EaglerForge/sources/main/java/com/google/common/collect/ArrayTable.java

794 lines
23 KiB
Java

/*
* 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.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Objects;
/**
* Fixed-size {@link Table} implementation backed by a two-dimensional array.
*
* <p>
* The allowed row and column keys must be supplied when the table is created.
* The table always contains a mapping for every row key / column pair. The
* value corresponding to a given row and column is null unless another value is
* provided.
*
* <p>
* The table's size is constant: the product of the number of supplied row keys
* and the number of supplied column keys. The {@code remove} and {@code
* clear} methods are not supported by the table or its views. The
* {@link #erase} and {@link #eraseAll} methods may be used instead.
*
* <p>
* The ordering of the row and column keys provided when the table is
* constructed determines the iteration ordering across rows and columns in the
* table's views. None of the view iterators support {@link Iterator#remove}. If
* the table is modified after an iterator is created, the iterator remains
* valid.
*
* <p>
* This class requires less memory than the {@link HashBasedTable} and
* {@link TreeBasedTable} implementations, except when the table is sparse.
*
* <p>
* Null row keys or column keys are not permitted.
*
* <p>
* This class provides methods involving the underlying array structure, where
* the array indices correspond to the position of a row or column in the lists
* of allowed keys and values. See the {@link #at}, {@link #set},
* {@link #toArray}, {@link #rowKeyList}, and {@link #columnKeyList} methods for
* more details.
*
* <p>
* Note that this implementation is not synchronized. If multiple threads access
* the same cell of an {@code ArrayTable} concurrently and one of the threads
* modifies its value, there is no guarantee that the new value will be fully
* visible to the other threads. To guarantee that modifications are visible,
* synchronize access to the table. Unlike other {@code Table} implementations,
* synchronization is unnecessary between a thread that writes to one cell and a
* thread that reads from another.
*
* <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
* @since 10.0
*/
@Beta
@GwtCompatible(emulated = true)
public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements Serializable {
/**
* Creates an empty {@code ArrayTable}.
*
* @param rowKeys row keys that may be stored in the generated table
* @param columnKeys column keys that may be stored in the generated table
* @throws NullPointerException if any of the provided keys is null
* @throws IllegalArgumentException if {@code rowKeys} or {@code columnKeys}
* contains duplicates or is empty
*/
public static <R, C, V> ArrayTable<R, C, V> create(Iterable<? extends R> rowKeys,
Iterable<? extends C> columnKeys) {
return new ArrayTable<R, C, V>(rowKeys, columnKeys);
}
/*
* TODO(jlevy): Add factory methods taking an Enum class, instead of an
* iterable, to specify the allowed row keys and/or column keys. Note that
* custom serialization logic is needed to support different enum sizes during
* serialization and deserialization.
*/
/**
* Creates an {@code ArrayTable} with the mappings in the provided table.
*
* <p>
* If {@code table} includes a mapping with row key {@code r} and a separate
* mapping with column key {@code c}, the returned table contains a mapping with
* row key {@code r} and column key {@code c}. If that row key / column key pair
* in not in {@code table}, the pair maps to {@code null} in the generated
* table.
*
* <p>
* The returned table allows subsequent {@code put} calls with the row keys in
* {@code table.rowKeySet()} and the column keys in {@code
* table.columnKeySet()}. Calling {@link #put} with other keys leads to an
* {@code IllegalArgumentException}.
*
* <p>
* The ordering of {@code table.rowKeySet()} and {@code
* table.columnKeySet()} determines the row and column iteration ordering of the
* returned table.
*
* @throws NullPointerException if {@code table} has a null key
* @throws IllegalArgumentException if the provided table is empty
*/
public static <R, C, V> ArrayTable<R, C, V> create(Table<R, C, V> table) {
return (table instanceof ArrayTable<?, ?, ?>) ? new ArrayTable<R, C, V>((ArrayTable<R, C, V>) table)
: new ArrayTable<R, C, V>(table);
}
private final ImmutableList<R> rowList;
private final ImmutableList<C> columnList;
// TODO(jlevy): Add getters returning rowKeyToIndex and columnKeyToIndex?
private final ImmutableMap<R, Integer> rowKeyToIndex;
private final ImmutableMap<C, Integer> columnKeyToIndex;
private final V[][] array;
private ArrayTable(Iterable<? extends R> rowKeys, Iterable<? extends C> columnKeys) {
this.rowList = ImmutableList.copyOf(rowKeys);
this.columnList = ImmutableList.copyOf(columnKeys);
checkArgument(!rowList.isEmpty());
checkArgument(!columnList.isEmpty());
/*
* TODO(jlevy): Support empty rowKeys or columnKeys? If we do, when columnKeys
* is empty but rowKeys isn't, the table is empty but containsRow() can return
* true and rowKeySet() isn't empty.
