com.google.crypto.tink.internal.ParametersParser Maven / Gradle / Ivy
// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////
package com.google.crypto.tink.internal;
import com.google.crypto.tink.Parameters;
import com.google.crypto.tink.util.Bytes;
import java.security.GeneralSecurityException;
/**
* Parses {@code Serialization} objects into {@code Parameters} objects of a certain kind.
*
* This class should eventually be in Tinks public API -- however, it might still change before
* that.
*/
public abstract class ParametersParser {
/**
* A function which parses a Parameters object.
*
* This interface exists only so we have a type we can reference in {@link #create}. Users
* should not use this directly; see the explanation in {@link #create}.
*/
public interface ParametersParsingFunction {
Parameters parseParameters(SerializationT serialization) throws GeneralSecurityException;
}
private final Bytes objectIdentifier;
private final Class serializationClass;
private ParametersParser(Bytes objectIdentifier, Class serializationClass) {
this.objectIdentifier = objectIdentifier;
this.serializationClass = serializationClass;
}
/**
* Parses a serialization into a {@link Parameters} object.
*
* This function is usually called with a Serialization matching the result of {@link
* getObjectIdentifier}. However, implementations should check that this is the case.
*/
public abstract Parameters parseParameters(SerializationT serialization)
throws GeneralSecurityException;
/**
* Returns the {@code objectIdentifier} for this serialization.
*
*
The object identifier is a unique identifier per registry for this object (in the standard
* proto serialization, it is the typeUrl). In other words, when registering a {@code
* ParametersParser}, the registry will invoke this to get the handled object identifier. In order
* to parse an object of type {@code SerializationT}, the registry will then obtain the {@code
* objectIdentifier} of this serialization object, and call the parser corresponding to this
* object.
*/
public final Bytes getObjectIdentifier() {
return objectIdentifier;
}
public final Class getSerializationClass() {
return serializationClass;
}
/**
* Creates a ParametersParser object.
*
* In order to create a ParametersParser object, one typically writes a function
*
*
{@code
* class MyClass {
* private static MyParameters parse(MySerialization parametersSerialization)
* throws GeneralSecurityException {
* ...
* }
* }
* }
*
* This function can then be used to create a {@code ParametersParser}:
*
* {@code
* ParametersParser parser =
* ParametersParser.create(MyClass::parse, objectIdentifier, MySerialization.class);
* }
*
* @param function The function used to parse a {@link Parameters} object.
* @param objectIdentifier The identifier to be returned by {@link #getObjectIdentifier}
* @param serializationClass The class object corresponding to {@code SerializationT}
*/
public static ParametersParser create(
ParametersParsingFunction function,
Bytes objectIdentifier,
Class serializationClass) {
return new ParametersParser(objectIdentifier, serializationClass) {
@Override
public Parameters parseParameters(SerializationT serialization)
throws GeneralSecurityException {
return function.parseParameters(serialization);
}
};
}
}