| /* |
| * Copyright (C) 2008 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.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.base.Function; |
| import com.google.common.base.Supplier; |
| |
| import java.io.Serializable; |
| import java.util.Comparator; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.NoSuchElementException; |
| import java.util.Set; |
| import java.util.SortedMap; |
| import java.util.SortedSet; |
| import java.util.TreeMap; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Implementation of {@code Table} whose row keys and column keys are ordered |
| * by their natural ordering or by supplied comparators. When constructing a |
| * {@code TreeBasedTable}, you may provide comparators for the row keys and |
| * the column keys, or you may use natural ordering for both. |
| * |
| * <p>The {@link #rowKeySet} method returns a {@link SortedSet} and the {@link |
| * #rowMap} method returns a {@link SortedMap}, instead of the {@link Set} and |
| * {@link Map} specified by the {@link Table} interface. |
| * |
| * <p>The views returned by {@link #column}, {@link #columnKeySet()}, and {@link |
| * #columnMap()} have iterators that don't support {@code remove()}. Otherwise, |
| * all optional operations are supported. Null row keys, columns keys, and |
| * values are not supported. |
| * |
| * <p>Lookups by row key are often faster than lookups by column key, because |
| * the data is stored in a {@code Map<R, Map<C, V>>}. A method call like {@code |
| * column(columnKey).get(rowKey)} still runs quickly, since the row key is |
| * provided. However, {@code column(columnKey).size()} takes longer, since an |
| * iteration across all row keys occurs. |
| * |
| * <p>Because a {@code TreeBasedTable} has unique sorted values for a given |
| * row, both {@code row(rowKey)} and {@code rowMap().get(rowKey)} are {@link |
| * SortedMap} instances, instead of the {@link Map} specified in the {@link |
| * Table} interface. |
| * |
| * <p>Note that this implementation is not synchronized. If multiple threads |
| * access this table concurrently and one of the threads modifies the table, it |
| * must be synchronized externally. |
| * |
| * <p>See the Guava User Guide article on <a href= |
| * "http://code.google.com/p/guava-libraries/wiki/NewCollectionTypesExplained#Table"> |
| * {@code Table}</a>. |
| * |
| * @author Jared Levy |
| * @author Louis Wasserman |
| * @since 7.0 |
| */ |
| @GwtCompatible(serializable = true) |
| @Beta |
| public class TreeBasedTable<R, C, V> extends StandardRowSortedTable<R, C, V> { |
| private final Comparator<? super C> columnComparator; |
| |
| private static class Factory<C, V> |
| implements Supplier<TreeMap<C, V>>, Serializable { |
| final Comparator<? super C> comparator; |
| Factory(Comparator<? super C> comparator) { |
| this.comparator = comparator; |
| } |
| @Override |
| public TreeMap<C, V> get() { |
| return new TreeMap<C, V>(comparator); |
| } |
| private static final long serialVersionUID = 0; |
| } |
| |
| /** |
| * Creates an empty {@code TreeBasedTable} that uses the natural orderings |
| * of both row and column keys. |
| * |
| * <p>The method signature specifies {@code R extends Comparable} with a raw |
| * {@link Comparable}, instead of {@code R extends Comparable<? super R>}, |
| * and the same for {@code C}. That's necessary to support classes defined |
| * without generics. |
| */ |
| public static <R extends Comparable, C extends Comparable, V> |
| TreeBasedTable<R, C, V> create() { |
| return new TreeBasedTable<R, C, V>(Ordering.natural(), |
| Ordering.natural()); |
| } |
| |
| /** |
| * Creates an empty {@code TreeBasedTable} that is ordered by the specified |
| * comparators. |
| * |
| * @param rowComparator the comparator that orders the row keys |
| * @param columnComparator the comparator that orders the column keys |
| */ |
| public static <R, C, V> TreeBasedTable<R, C, V> create( |
| Comparator<? super R> rowComparator, |
| Comparator<? super C> columnComparator) { |
| checkNotNull(rowComparator); |
| checkNotNull(columnComparator); |
| return new TreeBasedTable<R, C, V>(rowComparator, columnComparator); |
| } |
| |
| /** |
| * Creates a {@code TreeBasedTable} with the same mappings and sort order |
| * as the specified {@code TreeBasedTable}. |
| */ |
| public static <R, C, V> TreeBasedTable<R, C, V> create( |
| TreeBasedTable<R, C, ? extends V> table) { |
| TreeBasedTable<R, C, V> result |
| = new TreeBasedTable<R, C, V>( |
| table.rowComparator(), table.columnComparator()); |
| result.putAll(table); |
| return result; |
| } |
| |
| TreeBasedTable(Comparator<? super R> rowComparator, |
| Comparator<? super C> columnComparator) { |
| super(new TreeMap<R, Map<C, V>>(rowComparator), |
| new Factory<C, V>(columnComparator)); |
| this.columnComparator = columnComparator; |
| } |
| |
| // TODO(jlevy): Move to StandardRowSortedTable? |
| |
| /** |
| * Returns the comparator that orders the rows. With natural ordering, |
| * {@link Ordering#natural()} is returned. |
| */ |
| public Comparator<? super R> rowComparator() { |
| return rowKeySet().comparator(); |
| } |
| |
| /** |
| * Returns the comparator that orders the columns. With natural ordering, |
| * {@link Ordering#natural()} is returned. |
| */ |
