io.github.dmlloyd.classfile.attribute.ConstantValueAttribute Maven / Gradle / Ivy
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package io.github.dmlloyd.classfile.attribute;
import java.lang.constant.ConstantDesc;
import io.github.dmlloyd.classfile.Attribute;
import io.github.dmlloyd.classfile.FieldElement;
import io.github.dmlloyd.classfile.constantpool.ConstantValueEntry;
import io.github.dmlloyd.classfile.impl.BoundAttribute;
import io.github.dmlloyd.classfile.impl.TemporaryConstantPool;
import io.github.dmlloyd.classfile.impl.UnboundAttribute;
import io.github.dmlloyd.classfile.extras.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 io.github.dmlloyd.classfile.FieldElement} when traversing the elements of a
* {@link io.github.dmlloyd.classfile.FieldModel}.
*
* 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, 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(
value instanceof Integer i ? TemporaryConstantPool.INSTANCE.intEntry(i) :
value instanceof Float f ? TemporaryConstantPool.INSTANCE.floatEntry(f) :
value instanceof Long l ? TemporaryConstantPool.INSTANCE.longEntry(l) :
value instanceof Double d ? TemporaryConstantPool.INSTANCE.doubleEntry(d) :
value instanceof String s ? TemporaryConstantPool.INSTANCE.stringEntry(s) :
throwIt(value)
);
}
static ConstantValueEntry throwIt(ConstantDesc value) {
throw new IllegalArgumentException("Invalid ConstantValueAttribute value: " + value);
}
}