org.gradle.internal.id.ConfigurationCacheableIdFactory Maven / Gradle / Ivy
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/*
* Copyright 2023 the original author or authors.
*
* 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 org.gradle.internal.id;
import org.gradle.internal.service.scopes.Scopes;
import org.gradle.internal.service.scopes.ServiceScope;
import javax.annotation.concurrent.ThreadSafe;
import java.util.concurrent.atomic.AtomicLong;
/**
* Creates unique ids for objects created during configuration.
*
* Usage of this factory in object factories ensures that ids are reused consistently when loading from the configuration cache.
*/
@ThreadSafe
@ServiceScope(Scopes.BuildTree.class)
public class ConfigurationCacheableIdFactory {
private static final long USED_ASSIGNED_ID_MARKER = -1;
private final AtomicLong sequence = new AtomicLong(0);
/**
* Creates a new unique id.
*
* New ids can only be created if no ids have been loaded from the configuration cache.
* When re-creating an object due to loading from the configuration cache,
* {@link #idRecreated()} must be called before the object is re-created to make sure the consistency of the ids.
*
* @throws IllegalStateException if an id has already been loaded.
*/
public long createId() {
long newId = sequence.updateAndGet(it -> it == USED_ASSIGNED_ID_MARKER ? it : it + 1);
if (newId == USED_ASSIGNED_ID_MARKER) {
throw new IllegalStateException("Cannot create a new id after one has been loaded");
}
return newId;
}
/**
* This method must be called whenever an object is about to be re-created with the previously assigned id
* due to loading from the configuration cache.
*/
public void idRecreated() {
sequence.set(USED_ASSIGNED_ID_MARKER);
}
}