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POWhat advantage will Composite pattern bring me over just Array?
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  1. POWhat advantage will Composite pattern bring me over just Array?
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    copied!<p>I'm recently working on a tree structure, multiple nodes, multiple and increasable levels, and a print() method. At first, i thought it should be a Composite, i then wrote down some possible design and codes:</p> <p><img src="https://farm3.static.flickr.com/2596/3807730874_4d6d5ed7ee_o_d.gif" alt="alt text"></p> <pre><code>$struc = new Node(‘name0’, ‘id0’, ‘desc0’); $node1 = new Node(‘node1’, ‘id1’, ‘desc1’); $node2 = new Node(‘node2’, ‘id2’, ‘desc2’); $node3 = new Node(‘node3’, ‘id3’, ‘desc3’); $leaf1 = new Leaf(‘leaf1’, ‘ld1’, ‘lesc1’); $leaf2 = new Leaf(‘leaf2’, ‘ld2’, ‘lesc2’); $leaf3 = new Leaf(‘leaf3’, ‘ld3’, ‘lesc3’); $leaf4 = new Leaf(‘leaf4’, ‘ld4’, ‘lesc4’); $struc.add($node1); $struc.add($node3); $node1.add($leaf1); $node1.add($leaf2); $node1.add($node2); $node2.add($leaf3); $node3.add($leaf4); </code></pre> <p>Looks good, i think and begin coding, print() method may follow Iterator pattern later. But during coding, i feel is it too complex for these simple nodes? And i have to instantiate a lot of concrete classes (more than 50+, and increasing). I then stopped and thinking a simple similar way by using array:</p> <pre><code>-- Structure Class -- //To be more readable and clear, array here could be //divided to 3 arrays(root/nodes/leafs), then connect //in a similar way Composite does. $struc = array('name0', 'id0', 'desc0', 'children'=&gt;array( array('node1', 'id1', 'desc1', 'children' =&gt; array( array('leaf1', 'ld1', 'lesc1'), array('leaf2', 'ld2', 'lesc2'), array('node2', 'id2', 'desc2', 'children'=&gt;array(array('leaf3', 'ld3', 'lesc3')) ) ) ), array('node3', 'id3', 'desc3', 'children' =&gt; array(array('leaf4', 'ld4', 'lesc4')) ) ) ); function print($node = $this-&gt;struct) { ... if(isset($node['children'])) $this-&gt;print($node['children']); ... } </code></pre> <p>The two designs look very similar, now i'm a little confused, what's the value of Composite pattern, am i missed something important of this pattern?</p>
 

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