| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.cassandra.serializers; |
| |
| import java.nio.BufferUnderflowException; |
| import java.nio.ByteBuffer; |
| import java.util.*; |
| |
| import org.apache.cassandra.db.marshal.AbstractType; |
| import org.apache.cassandra.transport.Server; |
| import org.apache.cassandra.utils.Pair; |
| |
| public class MapSerializer<K, V> extends CollectionSerializer<Map<K, V>> |
| { |
| // interning instances |
| private static final Map<Pair<TypeSerializer<?>, TypeSerializer<?>>, MapSerializer> instances = new HashMap<Pair<TypeSerializer<?>, TypeSerializer<?>>, MapSerializer>(); |
| |
| public final TypeSerializer<K> keys; |
| public final TypeSerializer<V> values; |
| private final Comparator<Pair<ByteBuffer, ByteBuffer>> comparator; |
| |
| public static synchronized <K, V> MapSerializer<K, V> getInstance(TypeSerializer<K> keys, TypeSerializer<V> values, Comparator<ByteBuffer> comparator) |
| { |
| Pair<TypeSerializer<?>, TypeSerializer<?>> p = Pair.<TypeSerializer<?>, TypeSerializer<?>>create(keys, values); |
| MapSerializer<K, V> t = instances.get(p); |
| if (t == null) |
| { |
| t = new MapSerializer<K, V>(keys, values, comparator); |
| instances.put(p, t); |
| } |
| return t; |
| } |
| |
| private MapSerializer(TypeSerializer<K> keys, TypeSerializer<V> values, Comparator<ByteBuffer> comparator) |
| { |
| this.keys = keys; |
| this.values = values; |
| this.comparator = (p1, p2) -> comparator.compare(p1.left, p2.left); |
| } |
| |
| public List<ByteBuffer> serializeValues(Map<K, V> map) |
| { |
| List<Pair<ByteBuffer, ByteBuffer>> pairs = new ArrayList<>(map.size()); |
| for (Map.Entry<K, V> entry : map.entrySet()) |
| pairs.add(Pair.create(keys.serialize(entry.getKey()), values.serialize(entry.getValue()))); |
| Collections.sort(pairs, comparator); |
| List<ByteBuffer> buffers = new ArrayList<>(pairs.size() * 2); |
| for (Pair<ByteBuffer, ByteBuffer> p : pairs) |
| { |
| buffers.add(p.left); |
| buffers.add(p.right); |
| } |
| return buffers; |
| } |
| |
| public int getElementCount(Map<K, V> value) |
| { |
| return value.size(); |
| } |
| |
| public void validateForNativeProtocol(ByteBuffer bytes, int version) |
| { |
| try |
| { |
| if (bytes.remaining() == 0) |
| { |
| return; |
| } |
| ByteBuffer input = bytes.duplicate(); |
| int n = readCollectionSize(input, version); |
| for (int i = 0; i < n; i++) |
| { |
| keys.validate(readValue(input, version)); |
| values.validate(readValue(input, version)); |
| } |
| if (input.hasRemaining()) |
| throw new MarshalException("Unexpected extraneous bytes after map value"); |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a map"); |
| } |
| } |
| |
| public Map<K, V> deserializeForNativeProtocol(ByteBuffer bytes, int version) |
| { |
| try |
| { |
| ByteBuffer input = bytes.duplicate(); |
| int n = readCollectionSize(input, version); |
| |
| if (n < 0) |
| throw new MarshalException("The data cannot be deserialized as a map"); |
| |
| // If the received bytes are not corresponding to a map, n might be a huge number. |
| // In such a case we do not want to initialize the map with that initialCapacity as it can result |
| // in an OOM when put is called (see CASSANDRA-12618). On the other hand we do not want to have to resize |
| // the map if we can avoid it, so we put a reasonable limit on the initialCapacity. |
| Map<K, V> m = new LinkedHashMap<K, V>(Math.min(n, 256)); |
| for (int i = 0; i < n; i++) |
| { |
| ByteBuffer kbb = readValue(input, version); |
| keys.validate(kbb); |
| |
| ByteBuffer vbb = readValue(input, version); |
| values.validate(vbb); |
| |
| m.put(keys.deserialize(kbb), values.deserialize(vbb)); |
| } |
| if (input.hasRemaining()) |
| throw new MarshalException("Unexpected extraneous bytes after map value"); |
| return m; |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a map"); |
| } |
| } |
| |
| /** |
| * Given a serialized map, gets the value associated with a given key. |
| * @param serializedMap a serialized map |
| * @param serializedKey a serialized key |
| * @param keyType the key type for the map |
| * @return the value associated with the key if one exists, null otherwise |
| */ |
| public ByteBuffer getSerializedValue(ByteBuffer serializedMap, ByteBuffer serializedKey, AbstractType keyType) |
| { |
| try |
| { |
| ByteBuffer input = serializedMap.duplicate(); |
| int n = readCollectionSize(input, Server.VERSION_3); |
| for (int i = 0; i < n; i++) |
| { |
| ByteBuffer kbb = readValue(input, Server.VERSION_3); |
| ByteBuffer vbb = readValue(input, Server.VERSION_3); |
| int comparison = keyType.compare(kbb, serializedKey); |
| if (comparison == 0) |
| return vbb; |
| else if (comparison > 0) |
| // since the map is in sorted order, we know we've gone too far and the element doesn't exist |
| return null; |
| } |
| return null; |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a map"); |
| } |
| } |
| |
| public String toString(Map<K, V> value) |
| { |
| StringBuilder sb = new StringBuilder(); |
| sb.append('{'); |
| boolean isFirst = true; |
| for (Map.Entry<K, V> element : value.entrySet()) |
| { |
| if (isFirst) |
| isFirst = false; |
| else |
| sb.append(", "); |
| sb.append(keys.toString(element.getKey())); |
| sb.append(": "); |
| sb.append(values.toString(element.getValue())); |
| } |
| sb.append('}'); |
| return sb.toString(); |
| } |
| |
| public Class<Map<K, V>> getType() |
| { |
| return (Class)Map.class; |
| } |
| } |