https://github.com/eclipse-ee4j/jsonp: Jakarta JSON Processing defines a Java(R) based framework for parsing, generating, transforming, and querying JSON documents. (Eclipse Foundation)
  • Dmitry Kornilov (Oracle)
  • Lukas Jungmann (Oracle) 
/*
 * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.json;

import java.io.Closeable;


Reads a JSON object or an array structure from an input source. 
The class Json contains methods to create readers from input sources (InputStream and Reader). 

The following example demonstrates how to read an empty JSON array from
a string:


JsonReader jsonReader = Json.createReader(new StringReader("[]"));
JsonArray array = jsonReader.readArray();
jsonReader.close();




 The class JsonReaderFactory also contains methods to create JsonReader instances. A factory instance can be used to create multiple reader instances with the same configuration. This the preferred way to create multiple instances. A sample usage is shown in the following example: 

JsonReaderFactory factory = Json.createReaderFactory(config);
JsonReader reader1 = factory.createReader(...);
JsonReader reader2 = factory.createReader(...);




/**
 * Reads a JSON {@link JsonObject object} or an {@link JsonArray array}
 * structure from an input source.
 *
 * <p>The class {@link jakarta.json.Json} contains methods to create readers from
 * input sources ({@link java.io.InputStream} and {@link java.io.Reader}).
 *
 * <p>
 * The following example demonstrates how to read an empty JSON array from
 * a string:
 * <pre>
 * <code>
 * JsonReader jsonReader = Json.createReader(new StringReader("[]"));
 * JsonArray array = jsonReader.readArray();
 * jsonReader.close();
 * </code>
 * </pre>
 *
 * <p>
 * The class {@link JsonReaderFactory} also contains methods to create
 * {@code JsonReader} instances. A factory instance can be used to create
 * multiple reader instances with the same configuration. This the preferred
 * way to create multiple instances. A sample usage is shown in the following
 * example:
 * <pre>
 * <code>
 * JsonReaderFactory factory = Json.createReaderFactory(config);
 * JsonReader reader1 = factory.createReader(...);
 * JsonReader reader2 = factory.createReader(...);
 * </code>
 * </pre>
 */
public interface JsonReader extends  /*Auto*/Closeable {

    
Returns a JSON array or object that is represented in
the input source. This method needs to be called
only once for a reader instance.

Throws:
  • JsonException – if a JSON object or array cannot
    be created due to i/o error (IOException would be
cause of JsonException)
  • JsonParsingException – if a JSON object or array
    cannot be created due to incorrect representation
  • IllegalStateException – if read, readObject, readArray,
    readValue or close method is already called
Returns:a JSON object or array
/**
     * Returns a JSON array or object that is represented in
     * the input source. This method needs to be called
     * only once for a reader instance.
     *
     * @return a JSON object or array
     * @throws JsonException if a JSON object or array cannot
     *     be created due to i/o error (IOException would be
     * cause of JsonException)
     * @throws jakarta.json.stream.JsonParsingException if a JSON object or array
     *     cannot be created due to incorrect representation
     * @throws IllegalStateException if read, readObject, readArray,
     *     readValue or close method is already called
     */
    JsonStructure read();

    
Returns a JSON object that is represented in
the input source. This method needs to be called
only once for a reader instance.

Throws:
  • JsonException – if a JSON object cannot
    be created due to i/o error (IOException would be
    cause of JsonException)
  • JsonParsingException – if a JSON object cannot
    be created due to incorrect representation
  • IllegalStateException – if read, readObject, readArray,
    readValue or close method is already called
Returns:a JSON object
/**
     * Returns a JSON object that is represented in
     * the input source. This method needs to be called
     * only once for a reader instance.
     *
     * @return a JSON object
     * @throws JsonException if a JSON object cannot
     *     be created due to i/o error (IOException would be
     *     cause of JsonException)
     * @throws jakarta.json.stream.JsonParsingException if a JSON object cannot
     *     be created due to incorrect representation
     * @throws IllegalStateException if read, readObject, readArray,
     *     readValue or close method is already called
     */
    JsonObject readObject();

    
Returns a JSON array that is represented in
the input source. This method needs to be called
only once for a reader instance.

Throws:
  • JsonException – if a JSON array cannot
    be created due to i/o error (IOException would be
    cause of JsonException)
  • JsonParsingException – if a JSON array cannot
    be created due to incorrect representation
  • IllegalStateException – if read, readObject, readArray,
    readValue or close method is already called
Returns:a JSON array
/**
     * Returns a JSON array that is represented in
     * the input source. This method needs to be called
     * only once for a reader instance.
     *
     * @return a JSON array
     * @throws JsonException if a JSON array cannot
     *     be created due to i/o error (IOException would be
     *     cause of JsonException)
     * @throws jakarta.json.stream.JsonParsingException if a JSON array cannot
     *     be created due to incorrect representation
     * @throws IllegalStateException if read, readObject, readArray,
     *     readValue or close method is already called
     */
    JsonArray readArray();

    
Returns a JSON value that is represented in
the input source. This method needs to be called
only once for a reader instance.

Throws:
  • JsonException – if a JSON value
    be created due to i/o error (IOException would be
    cause of JsonException)
  • JsonParsingException – if a JSON value
    cannot be created due to incorrect representation
  • IllegalStateException – if read, readObject, readArray,
    readValue or close method is already called
Returns:a JSON value
Since:1.1
/**
     * Returns a JSON value that is represented in
     * the input source. This method needs to be called
     * only once for a reader instance.
     *
     * @return a JSON value
     * @throws JsonException if a JSON value
     *     be created due to i/o error (IOException would be
     *     cause of JsonException)
     * @throws jakarta.json.stream.JsonParsingException if a JSON value
     *     cannot be created due to incorrect representation
     * @throws IllegalStateException if read, readObject, readArray,
     *     readValue or close method is already called
     *
     * @since 1.1
     */
    default JsonValue readValue() {
        throw new UnsupportedOperationException();
    }

    
Closes this reader and frees any resources associated with the
reader. This method closes the underlying input source.

Throws:
  • JsonException – if an i/o error occurs (IOException would be
cause of JsonException)
/**
     * Closes this reader and frees any resources associated with the
     * reader. This method closes the underlying input source.
     *
     * @throws JsonException if an i/o error occurs (IOException would be
     * cause of JsonException)
     */
    @Override
    void close();

}