package net.jcip.examples;

import java.util.*;

import net.jcip.annotations.*;

/**

* BetterVector

* <p/>

* Extending Vector to have a put-if-absent method

*

* @author Brian Goetz and Tim Peierls

*/

@ThreadSafe

public class BetterVector <E> extends Vector<E> {

// When extending a serializable class, you should redefine serialVersionUID

static final long serialVersionUID = -3963416950630760754L;

public synchronized boolean putIfAbsent(E x) {

boolean absent = !contains(x);

if (absent)

add(x);

return absent;

}

}