AbstractJsonWriter (XStream Core 1.4.9 API)

java.lang.Object
- com.thoughtworks.xstream.io.AbstractWriter
- - com.thoughtworks.xstream.io.json.AbstractJsonWriter

All Implemented Interfaces:

ExtendedHierarchicalStreamWriter, HierarchicalStreamWriter

Direct Known Subclasses:

JsonWriter
```
public abstract class AbstractJsonWriter
extends AbstractWriter
```
An abstract implementation of a writer that calls abstract methods to build JSON structures. Note, that XStream's implicit collection feature is only compatible with the syntax in EXPLICIT_MODE.

Since:

1.4

Author:

Jörg Schaible

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class AbstractJsonWriter.Type

Nested Classes
Modifier and Type	Class and Description
`static class`	`AbstractJsonWriter.Type`

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`DROP_ROOT_MODE` DROP_ROOT_MODE drops the JSON root node.
`static int`	`EXPLICIT_MODE` EXPLICIT_MODE assures that all data has its explicit equivalent in the resulting JSON.
`static int`	`IEEE_754_MODE` IEEE_754_MODE keeps precision of 64-bit integer values.
`static int`	`STRICT_MODE` STRICT_MODE prevents invalid JSON for single value objects when dropping the root.

Constructor Summary

Constructors
Constructor and Description
`AbstractJsonWriter()` Construct a JSON writer.
`AbstractJsonWriter(int mode)` Construct a JSON writer with a special mode.
`AbstractJsonWriter(int mode, NameCoder nameCoder)` Construct a JSON writer with a special mode and name coder.
`AbstractJsonWriter(NameCoder nameCoder)` Construct a JSON writer with a special name coder.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addAttribute(String name, String value)`
`protected abstract void`	`addLabel(String name)` Add a label to a JSON object.
`protected abstract void`	`addValue(String value, AbstractJsonWriter.Type type)` Add a value to a JSON object's label or to an array.
`protected abstract void`	`endArray()` End the JSON array.
`void`	`endNode()`
`protected abstract void`	`endObject()` End the JSON object.
`protected AbstractJsonWriter.Type`	`getType(Class clazz)` Method to return the appropriate JSON type for a Java type.
`protected boolean`	`isArray(Class clazz)` Method to declare various Java types to be handles as JSON array.
`protected abstract void`	`nextElement()` Prepare a JSON object or array for another element.
`void`	`setValue(String text)` Write the value (text content) of the current node.
`protected abstract void`	`startArray()` Start a JSON array.
`void`	`startNode(String name)`
`void`	`startNode(String name, Class clazz)`
`protected abstract void`	`startObject()` Start a JSON object.

Methods inherited from class com.thoughtworks.xstream.io.AbstractWriter
encodeAttribute, encodeNode, underlyingWriter

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.thoughtworks.xstream.io.HierarchicalStreamWriter
close, flush

- Field Detail
  - DROP_ROOT_MODE
```
public static final int DROP_ROOT_MODE
```
    DROP_ROOT_MODE drops the JSON root node.
    The root node is the first level of the JSON object i.e.
```
 { "person": {
     "name": "Joe"
 }}
 
```
    will be written without root simply as
```
 {
     "name": "Joe"
 }
 
```
    Without a root node, the top level element might now also be an array. However, it is possible to generate invalid JSON unless STRICT_MODE is also set.
    Since:
    
    1.3.1
    
    See Also:
    
    Constant Field Values
  - STRICT_MODE
```
public static final int STRICT_MODE
```
    STRICT_MODE prevents invalid JSON for single value objects when dropping the root.
    The mode is only useful in combination with the DROP_ROOT_MODE. An object with a single value as first node i.e.
```
 { "name": "Joe" }
 
```
    is simply written as
```
 "Joe"
 
```
    However, this is no longer valid JSON. Therefore you can activate STRICT_MODE and a ConversionException is thrown instead.
    Since:
    
    1.3.1
    
    See Also:
    
    Constant Field Values
  - EXPLICIT_MODE
```
public static final int EXPLICIT_MODE
```
    EXPLICIT_MODE assures that all data has its explicit equivalent in the resulting JSON.
    XStream is normally using attributes in XML that have no real equivalent in JSON. Additionally it is essential in XML that the individual child elements of a tag keep order and may have the same tag name. XStream's model relies on both characteristics. However, properties of a JSON object do not have a defined order, but their names have to be unique. Only a JSON array defines the order of its elements.
    
    Therefore XStream uses in explicit mode a JSON format that supports the original requirements at the expense of the simplicity of the JSON objects and arrays. Each Java object will be represented by a JSON object with a single property representing the name of the object and an array as value that contains two more arrays. The first one contains a JSON object with all attributes, the second one the value of the Java object which can be null, a string or integer value or again a new JSON object representing a Java object. Here an example of an string array with one member, where the array and the string has an additional attribute 'id':
```
 {"string-array":[[{"id":"1"}],[{"string":[[{"id":"2"}],["Joe"]]}]]}
 
```
    This format can be used to always deserialize into Java again.
    
