Summary of Classes and Interfaces - Absolute Java - page 1156

Collection<T> Interface
Package: java.util
Ancestor interfaces: none
All the exception classes mentioned are unchecked exceptions, which means they are not
required to be caught in a catch block or declared in a throws clause.
All the exception classes mentioned are in the package java.lang and so do not require any
import statement.
CONSTRUCTORS
Although not offi cially required by the interface, any class that implements the Collection<T>
interface should have at least two constructors: a no-argument constructor that creates an
empty Collection<T> object, and a constructor with one parameter of type Collection<?
extends T> that creates a Collection<T> object with the same elements as the constructor
argument. The interface does not specify whether the copy produced by the one-argument
constructor is a shallow copy or a deep copy of its argument.
public boolean contains(Object target)
Returns true if the calling object contains at least one instance of target . Uses target.
equals to determine if target is in the calling object.
Throws:
ClassCastException if the type of target is incompatible with the calling object (optional).
NullPointerException if target is null and the calling object does not support null
elements (optional).
public boolean containsAll(Collection<?> collectionOfTargets)
Returns true if the calling object contains all of the elements in collectionOfTargets . For
element in collectionOfTargets , this method uses element.equals to determine if
element is in the calling object.
Throws:
ClassCastException if the types of one or more elements in collectionOfTargets are
incompatible with the calling object (optional).
NullPointerException if collectionOfTargets contains one or more null elements
and the calling object does not support null elements (optional).
NullPointerException if collectionOfTargets is null .
public boolean equals(Object other)
This is the equals of the collection, not the equals of the elements in the collection. Overrides
the inherited method equals . Although there are no offi cial constraints on equals for a
collection, it should be defi ned as we have described in Chapter 7 and also satisfy the intuitive
notion of collections being equal.