Added third concept of DNS batch.

Author: mderka

gcloud-java-core/src/main/java/com/google/gcloud/BatchResult.java

@@ -0,0 +1,37 @@
+/*
+ * 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.gcloud;
+
+/**
+ * The class that holds a single result of a batch call.
+ */
+public interface BatchResult<T, E extends Throwable> {
+
+  /**
+   * Returns {@code true} if the batch has been submitted and the result is available, and {@code
+   * false} otherwise
+   */
+  boolean submitted();
+
+  /**
+   * Returns result of this call.
+   *
+   * @throws IllegalArgumentException if the batch has not been submitted yet
+   * @throws E if an error occured when processing this request
+   */
+  T get() throws E;
+}

gcloud-java-dns/src/main/java/com/google/gcloud/dns/Dns.java

@@ -533,4 +533,12 @@ ChangeRequest getChangeRequest(String zoneName, String changeRequestId,
    * @see <a href="https://cloud.google.com/dns/api/v1/changes/list">Cloud DNS Chages: list</a>
    */
   Page<ChangeRequest> listChangeRequests(String zoneName, ChangeRequestListOption... options);
+
+  /**
+   * Initiates a new empty batch ready to be populated with service calls, which will use this
+   * {@code Dns} instance when submitted for processing to Google Cloud DNS.
+   */
+  DnsBatch batch();
+
+  void submitBatch(DnsBatch batch);
 }

gcloud-java-dns/src/main/java/com/google/gcloud/dns/DnsBatch.java

@@ -0,0 +1,205 @@
+/*
+ * 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.gcloud.dns;
+
+import com.google.gcloud.Page;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * A batch of operations to be submitted to Google Cloud DNS using a single HTTP request.
+ */
+public class DnsBatch {
+
+  private List<Request> requests = new LinkedList<>();
+  private Dns dns;
+
+  /**
+   * An operation to be submitted to Google Cloud DNS within this batch. Only an subset of the class
+   * attributes appropriate for the represented operation is initialized. Refer to the class method
+   * and attribute documentation for the specific fields.
+   */
+  public static class Request {
+
+    private final String zoneName;
+    private final String changeId;
+    private final ChangeRequest changeRequest;
+    private final ZoneInfo zoneInfo;
+    private final Operation operation;
+    private final AbstractOption[] options;
+    private final DnsBatchResult result;
+
+    private Request(RequestBuilder builder) {
+      this.zoneName = builder.zoneName;
+      this.changeId = builder.changeId;
+      this.changeRequest = builder.changeRequest;
+      this.zoneInfo = builder.zoneInfo;
+      this.operation = builder.operation;
+      this.options = builder.options;
+      this.result = builder.result;
+    }
+
+    private static RequestBuilder builder(Operation operation, DnsBatchResult result,
+        AbstractOption... options) {
+      return new RequestBuilder(operation, result, options);
+    }
+
+    /**
+     * Returns the name of the zone to which the operation is applied. This field is initialized for
+     * zone create, get and delete operation, and listing DNS records and changes within a zone.
+     * Returns {@code null} in other cases.
+     */
+    public String zoneName() {
+      return zoneName;
+    }
+
+    /**
+     * Returns the id of the change request which is being retrieved. Getting a change request is
+     * the only operation when this attribute is initialized. The method returns {@code null} in the
+     * remaining cases.
+     */
+    public String changeId() {
+      return changeId;
+    }
+
+    /**
+     * Returns the change request which is being created. Creating a change request is the only
+     * operation when this attribute is initialized. The method returns {@code null} in the
+     * remaining cases.
+     */
+    public ChangeRequest changeRequest() {
+      return changeRequest;
+    }
+
+    /**
+     * Returns the zone which is being created. Creating a zone is the only operation when this
+     * attribute is initialized. The method returns {@code null} in the remaining cases.
+     */
+    public ZoneInfo zoneInfo() {
+      return zoneInfo;
+    }
+
+    /**
+     * Returns the type of the operation represented by this {@link DnsBatch.Request}. This field is
+     * always initialized.
+     */
+    public Operation operation() {
+      return operation;
+    }
+
+    /**
+     * Returns options provided to the operation. Returns an empty array if no options were
+     * provided.
+     */
+    public AbstractOption[] options() {
+      return options == null ? new AbstractOption[0] : options;
+    }
+
+    DnsBatchResult result() {
+      return result;
+    }
+  }
+
+  static class RequestBuilder {
+    private final AbstractOption[] options;
+    private String zoneName;
+    private String changeId;
+    private ChangeRequest changeRequest;
+    private ZoneInfo zoneInfo;
+    private final Operation operation;
+    private final DnsBatchResult result;
+
+    RequestBuilder(Operation operation, DnsBatchResult result, AbstractOption... options) {
+      this.operation = operation;
+      this.options = options;
+      this.result = result;
+    }
+
+    RequestBuilder zoneName(String zoneName) {
+      this.zoneName = zoneName;
+      return this;
+    }
+
+    RequestBuilder changeId(String changeId) {
+      this.changeId = changeId;
+      return this;
+    }
+
+    RequestBuilder changeRequest(ChangeRequest changeRequest) {
+      this.changeRequest = changeRequest;
+      return this;
+    }
+
+    RequestBuilder zoneInfo(ZoneInfo zoneInfo) {
+      this.zoneInfo = zoneInfo;
+      return this;
+    }
+
+    Request build() {
+      return new Request(this);
+    }
+  }
+
+  /**
+   * Represents the type of the batch operation.
+   */
+  public enum Operation {
+    CREATE_ZONE,
+    DELETE_ZONE,
+    GET_ZONE,
+    LIST_ZONES,
+    APPLY_CHANGE_REQUEST,
+    GET_CHANGE_REQUEST,
+    LIST_CHANGES_REQUESTS,
+    LIST_DNS_RECORDS
+  }
+
+  DnsBatch(Dns dns) {
+    this.dns = dns;
+  }
+
+  public Dns service() {
+    return dns;
+  }
+
+  List<Request> requests() {
+    return requests;
+  }
+
+  /**
+   * Adds a {@code DnsBatch.Request} representing the list zones operation to this batch. The
+   * request will not have initialized any fields except for the operation type and options (if
+   * provided). The {@code options} can be used to restrict the fields returned or provide page size
+   * limits in the same way as for {@link Dns#listZones(Dns.ZoneListOption...)}.
+   */
+  public DnsBatchResult<Page<Zone>> listZones(Dns.ZoneListOption... options) {
+    DnsBatchResult<Page<Zone>> result = new DnsBatchResult<>();
+    Request request = Request.builder(Operation.LIST_ZONES, result, options).build();
+    requests.add(request);
+    return result;
+  }
+
+  // todo(mderka) add the rest of the operations
+
+  /**
+   * Submits this batch for processing using a single HTTP request.
+   */
+  public void submit() {
+    dns.submitBatch(this);
+  }
+}

