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copied!<p>Here is some sample code that lists them in a hierarchy using recursion. The Item class has a List of children. The trick is adding any new children to the right parent. Here is the method I created to do this:</p> <pre><code>public Item getItemWithParent(int parentID){ Item result = null; if(this.categoryID == parentID){ result = this; } else { for(Item nextChild : children){ result = nextChild.getItemWithParent(parentID); if(result != null){ break; } } } return result; } </code></pre> <p>There is probably a more efficient way, but this works.</p> <p>Then, when you want to add new items to your hierarchy, do something like this:</p> <pre><code>public void addItem(int categoryID, String name, int parentID) { Item parentItem = findParent(parentID); parentItem.addChild(new Item(categoryID, name, parentID)); } private Item findParent(int parentID) { return rootNode.getItemWithParent(parentID); } </code></pre> <p>For the actual display, I just pass in a "tab level" that says how far to tab in, then increment it for each child like this:</p> <pre><code>public String toStringHierarchy(int tabLevel){ StringBuilder builder = new StringBuilder(); for(int i = 0; i < tabLevel; i++){ builder.append("\t"); } builder.append("-" + name); builder.append("\n"); for(Item nextChild : children){ builder.append(nextChild.toStringHierarchy(tabLevel + 1)); } return builder.toString(); } </code></pre> <p>Which gives me this:</p> <pre><code>-electronics -Television -21inch -Test -23inch -LCD display -player -mp3player -vcd player -hd quality -dvd player </code></pre>

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