1 files changed, 57 insertions, 0 deletions
diff --git a/policy-utils/src/main/java/org/onap/policy/drools/utils/EnvironmentVariableWithDefaultLookup.java b/policy-utils/src/main/java/org/onap/policy/drools/utils/EnvironmentVariableWithDefaultLookup.java
new file mode 100644
index 00000000..e0d3e388
--- /dev/null
+++ b/policy-utils/src/main/java/org/onap/policy/drools/utils/EnvironmentVariableWithDefaultLookup.java
@@ -0,0 +1,57 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.policy.drools.utils;
+
+import com.google.common.base.Splitter;
+import java.util.List;
+import org.apache.commons.configuration2.interpol.Lookup;
+import org.apache.commons.lang3.StringUtils;
+
+/**
+ * Environment Variable with a default value.   The syntax is
+ * ${envd:variable-name:default-value}.
+ */
+public class EnvironmentVariableWithDefaultLookup implements Lookup {
+
+    @Override
+    public String lookup(String key) {
+        if (StringUtils.isBlank(key)) {
+            return null;
+        }
+
+        List<String> envWithDefault =
+            Splitter.on(":").trimResults().omitEmptyStrings().splitToList(key);
+        if (envWithDefault.isEmpty()) {
+            return StringUtils.EMPTY;
+        }
+
+        String envVar = System.getenv(envWithDefault.get(0));
+        if (StringUtils.isNotEmpty(envVar)) {
+            return envVar;
+        }
+
+        if (envWithDefault.size() > 1) {
+            return String.join(":", envWithDefault.subList(1, envWithDefault.size()));
+        }
+
+        return StringUtils.EMPTY;
+    }
+}