Class Var

src/main/java/org/mapdb/Atomic.java:712–798

Atomically updated variable which may contain any type of record.

     * Atomically updated variable which may contain any type of record.
     */
    public static final class Var<E> {

        protected final Store store;
        protected final long recid;
        protected final Serializer<E> serializer;

        public Var(Store store, long recid, Serializer<E> serializer) {
            this.store = store;
            this.recid = recid;
            this.serializer = serializer;
        }
//
//        /* used for deserialization */
//        protected Var(Store store, SerializerBase serializerBase, DataInput is, SerializerBase.FastArrayList<Object> objectStack) throws IOException {
//            objectStack.add(this);
//            this.store = store;
//            this.recid = DataIO.unpackLong(is);
//            this.serializer = (Serializer<E>) serializerBase.deserialize(is,objectStack);
//        }

        /**
         * @return recid under which value is saved
         */
        public long getRecid(){
            return recid;
        }


        public java.lang.String toString() {
            E v = get();
            return v==null? null : v.toString();
        }

        /**
         * Returns the current value.
         *
         * @return the current value
         */
        public final E get() {
            return store.get(recid, serializer);
        }

        /**
         * Atomically sets the value to the given updated value
         * if the current value equals the expected value.
         *
         * @param expect the expected value
         * @param update the new value
         * @return true if successful. False return indicates that
         * the actual value was not equal to the expected value.
         */
        public final boolean compareAndSet(E expect, E update) {
            return store.compareAndSwap(recid, expect, update, serializer);
        }


        /**
         * Unconditionally sets to the given value.