Java tutorial
/* * Copyright 2011-2019 the original author or 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 * * https://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.springframework.data.redis.serializer; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.LinkedHashMap; import java.util.LinkedHashSet; import java.util.List; import java.util.Map; import java.util.Set; import org.springframework.core.CollectionFactory; import org.springframework.lang.Nullable; /** * Utility class with various serialization-related methods. * * @author Costin Leau */ public abstract class SerializationUtils { static final byte[] EMPTY_ARRAY = new byte[0]; static boolean isEmpty(@Nullable byte[] data) { return (data == null || data.length == 0); } @SuppressWarnings("unchecked") static <T extends Collection<?>> T deserializeValues(@Nullable Collection<byte[]> rawValues, Class<T> type, @Nullable RedisSerializer<?> redisSerializer) { // connection in pipeline/multi mode if (rawValues == null) { return (T) CollectionFactory.createCollection(type, 0); } Collection<Object> values = (List.class.isAssignableFrom(type) ? new ArrayList<>(rawValues.size()) : new LinkedHashSet<>(rawValues.size())); for (byte[] bs : rawValues) { values.add(redisSerializer.deserialize(bs)); } return (T) values; } @SuppressWarnings("unchecked") public static <T> Set<T> deserialize(@Nullable Set<byte[]> rawValues, @Nullable RedisSerializer<T> redisSerializer) { return deserializeValues(rawValues, Set.class, redisSerializer); } @SuppressWarnings("unchecked") public static <T> List<T> deserialize(@Nullable List<byte[]> rawValues, @Nullable RedisSerializer<T> redisSerializer) { return deserializeValues(rawValues, List.class, redisSerializer); } @SuppressWarnings("unchecked") public static <T> Collection<T> deserialize(@Nullable Collection<byte[]> rawValues, RedisSerializer<T> redisSerializer) { return deserializeValues(rawValues, List.class, redisSerializer); } public static <T> Map<T, T> deserialize(@Nullable Map<byte[], byte[]> rawValues, RedisSerializer<T> redisSerializer) { if (rawValues == null) { return Collections.emptyMap(); } Map<T, T> ret = new LinkedHashMap<>(rawValues.size()); for (Map.Entry<byte[], byte[]> entry : rawValues.entrySet()) { ret.put(redisSerializer.deserialize(entry.getKey()), redisSerializer.deserialize(entry.getValue())); } return ret; } @SuppressWarnings("unchecked") public static <HK, HV> Map<HK, HV> deserialize(@Nullable Map<byte[], byte[]> rawValues, @Nullable RedisSerializer<HK> hashKeySerializer, @Nullable RedisSerializer<HV> hashValueSerializer) { if (rawValues == null) { return Collections.emptyMap(); } Map<HK, HV> map = new LinkedHashMap<>(rawValues.size()); for (Map.Entry<byte[], byte[]> entry : rawValues.entrySet()) { // May want to deserialize only key or value HK key = hashKeySerializer != null ? hashKeySerializer.deserialize(entry.getKey()) : (HK) entry.getKey(); HV value = hashValueSerializer != null ? hashValueSerializer.deserialize(entry.getValue()) : (HV) entry.getValue(); map.put(key, value); } return map; } }