Java Reference
In-Depth Information
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// Fig. 7.24: ArrayListCollection.java
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// Generic ArrayList<T> collection demonstration.
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import
java.util.ArrayList;
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public class
ArrayListCollection
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{
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public static void
main(String[] args)
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{
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// create a new ArrayList of Strings with an initial capacity of 10
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ArrayList<String> items =
new
ArrayList<String>();
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items.add(
"red"
);
// append an item to the list
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items.add(
0
,
"yellow")
;
// insert "yellow" at index 0
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// header
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System.out.print(
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"Display list contents with counter-controlled loop:")
;
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// display the colors in the list
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for
(
int
i =
0
; i < items.size(); i++)
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System.out.printf(
" %s"
, items.get(i));
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// display colors using enhanced for in the display method
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display(items,
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"%nDisplay list contents with enhanced for statement:"
);
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items.add(
"green"
);
// add "green" to the end of the list
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items.add(
"yellow"
);
// add "yellow" to the end of the list
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display(items,
"List with two new elements:"
);
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items.remove(
"yellow"
);
// remove the first "yellow"
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display(items,
"Remove first instance of yellow:"
);
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items.remove(
1
);
// remove item at index 1
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display(items,
"Remove second list element (green):"
);
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// check if a value is in the List
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System.out.printf(
"\"red\" is %sin the list%n"
,
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items.contains(
"red"
) ?
""
:
"not "
);
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// display number of elements in the List
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System.out.printf(
"Size: %s%n"
, items.size());
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}
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// display the ArrayList's elements on the console
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public static void
display(ArrayList<String> items, String header)
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{
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System.out.printf(header);
// display header
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// display each element in items
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for
(String item : items)
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System.out.printf(
" %s"
, item);
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Fig. 7.24
|
Generic
ArrayList<T>
collection demonstration. (Part 1 of 2.)
