org.waterken.syntax.json
Class JSONWriter

java.lang.Object
  org.waterken.syntax.json.JSONWriter

public final class JSONWriter
extends java.lang.Object

A SAX-like API for generating JSON text.

A client can only output a syntactically correct JSON text, or leave the JSONWriter in a detectable error state. The implementation does not enforce the constraint that names within an object SHOULD be unique.

For example, to output the JSON text:

 {
   "title" : "I Can Has Cheezburger?",
   "src" : { "@" : "http://www.example.com/image/481989943" },
   "height" : 125,
   "width" : 100,
   "tags" : [ "lolcat", "food" ],
   "score" : 9.5
 }
 

, write code:

 final Writer text = …
 final JSONWriter top = JSONWriter.make(text);
 final JSONWriter.ObjectWriter o = top.startObject();
 o.startMember("title").writeString("I Can Has Cheezburger?");
 o.startMember("src").writeLink("http://www.example.com/image/481989943");
 o.startMember("height").writeInt(125);
 o.startMember("width").writeInt(100);
 final JSONWriter.ArrayWriter tags = o.startMember("tags").startArray();
 tags.startElement().writeString("lolcat");
 tags.startElement().writeString("food");
 tags.finish();
 o.startMember("score").writeDouble(9.5);
 o.finish();
 if (!top.isWritten()) { throw new NullPointerException(); }
 text.flush();
 text.close();
 

An invalid sequence of calls to this API will cause a NullPointerException to be thrown. For example, calling writeString() twice in succession will throw a NullPointerException.

Nested Class Summary

class	JSONWriter.ArrayWriter A JSON array writer.
class	JSONWriter.ObjectWriter A JSON object writer.

Field Summary

static long	maxMagnitude maximum magnitude of a JavaScript number: 9007199254740992L
static java.lang.ArithmeticException	NaN Signals a number that cannot be represented in JavaScript.

Method Summary

boolean	isWritten()
static JSONWriter	make(java.io.Writer out) Constructs a JSON writer.
JSONWriter.ArrayWriter	startArray()
JSONWriter.ObjectWriter	startObject()
void	writeBoolean(boolean value)
void	writeDouble(double value)
void	writeFloat(float value)
void	writeInt(int value)
void	writeLink(java.lang.String URL)
void	writeLong(long value)
void	writeNull()
void	writeString(java.lang.String value)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

maxMagnitude

public static final long maxMagnitude

maximum magnitude of a JavaScript number: 9007199254740992L

See Also:

Constant Field Values

NaN

public static final java.lang.ArithmeticException NaN

Signals a number that cannot be represented in JavaScript.

Method Detail

make

public static JSONWriter make(java.io.Writer out)

Constructs a JSON writer.

Parameters:

out - UTF-8 output stream

isWritten

public boolean isWritten()

Returns:

true if a single JSON value was successfully written, else false

startObject

public JSONWriter.ObjectWriter startObject()
                                    throws java.io.IOException

Throws:

java.io.IOException

startArray

public JSONWriter.ArrayWriter startArray()
                                  throws java.io.IOException

Throws:

java.io.IOException

writeLink

public void writeLink(java.lang.String URL)
               throws java.io.IOException

Throws:

java.io.IOException

writeNull

public void writeNull()
               throws java.io.IOException

Throws:

java.io.IOException

writeBoolean

public void writeBoolean(boolean value)
                  throws java.io.IOException

Throws:

java.io.IOException

writeInt

public void writeInt(int value)
              throws java.io.IOException

Throws:

java.io.IOException

writeLong

public void writeLong(long value)
               throws java.lang.ArithmeticException,
                      java.io.IOException

Throws:

java.lang.ArithmeticException

java.io.IOException

writeFloat

public void writeFloat(float value)
                throws java.lang.ArithmeticException,
                       java.io.IOException

Throws:

java.lang.ArithmeticException

java.io.IOException

writeDouble

public void writeDouble(double value)
                 throws java.lang.ArithmeticException,
                        java.io.IOException

Throws:

java.lang.ArithmeticException

java.io.IOException

writeString

public void writeString(java.lang.String value)
                 throws java.io.IOException

Throws:

java.io.IOException