| /* |
| * 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 org.apache.cassandra.transport.Server; |
| |
| import java.nio.BufferUnderflowException; |
| import java.nio.ByteBuffer; |
| import java.util.*; |
| |
| public class ListSerializer<T> extends CollectionSerializer<List<T>> |
| { |
| // interning instances |
| private static final Map<TypeSerializer<?>, ListSerializer> instances = new HashMap<TypeSerializer<?>, ListSerializer>(); |
| |
| public final TypeSerializer<T> elements; |
| |
| public static synchronized <T> ListSerializer<T> getInstance(TypeSerializer<T> elements) |
| { |
| ListSerializer<T> t = instances.get(elements); |
| if (t == null) |
| { |
| t = new ListSerializer<T>(elements); |
| instances.put(elements, t); |
| } |
| return t; |
| } |
| |
| private ListSerializer(TypeSerializer<T> elements) |
| { |
| this.elements = elements; |
| } |
| |
| public List<ByteBuffer> serializeValues(List<T> values) |
| { |
| List<ByteBuffer> buffers = new ArrayList<>(values.size()); |
| for (T value : values) |
| buffers.add(elements.serialize(value)); |
| return buffers; |
| } |
| |
| public int getElementCount(List<T> value) |
| { |
| return value.size(); |
| } |
| |
| public void validateForNativeProtocol(ByteBuffer bytes, int version) |
| { |
| try |
| { |
| ByteBuffer input = bytes.duplicate(); |
| int n = readCollectionSize(input, version); |
| for (int i = 0; i < n; i++) |
| elements.validate(readValue(input, version)); |
| |
| if (input.hasRemaining()) |
| throw new MarshalException("Unexpected extraneous bytes after list value"); |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a list"); |
| } |
| } |
| |
| public List<T> 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 list"); |
| |
| // If the received bytes are not corresponding to a list, n might be a huge number. |
| // In such a case we do not want to initialize the list with that size as it can result |
| // in an OOM (see CASSANDRA-12618). On the other hand we do not want to have to resize the list |
| // if we can avoid it, so we put a reasonable limit on the initialCapacity. |
| List<T> l = new ArrayList<T>(Math.min(n, 256)); |
| for (int i = 0; i < n; i++) |
| { |
| // We can have nulls in lists that are used for IN values |
| ByteBuffer databb = readValue(input, version); |
| if (databb != null) |
| { |
| elements.validate(databb); |
| l.add(elements.deserialize(databb)); |
| } |
| else |
| { |
| l.add(null); |
| } |
| } |
| |
| if (input.hasRemaining()) |
| throw new MarshalException("Unexpected extraneous bytes after list value"); |
| |
| return l; |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a list"); |
| } |
| } |
| |
| /** |
| * Returns the element at the given index in a list. |
| * @param serializedList a serialized list |
| * @param index the index to get |
| * @return the serialized element at the given index, or null if the index exceeds the list size |
| */ |
| public ByteBuffer getElement(ByteBuffer serializedList, int index) |
| { |
| try |
| { |
| ByteBuffer input = serializedList.duplicate(); |
| int n = readCollectionSize(input, Server.VERSION_3); |
| if (n <= index) |
| return null; |
| |
| for (int i = 0; i < index; i++) |
| { |
| int length = input.getInt(); |
| input.position(input.position() + length); |
| } |
| return readValue(input, Server.VERSION_3); |
| } |
| catch (BufferUnderflowException e) |
| { |
| throw new MarshalException("Not enough bytes to read a list"); |
| } |
| } |
| |
| public String toString(List<T> value) |
| { |
| StringBuilder sb = new StringBuilder(); |
| boolean isFirst = true; |
| sb.append('['); |
| for (T element : value) |
| { |
| if (isFirst) |
| isFirst = false; |
| else |
| sb.append(", "); |
| sb.append(elements.toString(element)); |
| } |
| sb.append(']'); |
| return sb.toString(); |
| } |
| |
| public Class<List<T>> getType() |
| { |
| return (Class) List.class; |
| } |
| } |