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package com.sun.enterprise.instance;
import com.sun.appserv.server.util.Version;
import com.sun.enterprise.deployment.Application;
import com.sun.enterprise.deployment.util.ModuleDescriptor;
import com.sun.logging.LogDomains;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.jar.Manifest;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Handles the serialization and deserialization of descriptor object graphs.
* <p>
* The static "store" method is used from the deployment code to create the
* initial serialized data file for an application. In EE environments this
* file will be copied to the relevant instances during synchronization.
* <p>
* The static "load" method is used from the various subclasses of BaseManager
* to attempt to load the serialized object graph and then return an instance
* of SerializedDescriptorHelper.Loader. This object not only loads the
* serialized descriptor (if possible) but also allows
* the manager to get the loaded application object. If that object is null,
* the manager loads the application from the XML descriptors and should try to
* rewrite the file using the new application object by invoking the "store"
* method on the returned Loader object.
*
* @author tjquinn
*/
public class SerializedDescriptorHelper {
/** file name used for serializing (and deserializing) the DOL descriptor */
private static final String SERIALIZED_DESCRIPTOR_FILE_NAME = "appDescr.dat";
/** property that allows control of serialization */
private static final String SERIALIZATION_ENABLED_PROPERTY =
"com.sun.aas.deployment.serializeDescriptors";
/** default value for using descriptor serialization */
private static final String SERIALIZATION_ENABLED_DEFAULT = "true";
private static final boolean isSerializedDescriptorIOEnabled =
Boolean.parseBoolean(System.getProperty(
SERIALIZATION_ENABLED_PROPERTY,
SERIALIZATION_ENABLED_DEFAULT));
private static final Logger logger=LogDomains.getLogger(LogDomains.CORE_LOGGER);
/**
*Attempts to load the serialized object graph from the appropriate file.
*<p>
*Whether the attempt succeeds or not, the method returns an instance of
*Loader that the caller can use to retrieve the loaded application and, if
*appropriate, attempt to write the application object graph it built from
*the XML descriptors.
*<p>
*Because failures to load the serialized data are not fatal errors,
*this method throws no exceptions. Instead the loader's internal application
*object will be null. The caller should check for this and then load the
*application from the XML descriptors instead.
*
*@param moduleID the module ID of the application to load
*@param manager the manager for this type of module
*@return the SerializedDescriptorHelper.Loader the caller can use to
*retrieve the application and, if appropriate, rewrite the file
*/
public static Loader load(
String moduleID,
BaseManager manager) {
Loader loader = new Loader(moduleID, manager);
loader.loadSerializedDescriptor();
return loader;
}
/**
* Attempts to write the application object graph to the corresponding
* file.
* <p>
* Because failures to serialized the object graph are not fatal, the method
* throws no exceptions.
*
* @param moduleID the module being serialized
* @param manager the manager in charge of this type of application
* @param application the object graph to storeSerializedDescriptor
*/
public static void store(
String moduleID,
BaseManager manager,
Application application) {
File file = getSerializedDescriptorFile(moduleID, manager);
store(moduleID, manager, application, file);
}
/**
*Writes the specified application to the correct location for the module.
*
*@param moduleID the unique identifier of the module
*@param manager the BaseManager instance for this type of module
*@param application the Application object graph to be written
*@param serializedFile the File object that refers to the serialized file for this app
*/
private static void store(
String moduleID,
BaseManager manager,
Application application,
File serializedFile) {
if (isSerializedDescriptorIOEnabled()) {
/*
*Try to write the application object graph to the file.
*/
if ( ! storeSerializedDescriptor(
application,
serializedFile,
moduleID)) {
/*
*In case of any error serializing the descriptors, store an
*Exception object instead. This will save the server from
*future attempts to write the serialized descriptors that we
*expect will continue to fail.
*/
storeSerializedDescriptor(
new Exception(getCurrentSoftwareVersion()),
serializedFile,
moduleID);
}
}
}
/**
*Returns whether serialized descriptor processing is turned on or not.
*@return true if serialized reading and writing should take place
*/
private static boolean isSerializedDescriptorIOEnabled() {
return isSerializedDescriptorIOEnabled;
}
/**
*Returns an expression containing the major and minor version strings and
*the build ID of the currently-running software.
*/
private static String getCurrentSoftwareVersion() {
return Version.getMajorVersion() + "." +
Version.getMinorVersion() + "-" +
Version.getBuildVersion();
}
/**
*Returns a File object for the serialized descriptor file for the
*specified module overseen by the specified manager.
*@param moduleID the unique ID of the module
*@param manager the BaseManager concrete instance that manages apps of this type
*@return a File for the serialized descriptor file for this app
*/
private static File getSerializedDescriptorFile(String moduleID, BaseManager manager) {
return new File(
manager.getGeneratedXMLLocation(moduleID),
SERIALIZED_DESCRIPTOR_FILE_NAME);
}
/**
*Logs a message, looking up the message key and substituting arguments and
*including a Throwable indicating an error.
*@param level the logging level at which to log this message
*@param messageKey the key to the message
*@param t the Throwable to be recorded with the log message
*@param args... the arguments (if any) to be substituted into the looked-up message
*/
private static void log(Level level, String messageKey, Throwable t, Object... args) {
String msg = logger.getResourceBundle().getString(messageKey);
String formattedMsg = MessageFormat.format(msg, args);
logger.log(level, formattedMsg, t);
}
/*
*Logs a message, looking up the message key and substituting arguments.
*@param level the logging level at which to log this message
*@param messageKey the key to the message
*@param args... the arguments (if any) to be substituted into the looked-up message
*/
private static void log(Level level, String messageKey, Object... args) {
logger.log(level, messageKey, args);
}
/**
*Attempts to store the specified object in serialized form in the indicated
*file. The module ID is used in logging.
