Add log entry Payload class and tests

Author: mziccard

gcloud-java-logging/src/main/java/com/google/cloud/logging/Payload.java

@@ -0,0 +1,238 @@
+/*
+ * 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.cloud.logging;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.base.MoreObjects;
+import com.google.protobuf.Any;
+import com.google.protobuf.Struct;
+
+import java.io.Serializable;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * A base class for log entry payloads.
+ *
+ * @see <a href="https://cloud.google.com/logging/docs/view/logs_index">Log Entries and Logs</a>
+ */
+public abstract class Payload<T> implements Serializable {
+
+  private static final long serialVersionUID = -3802834715329130521L;
+
+  private final Type type;
+  private final T data;
+
+  /**
+   * Type for a log entry payload.
+   */
+  public enum Type {
+    /**
+     * Log entry data as UTF8 string.
+     */
+    STRING,
+
+    /**
+     * Log entry data as JSON.
+     */
+    JSON,
+
+    /**
+     * Log entry data as a protobuf object.
+     */
+    PROTO
+  }
+
+  /**
+   * A log entry payload as an UTF-8 string.
+   */
+  public static final class StringPayload extends Payload<String> {
+
+    private static final long serialVersionUID = 646595882175676029L;
+
+    StringPayload(String data) {
+      super(Type.STRING, data);
+    }
+
+    @Override
+    com.google.logging.v2.LogEntry.Builder toPb() {
+      return com.google.logging.v2.LogEntry.newBuilder().setTextPayload(data());
+    }
+
+    /**
+     * Creates a log entry payload given its data represented as an UTF-8 string.
+     */
+    public static StringPayload of(String data) {
+      return new StringPayload(data);
+    }
+
+    static StringPayload fromPb(com.google.logging.v2.LogEntry entryPb) {
+      return StringPayload.of(entryPb.getTextPayload());
+    }
+  }
+
+  /**
+   * A log entry's JSON payload.
+   */
+  public static final class JsonPayload extends Payload<Struct> {
+
+    private static final long serialVersionUID = 5747721918608143350L;
+
+    JsonPayload(Struct jsonData) {
+      super(Type.JSON, jsonData);
+    }
+
+    /**
+     * Returns the log entry's JSON data as an unmodifiable map.
+     */
+    public Map<String, Object> dataAsMap() {
+      return Structs.asMap(data());
+    }
+
+    @Override
+    com.google.logging.v2.LogEntry.Builder toPb() {
+      return com.google.logging.v2.LogEntry.newBuilder().setJsonPayload(data());
+    }
+
+    /**
+     * Creates a log entry payload given its JSON data represented as a map. The provided map is
+     * copied into a {@link Struct} object.
+     *
+     * <p>Notice that all numbers (int, long, float and double) are serialized as double values.
+     * Enums are serialized as strings.
+     *
+     * <p>Example usage of {@code JsonPayload}:
+     * <pre>{@code
+     *   List<Long> listValue = Arrays.asList(1L, 2L);
+     *   Map<String, Object> innerMap = new HashMap<String, Object>();
+     *   innerMap.put("booleanValue", true);
+     *   innerMap.put("stringValue", "stringValue");
+     *   Map<String, Object> jsonContent = new HashMap<String, Object>();
+     *   jsonContent.put("listValue", listValue);
+     *   jsonContent.put("integerValue", 42);
+     *   jsonContent.put("doubleValue", 42.0);
+     *   jsonContent.put("stringValue", "stringValue");
+     *   jsonContent.put("mapValue", innerMap);
+     *   JsonPayload payload = JsonPayload.of(jsonContent);
+     * }</pre>
+     */
+    public static JsonPayload of(Map<String, Object> data) {
+      return new JsonPayload(Structs.newStruct(data));
+    }
+
+    /**
+     * Creates a log entry payload given its JSON data represented as a protobuf struct.
+     */
+    public static JsonPayload of(Struct data) {
+      return new JsonPayload(data);
+    }
+
+    static JsonPayload fromPb(com.google.logging.v2.LogEntry entryPb) {
+      return JsonPayload.of(entryPb.getJsonPayload());
+    }
+  }
+
+  /**
+   * A log entry payload as a protobuf object.
+   */
+  public static final class ProtoPayload extends Payload<Any> {
+
+    private static final long serialVersionUID = 155951112369716872L;
+
+    ProtoPayload(Any data) {
+      super(Type.PROTO, data);
+    }
+
+    @Override
+    com.google.logging.v2.LogEntry.Builder toPb() {
+      return com.google.logging.v2.LogEntry.newBuilder().setProtoPayload(data());
+    }
+
+    /**
+     * Creates a log entry payload given its data as a protobuf object.
+     */
+    public static ProtoPayload of(Any data) {
+      return new ProtoPayload(data);
+    }
+
+    static ProtoPayload fromPb(com.google.logging.v2.LogEntry entryPb) {
+      return ProtoPayload.of(entryPb.getProtoPayload());
+    }
+  }
+
+  private Payload(Type type, T data) {
+    this.type = checkNotNull(type);
+    this.data = checkNotNull(data);
+  }
+
+  /**
+   * Returns the payload type. Payload can be an UTF-8 string ({@link Type#STRING}), a JSON object
+   * ({@link Type#JSON}) or a protobuf object ({@link Type#PROTO}).
+   */
+  public Type type() {
+    return type;
+  }
+
+  /**
+   * Returns the log entry payload's data.
+   */
+  public T data() {
+    return data;
+  }
+
+  @Override
+  public final boolean equals(Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (obj == null || !(obj instanceof Payload)) {
+      return false;
+    }
+    Payload<?> other = (Payload<?>) obj;
+    return Objects.equals(type, other.type) && Objects.equals(data, other.data);
+  }
+
+  @Override
+  public final int hashCode() {
+    return Objects.hash(type, data);
+  }
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this).add("type", type).add("data", data).toString();
+  }
+
+  abstract com.google.logging.v2.LogEntry.Builder toPb();
+
+  @SuppressWarnings("unchecked")
+  static <T extends Payload<?>> T fromPb(com.google.logging.v2.LogEntry entryPb) {
+    switch (entryPb.getPayloadCase()) {
+      case TEXT_PAYLOAD:
+        return (T) StringPayload.fromPb(entryPb);
+      case JSON_PAYLOAD:
+        return (T) JsonPayload.fromPb(entryPb);
+      case PROTO_PAYLOAD:
+        return (T) ProtoPayload.fromPb(entryPb);
+      case PAYLOAD_NOT_SET:
+        return null;
+      default:
+        // should never occur
+        throw new IllegalArgumentException("Unrecognized log entry payload");
+    }
+  }
+}