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Abstraction for eventing services.
/*******************************************************************************
* Copyright (c) 2015, 2016 EclipseSource.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
******************************************************************************/
package org.cohesive.envoy.json;
import java.io.IOException;
import java.io.Reader;
/**
* This class serves as the entry point to the minimal-json API.
*
* To parse a given JSON input, use the parse() methods like in this
* example:
*
*
* JsonObject object = Json.parse(string).asObject();
*
*
* To create a JSON data structure to be serialized, use the methods
* value(), array(), and object(). For example, the following
* snippet will produce the JSON string {"foo": 23, "bar": true}:
*
*
* String string = Json.object().add("foo", 23).add("bar", true).toString();
*
*
* To create a JSON array from a given Java array, you can use one of the array()
* methods with varargs parameters:
*
*
* String[] names = ...
* JsonArray array = Json.array(names);
*
*/
public final class Json {
private Json() {
// not meant to be instantiated
}
/**
* Represents the JSON literal null.
*/
public static final JsonValue NULL = new JsonLiteral("null");
/**
* Represents the JSON literal true.
*/
public static final JsonValue TRUE = new JsonLiteral("true");
/**
* Represents the JSON literal false.
*/
public static final JsonValue FALSE = new JsonLiteral("false");
/**
* Returns a JsonValue instance that represents the given int value.
*
* @param value
* the value to get a JSON representation for
* @return a JSON value that represents the given value
*/
public static JsonValue value(int value) {
return new JsonNumber(Integer.toString(value, 10));
}
/**
* Returns a JsonValue instance that represents the given long value.
*
* @param value
* the value to get a JSON representation for
* @return a JSON value that represents the given value
*/
public static JsonValue value(long value) {
return new JsonNumber(Long.toString(value, 10));
}
/**
* Returns a JsonValue instance that represents the given float value.
*
* @param value
* the value to get a JSON representation for
* @return a JSON value that represents the given value
*/
public static JsonValue value(float value) {
if (Float.isInfinite(value) || Float.isNaN(value)) {
throw new IllegalArgumentException("Infinite and NaN values not permitted in JSON");
}
return new JsonNumber(cutOffPointZero(Float.toString(value)));
}
/**
* Returns a JsonValue instance that represents the given double value.
*
* @param value
* the value to get a JSON representation for
* @return a JSON value that represents the given value
*/
public static JsonValue value(double value) {
if (Double.isInfinite(value) || Double.isNaN(value)) {
throw new IllegalArgumentException("Infinite and NaN values not permitted in JSON");
}
return new JsonNumber(cutOffPointZero(Double.toString(value)));
}
/**
* Returns a JsonValue instance that represents the given string.
*
* @param string
* the string to get a JSON representation for
* @return a JSON value that represents the given string
*/
public static JsonValue value(String string) {
return string == null ? NULL : new JsonString(string);
}
/**
* Returns a JsonValue instance that represents the given boolean value.
*
* @param value
* the value to get a JSON representation for
* @return a JSON value that represents the given value
*/
public static JsonValue value(boolean value) {
return value ? TRUE : FALSE;
}
/**
* Creates a new empty JsonArray. This is equivalent to creating a new JsonArray using the
* constructor.
*
* @return a new empty JSON array
*/
public static JsonArray array() {
return new JsonArray();
}
/**
* Creates a new JsonArray that contains the JSON representations of the given int
* values.
*
* @param values
* the values to be included in the new JSON array
* @return a new JSON array that contains the given values
*/
public static JsonArray array(int... values) {
if (values == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (int value : values) {
array.add(value);
}
return array;
}
/**
* Creates a new JsonArray that contains the JSON representations of the given long
* values.
*
* @param values
* the values to be included in the new JSON array
* @return a new JSON array that contains the given values
*/
public static JsonArray array(long... values) {
if (values == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (long value : values) {
array.add(value);
}
return array;
}
/**
* Creates a new JsonArray that contains the JSON representations of the given float
* values.
*
* @param values
* the values to be included in the new JSON array
* @return a new JSON array that contains the given values
*/
public static JsonArray array(float... values) {
if (values == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (float value : values) {
array.add(value);
}
return array;
}
/**
* Creates a new JsonArray that contains the JSON representations of the given double
* values.
*
* @param values
* the values to be included in the new JSON array
* @return a new JSON array that contains the given values
*/
public static JsonArray array(double... values) {
if (values == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (double value : values) {
array.add(value);
}
return array;
}
/**
* Creates a new JsonArray that contains the JSON representations of the given
* boolean values.
*
* @param values
* the values to be included in the new JSON array
* @return a new JSON array that contains the given values
*/
public static JsonArray array(boolean... values) {
if (values == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (boolean value : values) {
array.add(value);
}
return array;
}
/**
* Creates a new JsonArray that contains the JSON representations of the given strings.
*
* @param strings
* the strings to be included in the new JSON array
* @return a new JSON array that contains the given strings
*/
public static JsonArray array(String... strings) {
if (strings == null) {
throw new NullPointerException("values is null");
}
JsonArray array = new JsonArray();
for (String value : strings) {
array.add(value);
}
return array;
}
/**
* Creates a new empty JsonObject. This is equivalent to creating a new JsonObject using the
* constructor.
*
* @return a new empty JSON object
*/
public static JsonObject object() {
return new JsonObject();
}
/**
* Parses the given input string as JSON. The input must contain a valid JSON value, optionally
* padded with whitespace.
*
* @param string
* the input string, must be valid JSON
* @return a value that represents the parsed JSON
* @throws ParseException
* if the input is not valid JSON
*/
public static JsonValue parse(String string) {
if (string == null) {
throw new NullPointerException("string is null");
}
DefaultHandler handler = new DefaultHandler();
new JsonParser(handler).parse(string);
return handler.getValue();
}
/**
* Reads the entire input from the given reader and parses it as JSON. The input must contain a
* valid JSON value, optionally padded with whitespace.
*
* Characters are read in chunks into an input buffer. Hence, wrapping a reader in an additional
* BufferedReader likely won't improve reading performance.
*
*
* @param reader
* the reader to read the JSON value from
* @return a value that represents the parsed JSON
* @throws IOException
* if an I/O error occurs in the reader
* @throws ParseException
* if the input is not valid JSON
*/
public static JsonValue parse(Reader reader) throws IOException {
if (reader == null) {
throw new NullPointerException("reader is null");
}
DefaultHandler handler = new DefaultHandler();
new JsonParser(handler).parse(reader);
return handler.getValue();
}
private static String cutOffPointZero(String string) {
if (string.endsWith(".0")) {
return string.substring(0, string.length() - 2);
}
return string;
}
static class DefaultHandler extends JsonHandler {
protected JsonValue value;
@Override
public JsonArray startArray() {
return new JsonArray();
}
@Override
public JsonObject startObject() {
return new JsonObject();
}
@Override
public void endNull() {
value = NULL;
}
@Override
public void endBoolean(boolean bool) {
value = bool ? TRUE : FALSE;
}
@Override
public void endString(String string) {
value = new JsonString(string);
}
@Override
public void endNumber(String string) {
value = new JsonNumber(string);
}
@Override
public void endArray(JsonArray array) {
value = array;
}
@Override
public void endObject(JsonObject object) {
value = object;
}
@Override
public void endArrayValue(JsonArray array) {
array.add(value);
}
@Override
public void endObjectValue(JsonObject object, String name) {
object.add(name, value);
}
JsonValue getValue() {
return value;
}
}
}