Add dagger map for injecting DnsWriter implementations

This is one of several CLs in a sequence for allowing per-TLD DNS
implementations.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=129445641

java/google/registry/model/dns/DnsWriter.java

@@ -1,56 +0,0 @@
-// 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.dns;
-
-/**
- * Transaction object for sending an atomic batch of updates for a single zone to the DNS server.
- *
- * <p>Here's an example of how you would publish updates for a domain and host:
- * <pre>
- * &#064;Inject Provider&lt;DnsWriter&gt; dnsWriter;
- * try (DnsWriter writer = dnsWriter.get()) {
- *   writer.publishDomain(domainName);
- *   writer.publishHost(hostName);
- * }
- * </pre>
- */
-public interface DnsWriter extends AutoCloseable {
-
-  /**
-   * Loads {@code domainName} from datastore and publishes its NS/DS records to the DNS server.
-   * Replaces existing records for the exact name supplied with an NS record for each name server
-   * and a DS record for each delegation signer stored in the registry for the supplied domain name.
-   * If the domain is deleted or is in a "non-publish" state then any existing records are deleted.
-   *
-   * @param domainName the fully qualified domain name, with no trailing dot
-   */
-  void publishDomain(String domainName);
-
-  /**
-   * Loads {@code hostName} from datastore and publishes its A/AAAA glue records to the DNS server,
-   * if it is used as an in-bailiwick nameserver. Orphaned glue records are prohibited. Replaces
-   * existing records for the exact name supplied, with an A or AAAA record (as appropriate) for
-   * each address stored in the registry, for the supplied host name. If the host is deleted then
-   * the existing records are deleted. Assumes that this method will only be called for in-bailiwick
-   * hosts. The registry does not have addresses for other hosts.
-   *
-   * @param hostName the fully qualified host name, with no trailing dot
-   */
-  void publishHost(String hostName);
-
-  /** Commits the updates to the DNS server atomically. */
-  @Override
-  void close();
-}

java/google/registry/model/dns/DnsWriterZone.java

@@ -1,23 +0,0 @@
-// 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.dns;
-
-import java.lang.annotation.Documented;
-import javax.inject.Qualifier;
-
-/** Dagger qualifier for the fully-qualified zone name that's being updated. */
-@Qualifier
-@Documented
-public @interface DnsWriterZone {}

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

@@ -255,6 +255,16 @@ public class Registry extends ImmutableObject implements Buildable {
     }
   }
 
+  /** Backfill the Registry entities that were saved before this field was added. */
+  // TODO(shikhman): Remove this backfill once it is populated on all Registry entities.
+  @OnLoad
+  void backfillDnsWriter() {
+    if (dnsWriter == null) {
+      dnsWriter = "VoidDnsWriter";
+    }
+  }
+
+
   /**
    * The name of the pricing engine that this TLD uses.
    *
@@ -266,6 +276,14 @@ public class Registry extends ImmutableObject implements Buildable {
    */
   String pricingEngineClassName;
 
+  /**
+   * The name of the DnsWriter that this TLD uses.
+   *
+   * <p>This must be a valid key for the map of DnsWriters injected by <code>
+   * @Inject Map<String, DnsWriter></code>
+   */
+  String dnsWriter;
+
   /**
    * The unicode-aware representation of the TLD associated with this {@link Registry}.
    *
@@ -545,6 +563,10 @@ public class Registry extends ImmutableObject implements Buildable {
     return pricingEngineClassName;
   }
 
+  public String getDnsWriter() {
+    return dnsWriter;
+  }
+
   public ImmutableSet<String> getAllowedRegistrantContactIds() {
     return nullToEmptyImmutableCopy(allowedRegistrantContactIds);
   }
@@ -616,6 +638,12 @@ public class Registry extends ImmutableObject implements Buildable {
       return this;
     }
 
+    public Builder setDnsWriter(String dnsWriter) {
+      getInstance().dnsWriter = checkArgumentNotNull(dnsWriter);
+      return this;
+    }
+
+
     public Builder setAddGracePeriodLength(Duration addGracePeriodLength) {
       checkArgument(addGracePeriodLength.isLongerThan(Duration.ZERO),
           "addGracePeriodLength must be non-zero");