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    <p>Follow an implementation of naive implementation of a visitable tree:</p> <pre><code>class Tree&lt;T&gt; implements Visitable&lt;T&gt; { // NB: LinkedHashSet preserves insertion order private final Set&lt;Tree&gt; children = new LinkedHashSet&lt;Tree&gt;(); private final T data; Tree(T data) { this.data = data; } void accept(Visitor&lt;T&gt; visitor) { visitor.visitData(this, data); for (Tree child : children) { Visitor&lt;T&gt; childVisitor = visitor.visitTree(child); child.accept(childVisitor); } } Tree child(T data) { for (Tree child: children ) { if (child.data.equals(data)) { return child; } } return child(new Tree(data)); } Tree child(Tree&lt;T&gt; child) { children.add(child); return child; } } </code></pre> <p>interfaces for Visitor Pattern:</p> <pre><code>interface Visitor&lt;T&gt; { Visitor&lt;T&gt; visitTree(Tree&lt;T&gt; tree); void visitData(Tree&lt;T&gt; parent, T data); } interface Visitable&lt;T&gt; { void accept(Visitor&lt;T&gt; visitor); } </code></pre> <p>sample implementation for Visitor Pattern:</p> <pre><code>class PrintIndentedVisitor implements Visitor&lt;String&gt; { private final int indent; PrintIndentedVisitor(int indent) { this.indent = indent; } Visitor&lt;String&gt; visitTree(Tree&lt;String&gt; tree) { return new IndentVisitor(indent + 2); } void visitData(Tree&lt;String&gt; parent, String data) { for (int i = 0; i &lt; indent; i++) { // TODO: naive implementation System.out.print(" "); } System.out.println(data); } } </code></pre> <p>and finally (!!!) a simple test case:</p> <pre><code> Tree&lt;String&gt; forest = new Tree&lt;String&gt;("forest"); Tree&lt;String&gt; current = forest; for (String tree : Arrays.asList("x1/x2/x3", "x1/x2/x4", "x1/x5")) { Tree&lt;String&gt; root = current; for (String data : tree.split("/")) { current = current.child(data); } current = root; } forest.accept(new PrintIndentedVisitor(0)); </code></pre> <p>output:</p> <pre> forest x1 x2 x3 x4 x5 </pre>
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    1. POConstruct a tree structure from list of string paths
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    1. COThanks for the code dfa; it works like a charm. Visitor pattern implementation is neat.
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    2. COMarry me! Thanks for the very helpful answer.
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