Move java api to extras/

[vpp.git] / extras / japi / java / jvpp-registry / io / fd / vpp / jvpp / NativeLibraryLoader.java

diff --git a/extras/japi/java/jvpp-registry/io/fd/vpp/jvpp/NativeLibraryLoader.java b/extras/japi/java/jvpp-registry/io/fd/vpp/jvpp/NativeLibraryLoader.java
new file mode 100644 (file)
index 0000000..ce6d1bf
--- /dev/null
+++ b/extras/japi/java/jvpp-registry/io/fd/vpp/jvpp/NativeLibraryLoader.java
@@ -0,0 +1,73 @@
+/*
+ * 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 io.fd.vpp.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.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Utility class for loading JNI libraries.
+ */
+public final class NativeLibraryLoader {
+
+    private static final Logger LOG = Logger.getLogger(NativeLibraryLoader.class.getName());
+
+    private NativeLibraryLoader() {
+        throw new UnsupportedOperationException("This utility class cannot be instantiated.");
+    }
+
+    /**
+     * Loads JNI library using class loader of the given class.
+     *
+     * @param libName name of the library to be loaded
+     */
+    public static void loadLibrary(final String libName, final Class clazz) throws IOException {
+        java.util.Objects.requireNonNull(libName, "libName should not be null");
+        java.util.Objects.requireNonNull(clazz, "clazz should not be null");
+        try (final InputStream is = clazz.getResourceAsStream('/' + libName)) {
+            if (is == null) {
+                throw new IOException("Failed to open library resource " + libName);
+            }
+            loadStream(libName, is);
+        }
+    }
+
+    private static void loadStream(final String libName, 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);
+            Runtime.getRuntime().load(p.toString());
+        } catch (Exception e) {
+            throw new IOException("Failed to load library " + p, e);
+        } finally {
+            try {
+                Files.deleteIfExists(p);
+            } catch (IOException e) {
+                LOG.log(Level.WARNING, String.format("Failed to delete temporary file %s.", p), e);
+            }
+        }
+    }
+}