Added DnsRecord as a part of the basic data model.

ManagedZoneInfo is to be completed and it is included
only as it is required as a builder parameter. This class
will change in the near future.

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

@@ -0,0 +1,254 @@
+/*
+ * 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 static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableList;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * A class that represents Google Cloud DNS record set.
+ *
+ * <p>
+ * A unit of data that will be returned by the DNS servers.
+ *
+ * @see <a href="https://cloud.google.com/dns/api/v1/resourceRecordSets">Google
+ * Cloud DNS documentation</a>
+ */
+public class DnsRecord {
+
+  private String name;
+  private List<String> rrdatas = new LinkedList<>();
+  private Integer ttl = 86400; // the default ttl of 24 hours
+  private DnsRecordType type;
+  private String parentName;
+  private Long parentId;
+
+  /**
+   * A private constructor. Obtain an instance using {@link DnsRecord#Builder}.
+   */
+  private DnsRecord() {
+  }
+
+  DnsRecord(Builder builder) {
+    this.name = builder.name;
+    this.rrdatas = ImmutableList.copyOf(builder.rrdatas);
+    this.ttl = builder.ttl;
+    this.type = builder.type;
+    this.parentName = builder.parentName;
+    this.parentId = builder.parentId;
+  }
+
+  /**
+   * Enum for the DNS record types supported by Cloud DNS.
+   *
+   * <p>
+   * Google Cloud DNS currently supports records of type A, AAAA, CNAME, MX
+   * NAPTR, NS, PTR, SOA, SPF, SRV, TXT.
+   *
+   * @see
+   * <a href="https://cloud.google.com/dns/what-is-cloud-dns#supported_record_types">Cloud
+   * DNS supported record types</a>
+   */
+  public enum DnsRecordType {
+    A("A"),
+    AAAA("AAAA"),
+    CNAME("CNAME"),
+    MX("MX"),
+    NAPTR("NAPTR"),
+    NS("NS"),
+    PTR("PTR"),
+    SOA("SOA"),
+    SPF("SPF"),
+    SRV("SRV"),
+    TXT("TXT");
+
+    private final String type;
+
+    private DnsRecordType(String type) {
+      this.type = type;
+    }
+  }
+
+  public static class Builder {
+
+    private List<String> rrdatas = new LinkedList<>();
+    private String name;
+    private Integer ttl = 86400; // default ttl of 24 hours
+    private DnsRecordType type;
+    private String parentName;
+    private Long parentId;
+
+    private Builder() {
+    }
+
+    /**
+     * Creates a builder and pre-populates attributes with the values from the
+     * provided DnsRecord instance.
+     */
+    public Builder(DnsRecord record) {
+      this.name = record.name;
+      this.ttl = record.ttl;
+      this.type = record.type;
+      this.parentId = record.parentId;
+      this.parentName = record.parentName;
+      this.rrdatas.addAll(record.rrdatas);
+    }
+
+    /**
+     * Adds a record to the record set.
+     *
+     * <p>
+     * The records should be as defined in RFC 1035 (section 5) and RFC 1034
+     * (section 3.6.1). Examples of records are available in
+     * <a href="https://cloud.google.com/dns/what-is-cloud-dns#supported_record_types">Cloud
+     * DNS documentation</a>.
+     */
+    public Builder add(String record) {
+      this.rrdatas.add(checkNotNull(record));
+      return this;
+    }
+
+    /**
+     * Sets name for this DNS record set. For example, www.example.com.
+     */
+    public Builder name(String name) {
+      this.name = checkNotNull(name);
+      return this;
+    }
+
+    /**
+     * Sets the number of seconds that this record can be cached by resolvers.
+     * This number must be non-negative.
+     *
+     * @param ttl A non-negative number of seconds
+     */
+    public Builder ttl(int ttl) {
+      // change only if 
+      if (ttl < 0) {
+        throw new IllegalArgumentException(
+                "TTL cannot be negative. The supplied value was " + ttl + "."
+        );
+      }
+      this.ttl = ttl;
+      return this;
+    }
+
+    /**
+     * The identifier of a supported record type, for example, A, AAAA, MX, TXT,
+     * and so on.
+     */
+    public Builder type(DnsRecordType type) {
+      this.type = checkNotNull(type);
+      return this;
+    }
+
+    /**
+     * Builds the DNS record.
+     */
+    public DnsRecord build() {
+      return new DnsRecord(this);
+    }
+
+    /**
+     * Sets references to the managed zone that this DNS record belongs to.
+     */
+    public Builder managedZone(ManagedZoneInfo parent) {
+      checkNotNull(parent);
+      this.parentId = parent.id();
+      this.parentName = parent.name();
+      return this;
+    }
+  }
+
+  /**
+   * Creates a builder pre-populated with the attribute values of this instance.
+   */
+  public Builder toBuilder() {
+    return new Builder(this);
+  }
+
+  /**
+   * Creates an empty builder
+   */
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  /**
+   * Get user assigned name of this DNS record.
+   *
+   * TODO: is this field mandatory?
+   */
+  public String name() {
+    return name;
+  }
+
+  /**
+   * Returns a list of DNS record stored in this record set.
+   */
+  public List<String> rrdatas() {
+    return rrdatas;
+  }
+
+  /**
+   * Returns the number of seconds that this ResourceRecordSet can be cached by
+   * resolvers.
+   *
+   * <p>
+   * This number is provided by the user. If this values is not set, we use
+   * default of 86400.
+   */
+  public Integer ttl() {
+    return ttl;
+  }
+
+  /**
+   * Returns the type of this DNS record.
+   */
+  public DnsRecordType type() {
+    return type;
+  }
+
+  /**
+   * Returns name of the managed zone that this record belongs to.
+   *
+   * <p>
+   * The name of the managed zone is provided by the user when the managed zone
+   * is created. It is unique within a project. If this DNS record is not
+   * associated with a managed zone, this returns null.
+   */
+  public String parentName() {
+    return parentName;
+  }
+
+  /**
+   * Returns name of the managed zone that this record belongs to.
+   *
+   * <p>
+   * The id of the managed zone is determined by the server when the managed
+   * zone is created. It is a read only value. If this DNS record is not
+   * associated with a managed zone, or if the id of the managed zone was not
+   * loaded from the cloud service, this returns null.
+   */
+  public Long parentId() {
+    return parentId;
+  }
+
+}

