com.pushtechnology.diffusion.examples.ControlClientUpdatingRecordV2Topics Maven / Gradle / Ivy
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* Copyright (C) 2017, 2023 DiffusionData Ltd.
*
* 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
* 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 com.pushtechnology.diffusion.examples;
import static com.pushtechnology.diffusion.client.Diffusion.newTopicSpecification;
import static com.pushtechnology.diffusion.client.topics.details.TopicSpecification.REMOVAL;
import static com.pushtechnology.diffusion.client.topics.details.TopicSpecification.SCHEMA;
import static com.pushtechnology.diffusion.client.topics.details.TopicType.RECORD_V2;
import static com.pushtechnology.diffusion.client.topics.details.TopicType.STRING;
import static java.util.concurrent.TimeUnit.SECONDS;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import com.pushtechnology.diffusion.client.Diffusion;
import com.pushtechnology.diffusion.client.features.TopicUpdate;
import com.pushtechnology.diffusion.client.features.control.topics.TopicControl;
import com.pushtechnology.diffusion.client.session.Session;
import com.pushtechnology.diffusion.client.topics.details.TopicSpecification;
import com.pushtechnology.diffusion.datatype.recordv2.RecordV2;
import com.pushtechnology.diffusion.datatype.recordv2.RecordV2DataType;
import com.pushtechnology.diffusion.datatype.recordv2.model.MutableRecordModel;
import com.pushtechnology.diffusion.datatype.recordv2.schema.Schema;
/**
* An example of using a control client to create and update a RecordV2 topic in
* exclusive mode.
*
* This uses the 'TopicControl' feature to create a topic and the
* 'TopicUpdate' feature to send updates to it.
*
* To send updates to a topic, the client session requires the 'update_topic'
* permission for that branch of the topic tree.
*
* The example can be used with or without the use of a schema. This is simply
* to demonstrate the different mechanisms and is not necessarily demonstrating
* the most efficient way to update such a topic.
*
* @author DiffusionData Limited
* @since 6.0
* @see com.pushtechnology.diffusion.examples.RecordV2Subscribing
*/
public final class ControlClientUpdatingRecordV2Topics {
private static final String ROOT_TOPIC = "FX";
private final Session session;
private final TopicControl topicControl;
private final TopicSpecification topicSpecification;
private final Schema schema;
private final RecordV2DataType dataType;
/**
* Constructor.
*
* @param serverUrl for example "ws://diffusion.example.com:80"
*/
public ControlClientUpdatingRecordV2Topics(
String serverUrl,
boolean withSchema)
throws InterruptedException, ExecutionException, TimeoutException {
session =
Diffusion.sessions().principal("control").password("password")
.open(serverUrl);
topicControl = session.feature(TopicControl.class);
// Create the root topic that will remove itself when the session closes
final TopicSpecification specification =
newTopicSpecification(STRING)
.withProperty(
REMOVAL,
"when this session closes remove '?" + ROOT_TOPIC + "//'");
topicControl.addTopic(ROOT_TOPIC, specification).get(5, SECONDS);
dataType = Diffusion.dataTypes().recordV2();
if (withSchema) {
schema = dataType.schemaBuilder()
.record("Rates").decimal("Bid", 5).decimal("Ask", 5).build();
// Create the topic specification to be used for all rates topics
topicSpecification =
newTopicSpecification(RECORD_V2)
.withProperty(
SCHEMA,
schema.asJSONString());
}
else {
schema = null;
// Create the topic specification to be used for all rates topics
topicSpecification =
newTopicSpecification(RECORD_V2);
}
}
/**
* Adds a new conversion rate in terms of base currency and target currency.
*
* The bid and ask rates are entered as strings which may be a decimal value
* which will be parsed and validated, rounding to 5 decimal places.
*
* @param currency the base currency (e.g. GBP)
*
* @param targetCurrency the target currency (e.g. USD)
*/
public void addRateTopic(
String currency,
String targetCurrency)
throws InterruptedException, ExecutionException, TimeoutException {
topicControl.addTopic(
rateTopicName(currency, targetCurrency),
topicSpecification).get(5, SECONDS);
}
/**
* Set a rate.
*
* The rate topic in question must have been added first using
* {@link #addRateTopic} otherwise this will fail.
*
* @param currency the base currency
*
* @param targetCurrency the target currency
*
* @param bid the new bid rate
*
* @param ask the new ask rate
* @return a CompletableFuture that completes when a response is received
* from the server
*/
public CompletableFuture setRate(
String currency,
String targetCurrency,
String bid,
String ask) {
final RecordV2 value;
if (schema == null) {
value = dataType.valueBuilder().addFields(bid, ask).build();
}
else {
// Mutable models could be kept and reused but for this simple
// example one is created every time
final MutableRecordModel model =
schema.createMutableModel();
model.set("Bid", bid);
model.set("Ask", ask);
value = model.asValue();
}
return session.feature(TopicUpdate.class).set(
rateTopicName(currency, targetCurrency),
RecordV2.class,
value);
}
/**
* Remove a rate (removes its topic).
*
* @param currency the base currency
*
* @param targetCurrency the target currency
*/
public void removeRate(
String currency,
String targetCurrency)
throws InterruptedException, ExecutionException, TimeoutException {
topicControl.removeTopics(
rateTopicName(currency, targetCurrency))
.get(5, SECONDS);
}
/**
* Removes a currency (removes its topic and all subordinate rate topics).
*
* @param currency the base currency
*/
public void removeCurrency(String currency)
throws InterruptedException, ExecutionException, TimeoutException {
topicControl
.removeTopics(String.format("?%s/%s//", ROOT_TOPIC, currency))
.get(5, SECONDS);
}
/**
* Close the session.
*/
public void close() throws InterruptedException {
session.close();
}
/**
* Generates a hierarchical topic name for a rate topic.
*
* e.g. for currency=GBP and targetCurrency=USD would return "FX/GBP/USD".
*
* @param currency the base currency
* @param targetCurrency the target currency
* @return the topic name
*/
private static String rateTopicName(String currency,
String targetCurrency) {
return String.format("%s/%s/%s", ROOT_TOPIC, currency, targetCurrency);
}
}