Add methods to Configuration to more easily express the default-value and throw-if-absent modes

writeoncereadmany · writeoncereadmany · commit 486a4f3e68db · 2018-06-11T05:57:00.000+01:00
diff --git a/src/main/java/co/unruly/config/Configuration.java b/src/main/java/co/unruly/config/Configuration.java
@@ -25,6 +25,14 @@ public Optional<String> get(String s) {
         return Optional.ofNullable(func.get(s));
     }
 
+    public String get(String s, String defaultValue) {
+        return get(s).orElse(defaultValue);
+    }
+
+    public String require(String s) {
+        return get(s).orElseThrow(() -> new ConfigurationMissing(s));
+    }
+
     public Configuration or(ConfigurationSource next) {
         return new Configuration(this.func.or(next));
     }
diff --git a/src/main/java/co/unruly/config/ConfigurationMissing.java b/src/main/java/co/unruly/config/ConfigurationMissing.java
@@ -0,0 +1,8 @@
+package co.unruly.config;
+
+public class ConfigurationMissing extends RuntimeException {
+
+    public ConfigurationMissing(String property) {
+        super(property + " not found in configuration");
+    }
+}
diff --git a/src/test/java/co/unruly/config/ConfigurationTest.java b/src/test/java/co/unruly/config/ConfigurationTest.java
@@ -27,6 +27,24 @@ public void shouldReturnEmptyOptionalIfValueNotFound() {
         assertThat(config.get("some-variable"), is(empty()));
     }
 
+    @Test
+    public void shouldReturnDefaultValueIfProvidedAndValueNotFound() {
+        Map<String, String> input = Collections.emptyMap();
+
+        Configuration config = Configuration.from(map(input));
+
+        assertThat(config.get("some-variable", "default-value"), is("default-value"));
+    }
+
+    @Test(expected = ConfigurationMissing.class)
+    public void shouldThrowIfRequiredValueNotFound() {
+        Map<String, String> input = Collections.emptyMap();
+
+        Configuration config = Configuration.from(map(input));
+
+        config.require("some-variable");
+    }
+
     @Test
     public void shouldReturnOptionalIfValueIsPresent() {
         Map<String, String> input = new HashMap<>();

Original file line number	Diff line number	Diff line change
`@@ -25,6 +25,14 @@ public Optional<String> get(String s) {`
`25`	`25`	`return Optional.ofNullable(func.get(s));`
`26`	`26`	`}`
`27`	`27`
	`28`	`+ public String get(String s, String defaultValue) {`
	`29`	`+ return get(s).orElse(defaultValue);`
	`30`	`+ }`
	`31`	`+`
	`32`	`+ public String require(String s) {`
	`33`	`+ return get(s).orElseThrow(() -> new ConfigurationMissing(s));`
	`34`	`+ }`
	`35`	`+`
`28`	`36`	`public Configuration or(ConfigurationSource next) {`
`29`	`37`	`return new Configuration(this.func.or(next));`
`30`	`38`	`}`