Revize 22d0b32a

simplified modularization by using Java's native SPI

sources/imiger-core/pom.xml

@@ -58 +58 @@
     </build>
 
     <dependencies>
+        <dependency>
+            <groupId>cz.zcu.kiv</groupId>
+            <artifactId>imiger-module</artifactId>
+            <version>${project.version}</version>
+        </dependency>
         <dependency>
             <groupId>cz.zcu.kiv</groupId>
             <artifactId>imiger-spade-converter</artifactId>

sources/imiger-core/src/main/java/cz/zcu/kiv/offscreen/modularization/ModuleLoader.java

@@ -1 @@
-package cz.zcu.kiv.offscreen.modularization;
-
-import javafx.util.Pair;
-import org.apache.commons.io.FileUtils;
-import org.apache.commons.io.FilenameUtils;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.Arrays;
-import java.util.Optional;
-import java.util.Set;
-import java.util.jar.Attributes;
-import java.util.jar.JarInputStream;
-import java.util.jar.Manifest;
-import java.util.stream.Collectors;
-
-/**
- * @author Tomáš Šimandl
- */
-class ModuleLoader {
-
-    private static final Logger logger = LogManager.getLogger();
-    /** Valid file extension of Java module. */
-    private static final String VALID_MODULE_EXTENSION = "jar";
-    /** Identification of section in manifest containing other information about the module. */
-    private static final String MODULE_SECTION_IDENTIFIER = "cz.zcu.kiv.imiger.plugin";
-    /** Identification of class name in modules manifest. */
-    private static final String MODULE_CLASS_IDENTIFIER = "Module-Class";
-    /** Identification of modules visible name in modules manifest. */
-    private static final String MODULE_NAME_IDENTIFIER = "Module-Name";
-
-    /** Name of method which must contains every module. */
-    private final String methodName;
-    /** Class type of parameter to method which must contains every module. */
-    private final Class methodParamClass;
-
-
-    /**
-     * Only story  input parameters
-     * @param methodName Name of method which must contains every module.
-     * @param methodParamClass Class type of parameter to method which must contains every module.
-     */
-    ModuleLoader(String methodName, Class methodParamClass) {
-        this.methodName = methodName;
-        this.methodParamClass = methodParamClass;
-        logger.info("Initializing new ModuleLoader");
-    }
-
-    /**
-     * Method starts process of loading all modules from modules folder (defined in constructor).
-     * @return set of loaded modules in Pair where key is: 'Visible name' and value: 'Class to be called'.
-     */
-    Set<Pair<String, Class>> loadModules() {
-        logger.info("Loading all modules from file.");
-        final URL[] resources = ((URLClassLoader) getClass().getClassLoader()).getURLs();
-        return Arrays.stream(resources)
-                .filter(this::isJarFile) // remove resources which are not jar files
-                .map(this::loadModule) // call method loadModule for every module
-                .filter(Optional::isPresent) // remove modules which were not loaded
-                .map(Optional::get) // extract modules from Optional class
-                .collect(Collectors.toSet()); // return set of modules
-    }
-
-    /**
-     * Checks if resource is a jar file by its extension.
-     *
-     * @param resourceUrl URL of the resource in local filesystem
-     * @return true if the resource is a jar file, otherwise false
-     */
-    private boolean isJarFile(URL resourceUrl) {
-        return FilenameUtils.getExtension(resourceUrl.getFile()).equals(VALID_MODULE_EXTENSION);
-    }
-
-    /**
-     * Load one particular module given by input File containing opened jar file.
-     * Method returns module in Optional in Pair where key is visible modules name and value is access Class from module.
-     *
-     * @param moduleUrl URL of the module in local filesystem
-     * @return opened module or empty Optional where some error occurs.
-     */
-    private Optional<Pair<String, Class>> loadModule(URL moduleUrl) {
-        JarInputStream jis = null;
-        try {
-            jis = new JarInputStream(new FileInputStream(FileUtils.toFile(moduleUrl)));
-            final Manifest mf = jis.getManifest();
-            final Attributes attributes = mf.getAttributes(MODULE_SECTION_IDENTIFIER);
-            if (attributes == null) {
-                throw new NotModuleException();
-            }
-
-            final String moduleClassName = attributes.getValue(MODULE_CLASS_IDENTIFIER);
-            final String moduleVisibleName = attributes.getValue(MODULE_NAME_IDENTIFIER);
-
-            final Class<?> clazz = Class.forName(moduleClassName, true, getClass().getClassLoader());
-            // checking if method exists, if not throw exception
-            clazz.getMethod(methodName, methodParamClass);
-
-            return Optional.of(new Pair<>(moduleVisibleName, clazz));
-
-        } catch (NotModuleException e) {
-            return Optional.empty();
-        } catch (Exception e) {
-            logger.debug("Invalid module throw exception: ", e);
-            return Optional.empty();
-        } finally {
-            try {
-                if (jis != null) jis.close();
-            } catch (IOException e) {
-                logger.error("Can not close opened jar file: ", e);
-            }
-        }
-    }
-}