*/
rowKeyToIndex = index(rowList);
columnKeyToIndex = index(columnList);
@SuppressWarnings("unchecked")
V[][] tmpArray = (V[][]) new Object[rowList.size()][columnList.size()];
array = tmpArray;
// Necessary because in GWT the arrays are initialized with "undefined" instead
// of null.
eraseAll();
}
private static <E> ImmutableMap<E, Integer> index(List<E> list) {
ImmutableMap.Builder<E, Integer> columnBuilder = ImmutableMap.builder();
for (int i = 0; i < list.size(); i++) {
columnBuilder.put(list.get(i), i);
}
return columnBuilder.build();
}
private ArrayTable(Table<R, C, V> table) {
this(table.rowKeySet(), table.columnKeySet());
putAll(table);
}
private ArrayTable(ArrayTable<R, C, V> table) {
rowList = table.rowList;
columnList = table.columnList;
rowKeyToIndex = table.rowKeyToIndex;
columnKeyToIndex = table.columnKeyToIndex;
@SuppressWarnings("unchecked")
V[][] copy = (V[][]) new Object[rowList.size()][columnList.size()];
array = copy;
// Necessary because in GWT the arrays are initialized with "undefined" instead
// of null.
eraseAll();
for (int i = 0; i < rowList.size(); i++) {
System.arraycopy(table.array[i], 0, copy[i], 0, table.array[i].length);
}
}
private abstract static class ArrayMap<K, V> extends Maps.ImprovedAbstractMap<K, V> {
private final ImmutableMap<K, Integer> keyIndex;
private ArrayMap(ImmutableMap<K, Integer> keyIndex) {
this.keyIndex = keyIndex;
}
@Override
public Set<K> keySet() {
return keyIndex.keySet();
}
K getKey(int index) {
return keyIndex.keySet().asList().get(index);
}
abstract String getKeyRole();
@Nullable
abstract V getValue(int index);
@Nullable
abstract V setValue(int index, V newValue);
@Override
public int size() {
return keyIndex.size();
}
@Override
public boolean isEmpty() {
return keyIndex.isEmpty();
}
@Override
protected Set<Entry<K, V>> createEntrySet() {
return new Maps.EntrySet<K, V>() {
@Override
Map<K, V> map() {
return ArrayMap.this;
}
@Override
public Iterator<Entry<K, V>> iterator() {
return new AbstractIndexedListIterator<Entry<K, V>>(size()) {
@Override
protected Entry<K, V> get(final int index) {
return new AbstractMapEntry<K, V>() {
@Override
public K getKey() {
return ArrayMap.this.getKey(index);
}
@Override
public V getValue() {
return ArrayMap.this.getValue(index);
}
@Override
public V setValue(V value) {
return ArrayMap.this.setValue(index, value);
}
};
}
};
}
};
}
// TODO(user): consider an optimized values() implementation
@Override
public boolean containsKey(@Nullable Object key) {
return keyIndex.containsKey(key);
}
@Override
public V get(@Nullable Object key) {
Integer index = keyIndex.get(key);
if (index == null) {
return null;
} else {
return getValue(index);
}
}
@Override
public V put(K key, V value) {
Integer index = keyIndex.get(key);
if (index == null) {
throw new IllegalArgumentException(getKeyRole() + " " + key + " not in " + keyIndex.keySet());
}
return setValue(index, value);
}
@Override
public V remove(Object key) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
}
/**
* Returns, as an immutable list, the row keys provided when the table was
* constructed, including those that are mapped to null values only.
