com.goldencode.p2j.oo.json

Class JsonBackend

java.lang.Object

com.goldencode.p2j.oo.json.JsonBackend

public class JsonBackend
extends java.lang.Object

Json backend implementation providing methods for the json legacy classes and functions. The idea is to hide the specific json implementation behind this facade.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	JsonBackend.ProCharacterEscapes A singleton class used for escaping characters while writing JSON strings.
private static class	JsonBackend.ProPrettyPrinter Singleton used for overwriting the separator between the field name and its value in a JSON string.
private static class	JsonBackend.TwoSpacesIndenter Singleton used for matching the indentation of the output JSON string with 4GL.

Field Summary

Fields

Modifier and Type	Field and Description
private com.fasterxml.jackson.core.JsonFactory	factory Thread-safe factory instance.
private static JsonBackend	instance The singleton instance.
static int	JSON_ARRAY Numeric value for JSON Array type.
static int	JSON_BOOLEAN Numeric value for JSON Logical type.
static int	JSON_NULL Numeric value for JSON null type.
static int	JSON_NUMBER Numeric value for JSON Number type.
static int	JSON_OBJECT Numeric value for JSON Object type.
static int	JSON_STRING Numeric value for JSON String type.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	JsonBackend() Default constructor.

Method Summary

Modifier and Type	Method and Description
private static void	checkValidConstruct(JsonConstruct con, com.fasterxml.jackson.core.JsonParser parser) Throw a JsonParseException if the the argument is not a valid construct.
static java.lang.Object	convertLegacyValueToJson(BaseDataType value) Converts the legacy value to a native Java value suitable for json serialization.
private static com.fasterxml.jackson.core.JsonEncoding	getEncoding(java.lang.String legacyEncoding) Converts the legacy encoding name to JsonEncoding.
static int	getJsonDataType(java.lang.Object value) Implementation of getType legacy method of JsonArray and JsonConstruct.
static java.lang.String	getJsonDataTypeName(int type) Returns the string representation of object's corresponding JSON data type.
static JsonBackend	instance() Returns the singleton instance.
object<? extends JsonConstruct>	parse(java.io.Reader source) Deserializes the supplied input stream into a json object tree.
object<? extends JsonConstruct>	parse(java.lang.String source) Deserializes the source text into a json object tree.
private static object<? extends JsonConstruct>	parseImpl(com.fasterxml.jackson.core.JsonParser parser) Deserializes json object tree using the supplied parser as the input of json tokens.
private static void	throwParserException(com.fasterxml.jackson.core.JsonParser parser) Convenience function to throw JsonParseException.
java.lang.String	write(java.io.OutputStream target, JsonConstruct construct, boolean prettyPrint, java.lang.String legacyEnc) Serializes the supplied json construct instance to the target output stream.
private void	writeConstruct(com.fasterxml.jackson.core.JsonGenerator jsonGen, JsonConstruct construct) Implements serialization of the supplied json construct instance using the supplied json generator.
private void	writeValue(com.fasterxml.jackson.core.JsonGenerator jsonGen, java.lang.Object value) Implements serialization of the supplied json construct instance using the supplied json generator.

Methods inherited from class java.lang.Object

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

Field Detail

JSON_STRING

public static final int JSON_STRING

Numeric value for JSON String type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

JSON_NUMBER

public static final int JSON_NUMBER

Numeric value for JSON Number type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

JSON_BOOLEAN

public static final int JSON_BOOLEAN

Numeric value for JSON Logical type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

JSON_OBJECT

public static final int JSON_OBJECT

Numeric value for JSON Object type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

JSON_ARRAY

public static final int JSON_ARRAY

Numeric value for JSON Array type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

JSON_NULL

public static final int JSON_NULL

Numeric value for JSON null type. Returned by getType() / getJsonDataType().

See Also:

Constant Field Values

instance

private static final JsonBackend instance

The singleton instance.

factory

private final com.fasterxml.jackson.core.JsonFactory factory

Thread-safe factory instance.

Constructor Detail

JsonBackend

private JsonBackend()

Default constructor.

Method Detail

instance

public static JsonBackend instance()

Returns the singleton instance.

