| /* |
| * 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.cql3.functions; |
| |
| import org.apache.cassandra.db.marshal.AbstractType; |
| import org.apache.cassandra.db.marshal.UTF8Type; |
| import org.apache.cassandra.exceptions.InvalidRequestException; |
| import org.apache.cassandra.transport.ProtocolVersion; |
| import org.apache.cassandra.utils.ByteBufferUtil; |
| |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import static java.lang.String.format; |
| |
| public class ToJsonFct extends NativeScalarFunction |
| { |
| private static final Map<AbstractType<?>, ToJsonFct> instances = new ConcurrentHashMap<>(); |
| |
| public static ToJsonFct getInstance(String name, List<AbstractType<?>> argTypes) throws InvalidRequestException |
| { |
| if (argTypes.size() != 1) |
| throw new InvalidRequestException(format("%s() only accepts one argument (got %d)", name, argTypes.size())); |
| |
| AbstractType<?> fromType = argTypes.get(0); |
| ToJsonFct func = instances.get(fromType); |
| if (func == null) |
| { |
| func = new ToJsonFct(name, fromType); |
| instances.put(fromType, func); |
| } |
| return func; |
| } |
| |
| private ToJsonFct(String name, AbstractType<?> argType) |
| { |
| super(name, UTF8Type.instance, argType); |
| } |
| |
| public ByteBuffer execute(ProtocolVersion protocolVersion, List<ByteBuffer> parameters) throws InvalidRequestException |
| { |
| assert parameters.size() == 1 : format("Expected 1 argument for %s(), but got %d", name.name, parameters.size()); |
| ByteBuffer parameter = parameters.get(0); |
| if (parameter == null) |
| return ByteBufferUtil.bytes("null"); |
| |
| return ByteBufferUtil.bytes(argTypes.get(0).toJSONString(parameter, protocolVersion)); |
| } |
| |
| public static void addFunctionsTo(NativeFunctions functions) |
| { |
| functions.add(new Factory("to_json")); |
| functions.add(new Factory("tojson")); // deprecated pre-5.0 name |
| } |
| |
| private static class Factory extends FunctionFactory |
| { |
| public Factory(String name) |
| { |
| super(name, FunctionParameter.anyType(false)); |
| } |
| |
| @Override |
| protected NativeFunction doGetOrCreateFunction(List<AbstractType<?>> argTypes, AbstractType<?> receiverType) |
| { |
| return ToJsonFct.getInstance(name.name, argTypes); |
| } |
| } |
| } |