The Java Developers Almanac 1.4

Home > List of Packages > java.util [51 examples] > Sorted Collections [6 examples]

e362. Inserting an Element into a Sorted List

This example demonstrates how to determine the index at which an element should be inserted into a sorted list. Although binarySearch() is used to locate existent elements, it can also be used to determine the insert index for non-existent elements. Specifically, the insertion index is computed in the following way: insert-index = (-return-value)-1

    // Create a list with an ordered list of items
    List sortedList = new LinkedList();
    sortedList.addAll(Arrays.asList(new String[]{"ant", "bat", "cat", "dog"}));
    
    // Search for the non-existent item
    int index = Collections.binarySearch(sortedList, "cow");      // -4
    
    // Add the non-existent item to the list
    if (index < 0) {
        sortedList.add(-index-1, "cow");
    }

Related Examples

e358. Creating a Sorted Set
e359. Sorting an Array
e360. Finding an Element in a Sorted Array
e1075. Inserting an Element into a Sorted Array
e361. Finding an Element in a Sorted List

See also: Arrays Bits Collections Dates Hash Tables Lists Property Files Sets Time Timers

© 2002 Addison-Wesley.