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

@@ -0,0 +1,44 @@
+/*
+ * 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;
+
+/**
+ * TODO: Implement.
+ * TODO: Add documentation.
+ */
+public class ManagedZoneInfo {
+
+  private final String name;
+  private final Long id;
+
+  public String name() {
+    throw new UnsupportedOperationException("Not implemented yet.");
+    // TODO: Implement
+  }
+
+  public Long id() {
+    return id;
+    // TODO: Implement
+  }
+
+  private ManagedZoneInfo() {
+    name = null;
+    id = null;
+    throw new UnsupportedOperationException("Not implemented yet");
+    // TODO: Implement
+  }
+
+}

gcloud-java-dns/src/test/java/com/google/gcloud/dns/DnsRecordTest.java

@@ -0,0 +1,94 @@
+/*
+ * 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 org.easymock.EasyMock;
+
+import org.junit.Test;
+import org.junit.Before;
+
+import static org.junit.Assert.*;
+
+public class DnsRecordTest {
+
+  private static final String NAME = "example.com.";
+  private static final Integer TTL = 3600;
+  private static final DnsRecord.DnsRecordType TYPE = DnsRecord.DnsRecordType.AAAA;
+  private static final ManagedZoneInfo MANAGED_ZONE_INFO_MOCK
+          = EasyMock.createMock(ManagedZoneInfo.class);
+  private static final Long PARENT_ID = 12L;
+  private static final String PARENT_NAME = "name";
+  static {
+    EasyMock.expect(MANAGED_ZONE_INFO_MOCK.id()).andReturn(PARENT_ID);
+    EasyMock.expect(MANAGED_ZONE_INFO_MOCK.name()).andReturn(PARENT_NAME);
+    EasyMock.replay(MANAGED_ZONE_INFO_MOCK);
+  }
+  private static final DnsRecord RECORD = DnsRecord.builder()
+          .name(NAME)
+          .ttl(TTL)
+          .managedZone(MANAGED_ZONE_INFO_MOCK)
+          .build();
+  private static final Integer DEFAULT_TTL = 86400;
+
+  @Test
+  public void testDefaultDnsRecord() {
+    DnsRecord record = DnsRecord.builder().build();
+    assertEquals(DEFAULT_TTL, record.ttl());
+    assertEquals(0, record.rrdatas().size());
+  }
+
+  @Test
+  public void testBuilder() {
+
+    assertEquals(NAME, RECORD.name());
+    assertEquals(TTL, RECORD.ttl());
+
+    assertEquals(PARENT_ID, RECORD.parentId()); // this was never assigned
+    assertEquals(PARENT_NAME, RECORD.parentName());
+    assertEquals(0, RECORD.rrdatas().size());
+    // verify that one can add records to the record set
+    String testingRecord = "Testing record";
+    String anotherTestingRecord = "Another record 123";
+    DnsRecord anotherRecord = RECORD.toBuilder()
+            .add(testingRecord)
+            .add(anotherTestingRecord)
+            .build();
+    assertEquals(2, anotherRecord.rrdatas().size());
+    assertTrue(anotherRecord.rrdatas().contains(testingRecord));
+    assertTrue(anotherRecord.rrdatas().contains(anotherTestingRecord));
+  }
+
+  @Test
+  public void testValidTtl() {
+    try {
+      DnsRecord.builder().ttl(-1);
+      fail("A negative value is not acceptable for ttl.");
+    } catch (IllegalArgumentException e) {
+      // ok
+    }
+    try {
+      DnsRecord.builder().ttl(0);
+    } catch (IllegalArgumentException e) {
+      fail("0 is a valid value.");
+    }
+    try {
+      DnsRecord.builder().ttl(Integer.MAX_VALUE);
+    } catch (Exception e) {
+      fail("Large numbers should be ok too.");
+    }
+  }
+
+}