Rename PricingEngine to PremiumPricingEngine

This properly reflects the fact that other, separate things will now
be responsible both for EAP and for per-TLD custom pricing.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=124558165

java/google/registry/model/pricing/PremiumPricingEngine.java

@@ -0,0 +1,85 @@
+// 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.pricing;
+
+import com.google.common.base.Optional;
+
+import org.joda.money.Money;
+import org.joda.time.DateTime;
+
+/**
+ * A plugin interface for premium pricing engines.
+ *
+ * <p>A premium pricing engine is responsible solely for determining whether a given label is
+ * premium or not, and if it is, how much it should cost.
+ */
+public interface PremiumPricingEngine {
+
+  /**
+   * Returns the prices for the given fully qualified domain name at the given time.
+   *
+   * <p>Note that the fullyQualifiedDomainName must only contain a single part left of the TLD, i.e.
+   * subdomains are not allowed, but multi-part TLDs are.
+   */
+  public DomainPrices getDomainPrices(String fullyQualifiedDomainName, DateTime priceTime);
+
+  /**
+   * A class containing information on premium prices for a specific domain name.
+   *
+   * <p>Any implementation of PremiumPricingEngine is responsible for determining all of these.
+   */
+  public static class DomainPrices {
+
+    private boolean isPremium;
+    // TODO(b/26901539): Refactor return values to support an arbitrary list of costs for each of
+    // create, renew, restore, and transfer.
+    private Money createCost;
+    private Money renewCost;
+    private Optional<String> feeClass;
+
+    static DomainPrices create(
+        boolean isPremium,
+        Money createCost,
+        Money renewCost,
+        Optional<String> feeClass) {
+      DomainPrices instance = new DomainPrices();
+      instance.isPremium = isPremium;
+      instance.createCost = createCost;
+      instance.renewCost = renewCost;
+      instance.feeClass = feeClass;
+      return instance;
+    }
+
+    /** Returns whether the domain is premium. */
+    public boolean isPremium() {
+      return isPremium;
+    }
+
+    /** Returns the cost to create the domain. */
+    public Money getCreateCost() {
+      return createCost;
+    }
+
+    /** Returns the cost to renew the domain. */
+    public Money getRenewCost() {
+      return renewCost;
+    }
+
+    /** Returns the fee class of the cost (used for the Fee extension). */
+    public Optional<String> getFeeClass() {
+      return feeClass;
+    }
+  }
+}