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new 1c810bb637f ContextServicePlugin SPI - provides a plugin system for
Apache Camel that allows automatic discovery and initialization of third-party
components during CamelContext startup.
1c810bb637f is described below
commit 1c810bb637f546b960ea10c843b0ddf5937cb0b0
Author: Croway <[email protected]>
AuthorDate: Tue Sep 16 17:41:14 2025 +0200
ContextServicePlugin SPI - provides a plugin system for Apache Camel that
allows automatic discovery and initialization of third-party components during
CamelContext startup.
---
.../org/apache/camel/spi/ContextServicePlugin.java | 69 ++++++++++++++++++++
.../camel/impl/engine/AbstractCamelContext.java | 4 ++
.../engine/DefaultContextServiceLoaderPlugin.java | 75 ++++++++++++++++++++++
.../camel/impl/engine/SimpleCamelContext.java | 6 ++
4 files changed, 154 insertions(+)
diff --git
a/core/camel-api/src/main/java/org/apache/camel/spi/ContextServicePlugin.java
b/core/camel-api/src/main/java/org/apache/camel/spi/ContextServicePlugin.java
new file mode 100644
index 00000000000..22e6553f6c2
--- /dev/null
+++
b/core/camel-api/src/main/java/org/apache/camel/spi/ContextServicePlugin.java
@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.camel.spi;
+
+import org.apache.camel.CamelContext;
+
+/**
+ * A plugin interface that allows third-party components to perform
initialization tasks when a CamelContext is being
+ * configured and started.
+ * <p>
+ * Implementations of this interface are automatically discovered and loaded
via the Java ServiceLoader mechanism. To
+ * register a plugin, create a service provider configuration file at
+ * {@code META-INF/services/org.apache.camel.spi.ContextServicePlugin}
containing the fully qualified class name of your
+ * implementation.
+ * <p>
+ * Common use cases include:
+ * <ul>
+ * <li>Registering beans in the Camel registry</li>
+ * <li>Adding event notifiers for monitoring</li>
+ * <li>Configuring global interceptors</li>
+ * <li>Setting up custom type converters</li>
+ * </ul>
+ *
+ * <h3>Example Usage:</h3>
+ *
+ * <pre>
+ * <code>
+ * public class MyContextServicePlugin implements ContextServicePlugin {
+ * @Override
+ * public void load(CamelContext camelContext) {
+ * // Register a bean in the registry
+ * camelContext.getRegistry().bind("myBean", new MyBean());
+ *
+ * // Add an event notifier
+ * camelContext.getManagementStrategy().addEventNotifier(new
MyEventNotifier());
+ * }
+ * }
+ * </code>
+ * </pre>
+ *
+ * @see org.apache.camel.impl.engine.DefaultContextServiceLoaderPlugin
+ */
+public interface ContextServicePlugin {
+
+ /**
+ * Called during CamelContext initialization to allow the plugin to
configure or customize the context.
+ * <p>
+ * This method is invoked after the CamelContext has been created but
before routes are started. Implementations
+ * should perform any necessary setup operations such as registering
beans, adding event notifiers, or configuring
+ * global settings.
+ *
+ * @param camelContext the CamelContext being initialized, never {@code
null}
+ */
+ void load(CamelContext camelContext);
+}
diff --git
a/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/AbstractCamelContext.java
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/AbstractCamelContext.java
index 11effab6239..eec78125a9d 100644
---
a/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/AbstractCamelContext.java
+++
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/AbstractCamelContext.java
@@ -70,6 +70,7 @@ import org.apache.camel.ShutdownRunningTask;
import org.apache.camel.StartupListener;
import org.apache.camel.StartupStep;
import org.apache.camel.StartupSummaryLevel;
+import org.apache.camel.StatefulService;
import org.apache.camel.Suspendable;
import org.apache.camel.SuspendableService;
import org.apache.camel.TypeConverter;
@@ -349,6 +350,7 @@ public abstract class AbstractCamelContext extends
BaseService
* Called during object construction to initialize context plugins
*/
protected void initPlugins() {
+ camelContextExtension.addContextPlugin(StatefulService.class,
createContextServiceLoaderPlugin());
camelContextExtension.addContextPlugin(StartupConditionStrategy.class,
createStartupConditionStrategy());
camelContextExtension.addContextPlugin(CamelBeanPostProcessor.class,
createBeanPostProcessor());
camelContextExtension.addContextPlugin(CamelDependencyInjectionAnnotationFactory.class,
@@ -4471,6 +4473,8 @@ public abstract class AbstractCamelContext extends
BaseService
protected abstract StartupConditionStrategy
createStartupConditionStrategy();
+ protected abstract StatefulService createContextServiceLoaderPlugin();
+
protected abstract BackOffTimerFactory createBackOffTimerFactory();
protected abstract TaskManagerRegistry createTaskManagerRegistry();
diff --git
a/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/DefaultContextServiceLoaderPlugin.java
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/DefaultContextServiceLoaderPlugin.java
new file mode 100644
index 00000000000..5bcb73f65d5
--- /dev/null
+++
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/DefaultContextServiceLoaderPlugin.java
@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.camel.impl.engine;
+
+import java.util.ServiceLoader;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.CamelContextAware;
+import org.apache.camel.spi.ContextServicePlugin;
+import org.apache.camel.support.service.ServiceSupport;
+
+/**
+ * Default implementation that automatically discovers and loads {@link
ContextServicePlugin} implementations using the
+ * Java ServiceLoader mechanism.
