org.apache.juneau.json

Class JsonParser

java.lang.Object

org.apache.juneau.Context

org.apache.juneau.BeanContext

org.apache.juneau.parser.Parser

org.apache.juneau.parser.ReaderParser

org.apache.juneau.json.JsonParser

Direct Known Subclasses:

JsonParser.Strict

public class JsonParser
extends ReaderParser

Parses any valid JSON text into a POJO model.

Media types

Handles Content-Type types: application/json, text/json

Description

This parser uses a state machine, which makes it very fast and efficient. It parses JSON in about 70% of the time that it takes the built-in Java DOM parsers to parse equivalent XML.

This parser handles all valid JSON syntax. In addition, when strict mode is disable, the parser also handles the following:

• Javascript comments (both /* and //) are ignored.
• Both single and double quoted strings.
• Automatically joins concatenated strings (e.g. "aaa" + 'bbb').
• Unquoted attributes.

Also handles negative, decimal, hexadecimal, octal, and double numbers, including exponential notation.

This parser handles the following input, and automatically returns the corresponding Java class.

• JSON objects ("{...}") are converted to ObjectMaps. Note: If a _type='xxx' attribute is specified on the object, then an attempt is made to convert the object to an instance of the specified Java bean class. See the beanTypeName setting on the PropertyStore for more information about parsing beans from JSON.
• JSON arrays ("[...]") are converted to ObjectLists.
• JSON string literals ("'xyz'") are converted to Strings.
• JSON numbers ("123", including octal/hexadecimal/exponential notation) are converted to Integers, Longs, Floats, or Doubles depending on whether the number is decimal, and the size of the number.
• JSON booleans ("false") are converted to Booleans.
• JSON nulls ("null") are converted to null.
• Input consisting of only whitespace or JSON comments are converted to null.

Input can be any of the following:

• "{...}" - Converted to a ObjectMap or an instance of a Java bean if a _type attribute is present.
• "[...]" - Converted to a ObjectList.
• "123..." - Converted to a Number (either Integer, Long, Float, or Double).
• "true"/"false" - Converted to a Boolean.
• "null" - Returns null.
• "'xxx'" - Converted to a String.
• "\"xxx\"" - Converted to a String.
• "'xxx' + \"yyy\"" - Converted to a concatenated String.

TIP: If you know you're parsing a JSON object or array, it can be easier to parse it using the ObjectMap(CharSequence) or ObjectList(CharSequence) constructors instead of using this class. The end result should be the same.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JsonParser.Strict Default parser, strict mode.

Field Summary

Fields

Modifier and Type	Field and Description
static JsonParser	DEFAULT Default parser, all default settings.
static JsonParser	DEFAULT_STRICT Default parser, all default settings.
static String	JSON_validateEnd Configuration property: Validate end.

Fields inherited from class org.apache.juneau.parser.Parser

PARSER_autoCloseStreams, PARSER_fileCharset, PARSER_inputStreamCharset, PARSER_listener, PARSER_strict, PARSER_trimStrings, PARSER_unbuffered

Fields inherited from class org.apache.juneau.BeanContext

BEAN_beanClassVisibility, BEAN_beanConstructorVisibility, BEAN_beanDictionary, BEAN_beanDictionary_add, BEAN_beanDictionary_remove, BEAN_beanFieldVisibility, BEAN_beanFilters, BEAN_beanFilters_add, BEAN_beanFilters_remove, BEAN_beanMapPutReturnsOldValue, BEAN_beanMethodVisibility, BEAN_beansRequireDefaultConstructor, BEAN_beansRequireSerializable, BEAN_beansRequireSettersForGetters, BEAN_beansRequireSomeProperties, BEAN_beanTypePropertyName, BEAN_debug, BEAN_excludeProperties, BEAN_ignoreInvocationExceptionsOnGetters, BEAN_ignoreInvocationExceptionsOnSetters, BEAN_ignorePropertiesWithoutSetters, BEAN_ignoreUnknownBeanProperties, BEAN_ignoreUnknownNullBeanProperties, BEAN_implClasses, BEAN_includeProperties, BEAN_locale, BEAN_mediaType, BEAN_notBeanClasses, BEAN_notBeanClasses_add, BEAN_notBeanClasses_remove, BEAN_notBeanPackages, BEAN_notBeanPackages_add, BEAN_notBeanPackages_remove, BEAN_pojoSwaps, BEAN_pojoSwaps_add, BEAN_pojoSwaps_remove, BEAN_propertyNamer, BEAN_sortProperties, BEAN_timeZone, BEAN_useInterfaceProxies, BEAN_useJavaBeanIntrospector, DEFAULT_SORTED

Constructor Summary

Constructors

Constructor and Description
JsonParser(PropertyStore ps) Constructor.
JsonParser(PropertyStore ps, String... consumes) Constructor.

