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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

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 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

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 * particular file as subject to the "Classpath" exception as provided

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 * The Original Software is NetBeans. The Initial Developer of the Original

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 * "[Contributor] elects to include this software in this distribution

 * under the [CDDL or GPL Version 2] license." If you do not indicate a

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 * your version of this file under either the CDDL, the GPL Version 2 or

 * to extend the choice of license to its licensees as provided above.

 * However, if you add GPL Version 2 code and therefore, elected the GPL

 * Version 2 license, then the option applies only if the new code is

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 */

package net.java.html.json;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

/** Static methods in classes annotated by {@link Model}

 * can be marked by this annotation to establish a

 * <a href="http://en.wikipedia.org/wiki/JSON">JSON</a>

 * communication point. The first argument should be the

 * associated {@link Model} class. The second argument can

 * be another class generated by {@link Model} annotation,

 * or array of such classes or (since 0.8.1 version) a

 * {@link java.util.List} of such classes.

 * The associated model class then gets new method to invoke a network

 * connection asynchronously. Example follows:

 *

 * <pre>

 * {@link Model @Model}(className="MyModel", properties={

 *   {@link Property @Property}(name = "people", type=Person.class, array=true)

 * })

 * class MyModelImpl {

 *   {@link Model @Model}(className="Person", properties={

 *     {@link Property @Property}(name = "firstName", type=String.class),

 *     {@link Property @Property}(name = "lastName", type=String.class)

 *   })

 *   static class PersonImpl {

 *     {@link ComputedProperty @ComputedProperty}

 *     static String fullName(String firstName, String lastName) {

 *       return firstName + " " + lastName;

 *     }

 *   }

 *

 *   {@link OnReceive @OnReceive}(url = "{protocol}://your.server.com/person/{name}")

 *   static void getANewPerson(MyModel m, Person p) {

 *     System.out.println("Adding " + p.getFullName() + '!');

 *     m.getPeople().add(p);

 *   }

 *

 *   // the above will generate method <code>getANewPerson</code> in class <code>MyModel</code>.

 *   // with <code>protocol</code> and <code>name</code> arguments

 *   // which asynchronously contacts the server and in case of success calls

 *   // your {@link OnReceive @OnReceive} with parsed in data

 *

 *   {@link Function @Function}

 *   static void requestSmith(MyModel m) {

 *     m.getANewPerson("http", "Smith");

 *   }

 * }

 * </pre>

 * When the server returns <code>{ "firstName" : "John", "lastName" : "Smith" }</code>

 * the system will print a message <em>Adding John Smith!</em>. It is not

 * necessary to fully describe the server message - enumerate only the fields

 * in the response you are interested in. The others will be discarded. So,

 * if the server <code>{ "firstName" : "John", "lastName" : "Smith", "age" : 33 }</code>

 * the above code will behave the same (e.g. ignore the <code>age</code>

 * value).

 * <p>

 * One can use this method to communicate with the server

 * via <a href="doc-files/websockets.html">WebSocket</a> protocol since version 0.6.

 * Read the <a href="doc-files/websockets.html">tutorial</a> to see how.

 * The method shall be non-private

 * and unless {@link Model#instance() instance mode} is on also static.

 * <p>

 * Visit an <a target="_blank" href="http://dew.apidesign.org/dew/#7138581">on-line demo</a>

 * to see REST access via {@link OnReceive} annotation.

 *

 * @author Jaroslav Tulach

 * @since 0.3

 */

@Retention(RetentionPolicy.SOURCE)

@Target(ElementType.METHOD)

public @interface OnReceive {

    /** The URL to connect to. Can contain variable names surrounded by '{' and '}'.

     * Those names will then become parameters of the associated method.

     *

     * @return the (possibly parametrized) url to connect to

     */

    String url();

    /** Specifies HTTP request headers. Array of header lines

     * can contain variable names surrounded by '{' and '}'.

     * Those names will then become parameters of the associated method

     * (in addition to those added by {@link #url()} specification)

     * and can only be used with plain JSON(P) requests.

     * Headers are currently <b>not</b> supported by the

     * <a href="doc-files/websockets.html">WebSockets protocol</a>.

     * A sample follows. If you want to transmit <b>X-Birthday</b> header,

     * you can do it like this:

     * <pre>

     * {@code @}{@link OnReceive}(url="http://your.server.org", headers = {

     *   "X-Birthday: {dayOfBirth}"

     * })

     * <b>static void</b> knowingTheBirth({@link Model YourModel} model) {

     *   // handle the reply

     * }</pre>

     * a method <b>knowingTheBirth</b> is generated in

     * <code>YourModel</code> class with the <code>dayOfBirth</code> argument

     * which can be called like this:

     * <pre>

     * yourModel.knowingTheBirth("10. 12. 1973");

     * </pre>

     *

     * @return array of header lines - each line should be plain text with

     *   a header name, followed by ":" and value usually specified as

     *   '{' and '}' surrounded variable. The line shouldn't contain

     *   newline or other control characters

     * @since 1.2

     */

    String[] headers() default {};

    /** Support for <a href="http://en.wikipedia.org/wiki/JSONP">JSONP</a> requires

     * a callback from the server generated page to a function defined in the

     * system. The name of such function is usually specified as a property

     * (of possibly different names). By defining the <code>jsonp</code> attribute

     * one turns on the <a href="http://en.wikipedia.org/wiki/JSONP">JSONP</a>

     * transmission and specifies the name of the property. The property should

     * also be used in the {@link #url()} attribute on appropriate place.

     *

     * @return name of a property to carry the name of <a href="http://en.wikipedia.org/wiki/JSONP">JSONP</a>

     *    callback function.

     */

    String jsonp() default "";

    /** The model class to be send to the server as JSON data.

     * By default no data are sent. However certain {@link #method() transport methods}

     * (like <code>"PUT"</code> and <code>"POST"</code>) require the

     * data to be specified.

     *

     * @return name of a class generated using {@link Model @Model} annotation

     * @since 0.3

     */

    Class<?> data() default Object.class;

    /** The HTTP transfer method to use. Defaults to <code>"GET"</code>.

     * Other typical methods include <code>"HEAD"</code>,

     * <code>"DELETE"</code>, <code>"POST"</code>, <code>"PUT"</code>.

     * The last two mentioned methods require {@link #data()} to be specified.

     * <p>

     * When {@link #jsonp() JSONP} transport is requested, the method

     * has to be <code>"GET"</code>.

     * <p>

     * Since version 0.5 one can specify "<a href="doc-files/websockets.html">WebSocket</a>"

     * as the communication method.

     *

     * @return name of the HTTP transfer method

     * @since 0.3

     */

    String method() default "GET";

    /** Name of a method in this class which should be called in case of

     * an error. The method has to be non-private and take one model and

     * one {@link Exception}

     * parameter. If this method is not specified, the exception is just

     * printed to console.

     *

     * @return name of method in this class

     * @since 0.5

     */

    public String onError() default "";

}