/*
    * Copyright (C) 2009 The Guava Authors
    *
    * 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.common.collect;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  import com.google.common.annotations.GwtCompatible;
  
  import java.util.Map;
  
  /**
   * An implementation of {@link ImmutableTable} that holds a single cell.
   *
   * @author Gregory Kick
   */
  @GwtCompatible
  class SingletonImmutableTable<R, C, V> extends ImmutableTable<R, C, V> {
    final R singleRowKey;
    final C singleColumnKey;
    final V singleValue;
  
    SingletonImmutableTable(R rowKey, C columnKey, V value) {
      this.singleRowKey = checkNotNull(rowKey);
      this.singleColumnKey = checkNotNull(columnKey);
      this.singleValue = checkNotNull(value);
    }
  
    SingletonImmutableTable(Cell<R, C, V> cell) {
      this(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
    }
  
    @Override public ImmutableMap<R, V> column(C columnKey) {
      checkNotNull(columnKey);
      return containsColumn(columnKey)
          ? ImmutableMap.of(singleRowKey, singleValue)
          : ImmutableMap.<R, V>of();
    }
  
    @Override public ImmutableMap<C, Map<R, V>> columnMap() {
      return ImmutableMap.of(singleColumnKey,
          (Map<R, V>) ImmutableMap.of(singleRowKey, singleValue));
    }
  
    @Override public ImmutableMap<R, Map<C, V>> rowMap() {
      return ImmutableMap.of(singleRowKey,
          (Map<C, V>) ImmutableMap.of(singleColumnKey, singleValue));
    }
  
    @Override public int size() {
      return 1;
    }
  
    @Override
    ImmutableSet<Cell<R, C, V>> createCellSet() {
      return ImmutableSet.of(
          cellOf(singleRowKey, singleColumnKey, singleValue));
    }
  
    @Override ImmutableCollection<V> createValues() {
      return ImmutableSet.of(singleValue);
    }
  }