Abstract utility classes for re-use

When looking at the existing uses of BundleActivator(s), it became
immediately clear that other parts of the code have a strategy based
properties file resolution very similar to those abstracted by dblib.
This change aggregates a separate utils bundle for this functionality,
which is further abstracted for potential reuse with other use cases.

The next use case is in the sli bundle, which will be handled in
a follow-up patch.

Issue-Id: SDNC-54
Change-Id: Ie4d4bb679617474b1983e6044c08cca1742b9893
Signed-off-by: Ryan Goulding <ryandgoulding@gmail.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/utils/src/main/java/org/onap/ccsdk/sli/core/utils/KarafRootFileResolver.java b/utils/src/main/java/org/onap/ccsdk/sli/core/utils/KarafRootFileResolver.java
new file mode 100644
index 00000000..0cb75450
--- /dev/null
+++ b/utils/src/main/java/org/onap/ccsdk/sli/core/utils/KarafRootFileResolver.java
@@ -0,0 +1,63 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * onap
+ * ================================================================================
+ * Copyright (C) 2016 - 2017 ONAP
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.ccsdk.sli.core.utils;
+
+import java.io.File;
+import java.net.URL;
+import java.util.Optional;
+
+/**
+ * Resolves dblib properties files relative to the karaf root directory.
+ */
+public class KarafRootFileResolver implements PropertiesFileResolver {
+
+    final Object provider;
+
+    private final String successMessage;
+
+    public KarafRootFileResolver(final String successMessage, final Object provider) {
+        this.successMessage = successMessage;
+        this.provider = provider;
+    }
+
+    /**
+     * Parse a properties file location relative to the karaf root
+     *
+     * @return an Optional File containing the location if it exists, or an empty Optional
+     */
+    @Override
+    public Optional<File> resolveFile(final String filename) {
+        final URL fromKarafRoot = provider.getClass().getResource(filename);
+        if (fromKarafRoot != null) {
+            final File propertiesFile = new File(fromKarafRoot.getFile());
+            if (propertiesFile.exists()) {
+                return Optional.of(propertiesFile);
+            }
+            return Optional.empty();
+        }
+        return Optional.empty();
+    }
+
+    @Override
+    public String getSuccessfulResolutionMessage() {
+        return this.successMessage;
+    }
+}