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JCommon is a free general purpose Java class library that is used in several projects at www.jfree.org, including JFreeChart and JFreeReport.
/* ========================================================================
* JCommon : a free general purpose class library for the Java(tm) platform
* ========================================================================
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* -------------------
* PackageManager.java
* -------------------
* (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
*
* Original Author: Thomas Morgner;
* Contributor(s): David Gilbert (for Object Refinery Limited);
*
* $Id: PackageManager.java,v 1.10 2006/11/02 13:10:35 taqua Exp $
*
* Changes
* -------
* 26-Jun-2003 : Initial version
* 07-Jun-2004 : Added JCommon header (DG);
*
*/
package org.jfree.base.modules;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import org.jfree.base.AbstractBoot;
import org.jfree.base.config.HierarchicalConfiguration;
import org.jfree.base.config.PropertyFileConfiguration;
import org.jfree.base.log.PadMessage;
import org.jfree.util.Configuration;
import org.jfree.util.Log;
import org.jfree.util.ObjectUtilities;
/**
* The PackageManager is used to load and configure the modules of JFreeReport.
* Modules are used to extend the basic capabilities of JFreeReport by providing
* a simple plugin-interface.
*
* Modules provide a simple capability to remove unneeded functionality from the
* JFreeReport system and to reduce the overall code size. The modularisation provides
* a very strict way of removing unnecessary dependencies beween the various packages.
*
* The package manager can be used to add new modules to the system or to check
* the existence and state of installed modules.
*
* @author Thomas Morgner
*/
public final class PackageManager {
/**
* The PackageConfiguration handles the module level configuration.
*
* @author Thomas Morgner
*/
public static class PackageConfiguration extends PropertyFileConfiguration {
/**
* DefaultConstructor. Creates a new package configuration.
*/
public PackageConfiguration() {
// nothing required
}
/**
* The new configuartion will be inserted into the list of report configuration,
* so that this configuration has the given report configuration instance as parent.
*
* @param config the new report configuration.
*/
public void insertConfiguration(final HierarchicalConfiguration config) {
super.insertConfiguration(config);
}
}
/**
* An internal constant declaring that the specified module was already loaded.
*/
private static final int RETURN_MODULE_LOADED = 0;
/**
* An internal constant declaring that the specified module is not known.
*/
private static final int RETURN_MODULE_UNKNOWN = 1;
/**
* An internal constant declaring that the specified module produced an error while loading.
*/
private static final int RETURN_MODULE_ERROR = 2;
/**
* The module configuration instance that should be used to store module
* properties. This separates the user defined properties from the implementation
* defined properties.
*/
private final PackageConfiguration packageConfiguration;
/**
* A list of all defined modules.
*/
private final ArrayList modules;
/**
* A list of module name definitions.
*/
private final ArrayList initSections;
/** The boot implementation for which the modules are managed. */
private AbstractBoot booter;
/** The instances of all modules for all booters. */
private static HashMap instances;
/**
* Creates a package manager instance.
*
* @param booter the booter.
* @return A package manager.
*/
public static PackageManager createInstance(final AbstractBoot booter) {
PackageManager manager;
if (instances == null) {
instances = new HashMap();
manager = new PackageManager(booter);
instances.put(booter, manager);
return manager;
}
manager = (PackageManager) instances.get(booter);
if (manager == null) {
manager = new PackageManager(booter);
instances.put(booter, manager);
}
return manager;
}
/**
* Creates a new package manager.
*
* @param booter the booter (null not permitted).
*/
private PackageManager(final AbstractBoot booter) {
if (booter == null) {
throw new NullPointerException();
}
this.booter = booter;
this.packageConfiguration = new PackageConfiguration();
this.modules = new ArrayList();
this.initSections = new ArrayList();
}
/**
* Checks, whether a certain module is available.
*
* @param moduleDescription the module description of the desired module.
* @return true, if the module is available and the version of the module
* is compatible, false otherwise.