sources/imiger-core/src/main/java/cz/zcu/kiv/offscreen/modularization/ModuleProvider.java

@@ -1 +1 @@
 package cz.zcu.kiv.offscreen.modularization;
 
-import javafx.util.Pair;
+import cz.zcu.kiv.imiger.spi.IModule;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -8 +8 @@
 import java.net.URISyntaxException;
 import java.nio.file.*;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.Map;
-import java.util.Set;
+import java.util.ServiceLoader;
 import java.util.concurrent.*;
 
 /**
@@ -17 +18 @@
  */
 public class ModuleProvider {
 
-    /** Name of accessed method in every module. */
-    public static final String METHOD_NAME = "getRawJson";
-    /** Class of input parameter to accessed method in every module. */
-    public static final Class METHOD_PARAMETER_CLASS = String.class;
-
     private static final Logger logger = LogManager.getLogger();
     /** Instance of this class used for singleton pattern. */
     private static ModuleProvider instance = null;
 
-    /**
-     * Map containing actual loaded modules. Key is hash of visible name and value is pair of
-     * visible name na accessed method.
-     */
-    private ConcurrentMap<String, Pair<String, Class>> modules = new ConcurrentHashMap<>();
-    /** Instance of class ModuleLoader. */
-    private final ModuleLoader loader;
+    /** Queue containing actual loaded modules. */
+    private Map<String, IModule> modules = new ConcurrentHashMap<>();
+    /** Instance of ServiceLoader. */
+    private final ServiceLoader<IModule> loader;
 
     /** Instance of ScheduledExecutorService used for scheduling of module folder watcher. */
     private ScheduledExecutorService executor;
@@ -60 +53 @@
      * When watcher fails than is automatically starts new watcher after 5 minutes timeout.
      */
     private ModuleProvider() {
-        this.loader = new ModuleLoader(METHOD_NAME, METHOD_PARAMETER_CLASS);
+        this.loader = ServiceLoader.load(IModule.class);
 
-        processModules(loader.loadModules());
+        processModules(loader.iterator());
 
         executor = Executors.newSingleThreadScheduledExecutor();
         Runnable task = this::initModulesWatcher;
@@ -120 +113 @@
                         continue;
                     }
 
-                    processModules(loader.loadModules());
+                    loader.reload();
+                    processModules(loader.iterator());
                     break; // watching only one folder and loading all files every loop => Only one iteration is needed.
                 }
 
@@ -142 +136 @@
      *
      * @param unprocessedModules Set of loaded modules where first argument is visible name and second is accessible method.
      */
-    private void processModules(Set<Pair<String, Class>> unprocessedModules) {
+    private void processModules(Iterator<IModule> unprocessedModules) {
         long startTime = System.nanoTime();
-        Map<String, Pair<String, Class>> localModules = new HashMap<>();
+        Map<String, IModule> localModules = new HashMap<>();
 
-        logger.info("Processing " + unprocessedModules.size() + " modules.");
+        logger.info("Processing modules.");
 
-        for (Pair<String, Class> pair : unprocessedModules) {
-            localModules.put(String.valueOf(pair.getKey().hashCode()), pair);
-        }
+        unprocessedModules.forEachRemaining(module -> localModules.put(String.valueOf(module.getModuleName().hashCode()), module));
 
         modules.clear();
         modules.putAll(localModules);
@@ -163 +155 @@
      * 
      * @return all loaded modules.
      */
-    public Map<String, Pair<String, Class>> getModules() {
+    public Map<String, IModule> getModules() {
         return modules;
     }
 }

sources/imiger-core/src/main/java/cz/zcu/kiv/offscreen/modularization/NotModuleException.java