gcloud-java-dns/src/main/java/com/google/gcloud/dns/DnsBatchResult.java

@@ -0,0 +1,44 @@
+package com.google.gcloud.dns;
+
+import com.google.gcloud.BatchResult;
+
+/**
+ * This class holds a single result of a batch call to the Cloud DNS.
+ */
+public class DnsBatchResult<T> implements BatchResult<T, DnsException> {
+
+  private T result;
+  private boolean submitted = false;
+  private DnsException error;
+
+  DnsBatchResult() {
+  }
+
+  @Override
+  public boolean submitted() {
+    return submitted;
+  }
+
+  @Override
+  public T get() throws DnsException {
+    if(!submitted()) {
+      throw new IllegalStateException("Batch has not been submitted yet");
+    }
+    if(error != null) {
+      throw error;
+    }
+    return result;
+  }
+
+  void result(T result) {
+    this.result = result;
+  }
+
+  void error(DnsException error) {
+    this.error = error;
+  }
+
+  void submit() {
+    this.submitted = true;
+  }
+}

gcloud-java-dns/src/main/java/com/google/gcloud/dns/DnsException.java

@@ -16,6 +16,7 @@
 
 package com.google.gcloud.dns;
 
+import com.google.api.client.googleapis.json.GoogleJsonError;
 import com.google.common.collect.ImmutableSet;
 import com.google.gcloud.BaseServiceException;
 import com.google.gcloud.RetryHelper.RetryHelperException;
@@ -39,6 +40,10 @@ public class DnsException extends BaseServiceException {
       new Error(null, "rateLimitExceeded"));
   private static final long serialVersionUID = 490302380416260252L;
 
+  public DnsException(GoogleJsonError error) {
+    super(error, true);
+  }
+
   public DnsException(IOException exception) {
     super(exception, true);
   }