/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.ignite;

import java.io.*;

/**
 * This interface provides a rich API for working with distributed atomic reference.
 * <p>
 * <h1 class="header">Functionality</h1>
 * Distributed atomic reference includes the following main functionality:
 * <ul>
 * <li>
 * Method {@link #get()} synchronously gets current value of an atomic reference.
 * </li>
 * <li>
 * Method {@link #set(Object)} synchronously and unconditionally sets the value in the an atomic reference.
 * </li>
 * <li>
 * Methods {@code compareAndSet(...)} synchronously and conditionally set the value in the an atomic reference.
 * </li>
 * </ul>
 * All previously described methods have asynchronous analogs.
 * <ul>
 * <li>
 * Method {@link #name()} gets name of atomic reference.
 * </li>
 * </ul>
 * <h1 class="header">Creating Distributed Atomic Reference</h1>
 * Instance of distributed atomic reference can be created by calling the following method:
 * <ul>
 *     <li>{@link Ignite#atomicReference(String, Object, boolean)}</li>
 * </ul>
 * @see Ignite#atomicReference(String, Object, boolean)
 */
public interface IgniteAtomicReference<T> extends Closeable {
    /**
     * Name of atomic reference.
     *
     * @return Name of an atomic reference.
     */
    public String name();

    /**
     * Gets current value of an atomic reference.
     *
     * @return current value of an atomic reference.
     * @throws IgniteException If operation failed.
     */
    public T get() throws IgniteException;

    /**
     * Unconditionally sets the value.
     *
     * @param val Value.
     * @throws IgniteException If operation failed.
     */
    public void set(T val) throws IgniteException;

    /**
     * Conditionally sets the new value. That will be set if {@code expVal} is equal
     * to current value respectively.
     *
     * @param expVal Expected value.
     * @param newVal New value.
     * @return Result of operation execution. If {@code true} than value have been updated.
     * @throws IgniteException If operation failed.
     */
    public boolean compareAndSet(T expVal, T newVal) throws IgniteException;

    /**
     * Gets status of atomic.
     *
     * @return {@code true} if an atomic reference was removed from cache, {@code false} otherwise.
     */
    public boolean removed();

    /**
     * Removes this atomic reference.
     *
     * @throws IgniteException If operation failed.
     */
    @Override public void close();
}