com.github.wnameless.json.flattener

Class JsonFlattener

java.lang.Object

com.github.wnameless.json.flattener.JsonFlattener

public final class JsonFlattener
extends Object

JsonFlattener flattens any JSON nested objects or arrays into a flattened JSON string or a Map<Stirng, Object>. The String key will represents the corresponding position of value in the original nested objects or arrays and the Object value are either String, Boolean, Long, Double or null.

For example:
A nested JSON
{ "a" : { "b" : 1, "c": null, "d": [false, true] }, "e": "f", "g":2.3 }

can be turned into a flattened JSON
{ "a.b": 1, "a.c": null, "a.d[0]": false, "a.d[1]": true, "e": "f", "g":2.3 }

or into a Map
{
a.b=1,
a.c=null,
a.d[0]=false,
a.d[1]=true,
e=f,
g=2.3
}

Author:

Wei-Ming Wu

Field Summary

Fields

Modifier and Type	Field and Description
static String	ROOT ROOT is the default key of the Map returned by flattenAsMap(java.lang.String).

Constructor Summary

Constructors

Constructor and Description
JsonFlattener(Reader jsonReader) Creates a JSON flattener.
JsonFlattener(String json) Creates a JSON flattener.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
String	flatten() Returns a flattened JSON string.
static String	flatten(String json) Returns a flattened JSON string.
Map<String,Object>	flattenAsMap() Returns a flattened JSON as Map.
static Map<String,Object>	flattenAsMap(String json) Returns a flattened JSON as Map.
int	hashCode()
String	toString()
JsonFlattener	withFlattenMode(FlattenMode flattenMode) A fluent setter to setup a mode of the JsonFlattener.
JsonFlattener	withKeyTransformer(KeyTransformer keyTrans) A fluent setter to setup a KeyTransformer of the JsonFlattener.
JsonFlattener	withLeftAndRightBrackets(char leftBracket, char rightBracket) A fluent setter to setup the left and right brackets within a key in the flattened JSON.
JsonFlattener	withPrintMode(PrintMode printMode) A fluent setter to setup a print mode of the JsonFlattener.
JsonFlattener	withSeparator(char separator) A fluent setter to setup the separator within a key in the flattened JSON.
JsonFlattener	withStringEscapePolicy(CharSequenceTranslatorFactory policy) A fluent setter to setup the JSON string escape policy.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ROOT

public static final String ROOT

ROOT is the default key of the Map returned by flattenAsMap(java.lang.String). When JsonFlattener processes a JSON string which is not a JSON object or array, the final outcome may not suit in a Java Map. At that moment, JsonFlattener will put the result in the Map with ROOT as its key.

See Also:

Constant Field Values

Constructor Detail

JsonFlattener

public JsonFlattener(String json)

Creates a JSON flattener.

Parameters:

json - the JSON string

JsonFlattener

public JsonFlattener(Reader jsonReader)
              throws IOException

Creates a JSON flattener.

Parameters:

jsonReader - the JSON reader

Throws:

IOException - if jsonReader cannot be read

Method Detail

flatten

public static String flatten(String json)

Returns a flattened JSON string.

Parameters:

json - the JSON string

Returns:

a flattened JSON string

flattenAsMap

public static Map<String,Object> flattenAsMap(String json)

Returns a flattened JSON as Map.

Parameters:

json - the JSON string

Returns:

a flattened JSON as Map

withFlattenMode

public JsonFlattener withFlattenMode(FlattenMode flattenMode)

A fluent setter to setup a mode of the JsonFlattener.

Parameters:

flattenMode - a FlattenMode

Returns:

this JsonFlattener

withStringEscapePolicy

public JsonFlattener withStringEscapePolicy(CharSequenceTranslatorFactory policy)

A fluent setter to setup the JSON string escape policy.

Parameters:

policy - any CharSequenceTranslatorFactory or a StringEscapePolicy

Returns:

this JsonFlattener

withSeparator

public JsonFlattener withSeparator(char separator)

A fluent setter to setup the separator within a key in the flattened JSON. The default separator is a dot(.).

Parameters:

separator - any character

Returns:

this JsonFlattener

withLeftAndRightBrackets

public JsonFlattener withLeftAndRightBrackets(char leftBracket,
                                              char rightBracket)

A fluent setter to setup the left and right brackets within a key in the flattened JSON. The default left and right brackets are left square bracket([) and right square bracket(]).

Parameters:

leftBracket - any character

rightBracket - any character

Returns:

this JsonFlattener

withPrintMode

public JsonFlattener withPrintMode(PrintMode printMode)

A fluent setter to setup a print mode of the JsonFlattener. The default print mode is minimal.

Parameters:

printMode - a PrintMode

Returns:

this JsonFlattener

withKeyTransformer

public JsonFlattener withKeyTransformer(KeyTransformer keyTrans)

A fluent setter to setup a KeyTransformer of the JsonFlattener.

Parameters:

keyTrans - a KeyTransformer

Returns:

this JsonFlattener

flatten

public String flatten()

Returns a flattened JSON string.

Returns:

a flattened JSON string

flattenAsMap

public Map<String,Object> flattenAsMap()

Returns a flattened JSON as Map.

Returns:

a flattened JSON as Map

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object