Class JSONValue

java.lang.Object

com.leastfixedpoint.json.JSONValue

All Implemented Interfaces:

JSONSerializable

public class JSONValue
extends Object
implements JSONSerializable

Helper class for concise traversal and construction of JSON values in the representation used by JSONReader and JSONWriter. In general, will throw JSONTypeError when the shape of a given blob of JSON doesn't match expectations.

Field Summary

Fields

Modifier and Type	Field	Description
protected Object	blob

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JSONValue(Object blob)

Method Summary

Modifier and Type	Method	Description
JSONValue	add(Object value)	Append an object to the underlying list.
BigDecimal	bigDecimalValue()	Extract a BigDecimal value from the underlying object.
boolean	booleanValue()	Extract a boolean value from an underlying Boolean.
void	checkNull()
boolean	containsKey(String key)	Tests whether there is an object at the given key in the underlying map.
double	doubleValue()	Extract a double value from an underlying Number.
boolean	equals(Object other)
JSONValue	get(int index)	Retrieve the object at the index'th position in the underlying list.
JSONValue	get(int index, Object defaultValue)	Retrieve the object at the index'th position in the underlying list, or the given default value if there is no such index.
JSONValue	get(String key)	Retrieve the object at the given key in the underlying map.
JSONValue	get(String key, Object defaultValue)	Retrieve the object at the given key in the underlying map, or the given default value if there is no such key.
JSONValue	getRequired(int index)	Retrieve the object at the index'th position in the underlying list, throwing JSONMissingIndexError if there is no such index.
JSONValue	getRequired(String key)	Retrieve the object at the given key in the underlying map, throwing JSONMissingKeyError if there is no such key.
int	hashCode()
boolean	isBoolean()	Answers true iff the underlying value is a Boolean.
boolean	isList()	Answers true iff the underlying value is a List.
boolean	isMap()	Answers true iff the underlying value is a Map.
boolean	isNull()	Answers true iff the underlying value is a JSON null (i.e., JSONNull.INSTANCE).
boolean	isNumber()	Answers true iff the underlying value is a Number.
boolean	isString()	Answers true iff the underlying value is a String.
<W extends Writer> void	jsonSerialize(JSONWriter<W> w)	Called during serialization to JSON.
Iterable<JSONValue>	list()	Iterate over JSONValue-wrapped items in the underlying value, which is cast to a List
protected Iterable<JSONValue>	listIterable(Collection<Object> xs)
List<Object>	listValue()	Cast the underlying value to List.
long	longValue()	Extract a long value from an underlying Number.
Iterable<Map.Entry<String,JSONValue>>	mapEntries()	Iterate over JSONValue-wrapped entries in the underlying value, which is cast to a Map
Iterable<String>	mapKeys()	Iterate over keys of the underlying value, which is cast to a Map
Map<String,Object>	mapValue()	Cast the underlying value to Map.
Iterable<JSONValue>	mapValues()	Iterate over JSONValue-wrapped entries in the underlying value, which is cast to a Map
static JSONValue	newList()	Construct a new List, suitable for use as a JSON value.
static JSONValue	newMap()	Construct a new Map, suitable for use as a JSON value.
JSONValue	put(String key, Object value)	Replace the object at the given key in the underlying map.
JSONValue	remove(String key)	Remove the object at the given key in the underlying map.
JSONValue	set(int index, Object value)	Replace the object at the index'th position in the underlying list.
int	size()	Returns the number of elements held in the underlying List (Collection) or Map.
String	stringValue()	Cast the underlying value to String.
String	toString()
static Object	unwrap(Object value)	If given a JSONValue, extracts the underlying object; otherwise, simply returns the value given.
Object	value()	Extract the underlying value contained in this object.
static JSONValue	wrap(Object blob)	Returns a JSONValue wrapping the given object, unless the argument is null or already a JSONValue, in which case it is returned directly.

Methods inherited from class java.lang.Object

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

Field Details

blob

protected Object blob

Constructor Details

JSONValue

protected JSONValue(Object blob)

Method Details

wrap

public static JSONValue wrap(Object blob)

Returns a JSONValue wrapping the given object, unless the argument is null or already a JSONValue, in which case it is returned directly.

unwrap

public static Object unwrap(Object value)

If given a JSONValue, extracts the underlying object; otherwise, simply returns the value given.

newList

public static JSONValue newList()

Construct a new List, suitable for use as a JSON value.

newMap

public static JSONValue newMap()

Construct a new Map, suitable for use as a JSON value.

value

public Object value()

Extract the underlying value contained in this object.

isString

public boolean isString()

Answers true iff the underlying value is a String.

stringValue

public String stringValue()
                   throws JSONTypeError

Cast the underlying value to String.

Throws:

JSONTypeError - if it is not a string.

isNumber

public boolean isNumber()

Answers true iff the underlying value is a Number.

longValue

public long longValue()
               throws JSONTypeError

Extract a long value from an underlying Number.

Throws:

JSONTypeError - if it is not a number.

doubleValue

public double doubleValue()
                   throws JSONTypeError

Extract a double value from an underlying Number.

Throws:

JSONTypeError - if it is not a number.

bigDecimalValue

public BigDecimal bigDecimalValue()
                           throws JSONTypeError

Extract a BigDecimal value from the underlying object.

