org.apache.juneau.json.JsonParser Maven / Gradle / Ivy
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// * *
// * http://www.apache.org/licenses/LICENSE-2.0 *
// * *
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// ***************************************************************************************************************************
package org.apache.juneau.json;
import org.apache.juneau.*;
import org.apache.juneau.parser.*;
/**
* 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 {@code /*} and {@code //}) 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 {@link ObjectMap ObjectMaps}.
* Note: If a _type ='xxx' beanTypeName setting on the {@link PropertyStore} for more information about parsing
* beans from JSON.
* -
* JSON arrays (
"[...]" ) are converted to {@link ObjectList ObjectLists}.
* -
* JSON string literals (
"'xyz'" ) are converted to {@link String Strings}.
* -
* JSON numbers (
"123" , including octal/hexadecimal/exponential notation) are converted to
* {@link Integer Integers}, {@link Long Longs}, {@link Float Floats}, or {@link Double Doubles} depending on
* whether the number is decimal, and the size of the number.
* -
* JSON booleans (
"false" ) are converted to {@link Boolean 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 {@link ObjectMap} or an instance of a Java bean if a _type
* attribute is present.
* -
*
"[...]" - Converted to a {@link ObjectList}.
* -
*
"123..." - Converted to a {@link Number} (either {@link Integer}, {@link Long}, {@link Float},
* or {@link Double}).
* -
*
"true" /"false" - Converted to a {@link Boolean}.
* -
*
"null" - Returns null .
* -
*
"'xxx'" - Converted to a {@link String}.
* -
*
"\"xxx\"" - Converted to a {@link String}.
* -
*
"'xxx' + \"yyy\"" - Converted to a concatenated {@link String}.
*
*
*
* TIP: If you know you're parsing a JSON object or array, it can be easier to parse it using the
* {@link ObjectMap#ObjectMap(CharSequence) ObjectMap(CharSequence)} or {@link ObjectList#ObjectList(CharSequence)
* ObjectList(CharSequence)} constructors instead of using this class.
* The end result should be the same.
*/
public class JsonParser extends ReaderParser {
//-------------------------------------------------------------------------------------------------------------------
// Predefined instances
//-------------------------------------------------------------------------------------------------------------------
/** Default parser, all default settings.*/
public static final JsonParser DEFAULT = new JsonParser(PropertyStore.create());
/** Default parser, all default settings.*/
public static final JsonParser DEFAULT_STRICT = new JsonParser.Strict(PropertyStore.create());
//-------------------------------------------------------------------------------------------------------------------
// Predefined subclasses
//-------------------------------------------------------------------------------------------------------------------
/** Default parser, strict mode. */
public static class Strict extends JsonParser {
/**
* Constructor.
*
* @param propertyStore The property store containing all the settings for this object.
*/
public Strict(PropertyStore propertyStore) {
super(propertyStore.copy().append(PARSER_strict, true));
}
}
//-------------------------------------------------------------------------------------------------------------------
// Instance
//-------------------------------------------------------------------------------------------------------------------
private final JsonParserContext ctx;
/**
* Constructor.
*
* @param propertyStore The property store containing all the settings for this object.
*/
public JsonParser(PropertyStore propertyStore) {
this(propertyStore, "application/json", "text/json");
}
/**
* Constructor.
*
* @param propertyStore The property store containing all the settings for this object.
* @param consumes The list of media types that this parser consumes (e.g. "application/json" ).
*/
public JsonParser(PropertyStore propertyStore, String...consumes) {
super(propertyStore, consumes);
this.ctx = createContext(JsonParserContext.class);
}
@Override /* CoreObject */
public JsonParserBuilder builder() {
return new JsonParserBuilder(propertyStore);
}
@Override /* Parser */
public ReaderParserSession createSession(ParserSessionArgs args) {
return new JsonParserSession(ctx, args);
}
}