Java tutorial
/** * The contents of this file are subject to the OpenMRS Public License * Version 1.0 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * http://license.openmrs.org * * Software distributed under the License is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the * License for the specific language governing rights and limitations * under the License. * * Copyright (C) OpenMRS, LLC. All Rights Reserved. */ package org.openmrs.module.logmanager.impl; import java.util.Collection; import org.apache.commons.collections.buffer.CircularFifoBuffer; import org.apache.log4j.Appender; import org.apache.log4j.ConsoleAppender; import org.apache.log4j.DailyRollingFileAppender; import org.apache.log4j.FileAppender; import org.apache.log4j.RollingFileAppender; import org.apache.log4j.net.SocketAppender; import org.apache.log4j.nt.NTEventLogAppender; import org.apache.log4j.spi.LoggingEvent; import org.apache.log4j.spi.OptionHandler; import org.openmrs.module.logmanager.AbstractEditableProxy; import org.openmrs.module.logmanager.AppenderTypeException; import org.openmrs.module.logmanager.util.LogManagerUtils; import org.openmrs.util.MemoryAppender; /** * Used to edit appender objects without passing them directly to the SimpleFormController. * This ensures that an appender is only modified if all properties have been validated */ public class AppenderProxy extends AbstractEditableProxy<Appender> { protected AppenderType type; protected boolean existing; protected String name; protected LayoutProxy layout; protected static final String[] PROPS_CONSOLE = { "target", "follow" }; protected static final String[] PROPS_MEMORY = { "bufferSize" }; protected static final String[] PROPS_FILE = { "append", "bufferedIO", "bufferSize", "file" }; protected static final String[] PROPS_ROLLING_FILE = { "append", "bufferedIO", "bufferSize", "file", "maximumFileSize", "maxBackupIndex" }; protected static final String[] PROPS_DAILY_ROLLING_FILE = { "append", "bufferedIO", "bufferSize", "file", "datePattern" }; protected static final String[] PROPS_SOCKET = { "application", "locationInfo", "reconnectionDelay", "remoteHost", "port" }; protected static final String[] PROPS_NT_EVENT_LOG = { "source" }; protected static AppenderProxy systemAppender; /** * Creates a proxy for a new appender * @param type the type * @param name the name */ public AppenderProxy(AppenderType type, String name) { this.existing = false; // Create target based on type switch (type) { case CONSOLE: target = new ConsoleAppender(); break; case MEMORY: target = new MemoryAppender(); break; case FILE: target = new FileAppender(); break; case ROLLING_FILE: target = new RollingFileAppender(); break; case DAILY_ROLLING_FILE: target = new DailyRollingFileAppender(); break; case SOCKET: target = new SocketAppender(); break; case NT_EVENT_LOG: target = new NTEventLogAppender(); } this.target.setName(name); copyTarget(); } /** * Creates a proxy for an existing appender * @param target the appender */ public AppenderProxy(Appender target) { this.target = target; this.existing = true; copyTarget(); } /** * Copies name, type and property values from target */ protected void copyTarget() { this.type = AppenderType.fromAppender(target); this.name = target.getName(); switch (type) { case CONSOLE: copyPropertesFromTarget(PROPS_CONSOLE); break; case MEMORY: copyPropertesFromTarget(PROPS_MEMORY); break; case FILE: copyPropertesFromTarget(PROPS_FILE); break; case ROLLING_FILE: copyPropertesFromTarget(PROPS_ROLLING_FILE); break; case DAILY_ROLLING_FILE: copyPropertesFromTarget(PROPS_DAILY_ROLLING_FILE); break; case SOCKET: copyPropertesFromTarget(PROPS_SOCKET); break; case NT_EVENT_LOG: copyPropertesFromTarget(PROPS_NT_EVENT_LOG); break; } // Create proxy for layout if (target.getLayout() != null) this.layout = new LayoutProxy(target.getLayout()); else if (target.requiresLayout()) this.layout = new LayoutProxy(LayoutType.PATTERN); } /** * Updates the actual appender referenced by this proxy object */ public void updateTarget() { // Update general properties target.setName(name); switch (type) { case CONSOLE: updatePropertiesOnTarget(PROPS_CONSOLE); break; case MEMORY: updatePropertiesOnTarget(PROPS_MEMORY); break; case FILE: updatePropertiesOnTarget(PROPS_FILE); break; case ROLLING_FILE: updatePropertiesOnTarget(PROPS_ROLLING_FILE); break; case DAILY_ROLLING_FILE: updatePropertiesOnTarget(PROPS_DAILY_ROLLING_FILE); break; case SOCKET: updatePropertiesOnTarget(PROPS_SOCKET); break; case NT_EVENT_LOG: updatePropertiesOnTarget(PROPS_NT_EVENT_LOG); break; } // Update layout if (layout != null) { layout.updateTarget(); target.setLayout(layout.getTarget()); } } /** * Gets whether this proxy references an existing appender * @return true if appender already exists in log4j */ public boolean isExisting() { return existing; } /** * Gets the id * @return the id */ public int getId() { return target.hashCode(); } /** * Gets the type of the appender * @return the type */ public AppenderType getType() { return type; } /** * Gets the name of the appender * @return the name */ public String getName() { return name; } /** * Sets the name of the appender * @param name the name */ public void setName(String name) { this.name = name; } /** * Gets whether appender must be closed and restarted after changing * its properties * @return true if appender must be restarted */ public boolean isActivationRequired() { return target instanceof OptionHandler; } /** * Activates this appender by calling the target's activateOptions method * @throws AppenderTypeException if appender is not activatable */ public void activate() { if (target instanceof OptionHandler) ((OptionHandler) target).activateOptions(); else throw new AppenderTypeException("Cannot activate a non-activatable appender"); } /** * Gets whether this appender requires a layout, based on its type. Even tho this * module doesn't require it's memory appender to have a layout - the existing log * viewer page does * @return true if it requires a layout */ public boolean isLayoutRequired() { return target.requiresLayout(); } /** * Gets the layout used by this appender * @return the layout */ public LayoutProxy getLayout() { return layout; } /** * Sets the layout used by this appender * @param layout the layout */ public void setLayout(LayoutProxy layout) { this.layout = layout; } /** * Gets if this appender is viewable - i.e. is it a memory appender * @return true if appender is viewable */ public boolean isViewable() { return target instanceof MemoryAppender; } /** * Gets logging events from a memory appender * @return the list of logging events * @throws AppenderTypeException if appender is not viewable */ @SuppressWarnings("unchecked") public Collection<LoggingEvent> getLoggingEvents() { if (!isViewable()) throw new AppenderTypeException("Cannot access events on a non-viewable appender"); // Buffer is a private field in the MemoryAppender class CircularFifoBuffer buffer = (CircularFifoBuffer) LogManagerUtils.getPrivateField(target, "buffer"); return buffer; } /** * Gets whether this appender can be cleared, i.e. is it a memory appender * @return true if appender can be cleared */ public boolean isClearable() { return target instanceof MemoryAppender; } /** * Clears the events from this appender * @throws AppenderTypeException if appender is not clearable */ public void clear() { if (!isClearable()) throw new AppenderTypeException("Cannot clear events on a non-clearable appender"); // Buffer is a private field in the MemoryAppender class CircularFifoBuffer buffer = (CircularFifoBuffer) LogManagerUtils.getPrivateField(target, "buffer"); if (buffer != null) buffer.clear(); } /** * Gets the system appender * @return the system appender */ public static AppenderProxy getSystemAppender() { return systemAppender; } /** * Sets the system appender * @param systemAppender the new system appender */ public static void setSystemAppender(AppenderProxy systemAppender) { AppenderProxy.systemAppender = systemAppender; } /** * Gets whether this appender is the system appender * @return true if this appender is the system appender */ public boolean isSystemAppender() { return (systemAppender != null && systemAppender.target == this.target); } }