/*
 * 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.hudi.table.lookup;

import org.apache.flink.table.data.RowData;

import javax.annotation.Nullable;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Heap-based {@link LookupCache} backed by a {@link HashMap}.
 *
 * <p>Suitable for small-to-medium dimension tables. For large tables, use
 * {@link RocksDBLookupCache} to avoid JVM OutOfMemoryError.
 */
public class HeapLookupCache implements LookupCache {

  private final Map<RowData, List<RowData>> store = new HashMap<>();

  @Override
  public void addRow(RowData key, RowData row) {
    store.computeIfAbsent(key, k -> new ArrayList<>()).add(row);
  }

  @Override
  @Nullable
  public List<RowData> getRows(RowData key) {
    return store.get(key);
  }

  @Override
  public void clear() {
    store.clear();
  }

  @Override
  public void close() {
    store.clear();
  }
}
