Java tutorial
/**************************************************************** * 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.james.jmap.utils; import java.util.List; import java.util.Optional; import com.google.common.base.Preconditions; import com.google.common.base.Splitter; import com.google.common.base.Strings; import com.google.common.collect.Iterables; public class DownloadPath { public static DownloadPath from(String path) { Preconditions.checkArgument(!Strings.isNullOrEmpty(path), "'path' is mandatory"); // path = /blobId/name // idx = 0 1 2 List<String> pathVariables = Splitter.on('/').splitToList(path); Preconditions.checkArgument(pathVariables.size() >= 1 && pathVariables.size() <= 3, "'blobId' is mandatory"); String blobId = Iterables.get(pathVariables, 1, null); Preconditions.checkArgument(!Strings.isNullOrEmpty(blobId), "'blobId' is mandatory"); return new DownloadPath(blobId, name(pathVariables)); } private static Optional<String> name(List<String> pathVariables) { return Optional.ofNullable(Strings.emptyToNull(Iterables.get(pathVariables, 2, null))); } private final String blobId; private final Optional<String> name; private DownloadPath(String blobId, Optional<String> name) { this.blobId = blobId; this.name = name; } public String getBlobId() { return blobId; } public Optional<String> getName() { return name; } }