Use string keys for the multimap of pricing engines for TLDs

This is better than the previous way of using the canonical name of the class,
because the previous way did not allow for refactoring, and also required the
PremiumPricingEngine to live in the model package lest there be circular
dependencies, which does not seem ideal.

Note that, for reasons of backwards compatibility with existing persisted data,
the name of the static premium pricing engine has been set to its canonical
class name, but the class can now be refactored going forward so long as this
string remains unchanged, and any new pricing engine implementations can use
whatever string key they want (it doesn't have to be a canonical class name).

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=129215185

java/google/registry/model/pricing/StaticPremiumListPricingEngine.java

@@ -34,6 +34,9 @@ import org.joda.time.DateTime;
 /** A premium list pricing engine that stores static pricing information in Datastore entities. */
 public final class StaticPremiumListPricingEngine implements PremiumPricingEngine {
 
+  /** The name of the pricing engine, as used in {@code Registry.pricingEngineClassName}. */
+  public static final String NAME = "google.registry.model.pricing.StaticPremiumListPricingEngine";
+
   @Inject StaticPremiumListPricingEngine() {}
 
   @Override

java/google/registry/model/registry/Registry.java

@@ -58,7 +58,6 @@ import google.registry.model.common.EntityGroupRoot;
 import google.registry.model.common.TimedTransitionProperty;
 import google.registry.model.common.TimedTransitionProperty.TimedTransition;
 import google.registry.model.domain.fee.EapFee;
-import google.registry.model.pricing.PremiumPricingEngine;
 import google.registry.model.pricing.StaticPremiumListPricingEngine;
 import google.registry.model.registry.label.PremiumList;
 import google.registry.model.registry.label.ReservedList;
@@ -252,15 +251,18 @@ public class Registry extends ImmutableObject implements Buildable {
   @OnLoad
   void backfillPricingEngine() {
     if (pricingEngineClassName == null) {
-      pricingEngineClassName = StaticPremiumListPricingEngine.class.getCanonicalName();
+      pricingEngineClassName = StaticPremiumListPricingEngine.NAME;
     }
   }
 
   /**
-   * The fully qualified canonical classname of the pricing engine that this TLD uses.
+   * The name of the pricing engine that this TLD uses.
    *
    * <p>This must be a valid key for the map of pricing engines injected by
-   * <code>@Inject Map<String, PricingEngine></code>
+   * {@code @Inject Map<String, PricingEngine>}.
+   *
+   * <p>Note that it used to be the canonical class name, hence the name of this field, but this
+   * restriction has since been relaxed and it may now be any unique string.
    */
   String pricingEngineClassName;
 
@@ -609,10 +611,8 @@ public class Registry extends ImmutableObject implements Buildable {
       return this;
     }
 
-    public Builder setPremiumPricingEngineClass(
-        Class<? extends PremiumPricingEngine> pricingEngineClass) {
-      getInstance().pricingEngineClassName =
-          checkArgumentNotNull(pricingEngineClass).getCanonicalName();
+    public Builder setPremiumPricingEngine(String pricingEngineClass) {
+      getInstance().pricingEngineClassName = checkArgumentNotNull(pricingEngineClass);
       return this;
     }
 

java/google/registry/pricing/PricingComponent.java

@@ -29,5 +29,5 @@ import javax.inject.Singleton;
 @Singleton
 @Component(modules = {PricingModule.class})
 interface PricingComponent {
-  Map<Class<? extends PremiumPricingEngine>, PremiumPricingEngine> premiumPricingEngines();
+  Map<String, PremiumPricingEngine> premiumPricingEngines();
 }

java/google/registry/pricing/PricingEngineProxy.java

@@ -18,9 +18,6 @@ import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkState;
 import static google.registry.util.DomainNameUtils.getTldFromDomainName;
 
-import com.google.common.base.Function;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Maps;
 import google.registry.model.pricing.PremiumPricingEngine;
 import google.registry.model.pricing.PremiumPricingEngine.DomainPrices;
 import google.registry.model.registry.Registry;
@@ -34,20 +31,8 @@ import org.joda.time.DateTime;
  */
 public final class PricingEngineProxy {
 
-  private static final Map<Class<? extends PremiumPricingEngine>, PremiumPricingEngine>
-      premiumPricingEngineClasses = DaggerPricingComponent.create().premiumPricingEngines();
-
-  // Dagger map keys have to be provided with constant values that are known at compile time, so it
-  // can't be done using clazz.getCanonicalName().  So we construct the map by canonical name here,
-  // at runtime.
-  private static final ImmutableMap<String, PremiumPricingEngine> premiumPricingEngines =
-      Maps.uniqueIndex(
-          premiumPricingEngineClasses.values(),
-          new Function<PremiumPricingEngine, String>() {
-            @Override
-            public String apply(PremiumPricingEngine pricingEngine) {
-              return pricingEngine.getClass().getCanonicalName();
-            }});
+  private static final Map<String, PremiumPricingEngine>
+      premiumPricingEngines = DaggerPricingComponent.create().premiumPricingEngines();
 
