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