io.crums.model.hashing.Entity Maven / Gradle / Ivy
/*
* Copyright 2021 Babak Farhang
*/
package io.crums.model.hashing;
import java.nio.ByteBuffer;
import java.util.Objects;
import io.crums.util.IntegralStrings;
/**
* Every object in our model is an entity.
*/
public interface Entity {
/**
* Determines if the text representation of the instance is self-delimiting.
* This figures when deciding whether to bracket (group) entities in, for
* example, a binary operation.
*/
boolean delimited();
/**
* Returns the entity's state as a string of bytes.
* Depending on the entity type, this may involve a computation.
*
* @return a read-only view of the instance's bytes.
*/
ByteBuffer bytes();
/**
* Returns a parseable representation of the entity.
*/
CharSequence toText();
/**
* Returns {@linkplain #bytes()} as a hexadecimal string.
*/
default String bytesHex() {
return IntegralStrings.toHex(bytes());
}
/**
* Equality semantics is governed by {@linkplain #bytes()}. Implementations
* override to exploit logical shortcuts if computing {@linkplain #bytes()}
* is expensive.
*
* Independence From Object::equals
*
* Note this method is generally
* not consistent with Object.equals(Object) (and therefore
* not consistent with {@code Object.hashCode()} either).
*
*
* @param entity non-null
*/
default boolean equals(Entity entity) {
return entity == this || Objects.requireNonNull(entity, "null entity").bytes().equals(bytes());
}
}