HONEYCOMB-10: jVpp - the new java API. Java code generation

The old japi has two main drawbacks:

* it is not fully generated (requres manual coding for
every new api call that returns data other thanstatus code)

* it is not asynchronous from Java perspective (requires
active wait loops - big overhead due to JNI boundary being
crossed lots of times).

The new api is lightweight (fully generated except for connect,
disconenct and ping) and truly asynchronous (uses callbacks,
utilities that offer java.util.concurrent.Future interface
are also provided).

Change-Id: I531080ef651e8a74f19210490c71d161221ab600
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>
Signed-off-by: Ed Warnicke <eaw@cisco.com>

1 files changed, 144 insertions, 0 deletions

diff --git a/vpp-api/java/jvpp/org/openvpp/jvpp/VppJNIConnection.java b/vpp-api/java/jvpp/org/openvpp/jvpp/VppJNIConnection.java
new file mode 100644
index 00000000..9e07cc76
--- /dev/null
+++ b/vpp-api/java/jvpp/org/openvpp/jvpp/VppJNIConnection.java
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * 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 org.openvpp.jvpp;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.attribute.PosixFilePermission;
+import java.nio.file.attribute.PosixFilePermissions;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.logging.Logger;
+import org.openvpp.jvpp.callback.JVppCallback;
+
+/**
+ * JNI based representation of a management connection to VPP
+ */
+public final class VppJNIConnection implements VppConnection {
+    private final static Logger LOG = Logger.getLogger(VppJNIConnection.class.getName());
+    private static final String LIBNAME = "libjvpp.so.0.0.0";
+
+    static {
+        try {
+            loadLibrary();
+        } catch (Exception e) {
+            LOG.severe("Can't find vpp jni library: " + LIBNAME);
+            throw new ExceptionInInitializerError(e);
+        }
+    }
+
+    private static void loadStream(final InputStream is) throws IOException {
+        final Set<PosixFilePermission> perms = PosixFilePermissions.fromString("rwxr-x---");
+        final Path p = Files.createTempFile(LIBNAME, null, PosixFilePermissions.asFileAttribute(perms));
+        try {
+            Files.copy(is, p, StandardCopyOption.REPLACE_EXISTING);
+
+            try {
+                Runtime.getRuntime().load(p.toString());
+            } catch (UnsatisfiedLinkError e) {
+                throw new IOException("Failed to load library " + p, e);
+            }
+        } finally {
+            try {
+                Files.deleteIfExists(p);
+            } catch (IOException e) {
+            }
+        }
+    }
+
+    private static void loadLibrary() throws IOException {
+        try (final InputStream is = VppJNIConnection.class.getResourceAsStream('/' + LIBNAME)) {
+            if (is == null) {
+                throw new IOException("Failed to open library resource " + LIBNAME);
+            }
+            loadStream(is);
+        }
+    }
+
+    private final String clientName;
+    private volatile boolean disconnected = false;
+
+    private VppJNIConnection(final String clientName) {
+        if (clientName == null) {
+            throw new NullPointerException("Null clientName");
+        }
+        this.clientName = clientName;
+    }
+
+    /**
+     * Guarded by VppJNIConnection.class
+     */
+    private static final Map<String, VppJNIConnection> connections = new HashMap<>();
+
+    /**
+     * Create a new Vpp connection identified by clientName parameter.
+     *
+     * Multiple instances are allowed since this class is not a singleton
+     * (VPP allows multiple management connections).
+     *
+     * However only a single connection per clientName is allowed.
+     *
+     * @param clientName identifier of vpp connection
+     * @param callback global callback to receive response calls from vpp
+     *
+     * @return new Vpp connection
+     * @throws IOException in case the connection could not be established, or there already is a connection with the same name
+     */
+    public static VppJNIConnection create(final String clientName, final JVppCallback callback) throws IOException {
+        synchronized (VppJNIConnection.class) {
+            if(connections.containsKey(clientName)) {
+                throw new IOException("Client " + clientName + " already connected");
+            }
+
+            final VppJNIConnection vppJNIConnection = new VppJNIConnection(clientName);
+            final int ret = clientConnect(clientName, callback);
+            if (ret != 0) {
+                throw new IOException("Connection returned error " + ret);
+            }
+            connections.put(clientName, vppJNIConnection);
+            return vppJNIConnection;
+        }
+    }
+
+    @Override
+    public final void checkActive() {
+        if (disconnected) {
+            throw new IllegalStateException("Disconnected client " + clientName);
+        }
+    }
+
+    @Override
+    public synchronized final void close() {
+        if (!disconnected) {
+            disconnected = true;
+            try {
+                clientDisconnect();
+            } finally {
+                synchronized (VppJNIConnection.class) {
+                    connections.remove(clientName);
+                }
+            }
+        }
+    }
+
+    private static native int clientConnect(String clientName, JVppCallback callback);
+    private static native void clientDisconnect();
+}