com.google.gerrit.server.plugincontext.PluginSetContext Maven / Gradle / Ivy
// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.server.plugincontext;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Iterators;
import com.google.gerrit.extensions.registration.DynamicSet;
import com.google.gerrit.extensions.registration.Extension;
import com.google.gerrit.server.plugincontext.PluginContext.ExtensionImplConsumer;
import com.google.gerrit.server.plugincontext.PluginContext.PluginMetrics;
import com.google.inject.Inject;
import java.util.Iterator;
import java.util.SortedSet;
import java.util.stream.Stream;
/**
* Context to invoke extensions from a {@link DynamicSet}.
*
* 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:
*
*
* fooPluginSetContext.runEach(foo -> foo.doFoo());
*
*
* Example if all exceptions, but one, should be caught and logged:
*
*
* try {
* fooPluginSetContext.runEach(foo -> foo.doFoo(), MyException.class);
* } catch (MyException e) {
* // handle the exception
* }
*
*
* Example if return values should be handled:
*
*
* for (PluginSetEntryContext c : fooPluginSetContext) {
* if (c.call(foo -> foo.handles(x))) {
* c.run(foo -> foo.doFoo());
* }
* }
*
*
* Example if return values and a single exception should be handled:
*
*
* try {
* for (PluginSetEntryContext c : fooPluginSetContext) {
* if (c.call(foo -> foo.handles(x), MyException.class)) {
* c.run(foo -> foo.doFoo(), MyException.class);
* }
* }
* } catch (MyException e) {
* // handle the exception
* }
*
*
* Example if several exceptions should be handled:
*
*
* for (Extension fooExtension : fooDynamicSet.entries()) {
* try (TraceContext traceContext = PluginContext.newTrace(fooExtension)) {
* fooExtension.get().doFoo();
* } catch (MyException1 | MyException2 | MyException3 e) {
* // handle the exception
* }
* }
*
*/
public class PluginSetContext implements Iterable> {
private final DynamicSet dynamicSet;
private final PluginMetrics pluginMetrics;
@VisibleForTesting
@Inject
public PluginSetContext(DynamicSet dynamicSet, PluginMetrics pluginMetrics) {
this.dynamicSet = dynamicSet;
this.pluginMetrics = pluginMetrics;
}
/**
* Iterator that provides contexts for invoking the extensions in this set.
*
* 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
*
*/
@Override
public Iterator> iterator() {
return Iterators.transform(
dynamicSet.entries().iterator(), e -> new PluginSetEntryContext<>(e, pluginMetrics));
}
/**
* Checks if no implementations for this extension point have been registered.
*
* @return {@code true} if no implementations for this extension point have been registered,
* otherwise {@code false}
*/
public boolean isEmpty() {
return !dynamicSet.iterator().hasNext();
}
/**
* Returns a sorted list of the plugins that have registered implementations for this extension
* point.
*
* @return sorted list of the plugins that have registered implementations for this extension
* point
*/
public SortedSet plugins() {
return dynamicSet.plugins();
}
/**
* Invokes each extension in the set. All exceptions from the plugin extensions are caught and
* logged.
*
* The consumer gets the extension implementation provided that should be invoked.
*
*
All extension in the set are invoked, even if invoking some of the extensions failed.
*
* @param extensionImplConsumer consumer that invokes the extension
*/
public void runEach(ExtensionImplConsumer extensionImplConsumer) {
dynamicSet
.entries()
.forEach(p -> PluginContext.runLogExceptions(pluginMetrics, p, extensionImplConsumer));
}
public Stream stream() {
return dynamicSet.stream();
}
/**
* Invokes each extension in the set. All exceptions from the plugin extensions except exceptions
* of the specified type are caught and logged.
*
* The consumer gets the extension implementation provided that should be invoked.
*
*
All extension in the set are invoked, even if invoking some of the extensions failed.
*
* @param extensionImplConsumer consumer that invokes the extension
* @param exceptionClass type of the exceptions that should be thrown
* @throws X expected exception from the plugin extension
*/
public void runEach(
ExtensionImplConsumer extensionImplConsumer, Class exceptionClass) throws X {
for (Extension extension : dynamicSet.entries()) {
PluginContext.runLogExceptions(
pluginMetrics, extension, extensionImplConsumer, exceptionClass);
}
}
}