Add one more plugin!

$ ./gradlew clean core-cli:shadowJar plugin-tostring:shadowJar plugin-onlyyear:shadowJar

$ java -jar core-cli/build/libs/core-cli-0.0.1-all.jar plugin-tostring/build/libs/plugin-tostring-0.0.1-all.jar plugin-onlyyear/build/libs/plugin-onlyyear-0.0.1-all.jar

plugin-onlyyear/build.gradle

@@ -0,0 +1,20 @@
+buildscript {
+    repositories { jcenter() }
+    dependencies {
+        classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.0'
+    }
+}
+
+apply plugin: 'com.github.johnrengelman.shadow'
+
+dependencies {
+    // DO NOT DEPEND ON core-impl!
+    compile project(':core-iface')
+    compile 'joda-time:joda-time:2.9.9'  // Example: different version from core-impl.
+}
+
+shadowJar {
+    dependencies {
+        exclude(project(':core-iface'))
+    }
+}

plugin-onlyyear/src/main/java/Plugin.java

@@ -0,0 +1,8 @@
+import org.joda.time.DateTime;
+
+public class Plugin implements PluginSpi {
+    @Override
+    public String formatTimestamp(Timestamp timestamp) {
+        return "" + new DateTime(timestamp.getEpoch() * 1000).getYear();
+    }
+}

settings.gradle

@@ -3,4 +3,5 @@ rootProject.name = 'clean-pluggable-example'
 include 'core-iface'
 include 'core-impl'
 include 'core-cli'
+include 'plugin-onlyyear'
 include 'plugin-tostring'