NetBeans Plugin Development: JRebel Experience Report

NetBeans Plugin Development:JRebel Experience Report

JavaOne SF 2012

whoami

Anton ArhipovJRebel Product Lead

@[email protected]

Agenda• JRebel intro– Plugin requirements

• NetBeans plugin development• Integrating with NetBeans server adaptors• Integrating with NetBeans debugger• Packaging & publishing

ENTER JREBEL

The Turnaround Cycle

Make changes

Build, deploy,

wait

Observe results

AVG 2.5 min

MyObject

MyObject.class

ClassLoader

Code101000101100010010 New code

111000100101010010

Make changesin IDE

JRebel

Fram

ewor

k

Configuration(XML, annotations,..)

in action

Why IDE plugin?

UsabilityAutomationDebugger

JRebel Plugin for NetBeans

VM args

BreakpointsStepping

Settings, UX

Process Launcher

Debugger

Workbench

Net

Bean

sJRebel Plugin

ENTER NETBEANS PLUGINS

UI Elements

• Buttons/Actions• Toolbars/Menus• Settings/Options• Popups• etc

layers.xml <folder name="Actions"> <folder name="JRebel"> <file name="JRebelToggleAction.instance"> <attr name="delegate" newvalue="o.z.j.n.JRebelToggleAction"/> </file> </folder> </folder>

<folder name="Toolbars"> <folder name="Build"> <file name="JRebelToggleAction.shadow"> <attr name="originalFile" stringvalue="Actions/JRebel/JRebelToggleAction.instance"/> <attr name="position" intvalue="250"/>

Options

<folder name="OptionsDialog"> <file name="JRebelOptions.instance"> <attr name="instanceCreate" methodvalue="o.n.s.o.OptionsCategory.createCategory"/> <attr name="controller" newvalue="o.z.j.n.JRebelOptionsPanelController"/> </file></folder>

<folder name="Services"> <file name="org-zeroturnaround-jrebel-netbeans-options.settings" url="options.xml"/></folder>

Options (Old API)

Options (New API) @OptionsPanelController.SubRegistration( location = "Advanced", displayName = "#AdvancedOption_DisplayName_Super", keywords = "#AdvancedOption_Keywords_Super", keywordsCategory = "Advanced/Super")

@org.openide.util.NbBundle.Messages( {"AdvancedOption_DisplayName_Super=Super", "AdvancedOption_Keywords_Super=super"})

public final class SuperOptionsPanelController extends OptionsPanelController {

CUSTOM JVM ARGUMENTS

JVM arguments• JRebel is bootstrapped using JVM arguments:

• Various NetBeans project types pass JVM arguments slightly differently:

-javaagent:/path/to/jrebel.jar

-noverify -Xbootclasspath/p:jrebel-bootstrap.jar;jrebel.jar

-Drebel.log=true -Drebel.jersey_plugin=true

Web project VS Maven project

JBoss VS Tomcat VS Glassfish

Server settings: Tomcat

Can put your arguments here

Server settings: Glassfish

No VM arguments?

Project Deployment

Aha!!

Toggle

Simplest, from the user’s point of view: should not

care about project type of runtime differences

Togglepublic final class JRebelToggleAction extends BooleanStateAction { public void initialize() { super.initialize(); setBooleanState(JRebelSettings.isEnabled()); }

public void actionPerformed(ActionEvent ev) { super.actionPerformed(ev); JRebelSettings.setEnabled(getBooleanState()); // NbPreferences.forModule(JRebelSettings.class) // .putBoolean(“enabled”, true);

}}

Challenge

No extension points provided by the NetBeans platform

Load-Time Weaving of NetBeans platform classes

Might not be the brightest bulb idea, but seems to work fine

PATCHING THE PLATFORM

org.openide.modules.ModuleInstall

public class Installer extends ModuleInstall { @Override public void restored() { // patch platform classes here

}}

PatcherString classToPatch = …ClassLoader cl = Lookup.getDefault() .lookup(ClassLoader.class);Object o = ClassLoader#findLoadedClass(classToPatch )

ClassPool cp = new ClassPool();cp.appendClassPath(new LoaderClassPath(cl));CtClass ctc = cp.get(classToPatch);patch(cp, ctc);ctc.toClass(cl, null);



e.g.