Throws:

JSONTypeError - if it is not a BigDecimal.

isBoolean

public boolean isBoolean()

Answers true iff the underlying value is a Boolean.

booleanValue

public boolean booleanValue()
                     throws JSONTypeError

Extract a boolean value from an underlying Boolean.

Throws:

JSONTypeError - if it is not a boolean.

isNull

public boolean isNull()

Answers true iff the underlying value is a JSON null (i.e., JSONNull.INSTANCE).

checkNull

public void checkNull()
               throws JSONTypeError

Throws:

JSONTypeError - if the underlying object is not a JSON null (i.e., JSONNull.INSTANCE).

isList

public boolean isList()

Answers true iff the underlying value is a List.

listValue

public List<Object> listValue()
                       throws JSONTypeError

Cast the underlying value to List.

Throws:

JSONTypeError - if it is not a list.

list

public Iterable<JSONValue> list()
                         throws JSONTypeError

Iterate over JSONValue-wrapped items in the underlying value, which is cast to a List

Throws:

JSONTypeError - if the underlying value is not a list.

listIterable

protected Iterable<JSONValue> listIterable(Collection<Object> xs)
                                    throws JSONTypeError

Throws:

JSONTypeError

isMap

public boolean isMap()

Answers true iff the underlying value is a Map.

mapValue

public Map<String,Object> mapValue()
                            throws JSONTypeError

Cast the underlying value to Map.

Throws:

JSONTypeError - if it is not a map.

mapKeys

public Iterable<String> mapKeys()
                         throws JSONTypeError

Iterate over keys of the underlying value, which is cast to a Map

Throws:

JSONTypeError - if the underlying value is not a map.

mapValues

public Iterable<JSONValue> mapValues()
                              throws JSONTypeError

Iterate over JSONValue-wrapped entries in the underlying value, which is cast to a Map

Throws:

JSONTypeError - if the underlying value is not a map.

mapEntries

public Iterable<Map.Entry<String,JSONValue>> mapEntries()
                                                 throws JSONTypeError

Iterate over JSONValue-wrapped entries in the underlying value, which is cast to a Map

Throws:

JSONTypeError - if the underlying value is not a map.

get

public JSONValue get(int index)
              throws JSONTypeError

Retrieve the object at the index'th position in the underlying list.

Throws:

JSONTypeError - if the underlying object is not a List.

get

public JSONValue get(int index,
 Object defaultValue)
              throws JSONTypeError

Retrieve the object at the index'th position in the underlying list, or the given default value if there is no such index.

Throws:

JSONTypeError - if the underlying object is not a List.

getRequired

public JSONValue getRequired(int index)
                      throws JSONSchemaError

Retrieve the object at the index'th position in the underlying list, throwing JSONMissingIndexError if there is no such index.

Throws:

JSONTypeError - if the underlying object is not a List

JSONMissingIndexError - if the list is missing the requested index

JSONSchemaError

set

public JSONValue set(int index,
 Object value)
              throws JSONTypeError

Replace the object at the index'th position in the underlying list. Returns 'this' to allow for chaining-style building of complex values.

Throws:

JSONTypeError - if the underlying object is not a List.

add

public JSONValue add(Object value)
              throws JSONTypeError

Append an object to the underlying list. Returns 'this' to allow for chaining-style building of complex values.

Throws:

JSONTypeError - if the underlying object is not a List.

get

public JSONValue get(String key)
              throws JSONTypeError

Retrieve the object at the given key in the underlying map.

Throws:

JSONTypeError - if the underlying object is not a Map.

get

public JSONValue get(String key,
 Object defaultValue)
              throws JSONTypeError

Retrieve the object at the given key in the underlying map, or the given default value if there is no such key.

Throws:

JSONTypeError - if the underlying object is not a Map.

getRequired

public JSONValue getRequired(String key)
                      throws JSONSchemaError

Retrieve the object at the given key in the underlying map, throwing JSONMissingKeyError if there is no such key.

Throws:

JSONTypeError - if the underlying object is not a Map

JSONMissingKeyError - if the map is missing the requested key

JSONSchemaError

put

public JSONValue put(String key,
 Object value)
              throws JSONTypeError

Replace the object at the given key in the underlying map. Returns 'this' to allow for chaining-style building of complex values.

Throws:

JSONTypeError - if the underlying object is not a Map.

remove

public JSONValue remove(String key)
                 throws JSONTypeError

Remove the object at the given key in the underlying map. Returns 'this' to allow for chaining-style building of complex values.

Throws:

JSONTypeError - if the underlying object is not a Map.

containsKey

public boolean containsKey(String key)
                    throws JSONTypeError

Tests whether there is an object at the given key in the underlying map.

Throws:

JSONTypeError - if the underlying object is not a Map.

size

public int size()
         throws JSONTypeError

Returns the number of elements held in the underlying List (Collection) or Map.

Throws:

JSONTypeError - if the underlying object is not any of these.

jsonSerialize

public <W extends Writer> void jsonSerialize(JSONWriter<W> w)
                                      throws IOException

Description copied from interface: JSONSerializable

Called during serialization to JSON.

Specified by:

jsonSerialize in interface JSONSerializable

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object