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    <p><em>12/05/2013 Heavily Edited.</em></p> <p><strong>Answering the question that was asked.</strong></p> <blockquote> <p>Is it possible to break out of a Closure?</p> </blockquote> <p>You would <em>"break"</em> out of a closure by issuing the <code>return</code> keyword. However that isn't helpful in the example that is given. The reason for this is that the closure (think of it as a method) is called by the <code>each</code> method for every item in the collection.</p> <p>If you run this example you will see it will print 1 then 3.</p> <pre><code>[1, 2, 3].each { if (it == 2) return println(it) } </code></pre> <p><strong>Why <code>break</code> in the context of <code>each</code> doesn't make sense.</strong></p> <p>To understand why you cannot break out of the <code>each</code> method like you could break out of a <code>for</code> loop you need to understand a bit of what is actually happening. Here is a gross simplification what the each method on a collection does.</p> <pre><code>myEach([0,1,3]) void myEach(List things) { for (i in things) { myEachMethod(i) } } void myEachMethod(Object it) { // this is your Closure if(it == 2) return println it } </code></pre> <p>As you can see the closure is basically a method that can be passed around. Just as in java you cannot break from within method call or closure.</p> <p><strong>What to do instead of breaking from <code>each</code>.</strong></p> <p>In Groovy you are supposed to express your code using high level abstractions as such primitive looping is not idiomatic. For the example that you gave I would consider making use of findAll. For example:</p> <pre><code>[1,2,3].findAll { it &lt; 2 }.each { println it } </code></pre> <p>I hope this helps you understand what is going on.</p> <p><strong>Answering the implied question.</strong></p> <blockquote> <p>Can you break out of the <code>Collection.each</code> iterations against your supplied closure?</p> </blockquote> <p>You cannot break out of the <code>each</code> method without throwing and catching an exception as John Wagenleitner has said. Although I would argue that throwing and catching an exception in the name of flow control is a code smell and a fellow programmer might slap your hands.</p>
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    1. COYour code prints 1, 2, 3 - return will not return from a closure.
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    2. COJust wanted to clarify that return will not "break" out of the closure, it will just return the method executing the closure. In the above case, had there been a println below the return it only would have printed for 1 and 3, however 1, 2 and 3 still would have been printed by the first println.
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    3. COI think you are confused. "each" is a METHOD that takes a closure as an argument. Then iterates over the collection calling your closure and passing in the current object as an argument to the closure. I have updated my answer to make this more clear.
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