google-nomulus/java/google/registry/model/index/DomainApplicationIndex.java
cgoldfeder 5098b03af4 DeReference the codebase
This change replaces all Ref objects in the code with Key objects. These are
stored in datastore as the same object (raw datastore keys), so this is not
a model change.

Our best practices doc says to use Keys not Refs because:
 * The .get() method obscures what's actually going on
   - Much harder to visually audit the code for datastore loads
   - Hard to distinguish Ref<T> get()'s from Optional get()'s and Supplier get()'s
 * Implicit ofy().load() offers much less control
   - Antipattern for ultimate goal of making Ofy injectable
   - Can't control cache use or batch loading without making ofy() explicit anyway
 * Serialization behavior is surprising and could be quite dangerous/incorrect
   - Can lead to serialization errors. If it actually worked "as intended",
     it would lead to a Ref<> on a serialized object being replaced upon
     deserialization with a stale copy of the old value, which could potentially
     break all kinds of transactional expectations
 * Having both Ref<T> and Key<T> introduces extra boilerplate everywhere
   - E.g. helper methods all need to have Ref and Key overloads, or you need to
     call .key() to get the Key<T> for every Ref<T> you want to pass in
   - Creating a Ref<T> is more cumbersome, since it doesn't have all the create()
     overloads that Key<T> has, only create(Key<T>) and create(Entity) - no way to
     create directly from kind+ID/name, raw Key, websafe key string, etc.

(Note that Refs are treated specially by Objectify's @Load method and Keys are not;
we don't use that feature, but it is the one advantage Refs have over Keys.)

The direct impetus for this change is that I am trying to audit our use of memcache,
and the implicit .get() calls to datastore were making that very hard.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=131965491
2016-09-02 13:50:20 -04:00

130 lines
5.3 KiB
Java

// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
//
// 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 google.registry.model.index;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Strings.isNullOrEmpty;
import static google.registry.model.ofy.ObjectifyService.ofy;
import static google.registry.model.ofy.Ofy.RECOMMENDED_MEMCACHE_EXPIRATION;
import static google.registry.util.CollectionUtils.isNullOrEmpty;
import static google.registry.util.DateTimeUtils.latestOf;
import com.google.common.collect.ImmutableSet;
import com.googlecode.objectify.Key;
import com.googlecode.objectify.annotation.Cache;
import com.googlecode.objectify.annotation.Entity;
import com.googlecode.objectify.annotation.Id;
import google.registry.model.BackupGroupRoot;
import google.registry.model.domain.DomainApplication;
import google.registry.util.CollectionUtils;
import java.util.Set;
import javax.annotation.Nullable;
import org.joda.time.DateTime;
/**
* Entity for tracking all domain applications with a given fully qualified domain name. Since this
* resource is always kept up to date as additional domain applications are created, it is never
* necessary to query them explicitly from Datastore.
*/
@Entity
@Cache(expirationSeconds = RECOMMENDED_MEMCACHE_EXPIRATION)
public class DomainApplicationIndex extends BackupGroupRoot {
@Id
String fullyQualifiedDomainName;
/**
* A set of all domain applications with this fully qualified domain name. Never null or empty.
*
* <p>Although this stores {@link Key}s it is named "references" for historical reasons.
*/
Set<Key<DomainApplication>> references;
/** Returns a cloned list of all keys on this index. */
public ImmutableSet<Key<DomainApplication>> getKeys() {
return ImmutableSet.copyOf(references);
}
public String getFullyQualifiedDomainName() {
return fullyQualifiedDomainName;
}
/**
* Creates a DomainApplicationIndex with the specified list of keys. Only use this method for data
* migrations. You probably want {@link #createUpdatedInstance}.
*/
public static DomainApplicationIndex createWithSpecifiedKeys(
String fullyQualifiedDomainName,
ImmutableSet<Key<DomainApplication>> keys) {
checkArgument(!isNullOrEmpty(fullyQualifiedDomainName),
"fullyQualifiedDomainName must not be null or empty.");
checkArgument(!isNullOrEmpty(keys), "Keys must not be null or empty.");
DomainApplicationIndex instance = new DomainApplicationIndex();
instance.fullyQualifiedDomainName = fullyQualifiedDomainName;
instance.references = keys;
return instance;
}
public static Key<DomainApplicationIndex> createKey(DomainApplication application) {
return Key.create(DomainApplicationIndex.class, application.getFullyQualifiedDomainName());
}
/**
* Returns an iterable of all DomainApplications for the given fully qualified domain name that
* do not have a deletion time before the supplied DateTime.
*/
public static Iterable<DomainApplication> loadActiveApplicationsByDomainName(
String fullyQualifiedDomainName, DateTime now) {
DomainApplicationIndex index = load(fullyQualifiedDomainName);
if (index == null) {
return ImmutableSet.of();
}
ImmutableSet.Builder<DomainApplication> apps = new ImmutableSet.Builder<>();
for (DomainApplication app : ofy().load().keys(index.getKeys()).values()) {
DateTime forwardedNow = latestOf(now, app.getUpdateAutoTimestamp().getTimestamp());
if (app.getDeletionTime().isAfter(forwardedNow)) {
apps.add(app.cloneProjectedAtTime(forwardedNow));
}
}
return apps.build();
}
/**
* Returns the DomainApplicationIndex for the given fully qualified domain name. Note that this
* can return null if there are no domain applications for this fully qualified domain name.
*/
@Nullable
public static DomainApplicationIndex load(String fullyQualifiedDomainName) {
return ofy()
.load()
.type(DomainApplicationIndex.class)
.id(fullyQualifiedDomainName)
.now();
}
/**
* Saves a new DomainApplicationIndex for this resource or updates the existing one. This is
* the preferred method for creating an instance of DomainApplicationIndex because this performs
* the correct merging logic to add the given domain application to an existing index if there
* is one.
*/
public static DomainApplicationIndex createUpdatedInstance(DomainApplication application) {
DomainApplicationIndex existing = load(application.getFullyQualifiedDomainName());
ImmutableSet<Key<DomainApplication>> newKeys = CollectionUtils.union(
(existing == null ? ImmutableSet.<Key<DomainApplication>>of() : existing.getKeys()),
Key.create(application));
return createWithSpecifiedKeys(application.getFullyQualifiedDomainName(), newKeys);
}
}