Switch sampler to use more of Spring to make the code simplier

tools/plugs-packager-core/pom.xml

@@ -57,7 +57,7 @@
     <!-- Tests -->
     <dependency>
       <groupId>pl.wavesoftware.plugs.tools</groupId>
-      <artifactId>plugs-packager-testing</artifactId>
+      <artifactId>plugs-packager-samples</artifactId>
       <version>${project.version}</version>
       <scope>test</scope>
     </dependency>
@@ -67,6 +67,11 @@
       <version>${project.version}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-test</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
 </project>

tools/plugs-packager-core/src/test/java/pl/wavesoftware/plugs/tools/packager/core/digest/ProjectDigestImplTest.java

@@ -18,11 +18,14 @@
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
 import pl.wavesoftware.plugs.tools.packager.api.digest.ProjectDigest;
 import pl.wavesoftware.plugs.tools.packager.api.model.Project;
+import pl.wavesoftware.plugs.tools.packager.sample.PackagerSamplerContext;
 import pl.wavesoftware.plugs.tools.packager.sample.SamplerContext;
-import pl.wavesoftware.plugs.tools.packager.sample.project.Projects;
-import pl.wavesoftware.plugs.tools.packager.testing.SamplerExtension;
+import pl.wavesoftware.plugs.tools.packager.sample.project.SimpleProject;
 
 import java.io.IOException;
 
@@ -32,14 +35,18 @@
  * @author <a href="mailto:[email protected]">Krzysztof Suszynski</a>
  * @since 0.1.0
  */
-@ExtendWith(SamplerExtension.class)
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration(classes = PackagerSamplerContext.class)
 class ProjectDigestImplTest {
 
+  @Autowired
+  private SamplerContext context;
+
   @Test
-  void digest(SamplerContext context) throws IOException {
+  void digest() throws IOException {
     // given
     ProjectDigest digester = new ProjectDigestImpl();
-    Project project = context.get(Projects.SIMPLE);
+    Project project = context.get(SimpleProject.class);
 
     // when
     CharSequence digest = digester.digest(project);

tools/plugs-packager-samples/pom.xml

@@ -57,6 +57,11 @@
       <version>${project.version}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-test</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
 </project>

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/AbstractSamplerContext.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019 Wave Software
+ *
+ * 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 pl.wavesoftware.plugs.tools.packager.sample;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+
+abstract class AbstractSamplerContext implements SamplerContext {
+  private static final Logger LOGGER =
+    LoggerFactory.getLogger(AbstractSamplerContext.class);
+  private final Map<Class<? extends Sampler<?>>, Object> samples =
+    new HashMap<>();
+
+  @Override
+  public <T> T get(Class<? extends Sampler<T>> spec) {
+    @SuppressWarnings("unchecked")
+    T val = (T) samples.computeIfAbsent(spec, ignored -> createNew(spec));
+    return val;
+  }
+
+  @Override
+  public <T> T createNew(Class<? extends Sampler<T>> spec) {
+    T sample = getSampler(spec).create();
+    if (LOGGER.isDebugEnabled()) {
+      LOGGER.debug(
+        "Created sample {} for spec {}",
+        Integer.toHexString(sample.hashCode()), spec
+      );
+    }
+    return sample;
+  }
+
+  @Override
+  public void destroy() {
+    samples.clear();
+  }
+
+  protected abstract <T> Sampler<T> getSampler(Class<? extends Sampler<T>> spec);
+}

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/Sample.java → tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/PackagerSamplerContext.java

@@ -16,16 +16,11 @@
 
 package pl.wavesoftware.plugs.tools.packager.sample;
 
-import java.util.function.Supplier;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Import;
 
-public interface Sample<T> extends Supplier<T>, AutoCloseable {
-  @Override
-  void close();
+@ComponentScan(includeFilters = @ComponentScan.Filter(Sampler.Component.class))
+@Import(SamplerContext.Configuration.class)
+public class PackagerSamplerContext {
 
-  interface Easy<T> extends Sample<T> {
-    @Override
-    default void close() {
-      // nothing here
-    }
-  }
 }

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/SamplerContextProxy.java → tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/RandomSeedSupplier.java

@@ -16,32 +16,18 @@
 
 package pl.wavesoftware.plugs.tools.packager.sample;
 
-import io.vavr.Lazy;
-
+import java.util.Random;
 import java.util.function.Supplier;
 
