data-structures/java/SList/Freelist.java

/** Singly linked list node with freelist support */
class Link<E> {
    private E element; // Value for this node
    private Link<E> next; // Point to next node in the list

    /** Constructors */
    Link (E it, Link<E> nextval)
    { element = it; next = nextval; }
    Link (Link<E> nextval) { next = nextval; }

    /** Get and set methods */
    Link<E> next() { return next; }
    Link<E> setNext(Link<E> nextval) { return next = nextval; }
    E element() { return element; }
    E setElement(E it) { return element = it; }

    /** Extensions to support freelists */
    static Link freelist = null; // Freelist for the class

    /** @return A new link */
    static <E> Link<E> get(E it, Link<E> nextval) {
	if (freelist == null)
	    return new Link<E> get(E it, Link<E> nextval); // Get from "new"
	Link<E> temp= freelist; // Get from freelist
	freelist = freelist.next();
	temp.setElement(it);
	temp.setNext(nextval);

	return temp;
    }

    /** Return a link to the freelist */
    void release() {
	element = null;
	next = freelist;
	freelist = this;
    }
}