }
        }
        assertEquals 26, i
    }

    void testSwitchNoStatementsAtEnd() {
        def a = ['FileName.java', 'AnotherFileName.groovy', 'foo']
        def i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                    i++
                    break
                case ~/.*groovy$/: break
            }
        }
        assertEquals 1, i
        i = 0
        a.each {
            switch (it) {
                case ~/.*java$/:
                    i++
                    break
                default: break
            }
        }
        assertEquals 1, i
    }
    
    void testSwitchReturnFromDefaultCase() {
        assert m3('a') == 'letter A' && m3('b') == 'letter B' && m3('z') == 'Unknown letter'
    }

    def m3(s) {
       switch(s) {
           case 'a': 'letter A'; break
           case 'b': 'letter B'; break
           default: 'Unknown letter'
       }
    }
}