/*
 * Copyright (C) 2012 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jboss.errai.ui.shared.api.annotations;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.jboss.errai.databinding.client.api.Converter;
import org.jboss.errai.databinding.client.api.DataBinder;

import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.HasText;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.Widget;

import jsinterop.annotations.JsType;

/**
 * Indicates that an annotated component (a {@link Widget}, {@link Element}, or native {@link JsType} wrapping a DOM
 * element) should automatically be bound to a property of a data model associated with a {@link DataBinder} (see
 * {@link AutoBound} and {@link Model}).
 * <p>
 * The annotated component can either be a field, method or constructor parameter or a method return value. If it is a
 * {@link Widget} or a templated Errai UI bean then it must implement either {@link HasText}, {@link HasValue} or
 * {@link TakesValue}. Note that a {@link Bound} field can but does not have to be injected. The following example shows
 * all valid use cases for the {@link Bound} annotation.
 *
 * <pre>
 *      public class MyBean {
 *        {@code @Inject} {@code @Model}
 *        private MyModel model;
 *
 *        {@code @Bound}
 *        private Label boundLabel = new Label();
 *
 *        {@code @Inject} {@code @Bound}
 *        private TextBox injectedBoundTextBox;
 *
 *        {@code @Inject}
 *        public MyBean({@code @Bound} SomeWidget boundWidget) {
 *          this.boundWidget = boundWidget;
 *        }
 *
 *        {@code @Inject}
 *        public void setWidget({@code @Bound} SomeWidget boundWidget) {
 *          this.boundWidget = boundWidget;
 *        }
 *
 *        {@code @Bound}
 *        public SomeWidget getWidget() {
 *          ...
 *        }
 *      }
 * </pre>
 *
 * If no property is specified, the component is bound to the data model property with the same name as the field,
 * parameter, or method which is the target of this annotation.
 * <p>
 *
 * @author Christian Sadilek <csadilek@redhat.com>
 */
@Documented
@Target({ ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@SuppressWarnings("rawtypes")
public @interface Bound {

  /**
   * The name of the data model property (or a property chain) to bind the
   * component to, following Java bean conventions. If omitted, the widget will be
   * bound to the data model property with the same name as the field, parameter
   * or method which is the target of this annotation.
   */
  String property() default "";

  /**
   * The {@link Converter} to use when setting values on the model or component.
   */
  // The NO_CONVERTER class needs to be fully qualified here to work around a
  // JDK bug: http://bugs.sun.com/view_bug.do?bug_id=6512707
  Class<? extends Converter> converter() default org.jboss.errai.ui.shared.api.annotations.Bound.NO_CONVERTER.class;

  static abstract class NO_CONVERTER implements Converter {
  }

  /**
   * A flag indicating whether or not the data model property should be updated
   * when the widget fires a {@link com.google.gwt.event.dom.client.KeyUpEvent},
   * in addition to the default
   * {@link com.google.gwt.event.logical.shared.ValueChangeEvent}.
   */
  boolean onKeyUp() default false;
}