Re-added EnvironmentVariableUtil. Updated version in read me.

Author: simasch

README.md

@@ -17,7 +17,7 @@ This is a Maven Library project, you can add on your Java project as a dependenc
 <dependency>
     <groupId>org.utplsql</groupId>
     <artifactId>utplsql-java-api</artifactId>
-    <version>3.1.15</version>
+    <version>3.1.16</version>
 </dependency>
 ```
 

src/main/java/org/utplsql/api/EnvironmentVariableUtil.java

@@ -0,0 +1,53 @@
+package org.utplsql.api;
+
+import javax.annotation.Nullable;
+
+/**
+ * This class provides an easy way to get environmental variables.
+ * This is mainly to improve testability but also to standardize the way how utPLSQL API and CLI read from
+ * environment.
+ * <p>
+ * Variables are obtained from the following scopes in that order (chain breaks as soon as a value is obtained):
+ * <ul>
+ * <li>Properties (System.getProperty())</li>
+ * <li>Environment (System.getEnv())</li>
+ * <li>Default value</li>
+ * </ul>
+ * <p>
+ * An empty string is treated the same as null.
+ *
+ * @author pesse
+ */
+public class EnvironmentVariableUtil {
+
+    private EnvironmentVariableUtil() {
+    }
+
+    /**
+     * Returns the value for a given key from environment (see class description)
+     *
+     * @param key Key of environment or property value
+     * @return Environment value or null
+     */
+    public static String getEnvValue(String key) {
+        return getEnvValue(key, null);
+    }
+
+    /**
+     * Returns the value for a given key from environment or a default value (see class description)
+     *
+     * @param key          Key of environment or property value
+     * @param defaultValue Default value if nothing found
+     * @return Environment value or defaultValue
+     */
+    public static String getEnvValue(String key, @Nullable String defaultValue) {
+
+        String val = System.getProperty(key);
+        if (val == null || val.isEmpty()) val = System.getenv(key);
+        if (val == null || val.isEmpty()) val = defaultValue;
+
+        return val;
+    }
+
+
+}