+ * <p>
+ * This service is responsible for scanning the classpath for implementations
of {@code ContextServicePlugin} and
+ * invoking their {@code load} method during CamelContext startup. Plugin
implementations are discovered through service
+ * provider configuration files located at: {@code
META-INF/services/org.apache.camel.spi.ContextServicePlugin}
+ * <p>
+ * The loading process occurs during the {@link #doStart()} phase, ensuring
that all plugins are initialized before
+ * routes are started but after the CamelContext has been created and
configured.
+ * <p>
+ * This class extends {@link ServiceSupport} to participate in the Camel
service lifecycle and implements
+ * {@link CamelContextAware} to receive the CamelContext instance that plugins
will operate on.
+ *
+ * @see ContextServicePlugin
+ * @see ServiceLoader
+ */
+public class DefaultContextServiceLoaderPlugin extends ServiceSupport
implements CamelContextAware {
+ private CamelContext camelContext;
+
+ /**
+ * Discovers and loads all {@link ContextServicePlugin} implementations
found on the classpath.
+ * <p>
+ * This method is called during service startup and uses {@link
ServiceLoader} to automatically discover plugin
+ * implementations. Each discovered plugin's {@code load} method is
invoked with the current CamelContext, allowing
+ * plugins to perform their initialization logic.
+ * <p>
+ * The plugins are loaded in the order they are discovered by the
ServiceLoader, which may vary between JVM
+ * implementations and is generally not guaranteed to be deterministic.
+ *
+ * @throws Exception if any plugin fails to load or throws an exception
during initialization
+ */
+ @Override
+ protected void doStart() throws Exception {
+ ServiceLoader<ContextServicePlugin> contextServicePlugins =
ServiceLoader.load(ContextServicePlugin.class);
+ for (ContextServicePlugin plugin : contextServicePlugins) {
+ plugin.load(camelContext);
+ }
+ }
+
+ @Override
+ public void setCamelContext(CamelContext camelContext) {
+ this.camelContext = camelContext;
+ }
+
+ @Override
+ public CamelContext getCamelContext() {
+ return camelContext;
+ }
+}
diff --git
a/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/SimpleCamelContext.java
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/SimpleCamelContext.java
index 941ce38253e..8b2ec46a60c 100644
---
a/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/SimpleCamelContext.java
+++
b/core/camel-base-engine/src/main/java/org/apache/camel/impl/engine/SimpleCamelContext.java
@@ -25,6 +25,7 @@ import org.apache.camel.Endpoint;
import org.apache.camel.Processor;
import org.apache.camel.Route;
import org.apache.camel.RouteTemplateContext;
+import org.apache.camel.StatefulService;
import org.apache.camel.TypeConverter;
import org.apache.camel.catalog.RuntimeCamelCatalog;
import org.apache.camel.console.DevConsoleRegistry;
@@ -755,6 +756,11 @@ public class SimpleCamelContext extends
AbstractCamelContext {
return new DefaultStartupConditionStrategy();
}
+ @Override
+ protected StatefulService createContextServiceLoaderPlugin() {
+ return new DefaultContextServiceLoaderPlugin();
+ }
+
@Override
protected BackOffTimerFactory createBackOffTimerFactory() {
return new DefaultBackOffTimerFactory(this);
