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Plugin system to choose StorageManager implementation
#281
1 parent fee0d27 commit fe40801

10 files changed

Lines changed: 447 additions & 6 deletions

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‎src/main/java/fr/inria/corese/core/next/storagemanager/api/plugin/PluginException.java‎

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package fr.inria.corese.core.next.storagemanager.api.plugin;
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import fr.inria.corese.core.next.storagemanager.api.support.exception.ErrorCode;
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import fr.inria.corese.core.next.storagemanager.api.support.exception.StorageException;
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/**
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* Exception thrown when a plugin fails to create a StorageManager instance.
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*/
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public class PluginException extends StorageException {
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public PluginException(String message) {
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super(ErrorCode.PLUGIN_CREATION_FAILED, message);
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}
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public PluginException(String message, Throwable cause) {
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super(ErrorCode.PLUGIN_CREATION_FAILED, message, cause);
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}
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}

‎src/main/java/fr/inria/corese/core/next/storagemanager/api/plugin/PluginNotFoundException.java‎

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package fr.inria.corese.core.next.storagemanager.api.plugin;
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/**
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* Exception thrown when no plugin is found for the requested configuration.
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*/
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public class PluginNotFoundException extends PluginException {
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public PluginNotFoundException(String message) {
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super(message);
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}
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}

‎src/main/java/fr/inria/corese/core/next/storagemanager/api/plugin/StoragePlugin.java‎

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package fr.inria.corese.core.next.storagemanager.api.plugin;
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import fr.inria.corese.core.next.storagemanager.api.StorageManager;
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import fr.inria.corese.core.next.storagemanager.api.support.config.StorageConfig;
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/**
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* Service Provider Interface (SPI) for StorageManager plugins.
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*/
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public interface StoragePlugin {
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/**
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* Returns the unique name of this plugin.
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*
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* @return the plugin name (must be unique and non-null)
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*/
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String getName();
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/**
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* Returns a human-readable description of this plugin.
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*
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* @return the plugin description (never null)
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*/
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default String getDescription() {
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return "StorageManager plugin: " + getName();
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}
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/**
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* Creates a StorageManager instance from the given configuration.
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*
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* @param config the storage configuration (never null)
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* @return a configured StorageManager instance (never null)
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* @throws PluginException if the StorageManager cannot be created
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* @throws IllegalArgumentException if config is null
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*/
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StorageManager create(StorageConfig config) throws PluginException;
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/**
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* Returns the priority of this plugin.
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*
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* @return the plugin priority
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*/
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default int getPriority() {
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return 0;
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}
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}

‎src/main/java/fr/inria/corese/core/next/storagemanager/api/plugin/StoragePluginManager.java‎

