| /* |
| * 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 accord.impl; |
| |
| import java.util.Collection; |
| import java.util.function.Supplier; |
| |
| import accord.impl.InMemoryCommandStore.GlobalCommand; |
| import accord.local.Command; |
| import accord.local.SafeCommand; |
| import accord.primitives.TxnId; |
| |
| public class InMemorySafeCommand extends SafeCommand implements SafeState<Command> |
| { |
| private static final Supplier<GlobalCommand> INVALIDATED = () -> null; |
| |
| private Supplier<GlobalCommand> lazy; |
| private GlobalCommand global; |
| |
| public InMemorySafeCommand(TxnId txnId, GlobalCommand global) |
| { |
| super(txnId); |
| this.global = global; |
| } |
| |
| public InMemorySafeCommand(TxnId txnId, Supplier<GlobalCommand> global) |
| { |
| super(txnId); |
| this.lazy = global; |
| } |
| |
| @Override |
| public Command current() |
| { |
| touch(); |
| return global.value(); |
| } |
| |
| @Override |
| protected void set(Command update) |
| { |
| touch(); |
| global.value(update); |
| } |
| |
| @Override |
| public void addListener(Command.TransientListener listener) |
| { |
| global.addListener(listener); |
| } |
| |
| @Override |
| public boolean removeListener(Command.TransientListener listener) |
| { |
| return global.removeListener(listener); |
| } |
| |
| @Override |
| public Collection<Command.TransientListener> transientListeners() |
| { |
| return global.transientListeners(); |
| } |
| |
| @Override |
| public void invalidate() |
| { |
| lazy = INVALIDATED; |
| } |
| |
| @Override |
| public boolean invalidated() |
| { |
| return lazy == INVALIDATED; |
| } |
| |
| private void touch() |
| { |
| if (invalidated()) |
| throw new IllegalStateException("Cannot access invalidated " + this); |
| if (lazy != null) |
| { |
| global = lazy.get(); |
| lazy = null; |
| } |
| } |
| |
| GlobalCommand global() |
| { |
| touch(); |
| return global; |
| } |
| } |