Rename Runnable classes from Tasks to Actions

This is cleanup relating to a naming decision that we made awhile ago
but never got around to.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=117244827

java/com/google/domain/registry/dns/RefreshDnsAction.java

@@ -0,0 +1,80 @@
+// Copyright 2016 Google Inc. 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 com.google.domain.registry.dns;
+
+import static com.google.domain.registry.model.EppResourceUtils.loadByUniqueId;
+
+import com.google.domain.registry.dns.DnsConstants.TargetType;
+import com.google.domain.registry.model.EppResource;
+import com.google.domain.registry.model.domain.DomainResource;
+import com.google.domain.registry.model.host.HostResource;
+import com.google.domain.registry.request.Action;
+import com.google.domain.registry.request.HttpException.BadRequestException;
+import com.google.domain.registry.request.HttpException.NotFoundException;
+import com.google.domain.registry.request.Parameter;
+import com.google.domain.registry.util.Clock;
+
+import javax.inject.Inject;
+
+/** Action that manually triggers refresh of DNS information. */
+@Action(path = "/_dr/dnsRefresh", automaticallyPrintOk = true)
+public final class RefreshDnsAction implements Runnable {
+
+  @Inject Clock clock;
+  @Inject DnsQueue dnsQueue;
+  @Inject @Parameter("name") String domainOrHostName;
+  @Inject @Parameter("type") TargetType type;
+  @Inject RefreshDnsAction() {}
+
+  @Override
+  public void run() {
+    if (!domainOrHostName.contains(".")) {
+      throw new BadRequestException("URL parameter 'name' must be fully qualified");
+    }
+
+    boolean domainLookup;
+    Class<? extends EppResource> clazz;
+    switch (type) {
+      case DOMAIN:
+        domainLookup = true;
+        clazz = DomainResource.class;
+        break;
+      case HOST:
+        domainLookup = false;
+        clazz = HostResource.class;
+        break;
+      default:
+        throw new BadRequestException("Unsupported type: " + type);
+    }
+
+    EppResource eppResource = loadByUniqueId(clazz, domainOrHostName, clock.nowUtc());
+    if (eppResource == null) {
+      throw new NotFoundException(
+          String.format("%s %s not found", type, domainOrHostName));
+    }
+
+    if (domainLookup) {
+      dnsQueue.addDomainRefreshTask(domainOrHostName);
+    } else {
+      if (((HostResource) eppResource).getSuperordinateDomain() == null) {
+        throw new BadRequestException(
+            String.format("%s isn't a subordinate hostname", domainOrHostName));
+      } else {
+        // Don't enqueue host refresh tasks for external hosts.
+        dnsQueue.addHostRefreshTask(domainOrHostName);
+      }
+    }
+  }
+}