*/
public ImmutableList<R> rowKeyList() {
return rowList;
}
/**
* Returns, as an immutable list, the column keys provided when the table was
* constructed, including those that are mapped to null values only.
*/
public ImmutableList<C> columnKeyList() {
return columnList;
}
/**
* Returns the value corresponding to the specified row and column indices. The
* same value is returned by {@code
* get(rowKeyList().get(rowIndex), columnKeyList().get(columnIndex))}, but this
* method runs more quickly.
*
* @param rowIndex position of the row key in {@link #rowKeyList()}
* @param columnIndex position of the row key in {@link #columnKeyList()}
* @return the value with the specified row and column
* @throws IndexOutOfBoundsException if either index is negative, {@code
* rowIndex} is greater then or equal to the number of
* allowed row keys, or {@code columnIndex} is
* greater then or equal to the number of
* allowed column keys
*/
public V at(int rowIndex, int columnIndex) {
// In GWT array access never throws IndexOutOfBoundsException.
checkElementIndex(rowIndex, rowList.size());
checkElementIndex(columnIndex, columnList.size());
return array[rowIndex][columnIndex];
}
/**
* Associates {@code value} with the specified row and column indices. The logic
* {@code
* put(rowKeyList().get(rowIndex), columnKeyList().get(columnIndex), value)} has
* the same behavior, but this method runs more quickly.
*
* @param rowIndex position of the row key in {@link #rowKeyList()}
* @param columnIndex position of the row key in {@link #columnKeyList()}
* @param value value to store in the table
* @return the previous value with the specified row and column
* @throws IndexOutOfBoundsException if either index is negative, {@code
* rowIndex} is greater then or equal to the number of
* allowed row keys, or {@code columnIndex} is
* greater then or equal to the number of
* allowed column keys
*/
public V set(int rowIndex, int columnIndex, @Nullable V value) {
// In GWT array access never throws IndexOutOfBoundsException.
checkElementIndex(rowIndex, rowList.size());
checkElementIndex(columnIndex, columnList.size());
V oldValue = array[rowIndex][columnIndex];
array[rowIndex][columnIndex] = value;
return oldValue;
}
/**
* Returns a two-dimensional array with the table contents. The row and column
* indices correspond to the positions of the row and column in the iterables
* provided during table construction. If the table lacks a mapping for a given
* row and column, the corresponding array element is null.
*
* <p>
* Subsequent table changes will not modify the array, and vice versa.
*
* @param valueClass class of values stored in the returned array
*/
@GwtIncompatible("reflection")
public V[][] toArray(Class<V> valueClass) {
// Can change to use varargs in JDK 1.6 if we want
@SuppressWarnings("unchecked") // TODO: safe?
V[][] copy = (V[][]) Array.newInstance(valueClass, new int[] { rowList.size(), columnList.size() });
for (int i = 0; i < rowList.size(); i++) {
System.arraycopy(array[i], 0, copy[i], 0, array[i].length);
}
return copy;
}
/**
* Not supported. Use {@link #eraseAll} instead.
*
* @throws UnsupportedOperationException always
* @deprecated Use {@link #eraseAll}
*/
@Override
@Deprecated
public void clear() {
throw new UnsupportedOperationException();
}
/**
* Associates the value {@code null} with every pair of allowed row and column
* keys.
*/
public void eraseAll() {
for (V[] row : array) {
Arrays.fill(row, null);
}
}
/**
* Returns {@code true} if the provided keys are among the keys provided when
* the table was constructed.
*/
@Override
public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey) {
return containsRow(rowKey) && containsColumn(columnKey);
}
/**
* Returns {@code true} if the provided column key is among the column keys
* provided when the table was constructed.
*/
@Override
public boolean containsColumn(@Nullable Object columnKey) {
return columnKeyToIndex.containsKey(columnKey);
}
/**
* Returns {@code true} if the provided row key is among the row keys provided
* when the table was constructed.
*/
@Override
public boolean containsRow(@Nullable Object rowKey) {
return rowKeyToIndex.containsKey(rowKey);
}
@Override
public boolean containsValue(@Nullable Object value) {
for (V[] row : array) {
for (V element : row) {
if (Objects.equal(value, element)) {
return true;
}
}
}
return false;
}
@Override
public V get(@Nullable Object rowKey, @Nullable Object columnKey) {
Integer rowIndex = rowKeyToIndex.get(rowKey);
Integer columnIndex = columnKeyToIndex.get(columnKey);
return (rowIndex == null || columnIndex == null) ? null : at(rowIndex, columnIndex);
}
/**
* Always returns {@code false}.
