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<h3>if - else statement</h3>

<p>Groovy supports the usual if - else syntax from Java</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
def x = false
def y = false

if ( !x ) {
    x = true
}

assert x == true

if ( x ) {
    x = false
} else {
    y = true
}

assert x == y
</pre></td></tr></table>

<p>Groovy also supports the normal Java &quot;nested&quot; if then else if syntax:</p>

<h3>ternary operator</h3>

<p>Groovy also supports the ternary operator:</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
def y = 5
def x = (y > 1) ? "worked" : "failed"
assert x == "worked"
</pre></td></tr></table>

<p>See also: the <a class="confluence-link" href="/display/GROOVY/Operators" data-linked-resource-id="12190097" data-linked-resource-type="page" data-linked-resource-default-alias="Operators" data-base-url="http://docs.codehaus.org">elvis operator</a></p>

<h3>switch statement</h3>

<p>The switch statement in Groovy is backwards compatible with Java code; so you can fall through cases sharing the same code for multiple matches.</p>

<p>One difference though is that the Groovy switch statement can handle any kind of switch value and different kinds of matching can be performed.</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
def x = 1.23
def result = ""

switch ( x ) {
    case "foo":
        result = "found foo"
        // lets fall through

case "bar":
        result += "bar"

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

case 12..30:
        result = "range"
        break

case Integer:
        result = "integer"
        break

case Number:
        result = "number"
        break

default:
        result = "default"
}

assert result == "number"
</pre></td></tr></table>
<p>Switch supports the following kinds of comparisons</p>
<ul>
	<li>Class case values matches if the switchValue is an instanceof the class</li>
	<li>Regular expression case value matches if the string of the switchValue matches the regex</li>
	<li>Collection case value matches if the switchValue is contained in the collection. This also includes ranges too (since they are Lists)</li>
	<li>if none of the above are used then the case value matches if the case value equals the switch value</li>
</ul>

<p><strong>default</strong>: must go at the end of the switch/case as Jochen outlined in <a href="http://groovy.markmail.org/message/6w6i647cbqnagrx5?q=Acceptable+Placement+of+default:+Within+Switch%3F&amp;page=1">this thread </a> from the groovy-user mailing list which Jochen states: </p>

<p>&quot;because a Java switch/Case does not work like a Groovy switch/case. In Java a case can take only int compatible constants, in Groovy it can take expressions. In Java all cases share a scope, in Groovy each case has its own scope. In Groovy we call the isCase method, in Java it has to be a number we switch with. If we for example use a closure as case, then this might cause side effects. There are cases where we can let them behave the same and usually when using the java version you won't see a difference in Groovy besides the placement and logic of default.&quot;</p>

<p>So, while in Java the <em>default</em> can be placed anywhere in the <em>switch/case</em>, the <em>default</em> in Groovy is used more as an <em>else</em> than assigning a <em>default</em> case.</p>

<h2>How switch works</h2>

<p>The case statement performs a <em>match</em> on the case value using the <em>isCase(switchValue)</em> method, which defaults to <em>call equals(switchValue)</em> but has been overloaded for various types like Class or regex etc.</p>

<p>So you could create your own kind of matcher class and add an <em>isCase(switchValue)</em> method to provide your own kind of matching.</p>