MultiArgumentsFilterBase.java

/*
 * Copyright (c) 2015 Spotify AB.
 *
 * 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 com.spotify.heroic.filter;

import com.google.common.collect.ImmutableList;
import com.spotify.heroic.common.BiConsumerIO;
import com.spotify.heroic.common.FunctionIO;
import lombok.RequiredArgsConstructor;

import java.io.IOException;
import java.util.List;
import java.util.Optional;
import java.util.function.Function;

@RequiredArgsConstructor
public class MultiArgumentsFilterBase<T extends Filter, A> implements FilterEncoding<T> {
    private final Function<List<A>, T> builder;
    private final Function<T, List<A>> argument;

    private final FunctionIO<Decoder, Optional<A>> decode;
    private final BiConsumerIO<Encoder, A> encode;

    public MultiArgumentsFilterBase(
        final Function<List<A>, T> builder, final Function<T, List<A>> argument,
        final FilterEncodingComponent<A> encoding
    ) {
        this.argument = argument;
        this.builder = builder;

        this.decode = encoding.getDecoder();
        this.encode = encoding.getEncoder();
    }

    @Override
    public T deserialize(Decoder decoder) throws IOException {
        final ImmutableList.Builder<A> terms = ImmutableList.builder();

        while (true) {
            final Optional<A> arg = decode.apply(decoder);

            if (!arg.isPresent()) {
                break;
            }

            terms.add(arg.get());
        }

        return builder.apply(terms.build());
    }

    @Override
    public void serialize(Encoder encoder, T filter) throws IOException {
        for (final A term : argument.apply(filter)) {
            encode.accept(encoder, term);
        }
    }
}