Collection Framework (Advanced functional Testing of the collection collection)

package cn.itcast_01;import java.util.arraylist;import java.util.collection;/* *  Boolean addall (COLLECTION C): Adds an element of a collection  * boolean removeall (collection c): Removes the element of a collection (is one or all)  * boolean containsall (COLLECTION C): Determines whether the collection contains the specified collection element (one or all)  *  boolean retainall (collection c): Two elements of a collection? Where is the thought element, and what does the Boolean return mean?  */public class  collectiondemo2 {public static void main (String[] args)  {//  Create the collection 1collection c1 = new arraylist (); C1.add ("ABC1"); C1.add ("ABC2"); C1.add ("ABC3"); C1.add (" ABC4 ");//  Create Collection 2collection c2 = new arraylist ();//c2.add (" ABC1 ");//c2.add (" ABC2 ");// C2.add ("ABC3"),//c2.add ("ABC4"), C2.add ("Abc5"), C2.add ("Abc6"), C2.add ("ABC7");// boolean addall ( COLLECTION C): Add an element of a collection// system.out.println ("AddAll:"  + c1.addall (C2)); C1 change, C1 C2 ABC4, Abc5,abc6,abc7 added (this shows that you can add a duplicate)//boolean removeall (collection c): Removes the element of a collection (is one or all)//returns True whenever an element is removed. System.out.println ("RemoveAll:" +c1.removeall (C2)); Who changed who, the results show as TRUE,    C1:[ABC1,ABC2,ABC3]        c2:[abc4,abc5,abc6,abc7]  This shows that removing one is called removing (the ABC4 in the C1 collection is gone)//boolean  containsall (COLLECTION C): Determines whether the collection contains the specified set element (is one or all)//only contains all elements, called contains// SYSTEM.OUT.PRINTLN (" Containsall: "+c1.containsall (C2));//boolean retainall (collection c): Two elements of a collection? Where is the thought element? What does the Boolean return mean?//Assume there are two sets, A, B. A to B intersection, the final result is saved in a, B unchanged. The return value indicates whether a has changed. System.out.println ("Retainall:" +c1.retainall (C2)); SYSTEM.OUT.PRINTLN ("C1:"  + C1); System.out.println ("C2:"  + C2);}}

Note that the methods above call themselves must be collection objects, and the method is a collection object, so start by creating two collection objects first

Collection interface member Methods

Boolean AddAll (Collection c)

Boolean RemoveAll (Collection c)

Boolean containsall (Collection c)

Boolean retainall (Collection c)

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Collection Framework (Advanced functional Testing of the collection collection)