Returns:

see above.

write

public java.lang.String write(java.io.OutputStream target,
                              JsonConstruct construct,
                              boolean prettyPrint,
                              java.lang.String legacyEnc)
                       throws java.io.IOException

Serializes the supplied json construct instance to the target output stream.

Parameters:

target - Target output stream.

construct - The json construct instance to serialize.

prettyPrint - If true the output will be formatted.

legacyEnc - The character encoding name to use.

Returns:

the Java encoding name resolved from the legacy encoding name.

Throws:

java.io.IOException - in case of an IO error.

parse

public object<? extends JsonConstruct> parse(java.lang.String source)
                                      throws com.fasterxml.jackson.core.JsonParseException,
                                             java.io.IOException

Deserializes the source text into a json object tree.

Parameters:

source - The source text to parse.

Returns:

json construct instance.

Throws:

java.io.IOException

com.fasterxml.jackson.core.JsonParseException

parse

public object<? extends JsonConstruct> parse(java.io.Reader source)
                                      throws com.fasterxml.jackson.core.JsonParseException,
                                             java.io.IOException

Deserializes the supplied input stream into a json object tree.

Parameters:

source - The input reader to parse.

Returns:

json construct instance.

Throws:

java.io.IOException

com.fasterxml.jackson.core.JsonParseException

convertLegacyValueToJson

public static java.lang.Object convertLegacyValueToJson(BaseDataType value)

Converts the legacy value to a native Java value suitable for json serialization.

Parameters:

value - The legacy value to convert.

Returns:

the converted value.

getJsonDataType

public static int getJsonDataType(java.lang.Object value)

Implementation of getType legacy method of JsonArray and JsonConstruct.

Parameters:

value - Json value.

Returns:

the numeric value representing the value type.

getJsonDataTypeName

public static java.lang.String getJsonDataTypeName(int type)

Returns the string representation of object's corresponding JSON data type.

Parameters:

type - Json data type.

Returns:

the string value representing the JSON data type.

writeConstruct

private void writeConstruct(com.fasterxml.jackson.core.JsonGenerator jsonGen,
                            JsonConstruct construct)
                     throws java.io.IOException

Implements serialization of the supplied json construct instance using the supplied json generator.

Parameters:

jsonGen - Json generator.

construct - The json construct instance to serialize.

Throws:

java.io.IOException - in case of an IO error.

writeValue

private void writeValue(com.fasterxml.jackson.core.JsonGenerator jsonGen,
                        java.lang.Object value)
                 throws java.io.IOException

Implements serialization of the supplied json construct instance using the supplied json generator.

Parameters:

jsonGen - Json generator.

value - The value to serialize.

Throws:

java.io.IOException - in case of an IO error.

parseImpl

private static object<? extends JsonConstruct> parseImpl(com.fasterxml.jackson.core.JsonParser parser)
                                                  throws com.fasterxml.jackson.core.JsonParseException

Deserializes json object tree using the supplied parser as the input of json tokens.

Parameters:

parser - Setup json parser.

Returns:

json construct instance.

Throws:

com.fasterxml.jackson.core.JsonParseException

checkValidConstruct

private static void checkValidConstruct(JsonConstruct con,
                                        com.fasterxml.jackson.core.JsonParser parser)
                                 throws com.fasterxml.jackson.core.JsonParseException

Throw a JsonParseException if the the argument is not a valid construct.

Parameters:

con - the construct to check.

parser - the parser to use to create the exception

Throws:

com.fasterxml.jackson.core.JsonParseException - if the argument is null

throwParserException

private static void throwParserException(com.fasterxml.jackson.core.JsonParser parser)
                                  throws com.fasterxml.jackson.core.JsonParseException

Convenience function to throw JsonParseException.

Parameters:

parser - the parser to use to create the exception

Throws:

com.fasterxml.jackson.core.JsonParseException

getEncoding

private static com.fasterxml.jackson.core.JsonEncoding getEncoding(java.lang.String legacyEncoding)

Converts the legacy encoding name to JsonEncoding.

Parameters:

legacyEncoding - Legacy encoding.

Returns:

see above.