*/
public boolean isModuleAvailable(final ModuleInfo moduleDescription) {
final PackageState[] packageStates =
(PackageState[]) this.modules.toArray(new PackageState[this.modules.size()]);
for (int i = 0; i < packageStates.length; i++) {
final PackageState state = packageStates[i];
if (state.getModule().getModuleClass().equals(moduleDescription.getModuleClass())) {
return (state.getState() == PackageState.STATE_INITIALIZED);
}
}
return false;
}
/**
* Loads all modules mentioned in the report configuration starting with
* the given prefix. This method is used during the boot process of
* JFreeReport. You should never need to call this method directly.
*
* @param modulePrefix the module prefix.
*/
public void load(final String modulePrefix) {
if (this.initSections.contains(modulePrefix)) {
return;
}
this.initSections.add(modulePrefix);
final Configuration config = this.booter.getGlobalConfig();
final Iterator it = config.findPropertyKeys(modulePrefix);
int count = 0;
while (it.hasNext()) {
final String key = (String) it.next();
if (key.endsWith(".Module")) {
final String moduleClass = config.getConfigProperty(key);
if (moduleClass != null && moduleClass.length() > 0) {
addModule(moduleClass);
count++;
}
}
}
Log.debug("Loaded a total of " + count + " modules under prefix: " + modulePrefix);
}
/**
* Initializes all previously uninitialized modules. Once a module is initialized,
* it is not re-initialized a second time.
*/
public synchronized void initializeModules() {
// sort by subsystems and dependency
PackageSorter.sort(this.modules);
for (int i = 0; i < this.modules.size(); i++) {
final PackageState mod = (PackageState) this.modules.get(i);
if (mod.configure(this.booter)) {
Log.debug(new Log.SimpleMessage("Conf: ",
new PadMessage(mod.getModule().getModuleClass(), 70),
" [", mod.getModule().getSubSystem(), "]"));
}
}
for (int i = 0; i < this.modules.size(); i++) {
final PackageState mod = (PackageState) this.modules.get(i);
if (mod.initialize(this.booter)) {
Log.debug(new Log.SimpleMessage("Init: ",
new PadMessage(mod.getModule().getModuleClass(), 70),
" [", mod.getModule().getSubSystem(), "]"));
}
}
}
/**
* Adds a module to the package manager.
* Once all modules are added, you have to call initializeModules()
* to configure and initialize the new modules.
*
* @param modClass the module class
*/
public synchronized void addModule(final String modClass) {
final ArrayList loadModules = new ArrayList();
final ModuleInfo modInfo = new DefaultModuleInfo
(modClass, null, null, null);
if (loadModule(modInfo, new ArrayList(), loadModules, false)) {
for (int i = 0; i < loadModules.size(); i++) {
final Module mod = (Module) loadModules.get(i);
this.modules.add(new PackageState(mod));
}
}
}
/**
* Checks, whether the given module is already loaded in either the given
* tempModules list or the global package registry. If tmpModules is null,
* only the previously installed modules are checked.
*
* @param tempModules a list of previously loaded modules.
* @param module the module specification that is checked.
* @return true, if the module is already loaded, false otherwise.
*/
private int containsModule(final ArrayList tempModules, final ModuleInfo module) {
if (tempModules != null) {
final ModuleInfo[] mods = (ModuleInfo[])
tempModules.toArray(new ModuleInfo[tempModules.size()]);
for (int i = 0; i < mods.length; i++) {
if (mods[i].getModuleClass().equals(module.getModuleClass())) {
return RETURN_MODULE_LOADED;
}
}
}
final PackageState[] packageStates =
(PackageState[]) this.modules.toArray(new PackageState[this.modules.size()]);
for (int i = 0; i < packageStates.length; i++) {
if (packageStates[i].getModule().getModuleClass().equals(module.getModuleClass())) {
if (packageStates[i].getState() == PackageState.STATE_ERROR) {
return RETURN_MODULE_ERROR;
}
else {
return RETURN_MODULE_LOADED;
}
}
}
return RETURN_MODULE_UNKNOWN;
}
/**
* A utility method that collects all failed modules. Such an module caused
* an error while being loaded, and is now cached in case it is referenced
* elsewhere.
*
* @param state the failed module.
*/
private void dropFailedModule(final PackageState state) {
if (this.modules.contains(state) == false) {
this.modules.add(state);
}
}
/**
* Tries to load a given module and all dependent modules. If the dependency check
* fails for that module (or for one of the dependent modules), the loaded modules
* are discarded and no action is taken.
