Package org.grails.web.json

Class JSONWriter

  • Direct Known Subclasses:
    PathCapturingJSONWriterWrapper, PrettyPrintJSONWriter
    public class JSONWriter
extends java.lang.Object
    JSONWriter provides a quick and convenient way of producing JSON text. The texts produced strictly conform to JSON syntax rules. No whitespace is added, so the results are ready for transmission or storage. Each instance of JSONWriter can produce one JSON text.

    A JSONWriter instance provides a value method for appending values to the text, and a key method for adding keys before values in objects. There are array and endArray methods that make and bound array values, and object and endObject methods which make and bound object values. All of these methods return the JSONWriter instance, permitting a cascade style. For example, 

     new JSONWriter(myWriter)
     .object()
         .key("JSON")
         .value("Hello, World!")
     .endObject();
    which writes 
     {"JSON":"Hello, World!"}

    The first method called must be array or object. There are no methods for adding commas or colons. JSONWriter adds them for you. Objects and arrays can be nested up to 20 levels deep.

    This can sometimes be easier than using a JSONObject to build a string.

    • Field Detail

      • comma

        protected boolean comma
        The comma flag determines if a comma should be output before the next value.

      • writer

        protected java.io.Writer writer
        The writer that will receive the output.

    • Constructor Detail

      • JSONWriter

        public JSONWriter​(java.io.Writer w)
        Make a fresh JSONWriter. It can be used to build one JSON text.

    • Method Detail

      • append

        protected JSONWriter append​(java.lang.String s)
        Append a value.
        Parameters:
        s - A string value.
        Returns:
        this

      • append

        protected JSONWriter append​(groovy.lang.Writable writableValue)

      • comma

        protected void comma()

      • array

        public JSONWriter array()
        Begin appending a new array. All values until the balancing endArray will be appended to this array. The endArray method must be called to mark the array's end.
        Returns:
        this

      • end

        protected JSONWriter end​(JSONWriter.Mode m,
                         char c)
        End something.
        Parameters:
        m - Mode
        c - Closing character
        Returns:
        this

      • endArray

        public JSONWriter endArray()
        End an array. This method most be called to balance calls to array.
        Returns:
        this

      • endObject

        public JSONWriter endObject()
        End an object. This method most be called to balance calls to object.
        Returns:
        this

      • key

        public JSONWriter key​(java.lang.String s)
        Append a key. The key will be associated with the next value. In an object, every value must be preceded by a key.
        Parameters:
        s - A key string.
        Returns:
        this

      • object

        public JSONWriter object()
        Begin appending a new object. All keys and values until the balancing endObject will be appended to this object. The endObject method must be called to mark the object's end.
        Returns:
        this

      • pop

        protected void pop​(JSONWriter.Mode c)
        Pop an array or object scope.
        Parameters:
        c - The scope to close.

      • push

        protected void push​(JSONWriter.Mode c)
        Push an array or object scope.
        Parameters:
        c - The scope to open.

      • value

        public JSONWriter value​(boolean b)
        Append either the value true or the value false.
        Parameters:
        b - A boolean.
        Returns:
        this

      • value

        public JSONWriter value​(double d)
        Append a double value.
        Parameters:
        d - A double.
        Returns:
        this

      • value

        public JSONWriter value​(long l)
        Append a long value.
        Parameters:
        l - A long.
        Returns:
        this

      • value

        public JSONWriter value​(java.lang.Number number)
        Append a number value
        Parameters:
        number -
        Returns:

      • value

        public JSONWriter value​(java.lang.Object o)
        Append an object value.
        Parameters:
        o - The object to append. It can be null, or a Boolean, Number, String, JSONObject, or JSONArray.
        Returns:
        this