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Java example source code file (RegularImmutableTable.java)
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The RegularImmutableTable.java Java example source code
/*
* 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.common.collect.Table.Cell;
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 javax.annotation.Nullable;
/**
* An implementation of {@link ImmutableTable} holding an arbitrary number of
* cells.
*
* @author Gregory Kick
*/
@GwtCompatible
abstract class RegularImmutableTable<R, C, V> extends ImmutableTable {
RegularImmutableTable() {}
abstract Cell<R, C, V> getCell(int iterationIndex);
@Override
final ImmutableSet<Cell createCellSet() {
return isEmpty() ? ImmutableSet.<Cellof() : new CellSet();
}
@WeakOuter
private final class CellSet extends ImmutableSet.Indexed<Cell {
@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 forCells(
List<Cell cells,
@Nullable final Comparator<? super R> rowComparator,
@Nullable final 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 comparator =
new Comparator<Cell() {
@Override
public int compare(Cell<R, C, V> cell1, Cell 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 forCells(Iterable> cells) {
return forCellsInternal(cells, null, null);
}
/**
* A factory that chooses the most space-efficient representation of the
* table.
*/
private static final <R, C, V> RegularImmutableTable forCellsInternal(
Iterable<Cell cells,
@Nullable Comparator<? super R> rowComparator,
@Nullable Comparator<? super C> columnComparator) {
Set<R> rowSpaceBuilder = new LinkedHashSet();
Set<C> columnSpaceBuilder = new LinkedHashSet();
ImmutableList<Cell 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(
Ordering.from(rowComparator).immutableSortedCopy(rowSpaceBuilder));
ImmutableSet<C> columnSpace =
(columnComparator == null)
? ImmutableSet.copyOf(columnSpaceBuilder)
: ImmutableSet.copyOf(
Ordering.from(columnComparator).immutableSortedCopy(columnSpaceBuilder));
// 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);
}
}
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