Java tutorial
/* * Copyright 2015 Collective, Inc. * * 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.collective.celos.servlet; import com.collective.celos.BucketID; import com.collective.celos.CelosClient; import com.collective.celos.RegisterKey; import com.collective.celos.Util; import com.collective.celos.database.StateDatabaseConnection; import com.fasterxml.jackson.databind.node.ArrayNode; import com.fasterxml.jackson.databind.node.ObjectNode; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.util.Set; public class RegisterKeysServlet extends AbstractJSONServlet { protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException { try { BucketID bucket = new BucketID(req.getParameter(CelosClient.BUCKET_PARAM)); String prefix = req.getParameter(CelosClient.PREFIX_PARAM); try (StateDatabaseConnection connection = getStateDatabase().openConnection()) { Set<RegisterKey> keys = connection.getRegisterKeys(bucket, prefix); ObjectNode object = Util.MAPPER.createObjectNode(); ArrayNode list = Util.MAPPER.createArrayNode(); object.put(CelosClient.KEYS_NODE, list); keys.stream().sorted().forEach(x -> list.add(x.toString())); writer.writeValue(res.getOutputStream(), object); } } catch (Exception e) { throw new ServletException(e); } } }