*@param obj the Object to be serialized
*@param file the File into which the object graph should be written
*@param moduleID the unique identifier for the module (used in logging)
*@return true if the object graph was written to the file successfully; false otherwise
*/
private static boolean storeSerializedDescriptor(Object obj, File file, String moduleID) {
if ( ! isSerializedDescriptorIOEnabled()) {
return false;
}
/*
*Predeployed system apps will not have generated/xml directories.
*/
if ( ! file.getParentFile().exists()) {
return false;
}
ObjectOutputStream oos = null;
boolean result;
try {
oos = new ObjectOutputStream(new FileOutputStream(file));
oos.writeObject(obj);
result = true;
if(logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE,
"Serialized application " + moduleID);
}
} catch (Throwable t) {
result = false;
log(Level.WARNING, "core.error_ser_descr", t, moduleID);
} finally {
if (oos != null) {
try {
oos.close();
} catch (IOException ioe) {
log(Level.WARNING, "core.error_ser_descr", ioe, moduleID);
}
}
}
return result;
}
/**
*Encapsulates information about a attempt to read an application object
*graph read from a serialized file.
*/
public static class Loader {
/*
* At most one of the next two instance variables will have meaning.
* At most one was read from the serialized file, since the file cannot
* contain more than one root for the serialized object graph.
*/
/** the app read from the file, if any */
private Application deserializedApplication;
/** the exception read from the file, if any */
private Exception deserializedException;
/** the unique module ID of the application being loaded or stored */
private String moduleID;
/** the manager responsible for handling this type of module */
private BaseManager manager;
/** the serialized descriptor file */
private File file;
/*
*New instances are manufactured only by the static load method.
*/
private Loader(String moduleID, BaseManager manager) {
this.moduleID = moduleID;
this.manager = manager;
file = getSerializedDescriptorFile(moduleID, manager);
}
/**
*Attempts to write the specified application to this app's serialized
*file.
*<p>
*Typically used by the deployment logic after it has built the
*application object graph from XML descriptors having seen that the
*serialized file could not be read.
*
*@param application the app's descriptor object graph
*/
public void store(Application application) {
/*
*Write out the application object graph into the file only if
*this loader's deserializedApplication is a different object from
*the application passed in. If they are the same object, then
*the manager is using the deserialized app that this loader read
*in before, and there is no point in rewriting the same data.
*/
if (application == deserializedApplication) {
return;
}
/*
*If the file contained a serialized exception, do not try to
*write the file if that exception's message is the same as the
*current software's version. This is because we assume that the
*same software will not be able to write the object graph now given
*that it could not do so before when it wrote the exception instead.
*
*But there is a chance that a later version of the software will be
*able to write the graph even though an earlier version of the
*software could not. So if the current software is not
*the same as the string in the serialized exception's message, try
*to write the object graph again.
*/
boolean tryToWrite = (deserializedException == null);
if ((deserializedException != null) &&
( ! deserializedException.getMessage().equals(getCurrentSoftwareVersion()))
) {
tryToWrite = true;
if(logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE,
"Trying to serialize an application that could not be serialized by " +
deserializedException.getMessage());
}
}
if (tryToWrite) {
SerializedDescriptorHelper.store(moduleID, manager, application, file);
}
}
/**
*Returns the loader's application.
*@return the application loaded from the serialized file; null if the
*file is absent or its contents could not be read.
*/
public Application getApplication() {
return deserializedApplication ;
}
/**
*Reads in the application descriptor object graph from a previously-
*serialized copy of it in a file if the serialized file is found. The
*private "application" variable is set to the deserialized application.
*In case of an error reading the file, application is left as null.
*<p>
*The method does not even try to load the serialized object graph if
*the timestamp on the XML descriptor is more recent than the timestamp
*on the serialized file.
*/
private void loadSerializedDescriptor() {
if ( ! isSerializedDescriptorIOEnabled()) {
return;
}
deserializedApplication = null;
deserializedException = null;
ObjectInputStream ois = null;
boolean fine = logger.isLoggable(Level.FINE);
try {
if ( ! file.exists()) {
if (fine) {
logger.fine("Serialized descriptor for " +
moduleID +
" not found. Will not try to read serialized file.");
}
return;
}
ois = new ObjectInputStream(new FileInputStream(file));
Object o = ois.readObject();
if (o instanceof Application) {
deserializedApplication = (Application) o;
if (fine) {
logger.fine("Serialized descriptor for " +
moduleID +
" loaded from " +
file.getAbsolutePath());
}
} else if (o instanceof Exception) {
/*
*The serialized file exists and contains another type of
*object, which should be an Exception because an earlier
*attempt at writing the file failed, most likely due to
*a NonSerializableException. Leave the application as null
*and save the exception.
*/
deserializedException = (Exception) o;
if (fine) {
logger.fine("Serialized descriptor file contained an exception " +
"with message \"" + deserializedException.getMessage() + "\" " +
"because a previous attempt to write it failed.");
}
} else {
/*
*The previously serialized object is of an unexpected type.
*Log a warning and continue.
*/
log(Level.WARNING, "core.unexp_deser_type", moduleID, o.getClass().getName());
}
} catch (Throwable thr) {
/*
*Any error is logged only. This allows the caller to proceed
*without requiring any special exception handling. The application
*instance variable remains null so the caller will see that.
*/
log(Level.WARNING, "core.error_deser_descr", moduleID, thr.getLocalizedMessage());
} finally {
if (ois != null) {
try {
ois.close();
} catch (IOException ioe) {
log(Level.WARNING, "core.error_deser_descr", moduleID, ioe.getLocalizedMessage(), ioe);
}
}
}
}
}
}
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