   /** Returns the billing cost for registering the specified domain name for this many years. */
   public static Money getDomainCreateCost(String domainName, DateTime priceTime, int years) {

java/google/registry/pricing/PricingModule.java

@@ -14,10 +14,10 @@
 
 package google.registry.pricing;
 
-import dagger.MapKey;
 import dagger.Module;
 import dagger.Provides;
 import dagger.multibindings.IntoMap;
+import dagger.multibindings.StringKey;
 import google.registry.model.pricing.PremiumPricingEngine;
 import google.registry.model.pricing.StaticPremiumListPricingEngine;
 
@@ -25,21 +25,14 @@ import google.registry.model.pricing.StaticPremiumListPricingEngine;
  * Dagger module for injecting pricing engines.
  *
  * <p>To add a new pricing engine, create a new class that implements {@link PremiumPricingEngine},
- * and add a module that provides an instance of {@link PremiumPricingEngine} with a
- * {@link PremiumPricingEngineClassKey} annotation with the class of the implementation and also
- * <code>@Provides @IntoMap</code> annotations.
+ * and add a module that provides an instance of {@link PremiumPricingEngine} with a unique
+ * {@link StringKey} annotation, and also <code>@Provides @IntoMap</code> annotations.
  */
 @Module
 public class PricingModule {
 
-  /** The annotation used for PricingEngine implementation keys. */
-  @MapKey
-  @interface PremiumPricingEngineClassKey {
-    Class<? extends PremiumPricingEngine> value();
-  }
-
   @Provides @IntoMap
-  @PremiumPricingEngineClassKey(StaticPremiumListPricingEngine.class)
+  @StringKey(StaticPremiumListPricingEngine.NAME)
   static PremiumPricingEngine provideStaticPremiumList(StaticPremiumListPricingEngine engine) {
     return engine;
   }

java/google/registry/tools/CreateOrUpdateTldCommand.java

@@ -252,7 +252,7 @@ abstract class CreateOrUpdateTldCommand extends MutatingCommand {
           oldRegistry == null
               ? new Registry.Builder()
                   .setTldStr(tld)
-                  .setPremiumPricingEngineClass(StaticPremiumListPricingEngine.class)
+                  .setPremiumPricingEngine(StaticPremiumListPricingEngine.NAME)
               : oldRegistry.asBuilder();
 
       if (escrow != null) {

javatests/google/registry/model/registry/label/PremiumListTest.java

@@ -70,7 +70,7 @@ public class PremiumListTest {
     persistResource(
         new Registry.Builder()
             .setTldStr("ghost")
-            .setPremiumPricingEngineClass(StaticPremiumListPricingEngine.class)
+            .setPremiumPricingEngine(StaticPremiumListPricingEngine.NAME)
             .build());
     assertThat(Registry.get("ghost").getPremiumList()).isNull();
     assertThat(getPremiumPrice("blah", "ghost")).isAbsent();

javatests/google/registry/pricing/PricingEngineProxyTest.java

@@ -25,7 +25,6 @@ import static google.registry.util.DateTimeUtils.START_OF_TIME;
 import static org.joda.money.CurrencyUnit.USD;
 
 import com.google.common.collect.ImmutableSortedMap;
-import google.registry.model.pricing.PremiumPricingEngine;
 import google.registry.model.registry.Registry;
 import google.registry.model.registry.label.PremiumList;
 import google.registry.testing.AppEngineRule;
@@ -145,14 +144,12 @@ public class PricingEngineProxyTest {
   public void testFailure_cantLoadPricingEngine() throws Exception {
     createTld("example");
     persistResource(
-        Registry.get("example").asBuilder().setPremiumPricingEngineClass(FakePricingEngine.class).build());
+        Registry.get("example")
+            .asBuilder()
+            .setPremiumPricingEngine("fake")
+            .build());
     thrown.expect(
-        IllegalStateException.class,
-        String.format(
-            "Could not load pricing engine %s for TLD example",
-            FakePricingEngine.class.getCanonicalName()));
+        IllegalStateException.class, "Could not load pricing engine fake for TLD example");
     getDomainCreateCost("bad.example", clock.nowUtc(), 1);
   }
-
-  private abstract static class FakePricingEngine implements PremiumPricingEngine {}
 }

javatests/google/registry/testing/DatastoreHelper.java

@@ -233,7 +233,7 @@ public class DatastoreHelper {
       .setServerStatusChangeBillingCost(Money.of(USD, 19))
       // Always set a default premium list. Tests that don't want it can delete it.
       .setPremiumList(persistPremiumList(tld, DEFAULT_PREMIUM_LIST_CONTENTS.get()))
-      .setPremiumPricingEngineClass(StaticPremiumListPricingEngine.class)
+      .setPremiumPricingEngine(StaticPremiumListPricingEngine.NAME)
       .build();
   }