-final class SamplerContextProxy implements SamplerContext {
-
-  private final Lazy<SamplerContext> context;
+final class RandomSeedSupplier implements Supplier<CharSequence> {
 
-  SamplerContextProxy(Supplier<SamplerContext> supplier) {
-    this.context = Lazy.of(supplier);
-  }
-
-  @Override
-  public <T> T get(SampleSpec<T> spec) {
-    return context.get().get(spec);
-  }
-
-  @Override
-  public <T> Sample<T> createNew(SampleSpec<T> spec) {
-    return context.get().createNew(spec);
-  }
+  private static final int BASE36 = 36;
+  private static final int MIN = 60_466_176;
+  private static final Random RANDOM = new Random();
 
   @Override
-  public void close() {
-    if (context.isEvaluated()) {
-      context.get().close();
-    }
+  public CharSequence get() {
+    int calc = RANDOM.nextInt(Integer.MAX_VALUE - MIN) + MIN;
+    return Integer.toString(calc, BASE36);
   }
 }

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/SampleSpec.java → tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/RandomSource.java

@@ -16,10 +16,8 @@
 
 package pl.wavesoftware.plugs.tools.packager.sample;
 
-/**
- * Defines a spec for a sample
- *
- * @param <T> a type of a sample
- */
-public interface SampleSpec<T> {
+import java.util.Random;
+import java.util.function.Supplier;
+
+public interface RandomSource extends Supplier<Random> {
 }

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/RandomSourceImpl.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2019 Wave Software
+ *
+ * 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 pl.wavesoftware.plugs.tools.packager.sample;
+
+import io.vavr.Lazy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.env.Environment;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Random;
+import java.util.zip.CRC32;
+
+final class RandomSourceImpl implements RandomSource {
+  private static final Logger LOGGER =
+    LoggerFactory.getLogger(RandomSourceImpl.class);
+  private static final String SAMPLER_SEED_PROPERTY = "sampler.seed";
+
+  private final RandomSeedSupplier seedSupplier = new RandomSeedSupplier();
+  private final Environment environment;
+  private final Lazy<Random> randomLazy = Lazy.of(this::doGet);
+
+  RandomSourceImpl(Environment environment) {
+    this.environment = environment;
+  }
+
+  @Override
+  public Random get() {
+    return randomLazy.get();
+  }
+
+  private Random doGet() {
+    String seed = environment.getProperty(
+      SAMPLER_SEED_PROPERTY,
+      seedSupplier.get().toString()
+    );
+    CRC32 crc32 = new CRC32();
+    crc32.update(seed.getBytes(StandardCharsets.UTF_8));
+    long randomSeed = crc32.getValue();
+    LOGGER.info(
+      "Using seed: {}. To re-execute same exact case, set " +
+        "environmental variable `export SAMPLER_SEED={}` or Java's " +
+        "property `-D{}={}` with that seed value.",
+      seed,
+      seed,
+      SAMPLER_SEED_PROPERTY, seed
+    );
+    return new Random(randomSeed);
+  }
+}

tools/plugs-packager-samples/src/main/java/pl/wavesoftware/plugs/tools/packager/sample/Sampler.java

@@ -16,24 +16,39 @@
 
 package pl.wavesoftware.plugs.tools.packager.sample;
 
+import org.springframework.core.annotation.AliasFor;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
 /**
  * Resolves a sample of a given spec.
  *
  * @param <T> a type of a sample
  */
 public interface Sampler<T> {
 
-  /**
-   * Whether this sampler supports a given spec of a sample
-   *
-   * @return a sample spec
-   */
-  boolean supports(SampleSpec<T> spec);
+  String SAMPLE_SCOPE = "sample";
 
   /**
-   * Creates a sample based on a spec
-   *
-   * @return a created sample
+   * Creates a new sample
    */
-  Sample<T> create(SampleSpec<T> spec);
+  T create();
+
+  @Target({ElementType.TYPE})
+  @Retention(RetentionPolicy.RUNTIME)
+  @Documented
+  @org.springframework.stereotype.Component
+  @interface Component {
+    /**
+     * The value may indicate a suggestion for a logical component name,
+     * to be turned into a Spring bean in case of an autodetected component.
+     * @return the suggested component name, if any (or empty String otherwise)
+     */
+    @AliasFor(annotation = org.springframework.stereotype.Component.class)
+    String value() default "";
+  }
 }