Updates for supporting the Android API

JSONWriter.java

@@ -1,6 +1,9 @@
 package org.json;
 
 import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.Collection;
+import java.util.Map;
 
 /*
 Copyright (c) 2006 JSON.org
@@ -117,6 +120,9 @@ public class JSONWriter {
                 }
                 this.writer.append(string);
             } catch (IOException e) {
+            	// Android as of API 25 does not support this exception constructor
+            	// however we won't worry about it. If an exception is happening here
+            	// it will just throw a "Method not found" exception instead.
                 throw new JSONException(e);
             }
             if (this.mode == 'o') {
@@ -164,6 +170,9 @@ public class JSONWriter {
         try {
             this.writer.append(c);
         } catch (IOException e) {
+        	// Android as of API 25 does not support this exception constructor
+        	// however we won't worry about it. If an exception is happening here
+        	// it will just throw a "Method not found" exception instead.
             throw new JSONException(e);
         }
         this.comma = true;
@@ -204,7 +213,12 @@ public class JSONWriter {
         }
         if (this.mode == 'k') {
             try {
-                this.stack[this.top - 1].putOnce(string, Boolean.TRUE);
+                JSONObject topObject = this.stack[this.top - 1];
+                // don't use the built in putOnce method to maintain Android support
+				if(topObject.has(string)) {
+					throw new JSONException("Duplicate key \"" + string + "\"");
+				}
+                topObject.put(string, true);
                 if (this.comma) {
                     this.writer.append(',');
                 }
@@ -214,6 +228,9 @@ public class JSONWriter {
                 this.mode = 'o';
                 return this;
             } catch (IOException e) {
+            	// Android as of API 25 does not support this exception constructor
+            	// however we won't worry about it. If an exception is happening here
+            	// it will just throw a "Method not found" exception instead.
                 throw new JSONException(e);
             }
         }
@@ -280,6 +297,81 @@ public class JSONWriter {
         this.top += 1;
     }
 
+    /**
+     * Make a JSON text of an Object value. If the object has an
+     * value.toJSONString() method, then that method will be used to produce the
+     * JSON text. The method is required to produce a strictly conforming text.
+     * If the object does not contain a toJSONString method (which is the most
+     * common case), then a text will be produced by other means. If the value
+     * is an array or Collection, then a JSONArray will be made from it and its
+     * toJSONString method will be called. If the value is a MAP, then a
+     * JSONObject will be made from it and its toJSONString method will be
+     * called. Otherwise, the value's toString method will be called, and the
+     * result will be quoted.
+     *
+     * <p>
+     * Warning: This method assumes that the data structure is acyclical.
+     *
+     * @param value
+     *            The value to be serialized.
+     * @return a printable, displayable, transmittable representation of the
+     *         object, beginning with <code>{</code>&nbsp;<small>(left
+     *         brace)</small> and ending with <code>}</code>&nbsp;<small>(right
+     *         brace)</small>.
+     * @throws JSONException
+     *             If the value is or contains an invalid number.
+     */
+    public static String valueToString(Object value) throws JSONException {
+        if (value == null || value.equals(null)) {
+            return "null";
+        }
+        if (value instanceof JSONString) {
+            Object object;
+            try {
+                object = ((JSONString) value).toJSONString();
+            } catch (Exception e) {
+                throw new JSONException(e);
+            }
+            if (object instanceof String) {
+                return (String) object;
+            }
+            throw new JSONException("Bad value from toJSONString: " + object);
+        }
+        if (value instanceof Number) {
+            // not all Numbers may match actual JSON Numbers. i.e. Fractions or Complex
+            final String numberAsString = JSONObject.numberToString((Number) value);
+            try {
+                // Use the BigDecimal constructor for it's parser to validate the format.
+                @SuppressWarnings("unused")
+                BigDecimal unused = new BigDecimal(numberAsString);
+                // Close enough to a JSON number that we will return it unquoted
+                return numberAsString;
+            } catch (NumberFormatException ex){
+                // The Number value is not a valid JSON number.
+                // Instead we will quote it as a string
+                return JSONObject.quote(numberAsString);
+            }
+        }
+        if (value instanceof Boolean || value instanceof JSONObject
+                || value instanceof JSONArray) {
+            return value.toString();
+        }
+        if (value instanceof Map) {
+            Map<?, ?> map = (Map<?, ?>) value;
+            return new JSONObject(map).toString();
+        }
+        if (value instanceof Collection) {
+            Collection<?> coll = (Collection<?>) value;
+            return new JSONArray(coll).toString();
+        }
+        if (value.getClass().isArray()) {
+            return new JSONArray(value).toString();
+        }
+        if(value instanceof Enum<?>){
+            return JSONObject.quote(((Enum<?>)value).name());
+        }
+        return JSONObject.quote(value.toString());
+    }
 
     /**
      * Append either the value <code>true</code> or the value
@@ -321,6 +413,6 @@ public class JSONWriter {
      * @throws JSONException If the value is out of sequence.
      */
     public JSONWriter value(Object object) throws JSONException {
-        return this.append(JSONObject.valueToString(object));
+        return this.append(valueToString(object));
     }
 }