@@ -1 @@
-package cz.zcu.kiv.offscreen.modularization;
-
-/**
- * Exception thrown when a jar file which is not a valid IMiGEr plugin is loaded.
- */
-class NotModuleException extends Exception {
-    NotModuleException() {
-        super("Jar file is not a valid IMiGEr plugin!");
-    }
-}

sources/imiger-core/src/main/java/cz/zcu/kiv/offscreen/servlets/api/GetSessionDiagram.java

@@ -1 +1 @@
 package cz.zcu.kiv.offscreen.servlets.api;
 
 import com.google.gson.JsonObject;
+import cz.zcu.kiv.imiger.spi.IModule;
 import cz.zcu.kiv.offscreen.modularization.ModuleProvider;
 import cz.zcu.kiv.offscreen.servlets.BaseServlet;
-import javafx.util.Pair;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -11 +11 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
-import java.lang.reflect.Method;
 import java.util.Optional;
 
 /**
@@ -85 +84 @@
     private Optional<String> callModuleConverter(String type, String stringToConvert){
         logger.debug("Processing json with module");
 
-        Pair<String, Class> module = ModuleProvider.getInstance().getModules().get(type);
-        if (module == null){
+        IModule module = ModuleProvider.getInstance().getModules().get(type);
+        if (module == null) {
             logger.debug("No loader available for type: " + type + ". Response BAD REQUEST");
             return Optional.empty();
         }
 
         try {
-            final Class<?> moduleClass = module.getValue();
-            // switching to class loader of module
-            final ClassLoader appClassLoader = Thread.currentThread().getContextClassLoader();
-            Thread.currentThread().setContextClassLoader(moduleClass.getClassLoader());
+            String rawJson = String.valueOf(module.getRawJson(stringToConvert));
 
-            final Method moduleMethod = moduleClass.getMethod(ModuleProvider.METHOD_NAME, ModuleProvider.METHOD_PARAMETER_CLASS);
-            String rawJson = String.valueOf(moduleMethod.invoke(moduleClass.newInstance(), stringToConvert));
-
-            // switching back to application class loader
-            Thread.currentThread().setContextClassLoader(appClassLoader);
-
-            if(StringUtils.isBlank(rawJson)){
+            if (StringUtils.isBlank(rawJson)){
                 return Optional.empty();
             } else {
                 return Optional.of(rawJson);
             }
 
         } catch (Exception e) {
-            logger.error("Can not call convert method in module. Module name: " + module.getKey(), e);
+            logger.error("Can not call convert method in module. Module name: " + module.getModuleName(), e);
             return Optional.empty();
         }
     }

sources/imiger-core/src/main/webapp/uploadFiles.jsp

@@ -74 +74 @@
 						Select type of data file:<br>
 						<label for="raw"><input type="radio" name="fileFormat" value="raw" id="raw" checked> Raw JSON</label><br>
 						<c:forEach items="${processingModules}" var="module">
-							<label for="${module.key}"><input type="radio" name="fileFormat" value="${module.key}" id="${module.key}"> ${module.value.key}</label><br>
+							<label for="${module.key}"><input type="radio" name="fileFormat" value="${module.key}" id="${module.key}"> ${module.value.moduleName}</label><br>
 						</c:forEach>
 					</div>
 

sources/imiger-module/src/main/java/cz/zcu/kiv/imiger/spi/IModule.java

@@ +1 @@
+package cz.zcu.kiv.imiger.spi;
+
+/**
+ * Service Provider Interface (SPI) that must be implemented by all modules.
+ */
+public interface IModule {
+    /**
+     * @return Display name of the module.
+     */
+    String getModuleName();
+
+    /**
+     * Converts input string in any format to raw JSON processable by IMiGEr.
+     *
+     * @param stringToConvert String to be converted to raw JSON.
+     * @return Raw JSON.
+     */
+    String getRawJson(String stringToConvert);
+}

