Using code templates

In this section you will use content assist to fill in a template for a common loop structure. Open junit.samples/ file in the Java editor if you do not already have it open.

  1. Start adding a new method by typing the following:

    public void testValues() {
        Integer[] expected= new Integer[3];

  2. With the cursor at the end of for, press Ctrl+Space to enable content assist.  You will see a list of common templates for "for" loops.  When you single-click a template, or select it with the Up or Down arrow keys, you'll see the code for the template in its help message.  Note that the local array name is guessed automatically.

    Content assist for for

  3. Choose the for - iterate over array entry and press Enter to confirm the template.  The template will be inserted in your source code.

    Inserted for template

  4. Next we change the name of the index variable from i to e. To do so simply press e, as the index variable is automatically selected. Observe that the name of the index variable changes at all places. When inserting a template all references to the same variable are connected to each other. So changing one changes all the other values as well.

    Altered for template

  5. Pressing the tab key moves the cursor to the next variable of the code template. This is the array expected.

    Altered for template

    Since we don't want to change the name (it was guessed right by the template) we press tab again, which leaves the template since there aren't any variables left to edit.
  6. Complete the for loop as follows:

    for (int e= 0; e < expected.length; e++) {
        expected[e]= new Integer(e + 1);
    Integer[] actual= to

  7. With the cursor at the end of to, press Ctrl+Space to enable content assist. Pick toarray - convert collection to array and press Enter to confirm the selection (or double-click the selection).

    toarray template

    The template is inserted in the editor and type is highlighted and selected.

    Inserted toarray template

  8. Overwrite the selection by typing Integer. The type of array constructor changes when you change the selection.
  9. Press Tab to move the selection to collection and overwrite it by typing fFull.

    Inserted toarray template

  10. Add a semicolon and the following lines of code to complete the method:

    assertEquals(expected.length, actual.length);
    for (int i= 0; i < actual.length; i++)
        assertEquals(expected[i], actual[i]);

  11. Save the file.
Java editor
Templates Templates Preferences
Java Editor Preferences