| /* |
| * 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.sling.api.request; |
| |
| import java.io.PrintWriter; |
| import java.util.Iterator; |
| |
| import org.jetbrains.annotations.Nullable; |
| import org.jetbrains.annotations.NotNull; |
| |
| import org.osgi.annotation.versioning.ProviderType; |
| |
| /** |
| * The <code>RequestProgressTracker</code> class provides the functionality to |
| * track the progress of request processing. Instances of this class are |
| * provided through the |
| * {@link org.apache.sling.api.SlingHttpServletRequest#getRequestProgressTracker()} |
| * method. |
| * <p> |
| * The following functionality is provided: |
| * <ol> |
| * <li>Track the progress of request processing through the |
| * {@link #log(String)} and {@link #log(String, Object...)} methods. |
| * <li>Ability to measure and track processing times of parts of request |
| * processing through the {@link #startTimer(String)}, |
| * {@link #logTimer(String)} and {@link #logTimer(String, String, Object...)} |
| * methods. |
| * <li>Dumping the recording messages through the {@link #dump(PrintWriter)} |
| * method. |
| * <li>Return the log messages through the {@link #getMessages()} method. |
| * </ol> |
| * <p> |
| * <b>Tracking Request Processing</b> |
| * <p> |
| * As the request being processed, certain steps may be tracked by calling |
| * either of the <code>log</code> methods. A tracking entry consists of a time |
| * stamp managed by this class and a tracking message noting the actual step |
| * being tracked. |
| * <p> |
| * <b>Timing Processing Steps</b> |
| * </p> |
| * Certain steps during request processing may need to be timed in that the time |
| * required for processing should be recorded. Instances of this class maintain |
| * a map of named timers. Each timer is started (initialized or reset) by |
| * calling the {@link #startTimer(String)} method. This method just records the |
| * starting time of the named timer and adds a tracking entry with the timer |
| * name as the message. |
| * <p> |
| * To record the number of milliseconds elapsed since a timer has been started, |
| * the {@link #logTimer(String)} or {@link #logTimer(String, String, Object...)} |
| * method may be called. This method logs a tracking entry with a message |
| * consisting of the name of the timer and the number of milliseconds elapsed |
| * since the timer was last {@link #startTimer(String) started}. The |
| * <code>logTimer</code> methods may be called multiple times to record |
| * several timed steps. |
| * <p> |
| * Calling the {@link #startTimer(String)} method with the name of timer which |
| * already exists, resets the start time of the named timer to the current |
| * system time. |
| * <p> |
| * <b>Retrieving Tracking Entries</b> |
| * <p> |
| * The {@link #dump(PrintWriter)} method may be used to write the tracking |
| * entries to the given <code>PrintWriter</code> to for example log them in a |
| * HTML comment. Alternatively the tracking entries may be retrieved as an |
| * iterator of messages through the {@link #getMessages()} method. The |
| * formatting of the tracking entries is implementation specific. |
| */ |
| @ProviderType |
| public interface RequestProgressTracker { |
| |
| /** |
| * Creates an entry with the given message |
| * @param message The message |
| */ |
| void log(@NotNull String message); |
| |
| /** |
| * Creates an entry with a message constructed from the given |
| * <code>MessageFormat</code> format evaluated using the given formatting |
| * arguments. |
| * @param format The message |
| * @param args Arguments for the message |
| */ |
| void log(@NotNull String format, Object... args); |
| |
| /** |
| * Starts a named timer. If a timer of the same name already exists, it is |
| * reset to the current time. |
| * @param timerName the name of the timer |
| */ |
| void startTimer(@NotNull String timerName); |
| |
| /** |
| * Logs an entry with the message set to the name of the timer and the |
| * number of milliseconds elapsed since the timer start. |
| * @param timerName the name of the timer |
| */ |
| void logTimer(@NotNull String timerName); |
| |
| /** |
| * Logs an entry with the message constructed from the given |
| * <code>MessageFormat</code> pattern evaluated using the given arguments |
| * and the number of milliseconds elapsed since the timer start. |
| * @param timerName the name of the timer |
| * @param format The message |
| * @param args Arguments for the message |
| */ |
| void logTimer(@NotNull String timerName, @NotNull String format, Object... args); |
| |
| /** |
| * Returns an <code>Iterator</code> of tracking entries. |
| * If there are no messages <code>null</code> is returned. |
| * @return An iterator with the messages or {@code null} |
| */ |
| @Nullable Iterator<String> getMessages(); |
| |
| /** |
| * Dumps the process timer entries to the given writer, one entry per line. |
| * @param writer Writer to dump to |
| */ |
| void dump(@NotNull PrintWriter writer); |
| |
| /** |
| * Call this when done processing the request - only the first call of this |
| * method is processed, all further calls to this method are ignored. |
| */ |
| void done(); |
| } |