    This mode cannot combined with STRICT_MODE or DROP_ROOT_MODE.
    Since:
    
    1.4
    
    See Also:
    
    Constant Field Values
  - IEEE_754_MODE
```
public static final int IEEE_754_MODE
```
    IEEE_754_MODE keeps precision of 64-bit integer values.
    In JavaScript every number is expressed as 64-bit double value with a precision of 53 bits following IEEE 754. Therefore it is not possible to represent the complete value range of 64-bit integer values. Any integer value > 2⁵³ (9007199254740992) or < -2⁵³ (-9007199254740992) will therefore be written as string value.
    
    CAUTION: A client must be aware that the element may contain a number or a string value.
    
    Since:
    
    1.4.5
    
    See Also:
    
    ECMA Specification: The Number Type, Constant Field Values
- Constructor Detail
  - AbstractJsonWriter
```
public AbstractJsonWriter()
```
    Construct a JSON writer.
    
    Since:
    
    1.4
  - AbstractJsonWriter
```
public AbstractJsonWriter(int mode)
```
    Construct a JSON writer with a special mode.
    
    Parameters:
    
    mode - a bit mask of the mode constants
    
    Since:
    
    1.4
  - AbstractJsonWriter
```
public AbstractJsonWriter(NameCoder nameCoder)
```
    Construct a JSON writer with a special name coder.
    
    Parameters:
    
    nameCoder - the name coder to use
    
    Since:
    
    1.4
  - AbstractJsonWriter
```
public AbstractJsonWriter(int mode,
                          NameCoder nameCoder)
```
    Construct a JSON writer with a special mode and name coder.
    
    Parameters:
    
    mode - a bit mask of the mode constants
    
    nameCoder - the name coder to use
    
    Since:
    
    1.4
- Method Detail
  - startNode
```
public void startNode(String name,
                      Class clazz)
```
    Description copied from class: AbstractWriter
    
    Specified by:
    
    startNode in interface ExtendedHierarchicalStreamWriter
    
    Overrides:
    
    startNode in class AbstractWriter
  - startNode
```
public void startNode(String name)
```
  - addAttribute
```
public void addAttribute(String name,
                         String value)
```
  - setValue
```
public void setValue(String text)
```
    Description copied from interface: HierarchicalStreamWriter
    
    Write the value (text content) of the current node.
  - endNode
```
public void endNode()
```
  - getType
```
protected AbstractJsonWriter.Type getType(Class clazz)
```
    Method to return the appropriate JSON type for a Java type.
    
    Parameters:
    
    clazz - the type
    
    Returns:
    
    One of the AbstractJsonWriter.Type instances
    
    Since:
    
    1.4.4
  - isArray
```
protected boolean isArray(Class clazz)
```
    Method to declare various Java types to be handles as JSON array.
    
    Parameters:
    
    clazz - the type
    
    Returns:
    
    true if handles as array
    
    Since:
    
    1.4
  - startObject
```
protected abstract void startObject()
```
    Start a JSON object.
    
    Since:
    
    1.4
  - addLabel
```
protected abstract void addLabel(String name)
```
    Add a label to a JSON object.
    
    Parameters:
    
    name - the label's name
    
    Since:
    
    1.4
  - addValue
```
protected abstract void addValue(String value,
                                 AbstractJsonWriter.Type type)
```
    Add a value to a JSON object's label or to an array.
    
    Parameters:
    
    value - the value itself
    
    type - the JSON type
    
    Since:
    
    1.4
  - startArray
```
protected abstract void startArray()
```
    Start a JSON array.
    
    Since:
    
    1.4
  - nextElement
```
protected abstract void nextElement()
```
    Prepare a JSON object or array for another element.
    
    Since:
    
    1.4
  - endArray
```
protected abstract void endArray()
```
    End the JSON array.
    
    Since:
    
    1.4
  - endObject
```
protected abstract void endObject()
```
    End the JSON object.
    
    Since:
    
    1.4

Class AbstractJsonWriter

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.thoughtworks.xstream.io.AbstractWriter

Methods inherited from class java.lang.Object

Methods inherited from interface com.thoughtworks.xstream.io.HierarchicalStreamWriter

Field Detail

DROP_ROOT_MODE

STRICT_MODE

EXPLICIT_MODE

IEEE_754_MODE

Constructor Detail

AbstractJsonWriter

AbstractJsonWriter

AbstractJsonWriter

AbstractJsonWriter

Method Detail

startNode

startNode

addAttribute

setValue

endNode

getType

isArray

startObject

addLabel

addValue

startArray

nextElement

endArray

endObject