“org.netbeans.modules.glassfish.common.StartTask”

“org.netbeans.modules.tomcat5.ide.StartTomcat$StartRunnable”

etc



a class loader capable for finding

resources from any module



Method m = ClassLoader.class

.getDeclaredMethod("findLoadedClass", String.class);

m.setAccessible(true);

Object o = m.invoke(cl, patchedClassName);



Enter Javassist



This is where patching

happens really

patch(…)final CtMethod method = ctc.getDeclaredMethod("run");

method.instrument(new ExprEditor() { public void edit(MethodCall m) { if ("getJavaOpts".equals(m.getMethodName())) { m.replace( "if (command == CommandType.START)" + OPTS + "$_ = opts + $proceed($$);"); } }});



Patching

StartTomcat$StartRunnable#run()

for Tomcat launcher



Should append custom options

to getJavaOpts result



String OPTS = "ClassLoader cl = (ClassLoader) Lookup.getDefault().lookup(ClassLoader.class);" +

"Class locator = cl.loadClass(\"org.zeroturnaround.jrebel.netbeans.JRebelLocator\");" +

"Method getJRebelOptsStr = locator.getMethod(\"getJRebelOptsStr\", null);" +

"String opts = (String) getJRebelOptsStr.invoke(null, null);";



String OPTS = "ClassLoader cl = (ClassLoader) Lookup.getDefault().lookup(ClassLoader.class);" +

"Class locator = cl.loadClass(\"org.zeroturnaround.jrebel.netbeans.JRebelLocator\");" +

"Method getJRebelOptsStr = locator.getMethod(\"getJRebelOptsStr\", null);" +

"String opts = (String) getJRebelOptsStr.invoke(null, null);";

-javaagent:/path/to/jrebel.jar etc

Pros & Cons

+ Can get stuff done even if the platform doesn’t provide a proper interface

- Brittle for maintenance

New API (7.2)

• SPI for JVM options passed to SE program or EE server (Bug 206196)

@StartupArgumentsProvider.Registration( position=10, displayName="#DESC_JRebel", startMode={StartMode.NORMAL, StartMode.DEBUG})

public class MyArgsProvider implements StartupArgumentsProvider {@Overridepublic List<String> getArguments(ServerInstance instance, StartMode mode)

http://netbeans.org/bugzilla/show_bug.cgi?id=206196

DEBUGGER INTEGRATION

Dude, where’s my car breakpoint?

Breakpoints

Line 11: initial breakpoint

Breakpoints

Line 14: same breakpoint, but new version of the class

Need to “transfer” the breakpoint from original class to versioned class

Patching

• o.n.m.d.jpda.breakpoints.LineBreakpointImpl– setRequests– getLocations

New API (7.3)

• Allow to provide additional binary classes to submit breakpoints on (Bug 215680)

@BreakpointClassFilter.Registrationpublic class MyFilter extends BreakpointClassFilter {

@Override public ClassNames filterClassNames(ClassNames classNames, JPDABreakpoint breakpoint){}

}

http://netbeans.org/bugzilla/show_bug.cgi?id=215680

RELEASING THE PLUGIN

Packaging

Packaging

Plugin has to be signed

Plugin itself

Module descriptor

JRebel distribution

Dependencies

Maven Build

• NetBeans modules maven plugin– nbm-maven-plugin

• Properties maven plugin– properties-maven-plugin

• Maven dependency plugin– maven-dependency-plugin

• Maven compiler plugin• Maven JAR plugin

Publishing

• http://plugins.netbeans.org/• Verification is performed manually (by

volunteers)• Main criteria: should not break the platform• Takes some time

http://plugins.netbeans.org/

http://plugins.netbeans.org/

Lessons Learned

• UX is hard• Follow the logic of the target IDE• Follow the new APIs • Annotations over layer.xml• If no required extension point provided, can

get around with patching via ModuleInstall• Publishing is not 100% predictable process

Credits

• Big thanks to NetBeans team for awesome co-operation & providing the new API for debugger and server adaptors!

NetBeans Plugin Development: JRebel Experience Report

Technology

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