CAY-2942 CayenneModeler MCP: cgen_run tool

removing hello tool now that we have a real one
cleanup

Author: andrus

cayenne-mcp-server/src/main/java/org/apache/cayenne/mcp/CayenneMcpServer.java

@@ -25,7 +25,6 @@
 import io.modelcontextprotocol.server.transport.StdioServerTransportProvider;
 import io.modelcontextprotocol.spec.McpSchema;
 import org.apache.cayenne.mcp.tools.cgen.CgenRunTool;
-import org.apache.cayenne.mcp.tools.hello.HelloTool;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -53,7 +52,7 @@ public void run(String version, InputStream in, OutputStream out) {
         McpSyncServer server = McpServer.sync(transport)
                 .serverInfo("cayenne-mcp-server", version)
                 .capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
-                .tools(HelloTool.spec(), CgenRunTool.spec(jsonMapper))
+                .tools(CgenRunTool.spec(jsonMapper))
                 .build();
 
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {

cayenne-mcp-server/src/main/java/org/apache/cayenne/mcp/tools/hello/HelloTool.java

@@ -0,0 +1,67 @@
+package org.apache.cayenne.mcp;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PipedInputStream;
+import java.io.PipedOutputStream;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Handles the lifecycle of a test in-process MCP server.
+ */
+public class InProcessMcpServer {
+
+    private final OutputStream outputStream;
+    private final InputStream inputStream;
+    private final Thread serverThread;
+
+    public static InProcessMcpServer start() {
+        try {
+            PipedOutputStream clientOut = new PipedOutputStream();
+            PipedInputStream serverIn = new PipedInputStream(clientOut);
+            PipedOutputStream serverOut = new PipedOutputStream();
+            PipedInputStream clientIn = new PipedInputStream(serverOut);
+
+            Thread serverThread = new Thread(
+                    () -> new CayenneMcpServer().run("test", serverIn, serverOut),
+                    "mcp-server");
+            serverThread.setDaemon(true);
+            serverThread.start();
+
+            return new InProcessMcpServer(clientOut, clientIn, serverThread);
+        } catch (IOException e) {
+            throw new RuntimeException("Failed to start in-process MCP server", e);
+        }
+    }
+
+    private InProcessMcpServer(OutputStream outputStream, InputStream inputStream, Thread serverThread) {
+        this.outputStream = outputStream;
+        this.inputStream = inputStream;
+        this.serverThread = serverThread;
+    }
+
+    /**
+     * Stream the test writes JSON-RPC requests to (→ server stdin).
+     */
+    public OutputStream getOutputStream() {
+        return outputStream;
+    }
+
+    /**
+     * Stream the test reads JSON-RPC responses from (← server stdout).
+     */
+    public InputStream getInputStream() {
+        return inputStream;
+    }
+
+    /**
+     * Waits for the server thread to finish, returning {@code true} if it stops
+     * within {@code timeout}. Closing {@link #getOutputStream()} signals EOF to
+     * the server and causes it to shut down.
+     */
+    public boolean waitFor(long timeout, TimeUnit unit) throws InterruptedException {
+        serverThread.join(unit.toMillis(timeout));
+        return !serverThread.isAlive();
+    }
+}

cayenne-mcp-server/src/test/java/org/apache/cayenne/mcp/InProcessMcpServer.java

@@ -49,8 +49,7 @@ public class CgenRunIT {
     void setUp() throws IOException {
         tool = new CgenRunTool();
         destDir = tempDir.resolve("generated");
-        writeFixture("PersonMap", "com.example", destDir, true);
-        projectFile = tempDir.resolve("cayenne-project.xml");
+        projectFile = writeFixture("PersonMap", "com.example", destDir, true);
     }
 
     @Test
@@ -117,10 +116,12 @@ public void subclassNotOverwrittenWhenMakePairsIsTrue() throws IOException {
         int skipped = result.summary().filesConsidered() - result.summary().filesWritten();
         assertTrue(skipped >= 1, "At least one file (the existing subclass) should have been skipped");
     }
-    
-    private void writeFixture(String mapName, String pkg, Path destDir, boolean makePairs) throws IOException {
+
+    private Path writeFixture(String mapName, String pkg, Path destDir, boolean makePairs) throws IOException {
+
         // Project descriptor
-        Files.writeString(tempDir.resolve("cayenne-project.xml"), String.format("""
+        Path projectDescriptor = tempDir.resolve("cayenne-project.xml");
+        Files.writeString(projectDescriptor, String.format("""
                 <?xml version="1.0" encoding="utf-8"?>
                 <domain xmlns="http://cayenne.apache.org/schema/12/domain" project-version="12">
                     <map name="%s"/>
@@ -144,5 +145,7 @@ private void writeFixture(String mapName, String pkg, Path destDir, boolean make
                     </cgen>
                 </data-map>
                 """, pkg, pkg, destDir.toAbsolutePath(), makePairs));
+
+        return projectDescriptor;
     }
 }

cayenne-mcp-server/src/test/java/org/apache/cayenne/mcp/McpHandle.java

@@ -18,8 +18,7 @@
  ****************************************************************/
 package org.apache.cayenne.mcp.tools.cgen;
 
-import org.apache.cayenne.mcp.McpHandle;
-import org.apache.cayenne.mcp.McpStarter;
+import org.apache.cayenne.mcp.InProcessMcpServer;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -52,7 +51,7 @@ public class CgenRunMcpIT {
     @TempDir
     Path tempDir;
 
-    private McpHandle handle;
+    private InProcessMcpServer server;
     private BufferedWriter writer;
     private BufferedReader reader;
     private Path projectFile;
@@ -64,9 +63,9 @@ void setUp() throws Exception {
         writeFixture("PersonMap", "com.example", destDir, true);
         projectFile = tempDir.resolve("cayenne-project.xml");
 
-        handle = McpStarter.start();
-        writer = new BufferedWriter(new OutputStreamWriter(handle.getOutputStream()));
-        reader = new BufferedReader(new InputStreamReader(handle.getInputStream()));
+        server = InProcessMcpServer.start();
+        writer = new BufferedWriter(new OutputStreamWriter(server.getOutputStream()));
+        reader = new BufferedReader(new InputStreamReader(server.getInputStream()));
 
         send("""
                 {"jsonrpc":"2.0","id":1,"method":"initialize","params":{\
@@ -83,7 +82,7 @@ void setUp() throws Exception {
     @AfterEach
     void stopServer() throws Exception {
         writer.close();
-        assertTrue(handle.waitFor(10, TimeUnit.SECONDS), "Server thread did not stop after stdin was closed");
+        assertTrue(server.waitFor(10, TimeUnit.SECONDS), "Server thread did not stop after stdin was closed");
     }
 
     @Test