Adding helpers to Config, PubSubMessage, Metadata. Coverage improved

src/main/java/com/yahoo/bullet/BulletConfig.java

@@ -7,8 +7,6 @@
 
 import lombok.extern.slf4j.Slf4j;
 
-import java.io.IOException;
-
 @Slf4j
 public class BulletConfig extends Config {
     public static final String SPECIFICATION_DEFAULT_DURATION = "bullet.query.default.duration";
@@ -55,9 +53,15 @@ public class BulletConfig extends Config {
      * Constructor that loads specific file augmented with defaults.
      *
      * @param file YAML file to load.
-     * @throws IOException if an error occurred with the file loading.
      */
-    public BulletConfig(String file) throws IOException {
+    public BulletConfig(String file) {
         super(file, DEFAULT_CONFIGURATION_NAME);
     }
+
+    /**
+     * Constructor that loads just the defaults.
+     */
+    public BulletConfig() {
+        super(DEFAULT_CONFIGURATION_NAME);
+    }
 }

src/main/java/com/yahoo/bullet/Config.java

@@ -17,6 +17,7 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 
@@ -29,26 +30,24 @@ public class Config implements Serializable {
      * Constructor that loads a specific file and loads the settings in that file.
      *
      * @param file YAML file to load.
-     * @throws IOException if an error occurred with the file loading.
      */
-    public Config(String file) throws IOException {
+    public Config(String file) {
         data = readYAML(file);
-        log.info("Configuration: {} ", data);
+        log.info("Final Configuration:\n{} ", data);
     }
 
     /**
      * Constructor that loads specific file augmented with defaults and the name of the default configuration file.
      *
      * @param file YAML file to load.
      * @param defaultConfigurationFile Default YAML file to load.
-     * @throws IOException if an error occurred with the file loading.
      */
-    public Config(String file, String defaultConfigurationFile) throws IOException {
-        this(defaultConfigurationFile);
+    public Config(String file, String defaultConfigurationFile) {
+        data = readYAML(defaultConfigurationFile);
         // Override
         Map<String, Object> specificConf = readYAML(file);
         data.putAll(specificConf);
-        log.info("Final configuration: {} ", data);
+        log.info("Final Configuration with defaults:\n{} ", data);
     }
 
     /**
@@ -73,6 +72,47 @@ public Object getOrDefault(String key, Object defaultValue) {
         return value != null ? value : defaultValue;
     }
 
+    /**
+     * Get a value from the config as a particular type.
+     *
+     * @param key The name of the config.
+     * @param clazz The Class of the type.
+     * @param <T> The type of the config.
+     * @return The config as the particular type or null.
+     * @throws ClassCastException if the value of the config could not be casted to the type.
+     */
+    public <T> T getAs(String key, Class<T> clazz) {
+        return clazz.cast(get(key));
+    }
+
+    /**
+     * Get a value from the config as a particular type or default to a provided value.
+     *
+     * @param key The name of the config.
+     * @param defaultValue A default of the same type to use if the config was not found.
+     * @param clazz The Class of the type.
+     * @param <T> The type of the config.
+     * @return The config or your default value as the particular type.
+     * @throws ClassCastException if the value of the config or default could not be casted to the type.
+     */
+    public <T> T getOrDefaultAs(String key, T defaultValue, Class<T> clazz) {
+        return clazz.cast(getOrDefault(key, defaultValue));
+    }
+
+    /**
+     * Get a value from the config as a particular type or throw an exception with a message if not found.
+     *
+     * @param key The name of the config.
+     * @param clazz The Class of the type.
+     * @param <T> The type of the config.
+     * @return The config as the particular type.
+     * @throws ClassCastException if the value of the config could not be casted to the type.
+     * @throws NullPointerException if the config was not found.
+     */
+    public <T> T getRequiredConfigAs(String key, Class<T> clazz) {
+        return Objects.requireNonNull(getAs(key, clazz), "Required value for " + key + " was missing");
+    }
+
     /**
      * Gets all mappings for a set of keys. If no keys are specified, all mappings
      * are returned.
@@ -152,15 +192,19 @@ public void clear() {
      *
      * @param yamlFile The String name of the YAML resource file in classpath or the path to a YAML file containing the mappings.
      * @return A {@link Map} of String names to Objects of the mappings in the YAML file.
-     * @throws IOException if the resource could not be read.
      */
-    protected Map<String, Object> readYAML(String yamlFile) throws IOException {
-        if (yamlFile != null && yamlFile.length() > 0) {
-            log.info("Loading configuration file: {}", yamlFile);
+    protected Map<String, Object> readYAML(String yamlFile) {
+        if (yamlFile == null || yamlFile.isEmpty()) {
+            return new HashMap<>();
+        }
+        log.info("Loading configuration file: {}", yamlFile);
+        try {
             InputStream is = this.getClass().getResourceAsStream("/" + yamlFile);
             Reader reader = (is != null ? new InputStreamReader(is) : new FileReader(yamlFile));
             return (Map<String, Object>) YAML.load(reader);
+        } catch (IOException ioe) {
+            log.error("Error loading configuration", ioe);
+            return new HashMap<>();
         }
-        return new HashMap<>();
     }
 }

