/*
 * 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 org.glassfish.jersey.internal.guava;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Supplier;

Implementation of Table using hash tables. 

The views returned by StandardTable.column, StandardTable.columnKeySet(), and StandardTable.columnMap() have iterators that don't support remove(). Otherwise, all optional operations are supported. Null row keys, columns keys, and values are not supported. 

Lookups by row key are often faster than lookups by column key, because the data is stored in a Map<R, Map<C, V>>. A method call like 
column(columnKey).get(rowKey) still runs quickly, since the row key is provided. However, column(columnKey).size() takes longer, since an iteration across all row keys occurs. 

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.

See the Guava User Guide article on  Table.
Author:
Jared Levy
Since:
7.0/**
 * Implementation of {@link Table} using hash tables.
 * <p>
 * <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>
 * <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>
 * <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>
 * <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
 */
public class HashBasedTable<R, C, V> extends StandardTable<R, C, V> {
    private static final long serialVersionUID = 0;

    private HashBasedTable(Map<R, Map<C, V>> backingMap, Factory<C, V> factory) {
        super(backingMap, factory);
    }

    
Creates an empty HashBasedTable. /**
     * 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));
    }

    // Overriding so NullPointerTester test passes.

    @Override
    public boolean contains(
            Object rowKey, Object columnKey) {
        return super.contains(rowKey, columnKey);
    }

    @Override
    public boolean containsColumn(Object columnKey) {
        return super.containsColumn(columnKey);
    }

    @Override
    public boolean containsValue(Object value) {
        return super.containsValue(value);
    }

    @Override
    public V get(Object rowKey, Object columnKey) {
        return super.get(rowKey, columnKey);
    }

    @Override
    public boolean equals(Object obj) {
        return super.equals(obj);
    }

    private static class Factory<C, V>
            implements Supplier<Map<C, V>>, Serializable {
        private static final long serialVersionUID = 0;
        final int expectedSize;

        Factory(int expectedSize) {
            this.expectedSize = expectedSize;
        }

        @Override
        public Map<C, V> get() {
            return Maps.newHashMapWithExpectedSize(expectedSize);
        }
    }
}