jdk/src/java.base/share/classes/java/lang/classfile/attribute/ConstantValueAttribute.java
Shaojin Wen 3ebfc6c1e2 8342336: Optimize ClassFile imports
Reviewed-by: liach
2024-10-17 10:49:53 +00:00

82 lines
3.4 KiB
Java

/*
* Copyright (c) 2022, 2024, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*
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package java.lang.classfile.attribute;
import java.lang.classfile.Attribute;
import java.lang.classfile.FieldElement;
import java.lang.classfile.constantpool.ConstantValueEntry;
import java.lang.constant.ConstantDesc;
import jdk.internal.classfile.impl.BoundAttribute;
import jdk.internal.classfile.impl.TemporaryConstantPool;
import jdk.internal.classfile.impl.UnboundAttribute;
import jdk.internal.javac.PreviewFeature;
/**
* Models the {@code ConstantValue} attribute (JVMS {@jvms 4.7.2}), which can appear on
* fields and indicates that the field's value is a constant. Delivered as a
* {@link java.lang.classfile.FieldElement} when traversing the elements of a
* {@link java.lang.classfile.FieldModel}.
* <p>
* The attribute does not permit multiple instances in a given location.
* Subsequent occurrence of the attribute takes precedence during the attributed
* element build or transformation.
*
* @since 22
*/
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public sealed interface ConstantValueAttribute
extends Attribute<ConstantValueAttribute>, FieldElement
permits BoundAttribute.BoundConstantValueAttribute,
UnboundAttribute.UnboundConstantValueAttribute {
/**
* {@return the constant value of the field}
*/
ConstantValueEntry constant();
/**
* {@return a {@code ConstantValue} attribute}
* @param value the constant value
*/
static ConstantValueAttribute of(ConstantValueEntry value) {
return new UnboundAttribute.UnboundConstantValueAttribute(value);
}
/**
* {@return a {@code ConstantValue} attribute}
* @param value the constant value
*/
static ConstantValueAttribute of(ConstantDesc value) {
return of(switch(value) {
case Integer i -> TemporaryConstantPool.INSTANCE.intEntry(i);
case Float f -> TemporaryConstantPool.INSTANCE.floatEntry(f);
case Long l -> TemporaryConstantPool.INSTANCE.longEntry(l);
case Double d -> TemporaryConstantPool.INSTANCE.doubleEntry(d);
case String s -> TemporaryConstantPool.INSTANCE.stringEntry(s);
default -> throw new IllegalArgumentException("Invalid ConstantValueAttribute value: " + value);
});
}
}