foundation/org.eclipse.persistence.core/src/org/eclipse/persistence/annotations/Property.java

/*******************************************************************************
 * Copyright (c) 1998, 2013 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the 
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 
 * which accompanies this distribution. 
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 * http://www.eclipse.org/org/documents/edl-v10.php.
 * 
 * Contributors:
 *     Andrei Ilitchev (Oracle), April 8, 2008 
 *        - New file introduced for bug 217168.  
 ******************************************************************************/  
package org.eclipse.persistence.annotations;

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

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Annotation for a user defined property.
 * A single Property may be specified directly on a mapped attribute or its 
 * get/set method. Multiple Properties should be wrapped into Properties 
 * annotation.
 *  
 * Property may be assigned to either a mapped attribute (or its get/set method)
 * within Entity, MappedSuperclass and Embeddable class;
 * or to Entity, MappedSuperclass and Embeddable class.
 * 
 * In case orm xml is used Property an Properties annotations specified on 
 * mapped attributes are ignored, specified on a class are merged with the ones 
 * specified in orm xml with the latter taking precedence in case of conflicts.
 * 
 * Properties defined in MappedSuperclass are passed to all inheriting Entities 
 * and MappedSuperclasses. In case of a conflict property value defined directly 
 * on a class always overrides the value passed from class's parent.
 * 
 * @see javax.persistence.Embeddable
 * @see javax.persistence.Entity
 * @see javax.persistence.Id
 * @see javax.persistence.Basic
 * @see javax.persistence.ManyToMany
 * @see javax.persistence.ManyToOne
 * @see javax.persistence.MappedSuperclass
 * @see javax.persistence.OneToMany
 * @see javax.persistence.OneToOne
 * @see org.eclipse.persistence.annotations.BasicCollection
 * @see org.eclipse.persistence.annotations.BasicMap
 * @see org.eclipse.persistence.annotations.Properties
 * @see org.eclipse.persistence.annotations.Transformation
 * @see org.eclipse.persistence.annotations.VariableOneToOne
 * 
 * @author Andrei Ilitchev
 * @since EclipseLink 1.0 
 */ 
@Target({METHOD, FIELD, TYPE})
@Retention(RUNTIME)
public @interface Property {
    /**
     * Property name.
     */ 
    String name();

    /**
     * String representation of Property value,
     * converted to an instance of valueType.
     */ 
    String value();

    /**
     * Property value type.
     * The value converted to valueType by ConversionManager.
     * If specified must be a simple type that could be handled by ConversionManager: 
     * numerical, boolean, temporal.  
     */ 
    Class valueType() default String.class;
}