fix(#707): register the simple-no-file language in the camel-core-languages bundle

core/camel-core-languages/pom.xml

@@ -61,6 +61,12 @@
                 <directory>../../src/main/resources</directory>
                 <filtering>false</filtering>
             </resource>
+            <!-- Declaring the module's own resources explicitly: the entry above replaces
+                 Maven's default resource directory, which would otherwise be inherited. -->
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>false</filtering>
+            </resource>
         </resources>
         <plugins>
             <plugin>

core/camel-core-languages/src/main/resources/META-INF/services/org/apache/camel/language/simple-no-file

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+# Camel-karaf specific: Apache Camel intentionally ships no service file for this
+# language, because DefaultLanguageResolver resolves the name through a hardcoded
+# branch instead. OsgiLanguageResolver has no such branch and looks the language up
+# in the OSGi service registry, so without this entry "simple-no-file" cannot be
+# resolved in Karaf and poll/pollEnrich with a simple expression fails with
+# NoSuchLanguageException. Keep this file across Camel upgrades. See issue #707.
+#
+class=org.apache.camel.language.simple.SimpleNoFileLanguage

tests/features/camel-core/src/main/java/org/apache/karaf/camel/test/CamelPollEnrichRouteSupplier.java

@@ -0,0 +1,71 @@
+/*
+ * 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.karaf.camel.test;
+
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.model.RouteDefinition;
+import org.apache.karaf.camel.itests.AbstractCamelSingleFeatureResultMockBasedRouteSupplier;
+import org.apache.karaf.camel.itests.CamelRouteSupplier;
+import org.osgi.service.component.annotations.Component;
+
+/**
+ * Covers the resolution of the internal {@code simple-no-file} language in OSGi.
+ * <p>
+ * When a {@code pollEnrich} is given a {@code simple} expression, {@code PollEnrichReifier} rewrites it to the
+ * {@code simple-no-file} language, so starting this route makes the Camel context resolve that name. Apache Camel
+ * ships no service file for it — {@code DefaultLanguageResolver} resolves it through a hardcoded branch — whereas
+ * camel-karaf's {@code OsgiLanguageResolver} goes through the OSGi service registry. Without the service file in
+ * the camel-core-languages bundle, this route fails to start with a {@code NoSuchLanguageException}.
+ *
+ * @see <a href="https://github.com/apache/camel-karaf/issues/707">issue #707</a>
+ */
+@Component(
+        name = "karaf-camel-poll-enrich-test",
+        immediate = true,
+        service = CamelRouteSupplier.class
+)
+public class CamelPollEnrichRouteSupplier extends AbstractCamelSingleFeatureResultMockBasedRouteSupplier {
+
+    private static final String FILE_NAME_VARIABLE = "sourceFileName";
+    private static final String SOURCE_FILE_NAME = "poll-enrich-source.txt";
+    private static final long POLL_TIMEOUT_MS = 10000L;
+
+    public String getBaseDir() {
+        return "%s/poll-enrich".formatted(System.getProperty("project.target"));
+    }
+
+    @Override
+    protected boolean consumerEnabled() {
+        // Everything happens in the producer route: it seeds the file, then polls it back.
+        return false;
+    }
+
+    @Override
+    protected void configureProducer(RouteBuilder builder, RouteDefinition producerRoute) {
+        String directory = getBaseDir();
+        producerRoute
+                .setVariable(FILE_NAME_VARIABLE, builder.constant(SOURCE_FILE_NAME))
+                .setBody(builder.constant("OK"))
+                .toF("file:%s?fileName=${variable.%s}", directory, FILE_NAME_VARIABLE)
+                // Clear the body so that only a successful enrichment can restore it.
+                .setBody(builder.constant(""))
+                .pollEnrich()
+                    .simple("file:%s?fileName=${variable.%s}&initialDelay=0&delay=100"
+                            .formatted(directory, FILE_NAME_VARIABLE))
+                .timeout(POLL_TIMEOUT_MS)
+                .toF("mock:%s", getResultMockName());
+    }
+}

tests/features/camel-core/src/test/java/org/apache/karaf/camel/itest/CamelCoreITest.java

@@ -14,6 +14,7 @@
 package org.apache.karaf.camel.itest;
 
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 
 import org.apache.camel.component.mock.MockEndpoint;
 import org.apache.karaf.camel.itests.AbstractCamelRouteWithBundleITest;
@@ -63,6 +64,11 @@ public void testCamelBean() throws Exception {
         new CamelBeanITest(this).testRoutes();
     }
 
+    @Test
+    public void testCamelPollEnrich() throws Exception {
+        new CamelPollEnrichITest(this).testRoutes();
+    }
+
     public static class CamelFileITest extends AbstractCamelSingleFeatureResultFileBasedRoute {
 
         public CamelFileITest(CamelContextProvider provider, String baseDir) {
@@ -110,4 +116,22 @@ public void configureMock(MockEndpoint mock) {
             mock.expectedBodiesReceived("OK");
         }
     }
+
+    /**
+     * Asserts that a {@code pollEnrich} driven by a {@code simple} expression starts and enriches, which requires the
+     * internal {@code simple-no-file} language to be resolvable in OSGi. See issue #707.
+     */
+    public static class CamelPollEnrichITest extends AbstractCamelSingleFeatureResultMockBasedRoute {
+
+        public CamelPollEnrichITest(CamelContextProvider provider) {
+            super(provider);
+        }
+
+        @Override
+        public void configureMock(MockEndpoint mock) {
+            // The route seeds a file and polls it back, so allow more headroom than the 10s default.
+            mock.setResultWaitTime(TimeUnit.SECONDS.toMillis(30));
+            mock.expectedBodiesReceived("OK");
+        }
+    }
 }