| public Comparator<? super C> columnComparator() { |
| return columnComparator; |
| } |
| |
| // TODO(user): make column return a SortedMap |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Because a {@code TreeBasedTable} has unique sorted values for a given |
| * row, this method returns a {@link SortedMap}, instead of the {@link Map} |
| * specified in the {@link Table} interface. |
| * @since 10.0 |
| * (<a href="http://code.google.com/p/guava-libraries/wiki/Compatibility" |
| * >mostly source-compatible</a> since 7.0) |
| */ |
| @Override |
| public SortedMap<C, V> row(R rowKey) { |
| return new TreeRow(rowKey); |
| } |
| |
| private class TreeRow extends Row implements SortedMap<C, V> { |
| @Nullable final C lowerBound; |
| @Nullable final C upperBound; |
| |
| TreeRow(R rowKey) { |
| this(rowKey, null, null); |
| } |
| |
| TreeRow(R rowKey, @Nullable C lowerBound, @Nullable C upperBound) { |
| super(rowKey); |
| this.lowerBound = lowerBound; |
| this.upperBound = upperBound; |
| checkArgument(lowerBound == null || upperBound == null |
| || compare(lowerBound, upperBound) <= 0); |
| } |
| |
| @Override public SortedSet<C> keySet() { |
| return new Maps.SortedKeySet<C, V>(this); |
| } |
| |
| @Override public Comparator<? super C> comparator() { |
| return columnComparator(); |
| } |
| |
| int compare(Object a, Object b) { |
| // pretend we can compare anything |
| @SuppressWarnings({"rawtypes", "unchecked"}) |
| Comparator<Object> cmp = (Comparator) comparator(); |
| return cmp.compare(a, b); |
| } |
| |
| boolean rangeContains(@Nullable Object o) { |
| return o != null && (lowerBound == null || compare(lowerBound, o) <= 0) |
| && (upperBound == null || compare(upperBound, o) > 0); |
| } |
| |
| @Override public SortedMap<C, V> subMap(C fromKey, C toKey) { |
| checkArgument(rangeContains(checkNotNull(fromKey)) |
| && rangeContains(checkNotNull(toKey))); |
| return new TreeRow(rowKey, fromKey, toKey); |
| } |
| |
| @Override public SortedMap<C, V> headMap(C toKey) { |
| checkArgument(rangeContains(checkNotNull(toKey))); |
| return new TreeRow(rowKey, lowerBound, toKey); |
| } |
| |
| @Override public SortedMap<C, V> tailMap(C fromKey) { |
| checkArgument(rangeContains(checkNotNull(fromKey))); |
| return new TreeRow(rowKey, fromKey, upperBound); |
| } |
| |
| @Override public C firstKey() { |
| SortedMap<C, V> backing = backingRowMap(); |
| if (backing == null) { |
| throw new NoSuchElementException(); |
| } |
| return backingRowMap().firstKey(); |
| } |
| |
| @Override public C lastKey() { |
| SortedMap<C, V> backing = backingRowMap(); |
| if (backing == null) { |
| throw new NoSuchElementException(); |
| } |
| return backingRowMap().lastKey(); |
| } |
| |
| transient SortedMap<C, V> wholeRow; |
| |
| /* |
| * If the row was previously empty, we check if there's a new row here every |
| * time we're queried. |
| */ |
| SortedMap<C, V> wholeRow() { |
| if (wholeRow == null |
| || (wholeRow.isEmpty() && backingMap.containsKey(rowKey))) { |
| wholeRow = (SortedMap<C, V>) backingMap.get(rowKey); |
| } |
| return wholeRow; |
| } |
| |
| @Override |
| SortedMap<C, V> backingRowMap() { |
| return (SortedMap<C, V>) super.backingRowMap(); |
| } |
| |
| @Override |
| SortedMap<C, V> computeBackingRowMap() { |
| SortedMap<C, V> map = wholeRow(); |
| if (map != null) { |
| if (lowerBound != null) { |
| map = map.tailMap(lowerBound); |
| } |
| if (upperBound != null) { |
| map = map.headMap(upperBound); |
| } |
| return map; |
| } |
| return null; |
| } |
| |
| @Override |
| void maintainEmptyInvariant() { |
| if (wholeRow() != null && wholeRow.isEmpty()) { |
| backingMap.remove(rowKey); |
| wholeRow = null; |
| backingRowMap = null; |
| } |
| } |
| |
| @Override public boolean containsKey(Object key) { |
| return rangeContains(key) && super.containsKey(key); |
| } |
| |
| @Override public V put(C key, V value) { |
| checkArgument(rangeContains(checkNotNull(key))); |
| return super.put(key, value); |
| } |
| } |
| |
| // rowKeySet() and rowMap() are defined here so they appear in the Javadoc. |
| |
| @Override public SortedSet<R> rowKeySet() { |
| return super.rowKeySet(); |
| } |
| |
| @Override public SortedMap<R, Map<C, V>> rowMap() { |
| return super.rowMap(); |
| } |
| |
| /** |
| * Overridden column iterator to return columns values in globally sorted |
| * order. |
| */ |
| @Override |
| Iterator<C> createColumnKeyIterator() { |
| final Comparator<? super C> comparator = columnComparator(); |
| |
| final Iterator<C> merged = |
| Iterators.mergeSorted(Iterables.transform(backingMap.values(), |
| new Function<Map<C, V>, Iterator<C>>() { |
| @Override |
| public Iterator<C> apply(Map<C, V> input) { |
| return input.keySet().iterator(); |
| } |
| }), comparator); |
| |
| return new AbstractIterator<C>() { |
| C lastValue; |
| |
| @Override |
| protected C computeNext() { |
| while (merged.hasNext()) { |
| C next = merged.next(); |
| boolean duplicate = |
| lastValue != null && comparator.compare(next, lastValue) == 0; |
| |
| // Keep looping till we find a non-duplicate value. |
| if (!duplicate) { |
| lastValue = next; |
| return lastValue; |
| } |
| } |
| |
| lastValue = null; // clear reference to unused data |
| return endOfData(); |
| } |
| }; |
| } |
| |
| private static final long serialVersionUID = 0; |
| } |