Update #0 - First Release

sources/main/java/com/google/common/collect/HashBasedTable.java

@@ -0,0 +1,154 @@
+/*
+ * 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.collect.CollectPreconditions.checkNonnegative;
+
+import java.io.Serializable;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.base.Supplier;
+
+/**
+ * Implementation of {@link Table} using hash tables.
+ *
+ * <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>
+ * 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
+ * @since 7.0
+ */
+@GwtCompatible(serializable = true)
+public class HashBasedTable<R, C, V> extends StandardTable<R, C, V> {
+	private static class Factory<C, V> implements Supplier<Map<C, V>>, Serializable {
+		final int expectedSize;
+
+		Factory(int expectedSize) {
+			this.expectedSize = expectedSize;
+		}
+
+		@Override
+		public Map<C, V> get() {
+			return Maps.newHashMapWithExpectedSize(expectedSize);
+		}
+
+		private static final long serialVersionUID = 0;
+	}
+
+	/**
+	 * Creates an empty {@code HashBasedTable}.
+	 */
+	public static <R, C, V> HashBasedTable<R, C, V> create() {
+		return new HashBasedTable<R, C, V>(new HashMap<R, Map<C, V>>(), new Factory<C, V>(0));
+	}
+
+	/**
+	 * Creates an empty {@code HashBasedTable} with the specified map sizes.
+	 *
+	 * @param expectedRows        the expected number of distinct row keys
+	 * @param expectedCellsPerRow the expected number of column key / value mappings
+	 *                            in each row
+	 * @throws IllegalArgumentException if {@code expectedRows} or {@code
+	 *     expectedCellsPerRow}      is negative
+	 */
+	public static <R, C, V> HashBasedTable<R, C, V> create(int expectedRows, int expectedCellsPerRow) {
+		checkNonnegative(expectedCellsPerRow, "expectedCellsPerRow");
+		Map<R, Map<C, V>> backingMap = Maps.newHashMapWithExpectedSize(expectedRows);
+		return new HashBasedTable<R, C, V>(backingMap, new Factory<C, V>(expectedCellsPerRow));
+	}
+
+	/**
+	 * Creates a {@code HashBasedTable} with the same mappings as the specified
+	 * table.
+	 *
+	 * @param table the table to copy
+	 * @throws NullPointerException if any of the row keys, column keys, or values
+	 *                              in {@code table} is null
+	 */
+	public static <R, C, V> HashBasedTable<R, C, V> create(Table<? extends R, ? extends C, ? extends V> table) {
+		HashBasedTable<R, C, V> result = create();
+		result.putAll(table);
+		return result;
+	}
+
+	HashBasedTable(Map<R, Map<C, V>> backingMap, Factory<C, V> factory) {
+		super(backingMap, factory);
+	}
+
+	// Overriding so NullPointerTester test passes.
+
+	@Override
+	public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey) {
+		return super.contains(rowKey, columnKey);
+	}
+
+	@Override
+	public boolean containsColumn(@Nullable Object columnKey) {
+		return super.containsColumn(columnKey);
+	}
+
+	@Override
+	public boolean containsRow(@Nullable Object rowKey) {
+		return super.containsRow(rowKey);
+	}
+
+	@Override
+	public boolean containsValue(@Nullable Object value) {
+		return super.containsValue(value);
+	}
+
+	@Override
+	public V get(@Nullable Object rowKey, @Nullable Object columnKey) {
+		return super.get(rowKey, columnKey);
+	}
+
+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return super.equals(obj);
+	}
+
+	@Override
+	public V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
+		return super.remove(rowKey, columnKey);
+	}
+
+	private static final long serialVersionUID = 0;
+}