com.google.gerrit.server.plugincontext.PluginItemContext 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 static com.google.common.base.Preconditions.checkState;
import com.google.common.annotations.VisibleForTesting;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.extensions.registration.DynamicItem;
import com.google.gerrit.extensions.registration.Extension;
import com.google.gerrit.server.plugincontext.PluginContext.CheckedExtensionImplFunction;
import com.google.gerrit.server.plugincontext.PluginContext.ExtensionImplConsumer;
import com.google.gerrit.server.plugincontext.PluginContext.ExtensionImplFunction;
import com.google.gerrit.server.plugincontext.PluginContext.PluginMetrics;
import com.google.inject.Inject;
/**
* Context to invoke an extension from a {@link DynamicItem}.
*
* When the 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.
*
*
The run* methods execute an extension but don't deliver a result back to the caller.
* Exceptions can be caught and logged.
*
*
The call* methods execute an extension and deliver a result back to the caller.
*
*
Example if all exceptions should be caught and logged:
*
*
* fooPluginItemContext.run(foo -> foo.doFoo());
*
*
* Example if all exceptions, but one, should be caught and logged:
*
*
* try {
* fooPluginItemContext.run(foo -> foo.doFoo(), MyException.class);
* } catch (MyException e) {
* // handle the exception
* }
*
*
* Example if return values should be handled:
*
*
* Object result = fooPluginItemContext.call(foo -> foo.getFoo());
*
*
* Example if return values and a single exception should be handled:
*
*
* Object result;
* try {
* result = fooPluginItemContext.call(foo -> foo.getFoo(), MyException.class);
* } catch (MyException e) {
* // handle the exception
* }
*
*
* Example if several exceptions should be handled:
*
*
* try (TraceContext traceContext = PluginContext.newTrace(fooDynamicItem.getEntry())) {
* fooDynamicItem.get().doFoo();
* } catch (MyException1 | MyException2 | MyException3 e) {
* // handle the exception
* }
*
*/
public class PluginItemContext {
@Nullable private final DynamicItem dynamicItem;
private final PluginMetrics pluginMetrics;
@VisibleForTesting
@Inject
public PluginItemContext(DynamicItem dynamicItem, PluginMetrics pluginMetrics) {
this.dynamicItem = dynamicItem;
this.pluginMetrics = pluginMetrics;
}
/**
* Checks if an implementation for this extension point has been registered.
*
* @return {@code true} if an implementation for this extension point has been registered,
* otherwise {@code false}
*/
public boolean hasImplementation() {
return dynamicItem.getEntry() != null;
}
/**
* Returns the name of the plugin that registered the extension.
*
* @return the plugin name, {@code null} if no implementation is registered for this extension
* point
*/
@Nullable
public String getPluginName() {
return dynamicItem.getPluginName();
}
/**
* Invokes the plugin extension of the item. All exceptions from the plugin extension are caught
* and logged.
*
* The consumer gets the extension implementation provided that should be invoked.
*
*
No-op if no implementation is registered for this extension point.
*
* @param extensionImplConsumer consumer that invokes the extension
*/
public void run(ExtensionImplConsumer extensionImplConsumer) {
Extension extension = dynamicItem.getEntry();
if (extension == null) {
return;
}
PluginContext.runLogExceptions(pluginMetrics, extension, extensionImplConsumer);
}
/**
* Invokes the plugin extension of the item. All exceptions from the plugin extension are caught
* and logged.
*
* The consumer gets the extension implementation provided that should be invoked.
*
*
No-op if no implementation is registered for this extension point.
*
* @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 run(
ExtensionImplConsumer extensionImplConsumer, Class exceptionClass) throws X {
Extension extension = dynamicItem.getEntry();
if (extension == null) {
return;
}
PluginContext.runLogExceptions(pluginMetrics, extension, extensionImplConsumer, exceptionClass);
}
/**
* Calls the plugin extension of the item and returns the result from the plugin extension call.
*
* The function gets the extension implementation provided that should be invoked.
*
*
Fails with {@link IllegalStateException} if no implementation is registered for the item.
*
* @param extensionImplFunction function that invokes the extension
* @return the result from the plugin extension
* @throws IllegalStateException if no implementation is registered for the item
*/
public R call(ExtensionImplFunction extensionImplFunction) {
Extension extension = dynamicItem.getEntry();
checkState(extension != null);
return PluginContext.call(pluginMetrics, extension, extensionImplFunction);
}
/**
* Calls the plugin extension of the item and returns the result from the plugin extension call.
* Exceptions of the specified type are thrown and must be handled by the caller.
*
* The function gets the extension implementation provided that should be invoked.
*
*
Fails with {@link IllegalStateException} if no implementation is registered for the item.
*
* @param checkedExtensionImplFunction function that invokes the extension
* @param exceptionClass type of the exceptions that should be thrown
* @return the result from the plugin extension
* @throws X expected exception from the plugin extension
* @throws IllegalStateException if no implementation is registered for the item
*/
public R call(
CheckedExtensionImplFunction checkedExtensionImplFunction, Class exceptionClass)
throws X {
Extension extension = dynamicItem.getEntry();
checkState(extension != null);
return PluginContext.call(
pluginMetrics, extension, checkedExtensionImplFunction, exceptionClass);
}
}