{"id":11272,"date":"2014-12-28T05:02:25","date_gmt":"2014-12-27T18:02:25","guid":{"rendered":"http:\/\/www.rjmprogramming.com.au\/wordpress\/?p=11272"},"modified":"2016-03-04T22:52:45","modified_gmt":"2016-03-04T12:52:45","slug":"java-hashtable-primer-tutorial","status":"publish","type":"post","link":"https:\/\/www.rjmprogramming.com.au\/ITblog\/java-hashtable-primer-tutorial\/","title":{"rendered":"Java Hashtable Primer Tutorial"},"content":{"rendered":"
\"Java<\/a>

Java Hashtable Primer Tutorial<\/p><\/div>\n

Some time ago (with Java XCode ArrayList Primer Tutorial<\/a> as shown below) we used a (Java “collection”) data structure called ArrayList<\/a> in Java via Xcode on a Mac laptop. Today we do this again (without the Xcode these days), but also use a Hashtable<\/a> (Java “collection”) data structure, to create a simple Contact List program. Are you familiar with Hashtables? They can simulate, in a lot of ways, what a relational database can do for you to use a Java collection<\/a> to address that “age old” programming logic “sentence” … <\/p>\n


\nhashtable[\"key\"] = \"value\"<\/i>
\n<\/code><\/p>\n

… do you see how like a database (table design) that statement is? And also how like the way a lot of us think, that is? Also close in thought to this are associative arrays.<\/p>\n

The combination of ArrayLists and Hashtables add many possibilities for sorting ideas for our Contact List (Java) program we develop (and compile) today. The population of the ArrayList can sometimes proceed at the same time as the Hashtable, as we (mostly) do with our code today (making use of the interactive (console) Scanner<\/a> class), but we also populate an ArrayList after the (populating) event for the reverse Enumeration part of the data, and this may interest you … look for …<\/p>\n


\n for (Enumeration e = contactsHT.elements(); e.hasMoreElements();) {
\n sortingEmail.add(e.nextElement());
\n }
\n<\/code><\/p>\n

The compilation instructions are very simple for a Terminal command line session on a Mac laptop (but could equally apply for other platforms too) …<\/p>\n