Merge pull request stleary#140 from douglascrockford/enum-support

stleary · stleary · commit ce2de45f648d · 2015-07-28T19:33:29.000-05:00
Enum support
diff --git a/JSONArray.java b/JSONArray.java
@@ -76,7 +76,7 @@ of this software and associated documentation files (the "Software"), to deal
  * </ul>
  *
  * @author JSON.org
- * @version 2015-07-06
+ * @version 2015-07-22
  */
 public class JSONArray implements Iterable<Object> {
 
@@ -247,6 +247,31 @@ public double getDouble(int index) throws JSONException {
         }
     }
 
+    /**
+    * Get the enum value associated with an index.
+    * 
+    * @param clazz
+    *            The type of enum to retrieve.
+    * @param index
+    *            The index must be between 0 and length() - 1.
+    * @return The enum value at the index location
+    * @throws JSONException
+    *            if the key is not found or if the value cannot be converted
+    *            to an enum.
+    */
+    public <E extends Enum<E>> E getEnum(Class<E> clazz, int index) throws JSONException {
+        E val = optEnum(clazz, index);
+        if(val==null) {
+            // JSONException should really take a throwable argument.
+            // If it did, I would re-implement this with the Enum.valueOf
+            // method and place any thrown exception in the JSONException
+            throw new JSONException("JSONObject[" + JSONObject.quote(Integer.toString(index))
+                    + "] is not an enum of type " + JSONObject.quote(clazz.getSimpleName())
+                    + ".");
+        }
+        return val;
+    }
+
     /**
      * Get the BigDecimal value associated with an index.
      *
@@ -531,6 +556,50 @@ public int optInt(int index, int defaultValue) {
         }
     }
 
+    /**
+     * Get the enum value associated with a key.
+     * 
+     * @param clazz
+     *            The type of enum to retrieve.
+     * @param index
+     *            The index must be between 0 and length() - 1.
+     * @return The enum value at the index location or null if not found
+     */
+    public <E extends Enum<E>> E optEnum(Class<E> clazz, int index) {
+        return this.optEnum(clazz, index, null);
+    }
+
+    /**
+     * Get the enum value associated with a key.
+     * 
+     * @param clazz
+     *            The type of enum to retrieve.
+     * @param index
+     *            The index must be between 0 and length() - 1.
+     * @param defaultValue
+     *            The default in case the value is not found
+     * @return The enum value at the index location or defaultValue if
+     *            the value is not found or cannot be assigned to clazz
+     */
+    public <E extends Enum<E>> E optEnum(Class<E> clazz, int index, E defaultValue) {
+        try {
+            Object val = this.opt(index);
+            if (JSONObject.NULL.equals(val)) {
+                return defaultValue;
+            }
+            if (clazz.isAssignableFrom(val.getClass())) {
+                // we just checked it!
+                @SuppressWarnings("unchecked")
+                E myE = (E) val;
+                return myE;
+            }
+            return Enum.valueOf(clazz, val.toString());
+        } catch (IllegalArgumentException | NullPointerException e) {
+            return defaultValue;
+        }
+    }
+
+
     /**
      * Get the optional BigInteger value associated with an index. The 
      * defaultValue is returned if there is no value for the index, or if the 
diff --git a/JSONObject.java b/JSONObject.java
@@ -92,7 +92,7 @@ of this software and associated documentation files (the "Software"), to deal
  * </ul>
  *
  * @author JSON.org
- * @version 2015-07-06
+ * @version 2015-07-22
  */
 public class JSONObject {
     /**
@@ -479,6 +479,31 @@ public Object get(String key) throws JSONException {
         return object;
     }
 
+    /**
+    * Get the enum value associated with a key.
+    * 
+    * @param clazz
+    *           The type of enum to retrieve.
+    * @param key
+    *           A key string.
+    * @return The enum value associated with the key
+    * @throws JSONException
+    *             if the key is not found or if the value cannot be converted
+    *             to an enum.
+    */
+    public <E extends Enum<E>> E getEnum(Class<E> clazz, String key) throws JSONException {
+        E val = optEnum(clazz, key);
+        if(val==null) {
+            // JSONException should really take a throwable argument.
+            // If it did, I would re-implement this with the Enum.valueOf
+            // method and place any thrown exception in the JSONException
+            throw new JSONException("JSONObject[" + quote(key)
+                    + "] is not an enum of type " + quote(clazz.getSimpleName())
+                    + ".");
+        }
+        return val;
+    }
+
     /**
      * Get the boolean value associated with a key.
      *
@@ -844,6 +869,49 @@ public Object opt(String key) {
         return key == null ? null : this.map.get(key);
     }
 
+    /**
+     * Get the enum value associated with a key.
+     * 
+     * @param clazz
+     *            The type of enum to retrieve.
+     * @param key
+     *            A key string.
+     * @return The enum value associated with the key or null if not found
+     */
+    public <E extends Enum<E>> E optEnum(Class<E> clazz, String key) {
+        return this.optEnum(clazz, key, null);
+    }
+
+    /**
+     * Get the enum value associated with a key.
+     * 
+     * @param clazz
+     *            The type of enum to retrieve.
+     * @param key
+     *            A key string.
+     * @param defaultValue
+     *            The default in case the value is not found
+     * @return The enum value associated with the key or defaultValue
+     *            if the value is not found or cannot be assigned to clazz
+     */
+    public <E extends Enum<E>> E optEnum(Class<E> clazz, String key, E defaultValue) {
+        try {
+            Object val = this.opt(key);
+            if (NULL.equals(val)) {
+                return defaultValue;
+            }
+            if (clazz.isAssignableFrom(val.getClass())) {
+                // we just checked it!
+                @SuppressWarnings("unchecked")
+                E myE = (E) val;
+                return myE;
+            }
+            return Enum.valueOf(clazz, val.toString());
+        } catch (IllegalArgumentException | NullPointerException e) {
+            return defaultValue;
+        }
+    }
+
     /**
      * Get an optional boolean associated with a key. It returns false if there
      * is no such key, or if the value is not Boolean.TRUE or the String "true".
