lazy: Add LazySingleton scope.

4 files changed, 227 insertions, 0 deletions

diff --git a/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazyScopes.java b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazyScopes.java
new file mode 100644
index 0000000..beb1294
--- /dev/null
+++ b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazyScopes.java
@@ -0,0 +1,59 @@
+/****************************************************************************
+ * Sangria                                                                  *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>             *
+ *                                                                          *
+ * Licensed under the Apache License, Version 2.0 (the "License");          *
+ * you may not use this file except in compliance with the License.         *
+ * You may obtain a copy of the License at                                  *
+ *                                                                          *
+ * http://www.apache.org/licenses/LICENSE-2.0                               *
+ *                                                                          *
+ * Unless required by applicable law or agreed to in writing, software      *
+ * distributed under the License is distributed on an "AS IS" BASIS,        *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
+ * See the License for the specific language governing permissions and      *
+ * limitations under the License.                                           *
+ ****************************************************************************/
+
+package com.tavianator.sangria.lazy;
+
+import com.google.inject.Key;
+import com.google.inject.Provider;
+import com.google.inject.Scope;
+import com.google.inject.Scopes;
+
+/**
+ * Lazy scope implementations.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.2
+ * @since 1.2
+ */
+public class LazyScopes {
+    /**
+     * Lazy version of {@link Scopes#SINGLETON}.
+     *
+     * @see LazySingleton
+     */
+    public static final Scope LAZY_SINGLETON = new Scope() {
+        public <T> Provider<T> scope(final Key<T> key, final Provider<T> creator) {
+            final Provider<T> singleton = Scopes.SINGLETON.scope(key, creator);
+
+            return new Provider<T>() {
+                public T get() {
+                    return singleton.get();
+                }
+
+                @Override
+                public String toString() {
+                    return String.format("%s[%s]", creator, LAZY_SINGLETON);
+                }
+            };
+        }
+
+        @Override
+        public String toString() {
+            return "LazyScopes.LAZY_SINGLETON";
+        }
+    };
+}
diff --git a/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazySingleton.java b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazySingleton.java
new file mode 100644
index 0000000..b8f0482
--- /dev/null
+++ b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/LazySingleton.java
@@ -0,0 +1,41 @@
+/****************************************************************************
+ * Sangria                                                                  *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>             *
+ *                                                                          *
+ * Licensed under the Apache License, Version 2.0 (the "License");          *
+ * you may not use this file except in compliance with the License.         *
+ * You may obtain a copy of the License at                                  *
+ *                                                                          *
+ * http://www.apache.org/licenses/LICENSE-2.0                               *
+ *                                                                          *
+ * Unless required by applicable law or agreed to in writing, software      *
+ * distributed under the License is distributed on an "AS IS" BASIS,        *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
+ * See the License for the specific language governing permissions and      *
+ * limitations under the License.                                           *
+ ****************************************************************************/
+
+package com.tavianator.sangria.lazy;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+import javax.inject.Scope;
+import javax.inject.Singleton;
+
+import static java.lang.annotation.ElementType.*;
+import static java.lang.annotation.RetentionPolicy.*;
+
+/**
+ * Like {@link Singleton}, but always lazy.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.2
+ * @since 1.2
+ */
+@Scope
+@Documented
+@Target({ TYPE, METHOD })
+@Retention(RUNTIME)
+public @interface LazySingleton {
+}
diff --git a/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/SangriaLazyModule.java b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/SangriaLazyModule.java
new file mode 100644
index 0000000..ff4a02a
--- /dev/null
+++ b/sangria-lazy/src/main/java/com/tavianator/sangria/lazy/SangriaLazyModule.java
@@ -0,0 +1,44 @@
+/****************************************************************************
+ * Sangria                                                                  *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>             *
+ *                                                                          *
+ * Licensed under the Apache License, Version 2.0 (the "License");          *
+ * you may not use this file except in compliance with the License.         *
+ * You may obtain a copy of the License at                                  *
+ *                                                                          *
+ * http://www.apache.org/licenses/LICENSE-2.0                               *
+ *                                                                          *
+ * Unless required by applicable law or agreed to in writing, software      *
+ * distributed under the License is distributed on an "AS IS" BASIS,        *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
+ * See the License for the specific language governing permissions and      *
+ * limitations under the License.                                           *
+ ****************************************************************************/
+
+package com.tavianator.sangria.lazy;
+
+import com.google.inject.AbstractModule;
+
+/**
+ * Module for lazy initialization features.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.2
+ * @since 1.2
+ */
+public class SangriaLazyModule extends AbstractModule {
+    @Override
+    protected void configure() {
+        bindScope(LazySingleton.class, LazyScopes.LAZY_SINGLETON);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return o instanceof SangriaLazyModule;
+    }
+
+    @Override
+    public int hashCode() {
+        return SangriaLazyModule.class.hashCode();
+    }
+}
diff --git a/sangria-lazy/src/test/java/com/tavianator/sangria/lazy/LazySingletonTest.java b/sangria-lazy/src/test/java/com/tavianator/sangria/lazy/LazySingletonTest.java
new file mode 100644
index 0000000..69fabce
--- /dev/null
+++ b/sangria-lazy/src/test/java/com/tavianator/sangria/lazy/LazySingletonTest.java
@@ -0,0 +1,83 @@
+/****************************************************************************
+ * Sangria                                                                  *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>             *
+ *                                                                          *
+ * Licensed under the Apache License, Version 2.0 (the "License");          *
+ * you may not use this file except in compliance with the License.         *
+ * You may obtain a copy of the License at                                  *
+ *                                                                          *
+ * http://www.apache.org/licenses/LICENSE-2.0                               *
+ *                                                                          *
+ * Unless required by applicable law or agreed to in writing, software      *
+ * distributed under the License is distributed on an "AS IS" BASIS,        *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
+ * See the License for the specific language governing permissions and      *
+ * limitations under the License.                                           *
+ ****************************************************************************/
+
+package com.tavianator.sangria.lazy;
+
+import javax.inject.Inject;
+import javax.inject.Provider;
+
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.Module;
+import com.google.inject.Stage;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+/**
+ * Tests for the {@link LazySingleton} scope.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.2
+ * @since 1.2
+ */
+public class LazySingletonTest {
+    @LazySingleton
+    private static class Scoped {
+        static final ThreadLocal<Integer> INSTANCES = new ThreadLocal<Integer>() {
+            @Override
+            protected Integer initialValue() {
+                return 0;
+            }
+        };
+
+        @Inject
+        Scoped() {
+            INSTANCES.set(INSTANCES.get() + 1);
+        }
+    }
+
+    @Test
+    public void testDevelopment() {
+        test(Stage.DEVELOPMENT, new SangriaLazyModule());
+    }
+
+    @Test
+    public void testProduction() {
+        test(Stage.PRODUCTION, new SangriaLazyModule());
+    }
+
+    @Test
+    public void testDuplicateModule() {
+        test(Stage.PRODUCTION, new SangriaLazyModule(), new SangriaLazyModule());
+    }
+
+    private void test(Stage stage, Module... modules) {
+        int before = Scoped.INSTANCES.get();
+
+        Injector injector = Guice.createInjector(stage, modules);
+        Provider<Scoped> provider = injector.getProvider(Scoped.class);
+        assertThat(Scoped.INSTANCES.get(), equalTo(before));
+
+        Scoped instance = provider.get();
+        assertThat(Scoped.INSTANCES.get(), equalTo(before + 1));
+
+        assertThat(provider.get(), sameInstance(instance));
+        assertThat(Scoped.INSTANCES.get(), equalTo(before + 1));
+    }
+}