Android examples for java.util:Map
Copies the given Map containing another Map into a new Map .
/****************************************************************************** * Copyright (c) 2007 Stefan Franke, Robert Hanussek, Benjamin Keil, * * Steffen Kie?, Johannes Langauf, * * Christoph Marian M?ller, Igor Podolskiy, * * Tilmann Scheller, Michael Starzmann, Markus Wittlinger * * All rights reserved. This file may be used, modifies and redistributed * * under the terms of either the Eclipse Public License v1.0 which * * accompanies this distribution and is available at * * http://www.eclipse.org/legal/epl-v10.html or the MIT license, available at * * http://www.opensource.org/licenses/mit-license.php * ******************************************************************************/ //package com.book2s; import java.util.*; public class Main { /**//from www .j av a 2 s . c o m * Copies the given {@link Map} containing another {@link Map} into a new * {@link Map}. * * @param <A> * the type of the keys of the outer map * @param <B> * the type of the keys of the map, that is the value of the * outer map * @param <C> * the type of the values of the map, that is the value of the * outer map * @param data * the given map * @return If the given map was empty, a {@link Collections#emptyMap()} is * returned<br> * If the given map contained only one entry, a * {@link Collections#singletonMap(Object, Object)}, containing * said entry, is returned <br> * If the given map contained more than one element, a * {@link Collections#unmodifiableMap(Map)}, containing the entries * of the given map, is returned. */ public static <A, B, C> Map<A, Map<B, C>> copyDeep( Map<A, Map<B, C>> data) { final int size = data.size(); switch (size) { case 0: return Collections.emptyMap(); case 1: final A key = data.keySet().iterator().next(); return Collections.singletonMap(key, copy(data.get(key))); default: final Map<A, Map<B, C>> newData = new HashMap<A, Map<B, C>>(); for (Map.Entry<A, Map<B, C>> entry : data.entrySet()) { newData.put(entry.getKey(), copy(entry.getValue())); } return Collections.unmodifiableMap(newData); } } /** * Copies the given {@link Set} into a new {@link Set}.<br> * * * @param <T> * the type of the entries of the set * @param data * the given set * @return If the given set was empty, a {@link Collections#emptySet()} is * returned<br> * If the given set contained only one element, a * {@link Collections#singleton(Object)}, containing said element, * is returned <br> * If the given set contained more than one element, a * {@link Collections#unmodifiableSet(Set)}, containing the * elements of the given set, is returned. */ public static <T> Set<T> copy(Set<T> data) { final int size = data.size(); switch (size) { case 0: return Collections.emptySet(); case 1: return Collections.singleton(data.iterator().next()); default: return Collections.unmodifiableSet(new HashSet<T>(data)); } } /** * Copies the given {@link List} into a new {@link List}.<br> * * * @param <T> * the type of the entries of the list * @param data * the given list * @return If the given list was empty, a {@link Collections#emptyList()} is * returned<br> * If the given list contained only one element, a * {@link Collections#singletonList(Object)}, containing said * element, is returned <br> * If the given list contained more than one element, a * {@link Collections#unmodifiableList(List)}, containing the * elements of the given list, is returned. */ public static <T> List<T> copy(List<T> data) { final int size = data.size(); switch (size) { case 0: return Collections.emptyList(); case 1: return Collections.singletonList(data.get(0)); default: return Collections.unmodifiableList(new ArrayList<T>(data)); } } /** * Copies the given {@link Map} into a new {@link Map}.<br> * * @param <A> * the type of the keys of the map * @param <B> * the type of the values of the map * @param data * the given map * @return If the given map was empty, a {@link Collections#emptyMap()} is * returned<br> * If the given map contained only one entry, a * {@link Collections#singletonMap(Object, Object)}, containing * said entry, is returned <br> * If the given map contained more than one element, a * {@link Collections#unmodifiableMap(Map)}, containing the entries * of the given map, is returned. */ public static <A, B> Map<A, B> copy(Map<A, B> data) { final int size = data.size(); switch (size) { case 0: return Collections.emptyMap(); case 1: final A key = data.keySet().iterator().next(); return Collections.singletonMap(key, data.get(key)); default: return Collections.unmodifiableMap(new HashMap<A, B>(data)); } } }