Added new EnvironmentVariableUtil

Samuel Nitsche · Samuel Nitsche · commit d7a61a5dfff9 · 2018-01-29T15:07:20.000+01:00
this is to simplify testing with environment setting preconditions
diff --git a/src/main/java/org/utplsql/api/EnvironmentVariableUtil.java b/src/main/java/org/utplsql/api/EnvironmentVariableUtil.java
@@ -0,0 +1,46 @@
+package org.utplsql.api;
+
+/**
+ * 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 {
+
+    /**
+     * 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, 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;
+    }
+}
diff --git a/src/test/java/org/utplsql/api/EnvironmentVariableUtilTest.java b/src/test/java/org/utplsql/api/EnvironmentVariableUtilTest.java
@@ -0,0 +1,40 @@
+package org.utplsql.api;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+
+public class EnvironmentVariableUtilTest {
+
+    @Test
+    public void testGetVariableFromEnvironment() {
+        // Let's find an environment variable which is not in Properties list and not empty
+        Set<Object> props = System.getProperties().keySet();
+        Optional<Map.Entry<String, String>> envVariable = System.getenv().entrySet().stream()
+                .filter((e) -> !props.contains(e.getKey()) && e.getValue() != null && !e.getValue().isEmpty())
+                .findFirst();
+
+        if ( !envVariable.isPresent() )
+            Assert.fail("Can't test for there is no environment variable not overridden by property");
+
+        Assert.assertEquals(envVariable.get().getValue(), EnvironmentVariableUtil.getEnvValue(envVariable.get().getKey()));
+    }
+
+    @Test
+    public void testGetVariableFromProperty() {
+        System.setProperty("PATH", "MyPath");
+
+        Assert.assertEquals("MyPath", EnvironmentVariableUtil.getEnvValue("PATH"));
+    }
+
+    @Test
+    public void testGetVariableFromDefault() {
+
+        Assert.assertEquals("defaultValue", EnvironmentVariableUtil.getEnvValue("RANDOM"+String.valueOf(System.currentTimeMillis()), "defaultValue"));
+    }
+
+}