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package fr.inria.corese.core.next.storagemanager.api.plugin;
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import fr.inria.corese.core.next.storagemanager.api.StorageManager;
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import fr.inria.corese.core.next.storagemanager.api.support.config.StorageConfig;
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import java.util.*;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.stream.Collectors;
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/**
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* Manager for discovering and creating StorageManager plugins.
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*/
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public class StoragePluginManager {
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/**
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* ServiceLoader for discovering plugins
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*/
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private static final ServiceLoader<StoragePlugin> serviceLoader =
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ServiceLoader.load(StoragePlugin.class);
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/**
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* Cache of discovered plugins (thread-safe)
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*/
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private static volatile List<StoragePlugin> cachedPlugins;
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/**
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* Plugin lookup cache by name (thread-safe)
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*/
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private static final Map<String, StoragePlugin> pluginsByName =
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new ConcurrentHashMap<>();
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/**
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* Private constructor - this is a static utility class.
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*/
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private StoragePluginManager() {
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throw new AssertionError("StoragePluginManager is a utility class");
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}
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/**
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* Creates a StorageManager instance from the given configuration.
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*
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* @param config the storage configuration (must not be null)
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* @return a configured StorageManager instance
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* @throws IllegalArgumentException if config is null
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* @throws PluginNotFoundException if no plugin supports the configuration
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* @throws PluginException if the StorageManager cannot be created
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*/
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public static StorageManager create(StorageConfig config) throws PluginException {
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if (config == null) {
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throw new IllegalArgumentException("StorageConfig must not be null");
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}
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// Get all available plugins
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List<StoragePlugin> allPlugins = getAvailablePlugins();
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// Find plugins that support this configuration
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List<StoragePlugin> supportingPlugins = allPlugins.stream()
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.sorted(Comparator.comparingInt(StoragePlugin::getPriority).reversed())
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.toList();
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if (supportingPlugins.isEmpty()) {
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String availableTypes = allPlugins.stream()
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.map(StoragePlugin::getName)
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.collect(Collectors.joining(", "));
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throw new PluginNotFoundException(
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String.format("No plugin found for storage type '%s'. Available types: [%s]",
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config.getType(), availableTypes)
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);
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}
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// Select plugin with highest priority
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StoragePlugin selectedPlugin = supportingPlugins.getFirst();
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// Log warning if multiple plugins match
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if (supportingPlugins.size() > 1) {
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String otherPlugins = supportingPlugins.stream()
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.skip(1)
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.map(p -> p.getName() + " (priority=" + p.getPriority() + ")")
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.collect(Collectors.joining(", "));
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System.out.println("WARNING: Multiple plugins support this configuration. " +
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"Selected '" + selectedPlugin.getName() + "' (priority=" +
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selectedPlugin.getPriority() + "). Ignored: " + otherPlugins);
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}
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// Create StorageManager
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try {
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return selectedPlugin.create(config);
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} catch (PluginException e) {
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throw e;
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} catch (Exception e) {
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throw new PluginException(
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"Failed to create StorageManager with plugin '" +
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selectedPlugin.getName() + "'", e);
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}
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}
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/**
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* Returns all available StoragePlugin implementations.
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*
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* @return unmodifiable list of available plugins (never null, may be empty)
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*/
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public static List<StoragePlugin> getAvailablePlugins() {
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if (cachedPlugins == null) {
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synchronized (StoragePluginManager.class) {
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if (cachedPlugins == null) {
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List<StoragePlugin> plugins = new ArrayList<>();
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// Reload ServiceLoader to discover new plugins
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serviceLoader.reload();
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// Collect all plugins
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for (StoragePlugin plugin : serviceLoader) {
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plugins.add(plugin);
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pluginsByName.put(plugin.getName(), plugin);
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}
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// Sort by priority (highest first)
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plugins.sort(Comparator.comparingInt(StoragePlugin::getPriority).reversed());
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// Make immutable
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cachedPlugins = Collections.unmodifiableList(plugins);
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}
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}
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}
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return cachedPlugins;
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}
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/**
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* Finds a plugin by its name.
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*
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* @param name the plugin name (case-sensitive)
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* @return the plugin with the given name, or empty if not found
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* @throws IllegalArgumentException if name is null
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*/
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public static Optional<StoragePlugin> findPlugin(String name) {
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if (name == null) {
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throw new IllegalArgumentException("Plugin name must not be null");
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}
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// Ensure plugins are loaded
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getAvailablePlugins();
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return Optional.ofNullable(pluginsByName.get(name));
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}
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/**
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* Returns the names of all available plugins.
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*
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* @return unmodifiable set of plugin names (never null, may be empty)
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*/
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public static Set<String> getPluginNames() {
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return getAvailablePlugins().stream()
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.map(StoragePlugin::getName)
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.collect(Collectors.collectingAndThen(
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Collectors.toSet(),
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Collections::unmodifiableSet
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));
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}
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/**
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* Reloads all plugins from the classpath.
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*/
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public static void reload() {
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synchronized (StoragePluginManager.class) {
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cachedPlugins = null;
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pluginsByName.clear();
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}
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}
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}

‎src/main/java/fr/inria/corese/core/next/storagemanager/api/support/config/StorageConfig.java‎

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@@ -19,7 +19,6 @@ public final class StorageConfig {
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*/
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private final boolean transactionSupport;
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/**
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* Private constructor — use {@link #builder()} to create instances.
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*
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return properties;
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}
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/**
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* Returns whether transaction support is enabled.
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*
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* @return {@code true} if transaction support is enabled
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*/
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public boolean isTransactionSupport() {
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return transactionSupport;
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}
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/**
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* Returns the storage type from properties.
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*
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* <p>This is a convenience method for {@code getProperty("type", String.class)}.
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* The type is used by the plugin system to select the appropriate StorageManager.
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*
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* @return the storage type, or empty if not set
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*/
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public Optional<String> getType() {
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return getProperty("type", String.class);
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}
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/**
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* Creates a new {@link Builder} for constructing {@code StorageConfig} instances.
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@Override
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public String toString() {
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return "StorageConfig{" +
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"transactionSupport=" + transactionSupport +
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"type=" + getType().orElse("not set") +
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", transactionSupport=" + transactionSupport +
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", properties=" + properties +
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'}';
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}
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*/
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public static final class Builder {
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private final Map<String, Object> properties = new HashMap<>();
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private final boolean transactionSupport = false;
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private boolean transactionSupport = false; // NOT final!
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/**
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* Private constructor — use {@link StorageConfig#builder()}.
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return this;
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}
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/**
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* Enables or disables transaction support.
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*
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* @param enable {@code true} to enable transaction support
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* @return this builder for method chaining
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*/
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public Builder transactionSupport(boolean enable) {
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this.transactionSupport = enable;
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return this;
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}
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/**
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* Builds the {@link StorageConfig} instance with the current configuration.

‎src/main/java/fr/inria/corese/core/next/storagemanager/api/support/exception/ErrorCode.java‎

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/** Restart failed and rollback also failed (critical) */
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RESTART_FAILED_ROLLBACK_FAILED("RESTART_FAIL_ROLLBACK_FAIL",
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"Restart failed and unable to restore previous configuration"),;
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"Restart failed and unable to restore previous configuration"),
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/**
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* Plugin failed to create StorageManager instance
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*/
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PLUGIN_CREATION_FAILED("PLUGIN_CREATION_FAILED", "Plugin failed to create StorageManager instance"),
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;
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private final String code;
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private final String description;

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