/*
 * 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
 * 
 *     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.
 *
 * $Header:$
 */
package org.apache.beehive.controls.api.versioning;

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

/**
 *  Specifies the minimum version of the control interface that this extension
 *  requires.  Allowed on control extensions (interfaces annotated with
 *  <sp>@ControlExtension), and on control field declarations (fields annotated
 *  with @Control).  The version requirement is enforced at compile time of
 *  extensions and control client, and at runtime when the appropriate control
 *  bean is classloaded.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.FIELD})
public @interface VersionRequired
{
    /**
     * The major version value required for this control extension or instance
     * declaration to work.  Any version number greater than or equal to this
     * value will suffice, implying that this requirement is valid only when
     * back compatibility is part of the contract when increasing the version
     * number.  Negative values mean that any major version is
     * acceptable (in which case this annotation should probably just not be
     * present).
     */
    int major(); 

    /**
     * The minor version value required for this control extension or instance
     * declaration to work.  Any version number greater than or equal to this
     * value will suffice.  Negative values mean that any minor version is
     * acceptable (the default case).
     */
    int minor() default -1;
}