*
* @param moduleInfo the module info of the module that should be loaded.
* @param incompleteModules a list of incompletly loaded modules. This are module
* specifications which depend on the current module and wait for the module to
* be completly loaded.
* @param modules the list of previously loaded modules for this module.
* @param fatal a flag that states, whether the failure of loading a module should
* be considered an error. Root-modules load errors are never fatal, as we try
* to load all known modules, regardless whether they are active or not.
* @return true, if the module was loaded successfully, false otherwise.
*/
private boolean loadModule(final ModuleInfo moduleInfo, final ArrayList incompleteModules,
final ArrayList modules, final boolean fatal) {
try {
final Class c = ObjectUtilities.getClassLoader(getClass()).loadClass(moduleInfo.getModuleClass());
final Module module = (Module) c.newInstance();
if (acceptVersion(moduleInfo, module) == false) {
// module conflict!
Log.warn("Module " + module.getName() + ": required version: "
+ moduleInfo + ", but found Version: \n" + module);
final PackageState state = new PackageState(module, PackageState.STATE_ERROR);
dropFailedModule(state);
return false;
}
final int moduleContained = containsModule(modules, module);
if (moduleContained == RETURN_MODULE_ERROR) {
// the module caused harm before ...
Log.debug("Indicated failure for module: " + module.getModuleClass());
final PackageState state = new PackageState(module, PackageState.STATE_ERROR);
dropFailedModule(state);
return false;
}
else if (moduleContained == RETURN_MODULE_UNKNOWN) {
if (incompleteModules.contains(module)) {
// we assume that loading will continue ...
Log.error(new Log.SimpleMessage
("Circular module reference: This module definition is invalid: ",
module.getClass()));
final PackageState state = new PackageState(module, PackageState.STATE_ERROR);
dropFailedModule(state);
return false;
}
incompleteModules.add(module);
final ModuleInfo[] required = module.getRequiredModules();
for (int i = 0; i < required.length; i++) {
if (loadModule(required[i], incompleteModules, modules, true) == false) {
Log.debug("Indicated failure for module: " + module.getModuleClass());
final PackageState state = new PackageState(module, PackageState.STATE_ERROR);
dropFailedModule(state);
return false;
}
}
final ModuleInfo[] optional = module.getOptionalModules();
for (int i = 0; i < optional.length; i++) {
if (loadModule(optional[i], incompleteModules, modules, true) == false) {
Log.debug(new Log.SimpleMessage("Optional module: ",
optional[i].getModuleClass(), " was not loaded."));
}
}
// maybe a dependent module defined the same base module ...
if (containsModule(modules, module) == RETURN_MODULE_UNKNOWN) {
modules.add(module);
}
incompleteModules.remove(module);
}
return true;
}
catch (ClassNotFoundException cnfe) {
if (fatal) {
Log.warn(new Log.SimpleMessage
("Unresolved dependency for package: ", moduleInfo.getModuleClass()));
}
Log.debug(new Log.SimpleMessage("ClassNotFound: ", cnfe.getMessage()));
return false;
}
catch (Exception e) {
Log.warn(new Log.SimpleMessage("Exception while loading module: ", moduleInfo), e);
return false;
}
}
/**
* Checks, whether the given module meets the requirements defined in the module
* information.
*
* @param moduleRequirement the required module specification.
* @param module the module that should be checked against the specification.
* @return true, if the module meets the given specifications, false otherwise.
*/
private boolean acceptVersion(final ModuleInfo moduleRequirement, final Module module) {
if (moduleRequirement.getMajorVersion() == null) {
return true;
}
if (module.getMajorVersion() == null) {
Log.warn("Module " + module.getName() + " does not define a major version.");
}
else {
final int compare = acceptVersion(moduleRequirement.getMajorVersion(),
module.getMajorVersion());
if (compare > 0) {
return false;
}
else if (compare < 0) {
return true;
}
}
if (moduleRequirement.getMinorVersion() == null) {
return true;
}
if (module.getMinorVersion() == null) {
Log.warn("Module " + module.getName() + " does not define a minor version.");
}
else {
final int compare = acceptVersion(moduleRequirement.getMinorVersion(),
module.getMinorVersion());
if (compare > 0) {
return false;
}
else if (compare < 0) {
return true;
}
}
if (moduleRequirement.getPatchLevel() == null) {
return true;
}
if (module.getPatchLevel() == null) {
Log.debug("Module " + module.getName() + " does not define a patch level.");
}
else {
if (acceptVersion(moduleRequirement.getPatchLevel(),
module.getPatchLevel()) > 0) {
Log.debug("Did not accept patchlevel: "
+ moduleRequirement.getPatchLevel() + " - "
+ module.getPatchLevel());
return false;
}
}
return true;
}
/**
* Compare the version strings. If the strings have a different length,
* the shorter string is padded with spaces to make them compareable.
