Merge branch 'master' of ../infrautils

[odlguice.git] / inject-guice-testutils / src / main / java / org / opendaylight / infrautils / inject / guice / testutils / GuiceRule.java

diff --git a/inject-guice-testutils/src/main/java/org/opendaylight/infrautils/inject/guice/testutils/GuiceRule.java b/inject-guice-testutils/src/main/java/org/opendaylight/infrautils/inject/guice/testutils/GuiceRule.java
new file mode 100644 (file)
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--- /dev/null
+++ b/inject-guice-testutils/src/main/java/org/opendaylight/infrautils/inject/guice/testutils/GuiceRule.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016 Red Hat, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.infrautils.inject.guice.testutils;
+
+import com.google.inject.ConfigurationException;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.Module;
+import com.google.inject.Stage;
+import com.mycila.guice.ext.closeable.CloseableInjector;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.junit.rules.MethodRule;
+import org.junit.runners.model.FrameworkMethod;
+import org.junit.runners.model.Statement;
+import org.opendaylight.infrautils.inject.PostFullSystemInjectionListener;
+
+/**
+ * JUnit Rule which initializes Guice {@link Injector} for tests.
+ *
+ * <p>Usage:
+ * <pre>
+ *   public {@literal @}Rule GuiceRule guice = new GuiceRule(YourGuiceModule.class);
+ *
+ *   {@literal @}Inject SomeClass someClass;
+ * </pre>
+ *
+ * @author Michael Vorburger.ch
+ */
+public class GuiceRule implements MethodRule {
+
+    /**
+     * Default Stage PRODUCTION.
+     * Note that this is different from Guice's DEVELOPMENT default.
+     * We do this to avoid having to declare bindings of Listeners asEagerSingleton(),
+     * because in typical OpenDaylight projects there are Listener classes which are not @Inject,
+     * but must still be created (so that they're registered).
+     * See <a href="https://github.com/google/guice/wiki/Bootstrap">Guice documentation</a>.
+     */
+    protected static final Stage DEFAULT_STAGE = Stage.PRODUCTION;
+
+    protected final Iterable<? extends Module> modules;
+    protected final Stage stage;
+
+    protected Injector injector;
+
+    public GuiceRule(Module... modules) {
+        this(DEFAULT_STAGE, modules);
+    }
+
+    protected GuiceRule(Stage stage, Module... modules) {
+        this.modules = Arrays.asList(modules);
+        this.stage = stage;
+    }
+
+    @SafeVarargs
+    public GuiceRule(Class<? extends Module>... moduleClasses) {
+        this.modules = createModules(Arrays.asList(moduleClasses));
+        this.stage = DEFAULT_STAGE;
+    }
+
+    private static Iterable<? extends Module> createModules(List<Class<? extends Module>> moduleClasses) {
+        return moduleClasses.stream().map(klass -> {
+            try {
+                return klass.getConstructor().newInstance();
+            } catch (ReflectiveOperationException | IllegalArgumentException | SecurityException e) {
+                throw new IllegalArgumentException("newInstance() failed: " + klass.getName(), e);
+            }
+        }).collect(Collectors.toList());
+    }
+
+    @Override
+    public Statement apply(Statement base, FrameworkMethod method, Object target) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                try {
+                    setUpGuice(target);
+                    base.evaluate();
+                } finally {
+                    tearDownGuice();
+                }
+            }
+        };
+    }
+
+    protected void setUpGuice(Object target) {
+        injector = Guice.createInjector(stage, modules);
+        injector.injectMembers(target);
+
+        try {
+            injector.getInstance(PostFullSystemInjectionListener.class).onFullSystemInjected();
+        } catch (ConfigurationException e) {
+            // It's OK if we didn't bind a PostFullSystemInjectionListener.
+        }
+    }
+
+    protected void tearDownGuice() {
+        if (injector != null) {
+            // http://code.mycila.com/guice/#3-jsr-250
+            try {
+                injector.getInstance(CloseableInjector.class).close();
+            } catch (ConfigurationException e) {
+                throw new IllegalStateException("You forgot to either add GuiceRule(..., AnnotationsModule.class), "
+                        + "or in your Module use an install(new AnnotationsModule()) with "
+                        + AnnotationsModule.class.getName(), e);
+            }
+        }
+    }
+
+}