/*
 * Copyright 2023 RisingWave Labs
 *
 * 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.risingwave.java.binding;

import com.risingwave.proto.JavaBinding.ReadPlan;

public class HummockIterator implements AutoCloseable {
    private final long pointer;
    private boolean isClosed;

    static {
        Binding.ensureInitialized();
    }

    // hummock iterator method
    // Return a pointer to the iterator
    private static native long iteratorNewHummock(byte[] readPlan);

    public HummockIterator(ReadPlan readPlan) {
        this.pointer = iteratorNewHummock(readPlan.toByteArray());
        this.isClosed = false;
    }

    public KeyedRow next() {
        boolean hasNext = Binding.iteratorNext(this.pointer);
        if (!hasNext) {
            return null;
        }
        return new KeyedRow(pointer);
    }

    @Override
    public void close() {
        if (!isClosed) {
            isClosed = true;
            Binding.iteratorClose(pointer);
        }
    }
}
