/**
 * Copyright 2012 Kjetil Ørbekk <kjetil.orbekk@gmail.com>
 *
 * Licensed 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 com.orbekk.same;

import com.orbekk.util.DelayedOperation;

public interface Variable<T> {
    public interface OnChangeListener<T> {
        /**
         * A notification that 'variable' has been changed.
         * 
         * The user must run variable.update() to get the updated value.
         */
        void valueChanged(Variable<T> variable);
    }

    T get();
    DelayedOperation set(T value);
    void update();
    void addOnChangeListener(OnChangeListener<T> listener);
    void removeOnChangeListener(OnChangeListener<T> listener);
}