Java tutorial
/* * Copyright 2016 Palantir Technologies, Inc. All rights reserved. * * 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.palantir.docker.compose.configuration; import static com.google.common.base.Strings.emptyToNull; import static com.palantir.docker.compose.configuration.EnvironmentVariables.TCP_PROTOCOL; import java.util.Optional; import org.apache.commons.lang3.StringUtils; public class RemoteHostIpResolver implements HostIpResolver { @Override public String resolveIp(String dockerHost) { return Optional.ofNullable(emptyToNull(dockerHost)) .map(host -> StringUtils.substringAfter(host, TCP_PROTOCOL)) .map(ipAndMaybePort -> StringUtils.substringBefore(ipAndMaybePort, ":")) .orElseThrow(() -> new IllegalArgumentException("DOCKER_HOST cannot be blank/null")); } }