src/main/java/com/yahoo/bullet/pubsub/Metadata.java

@@ -5,21 +5,59 @@
  */
 package com.yahoo.bullet.pubsub;
 
-import lombok.AllArgsConstructor;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
 import java.io.Serializable;
 
-@Getter @Setter @AllArgsConstructor @NoArgsConstructor
+@NoArgsConstructor
 public class Metadata implements Serializable {
     public enum Signal {
         ACKNOWLEDGE,
-        COMPLETE
+        COMPLETE,
+        FAIL
     }
+
+    private static final long serialVersionUID = 4234800234857923112L;
+
+    @Getter @Setter
     private Signal signal;
-    private Serializable content;
+
+    // This is a Serializable object enforced through the constructor, getter and setter. Storing it as an Object so
+    // GSON can reify an instance.
+    private Object content;
+
+    /**
+     * Allows you to create an instance with a {@link com.yahoo.bullet.pubsub.Metadata.Signal} and a
+     * {@link Serializable} object.
+     *
+     * @param signal The signal to set.
+     * @param object The object that is the metadata.
+     */
+    public Metadata(Signal signal, Serializable object) {
+        this.signal = signal;
+        this.content = object;
+    }
+
+    /**
+     * Set a serializable content for this metadata.
+     *
+     * @param content The content for this metadata.
+     */
+    public void setContent(Serializable content) {
+        this.content = content;
+    }
+
+    /**
+     * Returns the {@link Serializable} content in this metadata.
+     *
+     * @return The serializable content or null.
+     */
+    public Serializable getContent() {
+        return (Serializable) content;
+
+    }
 
     /**
      * Check if Metadata has content.
@@ -38,4 +76,14 @@ public boolean hasContent() {
     public boolean hasSignal() {
         return signal != null;
     }
+
+    /**
+     * Check if Metadata has the given signal.
+     *
+     * @param signal The signal to check against.
+     * @return true if message has {@link Metadata#signal}
+     */
+    public boolean hasSignal(Signal signal) {
+        return hasSignal() && this.signal == signal;
+    }
 }

src/main/java/com/yahoo/bullet/pubsub/PubSub.java

@@ -9,7 +9,6 @@
 
 import java.lang.reflect.Constructor;
 import java.util.List;
-import java.util.Objects;
 