sources/imiger-plugin-template/pom.xml

@@ -26 +26 @@
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-assembly-plugin</artifactId>
-                <configuration>
-                    <archive>
-                        <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
-                    </archive>
-                    <descriptorRefs>
-                        <descriptorRef>jar-with-dependencies</descriptorRef>
-                    </descriptorRefs>
-                </configuration>
-                <executions>
-                    <execution>
-                        <id>make-assembly</id> <!-- this is used for inheritance merges -->
-                        <phase>package</phase> <!-- bind to the packaging phase -->
-                        <goals>
-                            <goal>single</goal>
-                        </goals>
-                    </execution>
-                </executions>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.1.1</version>
             </plugin>
         </plugins>
     </build>

sources/imiger-plugin-template/src/main/java/cz/zcu/kiv/imiger/plugin/template/Converter.java

@@ -1 +1 @@
 package cz.zcu.kiv.imiger.plugin.template;
 
 import com.google.gson.Gson;
+import cz.zcu.kiv.imiger.spi.IModule;
 import cz.zcu.kiv.imiger.vo.Graph;
 
-public class Converter {
+public class Converter implements IModule {
+    @Override
+    public String getModuleName() {
+        return "Module Template";
+    }
 
     /**
      * Convert input file to RAW JSON and return it.
      */
+    @Override
     public String getRawJson(String inputFile) {
-
         Graph graph = new Graph();
         return new Gson().toJson(graph);
     }

sources/imiger-plugin-template/src/main/resources/META-INF/MANIFEST.MF

@@ -1 @@
-Manifest-Version: 1.0
-Created-By: Apache Maven ${maven.version}
-Built-By: ${user.name}
-Build-Jdk: ${java.version}
-Module-Class: cz.zcu.kiv.imiger.plugin.template.Converter
-Module-Name: My Convertor

sources/imiger-plugin-template/src/main/resources/META-INF/services/cz.zcu.kiv.imiger.spi.IModule

@@ +1 @@
+cz.zcu.kiv.imiger.plugin.template.Converter

sources/imiger-plugin-template/src/test/java/PluginTest.java

@@ +1 @@
+import cz.zcu.kiv.imiger.spi.IModule;
 import org.junit.jupiter.api.Test;
-import org.junit.platform.commons.util.StringUtils;
 
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.lang.reflect.Method;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
-import java.util.jar.Attributes;
-import java.util.jar.JarInputStream;
-import java.util.jar.Manifest;
+import java.util.Iterator;
+import java.util.ServiceLoader;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * This class is only for testing integrity of Jar file.
+ * <p>
  * Testing:
- *      Jar file can be open
- *      Manifest contains Module-Name and it is not blank
- *      Manifest contains Module-Class and this class exists in Jar file
- *      Given class contains method 'String getRawJson(String)'
- *
- *
- * !!! BEFORE USAGE PLEASE CHANGE VARIABLE 'ARCHIVE_WITH_DEPENDENCIES_PATH' !!!
+ * <ul>
+ *     <li>Jar file exists
+ *     <li>Jar file is valid service provider
+ *     <li>Jar file contains at least one service implementing {@link cz.zcu.kiv.imiger.spi.IModule} interface
+ * </ul>
+ * <p>
+ * !!! BEFORE USAGE PLEASE CHANGE VARIABLE 'ARCHIVE_PATH' !!!
  */
 class PluginTest {
 
-    private static final String ARCHIVE_WITH_DEPENDENCIES_PATH = "target\\imiger-plugin-template-1.0-SNAPSHOT-jar-with-dependencies.jar";
-
+    private static final String ARCHIVE_PATH = "target/imiger-plugin-template-1.0-SNAPSHOT.jar";
 