*/
@Override
public boolean isEmpty() {
return false;
}
/**
* {@inheritDoc}
*
* @throws IllegalArgumentException if {@code rowKey} is not in
* {@link #rowKeySet()} or {@code columnKey} is
* not in {@link #columnKeySet()}.
*/
@Override
public V put(R rowKey, C columnKey, @Nullable V value) {
checkNotNull(rowKey);
checkNotNull(columnKey);
Integer rowIndex = rowKeyToIndex.get(rowKey);
checkArgument(rowIndex != null, "Row %s not in %s", rowKey, rowList);
Integer columnIndex = columnKeyToIndex.get(columnKey);
checkArgument(columnIndex != null, "Column %s not in %s", columnKey, columnList);
return set(rowIndex, columnIndex, value);
}
/*
* TODO(jlevy): Consider creating a merge() method, similar to putAll() but
* copying non-null values only.
*/
/**
* {@inheritDoc}
*
* <p>
* If {@code table} is an {@code ArrayTable}, its null values will be stored in
* this table, possibly replacing values that were previously non-null.
*
* @throws NullPointerException if {@code table} has a null key
* @throws IllegalArgumentException if any of the provided table's row keys or
* column keys is not in {@link #rowKeySet()}
* or {@link #columnKeySet()}
*/
@Override
public void putAll(Table<? extends R, ? extends C, ? extends V> table) {
super.putAll(table);
}
/**
* Not supported. Use {@link #erase} instead.
*
* @throws UnsupportedOperationException always
* @deprecated Use {@link #erase}
*/
@Override
@Deprecated
public V remove(Object rowKey, Object columnKey) {
throw new UnsupportedOperationException();
}
/**
* Associates the value {@code null} with the specified keys, assuming both keys
* are valid. If either key is null or isn't among the keys provided during
* construction, this method has no effect.
*
* <p>
* This method is equivalent to {@code put(rowKey, columnKey, null)} when both
* provided keys are valid.
*
* @param rowKey row key of mapping to be erased
* @param columnKey column key of mapping to be erased
* @return the value previously associated with the keys, or {@code null} if no
* mapping existed for the keys
*/
public V erase(@Nullable Object rowKey, @Nullable Object columnKey) {
Integer rowIndex = rowKeyToIndex.get(rowKey);
Integer columnIndex = columnKeyToIndex.get(columnKey);
if (rowIndex == null || columnIndex == null) {
return null;
}
return set(rowIndex, columnIndex, null);
}
// TODO(jlevy): Add eraseRow and eraseColumn methods?
@Override
public int size() {
return rowList.size() * columnList.size();
}
/**
* Returns an unmodifiable set of all row key / column key / value triplets.
* Changes to the table will update the returned set.
*
* <p>
* The returned set's iterator traverses the mappings with the first row key,
* the mappings with the second row key, and so on.
*
* <p>
* The value in the returned cells may change if the table subsequently changes.
*
* @return set of table cells consisting of row key / column key / value
* triplets
*/
@Override
public Set<Cell<R, C, V>> cellSet() {
return super.cellSet();
}
@Override
Iterator<Cell<R, C, V>> cellIterator() {
return new AbstractIndexedListIterator<Cell<R, C, V>>(size()) {
@Override
protected Cell<R, C, V> get(final int index) {
return new Tables.AbstractCell<R, C, V>() {
final int rowIndex = index / columnList.size();
final int columnIndex = index % columnList.size();
@Override
public R getRowKey() {
return rowList.get(rowIndex);
}
@Override
public C getColumnKey() {
return columnList.get(columnIndex);
}
@Override
public V getValue() {
return at(rowIndex, columnIndex);
}
};
}
};
}
/**
* Returns a view of all mappings that have the given column key. If the column
* key isn't in {@link #columnKeySet()}, an empty immutable map is returned.
