New Dynamic Model pattern to support type-checked additional properties

src/main/java/com/ibm/cloud/sdk/core/service/model/DynamicModel.java

@@ -1,14 +1,103 @@
 package com.ibm.cloud.sdk.core.service.model;
 
 import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
 
+import com.google.gson.reflect.TypeToken;
 import com.ibm.cloud.sdk.core.util.GsonSingleton;
 
 /**
- * Abstract model class for objects which may have dynamic properties attached to them,
- * which is represented with an internal map.
+ * Abstract model class for a model which supports dynamic (arbitrary) properties of type T.
  */
-public abstract class DynamicModel extends HashMap<String, Object> implements ObjectModel {
+public abstract class DynamicModel<T> implements ObjectModel {
+  private TypeToken<T> additionalPropertyTypeToken;
+
+  // The set of dynamic properties associated with this object.
+  private Map<String, T> dynamicProperties = new HashMap<>();
+
+  /**
+   * Force use of 1-arg ctor.
+   */
+  @SuppressWarnings("unused")
+  private DynamicModel() {
+  }
+
+  /**
+   * This ctor accepts a TypeToken instance that represents the type of values stored in the map.
+   *
+   * @param t
+   *          the TypeToken which represents the type of map values
+   */
+  public DynamicModel(TypeToken<T> t) {
+    this.additionalPropertyTypeToken = t;
+  }
+
+  /**
+   * Returns the TypeToken which describes the type of additional properties stored in the map.
+   * @return The TypeToken which describes the map value type
+   */
+  public TypeToken<T> getAdditionalPropertyTypeToken() {
+    return this.additionalPropertyTypeToken;
+  }
+
+  /**
+   * Sets an arbitrary property.
+   *
+   * @param key
+   *          the name of the property to set
+   * @param value
+   *          the value of the property to be set
+   * @return the previous value of the property, or null if the property was not previously set
+   */
+  public T setProperty(String key, T value) {
+    return this.dynamicProperties.put(key, value);
+  }
+
+  /**
+   * Returns the value of the specified property.
+   *
+   * @param key
+   *          the name of the property to get
+   * @return the value of the property, or null if the property is not set
+   */
+  public T getProperty(String key) {
+    return this.dynamicProperties.get(key);
+  }
+
+  /**
+   * Returns a map containing the arbitrary properties set on this object.
+   *
+   * @return a copy of the map containing arbitrary properties set on this object
+   */
+  public Map<String, T> getProperties() {
+    return new HashMap<String, T>(this.dynamicProperties);
+  }
+
+  /**
+   * Returns the names of arbitrary properties set on this object.
+   * @return a set containing the names of arbitrary properties set on this object
+   */
+  public Set<String> getPropertyNames() {
+    return this.dynamicProperties.keySet();
+  }
+  /**
+   * Removes the specified property from this object's map of arbitrary properties.
+   *
+   * @param key
+   *          the name of the property to be removed
+   * @return the previous value of the property, or null if the property was not previously set
+   */
+  public T removeProperty(String key) {
+    return this.dynamicProperties.remove(key);
+  }
+
+  /**
+   * Removes all of the arbitrary properties set on this object.
+   */
+  public void removeProperties() {
+    this.dynamicProperties.clear();
+  }
 
   /*
    * (non-Javadoc)
@@ -23,7 +112,7 @@ public boolean equals(Object o) {
       return false;
     }
 
-    final DynamicModel other = (DynamicModel) o;
+    final DynamicModel<?> other = (DynamicModel<?>) o;
 
     return toString().equals(other.toString());
   }