Package com.google.gerrit.server.plugincontext

Class PluginMapContext<T>

java.lang.Object

com.google.gerrit.server.plugincontext.PluginMapContext<T>

All Implemented Interfaces:

Iterable<PluginMapEntryContext<T>>

public class PluginMapContext<T>
extends Object
implements Iterable<PluginMapEntryContext<T>>

Context to invoke extensions from a DynamicMap.

When a plugin extension is invoked a logging tag with the plugin name is set. This way any errors that are triggered by the plugin extension (even if they happen in Gerrit code which is called by the plugin extension) can be easily attributed to the plugin.

Example if all exceptions should be caught and logged:

 Map results = new HashMap<>();
 fooPluginMapContext.runEach(
     extension -> results.put(extension.getExportName(), extension.get().getFoo());
 

Example if all exceptions, but one, should be caught and logged:

 Map results = new HashMap<>();
 try {
   fooPluginMapContext.runEach(
       extension -> results.put(extension.getExportName(), extension.get().getFoo(),
       MyException.class);
 } catch (MyException e) {
   // handle the exception
 }
 

Example if return values should be handled:

 Map results = new HashMap<>();
 for (PluginMapEntryContext c : fooPluginMapContext) {
   if (c.call(extension -> extension.get().handles(x))) {
     c.run(extension -> results.put(extension.getExportName(), extension.get().getFoo());
   }
 }
 

Example if return values and a single exception should be handled:

 Map results = new HashMap<>();
 try {
   for (PluginMapEntryContext c : fooPluginMapContext) {
     if (c.call(extension -> extension.handles(x), MyException.class)) {
       c.run(extension -> results.put(extension.getExportName(), extension.get().getFoo(),
           MyException.class);
     }
   }
 } catch (MyException e) {
   // handle the exception
 }
 

Example if several exceptions should be handled:

 for (Extension fooExtension : fooDynamicMap) {
   try (TraceContext traceContext = PluginContext.newTrace(fooExtension)) {
     fooExtension.get().doFoo();
   } catch (MyException1 | MyException2 | MyException3 e) {
     // handle the exception
   }
 }
 

Constructor Summary

Constructors

Constructor	Description
PluginMapContext(DynamicMap<T> dynamicMap, PluginContext.PluginMetrics pluginMetrics)

Method Summary

Modifier and Type	Method	Description
boolean	isEmpty()	Checks if no implementations for this extension point have been registered.
Iterator<PluginMapEntryContext<T>>	iterator()	Iterator that provides contexts for invoking the extensions in this map.
SortedSet<String>	plugins()	Returns a sorted list of the plugins that have registered implementations for this extension point.
void	runEach(PluginContext.ExtensionConsumer<Extension<T>> extensionConsumer)	Invokes each extension in the map.
<X extends Exception> void	runEach(PluginContext.ExtensionConsumer<Extension<T>> extensionConsumer, Class<X> exceptionClass)	Invokes each extension in the map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

PluginMapContext

@Inject
public PluginMapContext(DynamicMap<T> dynamicMap,
                        PluginContext.PluginMetrics pluginMetrics)

Method Detail

iterator

public Iterator<PluginMapEntryContext<T>> iterator()

Iterator that provides contexts for invoking the extensions in this map.

This is useful if:

• invoking of each extension returns a result that should be handled
• a sequence of invocations should be done on each extension

Specified by:

iterator in interface Iterable<T>

isEmpty

public boolean isEmpty()

Checks if no implementations for this extension point have been registered.

Returns:

true if no implementations for this extension point have been registered, otherwise false

plugins

public SortedSet<String> plugins()

Returns a sorted list of the plugins that have registered implementations for this extension point.

Returns:

sorted list of the plugins that have registered implementations for this extension point

runEach

public void runEach(PluginContext.ExtensionConsumer<Extension<T>> extensionConsumer)

Invokes each extension in the map. All exceptions from the plugin extensions are caught and logged.

The consumer get the Extension provided that should be invoked. The extension provides access to the plugin name and the export name.

All extension in the map are invoked, even if invoking some of the extensions failed.

Parameters:

extensionConsumer - consumer that invokes the extension

runEach

public <X extends Exception> void runEach(PluginContext.ExtensionConsumer<Extension<T>> extensionConsumer,
                                          Class<X> exceptionClass)
                                   throws X extends Exception

Invokes each extension in the map. All exceptions from the plugin extensions except exceptions of the specified type are caught and logged.

The consumer get the Extension provided that should be invoked. The extension provides access to the plugin name and the export name.

All extension in the map are invoked, even if invoking some of the extensions failed.

Parameters:

extensionConsumer - consumer that invokes the extension

exceptionClass - type of the exceptions that should be thrown

Throws:

X - expected exception from the plugin extension

X extends Exception