com.github.triceo.robozonky.app.configuration.InvestmentStrategyLoader Maven / Gradle / Ivy
/*
* Copyright 2017 Lukáš Petrovický
*
* 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.github.triceo.robozonky.app.configuration;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Optional;
import java.util.ServiceLoader;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import com.github.triceo.robozonky.ExtensionsManager;
import com.github.triceo.robozonky.api.strategies.InvestmentStrategy;
import com.github.triceo.robozonky.api.strategies.InvestmentStrategyService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Implements Java's {@link ServiceLoader} to provide suitable {@link InvestmentStrategy} implementations.
*/
class InvestmentStrategyLoader {
private static final Logger LOGGER = LoggerFactory.getLogger(InvestmentStrategyLoader.class);
private static final ServiceLoader STRATEGY_LOADER =
ExtensionsManager.INSTANCE.getServiceLoader(InvestmentStrategyService.class);
private static URL convertToUrl(final String maybeUrl) {
try {
return new URL(maybeUrl);
} catch (final MalformedURLException e) {
try {
return new File(maybeUrl).toURI().toURL();
} catch (final MalformedURLException e1) {
throw new IllegalStateException("Cannot load " + maybeUrl, e1);
}
}
}
public static Optional load(final String maybeUrl) {
return InvestmentStrategyLoader.load(InvestmentStrategyLoader.convertToUrl(maybeUrl));
}
private static Optional load(final URL url) {
InvestmentStrategyLoader.LOGGER.trace("Loading strategies.");
return StreamSupport.stream(InvestmentStrategyLoader.STRATEGY_LOADER.spliterator(), true)
.peek(iss -> InvestmentStrategyLoader.LOGGER.debug("Evaluating strategy '{}' with '{}'.", url,
iss.getClass()))
.map(iss -> {
try (final InputStream stream = url.openStream()) {
return iss.parse(stream);
} catch (final IOException ex) {
InvestmentStrategyLoader.LOGGER.error("Failed reading strategy.", ex);
return Optional.empty();
}
}).flatMap(o -> o.isPresent() ? Stream.of((InvestmentStrategy)o.get()) : Stream.empty())
.findFirst();
}
}