AbstractCommandRegistry.java
/*
* Copyright (c) 2017 Bosch Software Innovations GmbH.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/org/documents/epl-2.0/index.php
*
* Contributors:
* Bosch Software Innovations GmbH - initial contribution
*/
package org.eclipse.ditto.signals.commands.base;
import java.util.Map;
import java.util.function.Supplier;
import javax.annotation.concurrent.Immutable;
import org.eclipse.ditto.json.JsonMissingFieldException;
import org.eclipse.ditto.json.JsonObject;
import org.eclipse.ditto.signals.base.AbstractJsonParsableRegistry;
import org.eclipse.ditto.signals.base.JsonParsable;
/**
* Abstract implementation of {@link CommandRegistry}.
*
* @param <T> the type of the Command to parse.
*/
@Immutable
public abstract class AbstractCommandRegistry<T extends Command> extends AbstractJsonParsableRegistry<T>
implements CommandRegistry<T> {
/**
* Constructs a new {@code AbstractCommandRegistry} for the specified {@code parseStrategies}.
*
* @param parseStrategies the parse strategies.
*/
protected AbstractCommandRegistry(final Map<String, JsonParsable<T>> parseStrategies) {
super(parseStrategies);
}
@Override
protected String resolveType(final JsonObject jsonObject) {
final Supplier<String> command = () -> jsonObject.getValue(Command.JsonFields.ID)
.map(cmd -> getTypePrefix() + cmd) // and transform to V2 format
// fail if "command" also is not present
.orElseThrow(() -> JsonMissingFieldException.newBuilder()
.fieldName(Command.JsonFields.TYPE.getPointer().toString())
.build());
// if type was not present (was included in V2) take "command" instead
return jsonObject.getValue(Command.JsonFields.TYPE).orElseGet(command);
}
/**
* Returns the type prefix to use when falling back to determining the type via the "old" V1.
*
* @return the type prefix to use.
*/
protected abstract String getTypePrefix();
}