*
* <p>
* Otherwise, for each row key in {@link #rowKeySet()}, the returned map
* associates the row key with the corresponding value in the table. Changes to
* the returned map will update the underlying table, and vice versa.
*
* @param columnKey key of column to search for in the table
* @return the corresponding map from row keys to values
*/
@Override
public Map<R, V> column(C columnKey) {
checkNotNull(columnKey);
Integer columnIndex = columnKeyToIndex.get(columnKey);
return (columnIndex == null) ? ImmutableMap.<R, V>of() : new Column(columnIndex);
}
private class Column extends ArrayMap<R, V> {
final int columnIndex;
Column(int columnIndex) {
super(rowKeyToIndex);
this.columnIndex = columnIndex;
}
@Override
String getKeyRole() {
return "Row";
}
@Override
V getValue(int index) {
return at(index, columnIndex);
}
@Override
V setValue(int index, V newValue) {
return set(index, columnIndex, newValue);
}
}
/**
* Returns an immutable set of the valid column keys, including those that are
* associated with null values only.
*
* @return immutable set of column keys
*/
@Override
public ImmutableSet<C> columnKeySet() {
return columnKeyToIndex.keySet();
}
private transient ColumnMap columnMap;
@Override
public Map<C, Map<R, V>> columnMap() {
ColumnMap map = columnMap;
return (map == null) ? columnMap = new ColumnMap() : map;
}
private class ColumnMap extends ArrayMap<C, Map<R, V>> {
private ColumnMap() {
super(columnKeyToIndex);
}
@Override
String getKeyRole() {
return "Column";
}
@Override
Map<R, V> getValue(int index) {
return new Column(index);
}
@Override
Map<R, V> setValue(int index, Map<R, V> newValue) {
throw new UnsupportedOperationException();
}
@Override
public Map<R, V> put(C key, Map<R, V> value) {
throw new UnsupportedOperationException();
}
}
/**
* Returns a view of all mappings that have the given row key. If the row key
* isn't in {@link #rowKeySet()}, an empty immutable map is returned.
*
* <p>
* Otherwise, for each column key in {@link #columnKeySet()}, the returned map
* associates the column key with the corresponding value in the table. Changes
* to the returned map will update the underlying table, and vice versa.
*
* @param rowKey key of row to search for in the table
* @return the corresponding map from column keys to values
*/
@Override
public Map<C, V> row(R rowKey) {
checkNotNull(rowKey);
Integer rowIndex = rowKeyToIndex.get(rowKey);
return (rowIndex == null) ? ImmutableMap.<C, V>of() : new Row(rowIndex);
}
private class Row extends ArrayMap<C, V> {
final int rowIndex;
Row(int rowIndex) {
super(columnKeyToIndex);
this.rowIndex = rowIndex;
}
@Override
String getKeyRole() {
return "Column";
}
@Override
V getValue(int index) {
return at(rowIndex, index);
}
@Override
V setValue(int index, V newValue) {
return set(rowIndex, index, newValue);
}
}
/**
* Returns an immutable set of the valid row keys, including those that are
* associated with null values only.
*
* @return immutable set of row keys
*/
@Override
public ImmutableSet<R> rowKeySet() {
return rowKeyToIndex.keySet();
}
private transient RowMap rowMap;
@Override
public Map<R, Map<C, V>> rowMap() {
RowMap map = rowMap;
return (map == null) ? rowMap = new RowMap() : map;
}
private class RowMap extends ArrayMap<R, Map<C, V>> {
private RowMap() {
super(rowKeyToIndex);
}
@Override
String getKeyRole() {
return "Row";
}
@Override
Map<C, V> getValue(int index) {
return new Row(index);
}
@Override
Map<C, V> setValue(int index, Map<C, V> newValue) {
throw new UnsupportedOperationException();
}
@Override
public Map<C, V> put(R key, Map<C, V> value) {
throw new UnsupportedOperationException();
}
}
/**
* Returns an unmodifiable collection of all values, which may contain
* duplicates. Changes to the table will update the returned collection.
*
* <p>
* The returned collection's iterator traverses the values of the first row key,
* the values of the second row key, and so on.
*
* @return collection of values
*/
@Override
public Collection<V> values() {
return super.values();
}
private static final long serialVersionUID = 0;
}