org.jmxtrans.agent.util.json

Class JsonHandler<A,O>

java.lang.Object

org.jmxtrans.agent.util.json.JsonHandler<A,O>

Type Parameters:

A - The type of handlers used for JSON arrays

O - The type of handlers used for JSON objects

public abstract class JsonHandler<A,O>
extends java.lang.Object

A handler for parser events. Instances of this class can be given to a JsonParser. The parser will then call the methods of the given handler while reading the input.

The default implementations of these methods do nothing. Subclasses may override only those methods they are interested in. They can use getLocation() to access the current character position of the parser at any point. The start* methods will be called while the location points to the first character of the parsed element. The end* methods will be called while the location points to the character position that directly follows the last character of the parsed element. Example:

 ["lorem ipsum"]
  ^            ^
  startString  endString
 

Subclasses that build an object representation of the parsed JSON can return arbitrary handler objects for JSON arrays and JSON objects in startArray() and startObject(). These handler objects will then be provided in all subsequent parser events for this particular array or object. They can be used to keep track the elements of a JSON array or object.

See Also:

JsonParser

Constructor Summary

Constructors

Constructor and Description
JsonHandler()

Method Summary

Modifier and Type	Method and Description
void	endArray(A array) Indicates the end of an array in the JSON input.
void	endArrayValue(A array) Indicates the end of an array element in the JSON input.
void	endBoolean(boolean value) Indicates the end of a boolean literal (true or false) in the JSON input.
void	endNull() Indicates the end of a null literal in the JSON input.
void	endNumber(java.lang.String string) Indicates the end of a number in the JSON input.
void	endObject(O object) Indicates the end of an object in the JSON input.
void	endObjectName(O object, java.lang.String name) Indicates the end of an object member name in the JSON input.
void	endObjectValue(O object, java.lang.String name) Indicates the end of an object member value in the JSON input.
void	endString(java.lang.String string) Indicates the end of a string in the JSON input.
protected Location	getLocation() Returns the current parser location.
A	startArray() Indicates the beginning of an array in the JSON input.
void	startArrayValue(A array) Indicates the beginning of an array element in the JSON input.
void	startBoolean() Indicates the beginning of a boolean literal (true or false) in the JSON input.
void	startNull() Indicates the beginning of a null literal in the JSON input.
void	startNumber() Indicates the beginning of a number in the JSON input.
O	startObject() Indicates the beginning of an object in the JSON input.
void	startObjectName(O object) Indicates the beginning of the name of an object member in the JSON input.
void	startObjectValue(O object, java.lang.String name) Indicates the beginning of the name of an object member in the JSON input.
void	startString() Indicates the beginning of a string in the JSON input.

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonHandler

public JsonHandler()

Method Detail

getLocation

protected Location getLocation()

Returns the current parser location.

Returns:

the current parser location

startNull

public void startNull()

Indicates the beginning of a null literal in the JSON input. This method will be called when reading the first character of the literal.

endNull

public void endNull()

Indicates the end of a null literal in the JSON input. This method will be called after reading the last character of the literal.

startBoolean

public void startBoolean()

Indicates the beginning of a boolean literal (true or false) in the JSON input. This method will be called when reading the first character of the literal.

endBoolean

public void endBoolean(boolean value)

Indicates the end of a boolean literal (true or false) in the JSON input. This method will be called after reading the last character of the literal.

Parameters:

value - the parsed boolean value

startString

public void startString()

Indicates the beginning of a string in the JSON input. This method will be called when reading the opening double quote character ('"').

endString

public void endString(java.lang.String string)

Indicates the end of a string in the JSON input. This method will be called after reading the closing double quote character ('"').

Parameters:

string - the parsed string

startNumber

public void startNumber()

Indicates the beginning of a number in the JSON input. This method will be called when reading the first character of the number.

endNumber

public void endNumber(java.lang.String string)

Indicates the end of a number in the JSON input. This method will be called after reading the last character of the number.

Parameters:

string - the parsed number string

startArray

public A startArray()

Indicates the beginning of an array in the JSON input. This method will be called when reading the opening square bracket character ('[').

This method may return an object to handle subsequent parser events for this array. This array handler will then be provided in all calls to startArrayValue(), endArrayValue(), and endArray() for this array.

Returns:

a handler for this array, or null if not needed

endArray

public void endArray(A array)

Indicates the end of an array in the JSON input. This method will be called after reading the closing square bracket character (']').

Parameters:

array - the array handler returned from startArray(), or null if not provided

startArrayValue

public void startArrayValue(A array)

Indicates the beginning of an array element in the JSON input. This method will be called when reading the first character of the element, just before the call to the start method for the specific element type (startString(), startNumber(), etc.).

Parameters:

array - the array handler returned from startArray(), or null if not provided

endArrayValue

public void endArrayValue(A array)

Indicates the end of an array element in the JSON input. This method will be called after reading the last character of the element value, just after the end method for the specific element type (like endString(), endNumber(), etc.).

Parameters:

array - the array handler returned from startArray(), or null if not provided

startObject

public O startObject()

Indicates the beginning of an object in the JSON input. This method will be called when reading the opening curly bracket character ('{').

This method may return an object to handle subsequent parser events for this object. This object handler will be provided in all calls to startObjectName(), endObjectName(), startObjectValue(), endObjectValue(), and endObject() for this object.

Returns:

a handler for this object, or null if not needed

endObject

public void endObject(O object)

Indicates the end of an object in the JSON input. This method will be called after reading the closing curly bracket character ('}').

Parameters:

object - the object handler returned from startObject(), or null if not provided

startObjectName

public void startObjectName(O object)

Indicates the beginning of the name of an object member in the JSON input. This method will be called when reading the opening quote character ('"') of the member name.

Parameters:

object - the object handler returned from startObject(), or null if not provided

endObjectName

public void endObjectName(O object,
                          java.lang.String name)

Indicates the end of an object member name in the JSON input. This method will be called after reading the closing quote character ('"') of the member name.

Parameters:

object - the object handler returned from startObject(), or null if not provided

name - the parsed member name

startObjectValue

public void startObjectValue(O object,
                             java.lang.String name)

Indicates the beginning of the name of an object member in the JSON input. This method will be called when reading the opening quote character ('"') of the member name.

Parameters:

object - the object handler returned from startObject(), or null if not provided

name - the member name

endObjectValue

public void endObjectValue(O object,
                           java.lang.String name)

Indicates the end of an object member value in the JSON input. This method will be called after reading the last character of the member value, just after the end method for the specific member type (like endString(), endNumber(), etc.).

Parameters:

object - the object handler returned from startObject(), or null if not provided

name - the parsed member name