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/*
* Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package vm.share.options;
import java.lang.annotation.*;
/**
* This annotation is the most useful one of the whole API.
* It is used to mark non-static fields of the object and to declare the
* corresponding options. The name of the option defaults to the name of the field.
* The help message for the option should also be also declared
* here (or it could be declared at the {@link ObjectFactory} level at any case it is mandatory).
* For non-simple option types a factory attribute should be provided which
* points to a class which implements {@link ObjectFactory} interface. That factory is
* then used to instantiate an object given the option value and to populate the
* annotated field.
*
* If a default value is provided it is used if the corresponding option is not declared
* at the command line. If it is not provided and there is no option then an error is thrown.
* For non-simple field types default values can be provided at ObjectFactory level.
* See also the documentation at the package level.).
*/
// kept at runtime, applied to fields only.
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface Option
{
// these strings help to find out if the corresponding attribute was not defined.
final public static String defName = "[no name]";
final public static String defDefaultValue = "[no default]";
final public static String defDescription = "[no description]";
/**
* The name of the option, defaults to the name of the annotated field.
*/
String name() default defName;
/**
* The default value for the option, option is mandatory if it is not specified here
* and at the ObjectFactory level.
*/
String default_value() default defDefaultValue;
/**
* A short description of the option used to generate a help message.
*/
String description() default defDescription;
/**
* The factory class to use for instantiating the corresponding option.
*/
Class<? extends OptionObjectFactory> factory() default OptionObjectFactory.class;
}
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