 /**
  * Notation: Partition is a unit of parallelism in the Pub/Sub queue.
@@ -113,7 +112,7 @@ public static PubSub from(BulletConfig config) throws PubSubException {
      */
     public <T> T getRequiredConfig(Class<T> clazz, String name) throws PubSubException {
         try {
-            return clazz.cast(Objects.requireNonNull(config.get(name)));
+            return config.getRequiredConfigAs(name, clazz);
         } catch (Exception e) {
             throw PubSubException.forArgument(name, e);
         }

src/main/java/com/yahoo/bullet/pubsub/PubSubMessage.java

@@ -6,6 +6,7 @@
 package com.yahoo.bullet.pubsub;
 
 import com.yahoo.bullet.pubsub.Metadata.Signal;
+import com.yahoo.bullet.result.JSONFormatter;
 import lombok.Getter;
 
 import java.io.Serializable;
@@ -17,14 +18,21 @@
  * emitted by Bullet.
  */
 @Getter
-public class PubSubMessage implements Serializable {
+public class PubSubMessage implements Serializable, JSONFormatter {
     private static final long serialVersionUID = 2407848310969237888L;
 
     private String id;
     private int sequence;
     private String content;
     private Metadata metadata;
 
+    /**
+     * Constructor for a message having no information. Used internally. Not recommended for use.
+     */
+    public PubSubMessage() {
+        this("", null);
+    }
+
     /**
      * Constructor for a message having only content.
      *
@@ -62,14 +70,14 @@ public PubSubMessage(String id, String content, Metadata metadata) {
      *
      * @param id The ID associated with the message.
      * @param content The content of the message.
-     * @param signal The Metadata.Signal to be sent with the message.
+     * @param signal The Signal to be sent with the message.
      */
     public PubSubMessage(String id, String content, Signal signal) {
         this(id, content, signal, -1);
     }
 
     /**
-     * Constructor for a message having content, a {@link Metadata.Signal} and a sequence number.
+     * Constructor for a message having content, a {@link Signal} and a sequence number.
      *
      * @param id The ID associated with the message.
      * @param content The content of the message.
@@ -113,6 +121,25 @@ public boolean hasMetadata() {
         return metadata != null;
     }
 
+    /**
+     * Check if message has a given {@link Signal}.
+     *
+     * @param signal The signal to check for.
+     * @return true if message has the given signal.
+     */
+    public boolean hasSignal(Signal signal) {
+        return hasMetadata() && metadata.hasSignal(signal);
+    }
+
+    /**
+     * Check if the message has a {@link Signal}.
+     *
+     * @return true if message has a signal.
+     */
+    public boolean hasSignal() {
+        return hasMetadata() && metadata.hasSignal();
+    }
+
     @Override
     public int hashCode() {
         return (id + sequence).hashCode();
@@ -126,4 +153,24 @@ public boolean equals(Object other) {
         PubSubMessage otherMessage = (PubSubMessage) other;
         return id.equals(otherMessage.getId()) && sequence == otherMessage.getSequence();
     }
+
+    @Override
+    public String toString() {
+        return asJSON();
+    }
+
+    @Override
+    public String asJSON() {
+        return JSONFormatter.asJSON(this);
+    }
+
+    /**
+     * Converts a json representation back to an instance.
+     *
+     * @param json The string representation of the JSON.
+     * @return An instance of this class.
+     */
+    public static PubSubMessage fromJSON(String json) {
+        return JSONFormatter.fromJSON(json, PubSubMessage.class);
+    }
 }

src/main/java/com/yahoo/bullet/result/JSONFormatter.java

@@ -24,6 +24,18 @@ static String asJSON(Object object) {
         return GSON.toJson(object);
     }
 
+    /**
+     * Returns a deserialized object from JSON using {@link JSONFormatter#GSON}.
+     *
+     * @param json The String json that represents the object.
+     * @param clazz The class of the object.
+     * @param <T> The type of the object. It must implement {@link JSONFormatter}.
+     * @return An instance of the object deserialized from JSON.
+     */
+    static <T extends JSONFormatter> T fromJSON(String json, Class<T> clazz) {
+        return GSON.fromJson(json, clazz);
+    }
+
     /**
      * Convert this object to a JSON string.
      * @return The JSON representation of this.