*
* @param modVer the version string of the module
* @param depModVer the version string of the dependent or optional module
* @return 0, if the dependent module version is equal tothe module's required
* version, a negative number if the dependent module is newer or a positive
* number if the dependent module is older and does not fit.
*/
private int acceptVersion(final String modVer, final String depModVer) {
final int mLength = Math.max(modVer.length(), depModVer.length());
final char[] modVerArray;
final char[] depVerArray;
if (modVer.length() > depModVer.length()) {
modVerArray = modVer.toCharArray();
depVerArray = new char[mLength];
final int delta = modVer.length() - depModVer.length();
Arrays.fill(depVerArray, 0, delta, ' ');
System.arraycopy(depVerArray, delta, depModVer.toCharArray(), 0, depModVer.length());
}
else if (modVer.length() < depModVer.length()) {
depVerArray = depModVer.toCharArray();
modVerArray = new char[mLength];
final char[] b1 = new char[mLength];
final int delta = depModVer.length() - modVer.length();
Arrays.fill(b1, 0, delta, ' ');
System.arraycopy(b1, delta, modVer.toCharArray(), 0, modVer.length());
}
else {
depVerArray = depModVer.toCharArray();
modVerArray = modVer.toCharArray();
}
return new String(modVerArray).compareTo(new String(depVerArray));
}
/**
* Returns the default package configuration. Private report configuration
* instances may be inserted here. These inserted configuration can never override
* the settings from this package configuration.
*
* @return the package configuration.
*/
public PackageConfiguration getPackageConfiguration() {
return this.packageConfiguration;
}
/**
* Returns an array of the currently active modules. The module definition
* returned contain all known modules, including buggy and unconfigured
* instances.
*
* @return the modules.
*/
public Module[] getAllModules() {
final Module[] mods = new Module[this.modules.size()];
for (int i = 0; i < this.modules.size(); i++) {
final PackageState state = (PackageState) this.modules.get(i);
mods[i] = state.getModule();
}
return mods;
}
/**
* Returns all active modules. This array does only contain modules
* which were successfully configured and initialized.
*
* @return the list of all active modules.
*/
public Module[] getActiveModules() {
final ArrayList mods = new ArrayList();
for (int i = 0; i < this.modules.size(); i++) {
final PackageState state = (PackageState) this.modules.get(i);
if (state.getState() == PackageState.STATE_INITIALIZED) {
mods.add(state.getModule());
}
}
return (Module[]) mods.toArray(new Module[mods.size()]);
}
/**
* Prints the modules that are used.
*
* @param p the print stream.
*/
public void printUsedModules(final PrintStream p) {
final Module[] allMods = getAllModules();
final ArrayList activeModules = new ArrayList();
final ArrayList failedModules = new ArrayList();
for (int i = 0; i < allMods.length; i++) {
if (isModuleAvailable(allMods[i])) {
activeModules.add(allMods[i]);
}
else {
failedModules.add(allMods[i]);
}
}
p.print("Active modules: ");
p.println(activeModules.size());
p.println("----------------------------------------------------------");
for (int i = 0; i < activeModules.size(); i++) {
final Module mod = (Module) activeModules.get(i);
p.print(new PadMessage(mod.getModuleClass(), 70));
p.print(" [");
p.print(mod.getSubSystem());
p.println("]");
p.print(" Version: ");
p.print(mod.getMajorVersion());
p.print("-");
p.print(mod.getMinorVersion());
p.print("-");
p.print(mod.getPatchLevel());
p.print(" Producer: ");
p.println(mod.getProducer());
p.print(" Description: ");
p.println(mod.getDescription());
}
}
}