/*
 * 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 com.google.j2objc.annotations.WeakOuter;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

An implementation of ImmutableTable holding an arbitrary number of cells.
Author:Gregory Kick
/** * An implementation of {@link ImmutableTable} holding an arbitrary number of cells. * * @author Gregory Kick */
@GwtCompatible abstract class RegularImmutableTable<R, C, V> extends ImmutableTable<R, C, V> { RegularImmutableTable() {} abstract Cell<R, C, V> getCell(int iterationIndex); @Override final ImmutableSet<Cell<R, C, V>> createCellSet() { return isEmpty() ? ImmutableSet.<Cell<R, C, V>>of() : new CellSet(); } @WeakOuter private final class CellSet extends IndexedImmutableSet<Cell<R, C, V>> { @Override public int size() { return RegularImmutableTable.this.size(); } @Override Cell<R, C, V> get(int index) { return getCell(index); } @Override public boolean contains(@Nullable Object object) { if (object instanceof Cell) { Cell<?, ?, ?> cell = (Cell<?, ?, ?>) object; Object value = RegularImmutableTable.this.get(cell.getRowKey(), cell.getColumnKey()); return value != null && value.equals(cell.getValue()); } return false; } @Override boolean isPartialView() { return false; } } abstract V getValue(int iterationIndex); @Override final ImmutableCollection<V> createValues() { return isEmpty() ? ImmutableList.<V>of() : new Values(); } @WeakOuter private final class Values extends ImmutableList<V> { @Override public int size() { return RegularImmutableTable.this.size(); } @Override public V get(int index) { return getValue(index); } @Override boolean isPartialView() { return true; } } static <R, C, V> RegularImmutableTable<R, C, V> forCells( List<Cell<R, C, V>> cells, final @Nullable Comparator<? super R> rowComparator, final @Nullable Comparator<? super C> columnComparator) { checkNotNull(cells); if (rowComparator != null || columnComparator != null) { /* * This sorting logic leads to a cellSet() ordering that may not be expected and that isn't * documented in the Javadoc. If a row Comparator is provided, cellSet() iterates across the * columns in the first row, the columns in the second row, etc. If a column Comparator is * provided but a row Comparator isn't, cellSet() iterates across the rows in the first * column, the rows in the second column, etc. */ Comparator<Cell<R, C, V>> comparator = new Comparator<Cell<R, C, V>>() { @Override public int compare(Cell<R, C, V> cell1, Cell<R, C, V> cell2) { int rowCompare = (rowComparator == null) ? 0 : rowComparator.compare(cell1.getRowKey(), cell2.getRowKey()); if (rowCompare != 0) { return rowCompare; } return (columnComparator == null) ? 0 : columnComparator.compare(cell1.getColumnKey(), cell2.getColumnKey()); } }; Collections.sort(cells, comparator); } return forCellsInternal(cells, rowComparator, columnComparator); } static <R, C, V> RegularImmutableTable<R, C, V> forCells(Iterable<Cell<R, C, V>> cells) { return forCellsInternal(cells, null, null); } private static <R, C, V> RegularImmutableTable<R, C, V> forCellsInternal( Iterable<Cell<R, C, V>> cells, @Nullable Comparator<? super R> rowComparator, @Nullable Comparator<? super C> columnComparator) { Set<R> rowSpaceBuilder = new LinkedHashSet<>(); Set<C> columnSpaceBuilder = new LinkedHashSet<>(); ImmutableList<Cell<R, C, V>> cellList = ImmutableList.copyOf(cells); for (Cell<R, C, V> cell : cells) { rowSpaceBuilder.add(cell.getRowKey()); columnSpaceBuilder.add(cell.getColumnKey()); } ImmutableSet<R> rowSpace = (rowComparator == null) ? ImmutableSet.copyOf(rowSpaceBuilder) : ImmutableSet.copyOf(ImmutableList.sortedCopyOf(rowComparator, rowSpaceBuilder)); ImmutableSet<C> columnSpace = (columnComparator == null) ? ImmutableSet.copyOf(columnSpaceBuilder) : ImmutableSet.copyOf(ImmutableList.sortedCopyOf(columnComparator, columnSpaceBuilder)); return forOrderedComponents(cellList, rowSpace, columnSpace); }
A factory that chooses the most space-efficient representation of the table.
/** A factory that chooses the most space-efficient representation of the table. */
static <R, C, V> RegularImmutableTable<R, C, V> forOrderedComponents( ImmutableList<Cell<R, C, V>> cellList, ImmutableSet<R> rowSpace, ImmutableSet<C> columnSpace) { // use a dense table if more than half of the cells have values // TODO(gak): tune this condition based on empirical evidence return (cellList.size() > (((long) rowSpace.size() * columnSpace.size()) / 2)) ? new DenseImmutableTable<R, C, V>(cellList, rowSpace, columnSpace) : new SparseImmutableTable<R, C, V>(cellList, rowSpace, columnSpace); } }