/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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
 *
 *    https://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 grails.databinding;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * This annotation may be applied to a class or to a field to
 * customize the data binding process.
 *
 * When the annotation is applied to a field, the value assigned to the
 * annotation should be a Closure which accepts 2 parameters.  The first
 * parameter is the object that data binding is being applied to.  The second
 * parameter is a {@link grails.databinding.DataBindingSource} containing the values being bound to the object.
 * The value returned by the Closure will be bound to the field.  The
 * following code demonstrates using this technique to bind an upper
 * case version of the value in the DataBindingSource to the field.
 *
<pre>
class SomeClass {
    &#064;BindUsing({
        obj, source -&gt; source['name']?.toUpperCase()
    })
    String name
}
</pre>
 *
 * When the annotation is applied to a class, the value assigned to the
 * annotation should be a class which implements the {@link BindingHelper}
 * interface.  An instance of that class will be used any time a value
 * is bound to a property in the class that this annotation has been
 * applied to.
<pre>
&#064;BindUsing(SomeClassWhichImplementsBindingHelper)
class SomeClass {
    String someProperty
    Integer someOtherProperty
}
</pre>
 *
 * @author Jeff Brown
 * @since 2.3
 * @see BindingHelper
 * @see DataBindingSource
 */
@Retention(RetentionPolicy.RUNTIME)
public @interface BindUsing {
    Class<?> value();
}