Method Summary

Modifier and Type	Method and Description
ObjectMap	asMap() Returns the properties defined on this bean context as a simple map for debugging purposes.
JsonParserBuilder	builder() Creates a builder from this context object.
static JsonParserBuilder	create() Instantiates a new clean-slate JsonParserBuilder object.
ReaderParserSession	createSession(ParserSessionArgs args) Create the session object that will be passed in to the parse method.

Methods inherited from class org.apache.juneau.parser.ReaderParser

isReaderParser

Methods inherited from class org.apache.juneau.parser.Parser

createDefaultSessionArgs, createSession, getMediaTypes, getPrimaryMediaType, parse, parse, parse, parseArgs, parseIntoCollection, parseIntoMap

Methods inherited from class org.apache.juneau.BeanContext

_class, createBeanSession, createBeanSession, createDefaultBeanSessionArgs, createSession, createSession, dumpCacheStats, getBeanMeta, getBeanRegistry, getBeanTypePropertyName, getClassMeta, getClassMeta, getClassMetaForObject, getExcludeProperties, getImplClassConstructor, getIncludeProperties, hasSameCache, isBean, isNotABean, newInstance, newInstance, newInstanceFromOuter, object, resolveClassMeta, string

Methods inherited from class org.apache.juneau.Context

equals, getArrayProperty, getArrayProperty, getBooleanProperty, getClassArrayProperty, getClassArrayProperty, getClassArrayProperty, getClassListProperty, getClassListProperty, getClassMapProperty, getClassMapProperty, getClassProperty, getClassSetProperty, getClassSetProperty, getInstanceArrayProperty, getInstanceArrayProperty, getInstanceArrayProperty, getInstanceProperty, getInstanceProperty, getInstanceProperty, getIntegerProperty, getListProperty, getListProperty, getLongProperty, getMapProperty, getProperty, getProperty, getPropertyKeys, getPropertyStore, getSetProperty, getSetProperty, getStringProperty, hashCode, toString

Methods inherited from class java.lang.Object

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

Field Detail

JSON_validateEnd

public static final String JSON_validateEnd

Configuration property: Validate end.

Property:

• Name: "JsonParser.validateEnd.b"
• Data type: Boolean
• Default: false
• Session-overridable: true
• Methods:
  • JsonParserBuilder.validateEnd(boolean)
  • JsonParserBuilder.validateEnd()

Description:

If true, after parsing a POJO from the input, verifies that the remaining input in the stream consists of only comments or whitespace.

Example:

// Create a parser that validates that there's no garbage at the end of the input. ReaderParser p = JsonParser. .create() .validateEnd() .build(); // Same, but use property. ReaderParser p = JsonParser. .create() .set(JSON_validateEnd, true) .build(); // Should fail because input has multiple POJOs. String in = "{foo:'bar'}{baz:'qux'}"; MyBean myBean = p.parse(in, MyBean.class);

See Also:

Constant Field Values

DEFAULT

public static final JsonParser DEFAULT

Default parser, all default settings.

DEFAULT_STRICT

public static final JsonParser DEFAULT_STRICT

Default parser, all default settings.

Constructor Detail

JsonParser

public JsonParser(PropertyStore ps)

Constructor.

Parameters:

ps - The property store containing all the settings for this object.

JsonParser

public JsonParser(PropertyStore ps,
                  String... consumes)

Constructor.

Parameters:

ps - The property store containing all the settings for this object.

consumes - The list of media types that this parser consumes (e.g. "application/json").

Method Detail

builder

public JsonParserBuilder builder()

Description copied from class: Context

Creates a builder from this context object.

Builders are used to define new contexts (e.g. serializers, parsers) based on existing configurations.

Overrides:

builder in class Parser

Returns:

A new ContextBuilder object.

create

public static JsonParserBuilder create()

Instantiates a new clean-slate JsonParserBuilder object.

This is equivalent to simply calling new JsonParserBuilder().

Note that this method creates a builder initialized to all default settings, whereas builder() copies the settings of the object called on.

Returns:

A new JsonParserBuilder object.

createSession

public ReaderParserSession createSession(ParserSessionArgs args)

Description copied from class: Parser

Create the session object that will be passed in to the parse method.

It's up to implementers to decide what the session object looks like, although typically it's going to be a subclass of ParserSession.

Specified by:

createSession in class Parser

Parameters:

args - Runtime arguments.

Returns:

The new session.

asMap

public ObjectMap asMap()

Description copied from class: Context

Returns the properties defined on this bean context as a simple map for debugging purposes.

Overrides:

asMap in class Parser

Returns:

A new map containing the properties defined on this context.