| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.cassandra.cql3.functions.masking; |
| |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| |
| import org.apache.cassandra.cql3.functions.FunctionFactory; |
| import org.apache.cassandra.cql3.functions.FunctionName; |
| import org.apache.cassandra.cql3.functions.FunctionParameter; |
| import org.apache.cassandra.cql3.functions.NativeFunction; |
| import org.apache.cassandra.db.marshal.AbstractType; |
| |
| /** |
| * A {@link MaskingFunction} that always returns a {@code null} column. The returned value is always an absent column, |
| * as it didn't exist, and not a not-null column representing a {@code null} value. |
| * <p> |
| * For example, given a text column named "username", {@code mask_null(username)} will always return {@code null}, |
| * independently of the actual value of that column. |
| */ |
| public class NullMaskingFunction extends MaskingFunction |
| { |
| public static final String NAME = "null"; |
| private static final Masker MASKER = new Masker(); |
| |
| private NullMaskingFunction(FunctionName name, AbstractType<?> inputType) |
| { |
| super(name, inputType, inputType); |
| } |
| |
| @Override |
| public Masker masker(ByteBuffer... parameters) |
| { |
| return MASKER; |
| } |
| |
| private static class Masker implements MaskingFunction.Masker |
| { |
| @Override |
| public ByteBuffer mask(ByteBuffer value) |
| { |
| return null; |
| } |
| } |
| |
| /** @return a {@link FunctionFactory} to build new {@link NullMaskingFunction}s. */ |
| public static FunctionFactory factory() |
| { |
| return new MaskingFunction.Factory(NAME, FunctionParameter.anyType(false)) |
| { |
| @Override |
| protected NativeFunction doGetOrCreateFunction(List<AbstractType<?>> argTypes, AbstractType<?> receiverType) |
| { |
| return new NullMaskingFunction(name, argTypes.get(0)); |
| } |
| }; |
| } |
| } |