     // ========================================= DO NOT CHANGE UNDER THIS LINE =========================================
 
-    private static final String MODULE_CLASS_IDENTIFIER = "Module-Class";
-    private static final String MODULE_NAME_IDENTIFIER = "Module-Name";
-    private static final String METHOD_NAME = "getRawJson";
-    private static final Class METHOD_PARAMETER_CLASS = String.class;
-
     @Test
-    void integrityTest() {
-        try {
-            File jarFile = new File(ARCHIVE_WITH_DEPENDENCIES_PATH);
-
-            JarInputStream jis = new JarInputStream(new FileInputStream(jarFile));
-            final Manifest mf = jis.getManifest();
-            final Attributes attributes = mf.getMainAttributes();
-            final String moduleClassName = attributes.getValue(MODULE_CLASS_IDENTIFIER);
-            final String moduleVisibleName = attributes.getValue(MODULE_NAME_IDENTIFIER);
-
-            assertFalse(StringUtils.isBlank(moduleClassName), "Blank module class name given by manifest attribute 'Module-Class'");
-            assertFalse(StringUtils.isBlank(moduleVisibleName), "Blank module visible name given by manifest attribute 'Module-Name'");
+    void integrityTest() throws MalformedURLException {
+        File jarFile = new File(ARCHIVE_PATH);
+        assertTrue(jarFile.exists(), "Jar file does not exist!");
 
-            final ClassLoader loader = URLClassLoader.newInstance(new URL[]{jarFile.toURI().toURL()});
-            final Class<?> clazz = Class.forName(moduleClassName, true, loader);
-            // checking if method exists, if not throw exception
-            Method method = clazz.getMethod(METHOD_NAME, METHOD_PARAMETER_CLASS);
+        ServiceLoader<IModule> serviceLoader = ServiceLoader.load(IModule.class, new URLClassLoader(new URL[] { jarFile.toURI().toURL() }));
+        Iterator<IModule> moduleIterator = serviceLoader.iterator();
 
-
-            assertEquals(String.class, method.getReturnType(), "Invalid method return type.");
-
-        } catch (IOException e){
-            fail("Can not open given Jar file. Given path is probably incorrect.");
-        } catch (ClassNotFoundException e) {
-            fail("Class given by attribute 'Module-Class' in MANIFEST.MF was not found in Jar file.");
-        } catch (NoSuchMethodException e) {
-            fail("Class given by attribute 'Module-Class' in MANIFEST.MF do not contains method: String getRawJson(String).");
+        int modulesCount = 0;
+        while (moduleIterator.hasNext()) {
+            modulesCount++;
+            moduleIterator.next();
         }
+
+        assertTrue(modulesCount > 0, "There should be at least one service provider in the Jar file!");
     }
 }

sources/imiger-spade-converter/pom.xml

@@ -21 +21 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
                 <version>3.1.1</version>
-                <configuration>
-                    <archive>
-                        <manifestSections>
-                            <manifestSection>
-                                <name>cz.zcu.kiv.imiger.plugin</name>
-                                <manifestEntries>
-                                    <Module-Class>cz.zcu.kiv.imiger.plugin.spade.Spade</Module-Class>
-                                    <Module-Name>Spade JSON</Module-Name>
-                                </manifestEntries>
-                            </manifestSection>
-                        </manifestSections>
-                    </archive>
-                </configuration>
             </plugin>
         </plugins>
     </build>

sources/imiger-spade-converter/src/main/java/cz/zcu/kiv/imiger/plugin/spade/Spade.java

@@ -1 +1 @@
 package cz.zcu.kiv.imiger.plugin.spade;
 
+import cz.zcu.kiv.imiger.spi.IModule;
 import cz.zcu.kiv.imiger.vo.Graph;
 import cz.zcu.kiv.imiger.plugin.spade.graph.GraphManager;
 import cz.zcu.kiv.imiger.plugin.spade.graph.loader.GraphJSONDataLoader;
 import cz.zcu.kiv.imiger.plugin.spade.graph.loader.JSONConfigLoader;
 import net.sf.json.JSONObject;
 
-public class Spade {
+public class Spade implements IModule {
+    @Override
+    public String getModuleName() {
+        return "Spade JSON";
+    }
 
     /**
-     * Convert input spade JSON to RAW JSON and return it.
+     * Convert input spade JSON to RAW JSON.
+     *
+     * @param file String to be converted to raw JSON.
+     * @return Raw JSON.
      */
+    @Override
     public String getRawJson(String file) {
         GraphManager graphManager = new GraphJSONDataLoader(file).loadData();
         JSONConfigLoader configLoader = new JSONConfigLoader(graphManager);

sources/imiger-spade-converter/src/main/resources/META-INF/services/cz.zcu.kiv.imiger.spi.IModule

@@ +1 @@
+cz.zcu.kiv.imiger.plugin.spade.Spade