Java Generics and Collections

Chapter 15. Lists

Lists are probably the most widely used Java collections in practice. A list is a collection which—unlike a set—can contain duplicates, and which—unlike a queue—gives the user full visibility and control over the ordering of its elements. The corresponding Collections Framework interface is List (see Figure 15-1).

In addition to the operations inherited from Collection, the List interface includes operations for the following:

Positional Access Methods that access elements based on their numerical position in the list:

void add(int index, E e)           // add element e at given index
boolean addAll(int index, Collection<? extends E> c)
                                   // add contents of c at given index
E get(int index)                   // return element with given index
E remove(int index)                // remove element with given index
E set(int index, E e)              // replace element with given index by e

Figure 15-1. List

Search Methods that search for a specified object in the list and return its numerical position. These methods return -1 if the object is not present:

int indexOf(Object o)             // return index of first occurrence of o
int lastIndexOf(Object o)         // return index of last occurrence of o

Range-View A method that gets a view of a range of the list:

List<E> subList(int fromIndex, int toIndex)
                                   // return a view of a portion of the list

The method subList works in a similar way to the subSet operations on SortedSet (see SortedSet and NavigableSet ...