lightning-core/src/main/java/org/apache/directmemory/lightning/metadata/Attribute.java

/*
 * 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.
 */
package org.apache.directmemory.lightning.metadata;

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

/**
 * Defines a property (annotated field or method) as an attribute to be serialized by Lightning.<br>
 * 
 * <pre>
 * 
 * public class MyEntity
 * {
 * 
 *     private long id;
 * 
 *     &#064;Attribute
 *     private String name;
 * 
 *     &#064;Attribute
 *     public long getId()
 *     {
 *         return id;
 *     }
 * 
 *     public void setId( long id )
 *     {
 *         this.id = id;
 *     }
 * 
 *     public String getName()
 *     {
 *         return name;
 *     }
 * 
 *     public void setName( String name )
 *     {
 *         this.name = name;
 *     }
 * }
 * </pre>
 */
@Documented
@Inherited
@Retention( RetentionPolicy.RUNTIME )
@Target( { ElementType.FIELD, ElementType.METHOD } )
public @interface Attribute
{

    public static final String NULL = "~~NULL~~";

    /**
     * If a method is annotated this value defines a property name differs from property name extracted from methodname.<br>
     * Means if method is "getFoo" property name defaults to "foo", but if the method is annotated by @Attribute("bar")
     * the property name will be explicitly "bar".
     * 
     * @return the defined property name
     */
    String property() default NULL;

    boolean nullable() default false;

}