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.protocols.pop3.core; import java.io.IOException; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; import org.apache.commons.configuration.Configuration; import org.apache.commons.configuration.ConfigurationException; import org.apache.james.protocols.api.Request; import org.apache.james.protocols.api.Response; import org.apache.james.protocols.api.ProtocolSession.State; import org.apache.james.protocols.api.handler.CommandHandler; import org.apache.james.protocols.pop3.POP3Response; import org.apache.james.protocols.pop3.POP3Session; import org.apache.james.protocols.pop3.mailbox.MessageMetaData; /** * Handles UIDL command */ public class UidlCmdHandler implements CommandHandler<POP3Session>, CapaCapability { private static final Collection<String> COMMANDS = Collections.unmodifiableCollection(Arrays.asList("UIDL")); private static final Set<String> CAPS = Collections.unmodifiableSet(new HashSet<String>(Arrays.asList("UIDL"))); @Override public void init(Configuration config) throws ConfigurationException { } @Override public void destroy() { } /** * Handler method called upon receipt of a UIDL command. Returns a listing * of message ids to the client. */ @SuppressWarnings("unchecked") public Response onCommand(POP3Session session, Request request) { POP3Response response = null; String parameters = request.getArgument(); if (session.getHandlerState() == POP3Session.TRANSACTION) { List<MessageMetaData> uidList = (List<MessageMetaData>) session.getAttachment(POP3Session.UID_LIST, State.Transaction); List<String> deletedUidList = (List<String>) session.getAttachment(POP3Session.DELETED_UID_LIST, State.Transaction); try { String identifier = session.getUserMailbox().getIdentifier(); if (parameters == null) { response = new POP3Response(POP3Response.OK_RESPONSE, "unique-id listing follows"); for (int i = 0; i < uidList.size(); i++) { MessageMetaData metadata = uidList.get(i); if (deletedUidList.contains(metadata.getUid()) == false) { StringBuilder responseBuffer = new StringBuilder().append(i + 1).append(" ") .append(metadata.getUid(identifier)); response.appendLine(responseBuffer.toString()); } } response.appendLine("."); } else { int num = 0; try { num = Integer.parseInt(parameters); MessageMetaData metadata = MessageMetaDataUtils.getMetaData(session, num); if (metadata == null) { StringBuilder responseBuffer = new StringBuilder(64).append("Message (").append(num) .append(") does not exist."); return new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString()); } if (deletedUidList.contains(metadata.getUid()) == false) { StringBuilder responseBuffer = new StringBuilder(64).append(num).append(" ") .append(metadata.getUid(identifier)); response = new POP3Response(POP3Response.OK_RESPONSE, responseBuffer.toString()); } else { StringBuilder responseBuffer = new StringBuilder(64).append("Message (").append(num) .append(") already deleted."); response = new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString()); } } catch (IndexOutOfBoundsException npe) { StringBuilder responseBuffer = new StringBuilder(64).append("Message (").append(num) .append(") does not exist."); response = new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString()); } catch (NumberFormatException nfe) { StringBuilder responseBuffer = new StringBuilder(64).append(parameters) .append(" is not a valid number"); response = new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString()); } } } catch (IOException e) { return POP3Response.ERR; } } else { return POP3Response.ERR; } return response; } /** * @see org.apache.james.pop3server.core.CapaCapability#getImplementedCapabilities(org.apache.james.pop3server.POP3Session) */ @SuppressWarnings("unchecked") public Set<String> getImplementedCapabilities(POP3Session session) { if (session.getHandlerState() == POP3Session.TRANSACTION) { return CAPS; } else { return Collections.EMPTY_SET; } } /** * @see org.apache.james.protocols.api.handler.CommandHandler#getImplCommands() */ public Collection<String> getImplCommands() { return COMMANDS; } }