Changing repository group handling

9 files changed, 956 insertions, 9 deletions

diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/CheckedResult.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/CheckedResult.java
new file mode 100644
index 000000000..41961a5e7
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/CheckedResult.java
@@ -0,0 +1,31 @@
+package org.apache.archiva.repository;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+/**
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface CheckedResult<R extends Repository, D>
+{
+    R getRepository();
+
+    boolean isValid();
+
+    D getResult();
+
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryHandler.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryHandler.java
new file mode 100644
index 000000000..49fc4de12
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryHandler.java
@@ -0,0 +1,178 @@
+package org.apache.archiva.repository;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.configuration.Configuration;
+import org.apache.archiva.repository.validation.RepositoryChecker;
+
+import java.util.Collection;
+import java.util.Map;
+
+/**
+ *
+ * This is the generic interface that handles different repository flavours.
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface RepositoryHandler<R extends Repository, C>
+{
+
+    /**
+     * Creates instances from the archiva configuration. The instances are not registered in the registry.
+     *
+     * @return A map of (repository id, Repository) pairs
+     */
+    Map<String, R> newInstancesFromConfig();
+
+    /**
+     * Creates a new instance without registering and without updating the archiva configuration
+     *
+     * @param type the repository type
+     * @param id the repository identifier
+     * @return the repository instance
+     * @throws RepositoryException if the creation failed
+     */
+    R newInstance(RepositoryType type, String id) throws RepositoryException;
+
+    /**
+     * Creates a new instance and updates the given configuration object.
+     *
+     * @param repositoryConfiguration the configuration instance
+     * @return a newly created instance
+     * @throws RepositoryException if the creation failed
+     */
+    R newInstance( C repositoryConfiguration ) throws RepositoryException;
+
+    /**
+     * Adds the given repository to the registry or replaces a already existing repository in the registry.
+     * If an error occurred during the update, it will revert to the old repository status.
+     *
+     * @param repository the repository
+     * @return the created or updated repository instance
+     * @throws RepositoryException if the update or creation failed
+     */
+    R put( R repository ) throws RepositoryException;
+
+    /**
+     * Adds the repository to the registry, based on the given configuration.
+     * If there is a repository registered with the given id, it is updated.
+     * The archiva configuration is updated. The status is not defined, if an error occurs during update. The
+     * The repository instance is registered and initialized if no error occurs
+     *
+     * @param repositoryConfiguration the repository configuration
+     * @return the updated or created repository instance
+     * @throws RepositoryException if the update or creation failed
+     */
+    R put( C repositoryConfiguration ) throws RepositoryException;
+
+    /**
+     * Adds a repository from the given repository configuration. The changes are stored in
+     * the configuration object. The archiva registry is not updated.
+     * The returned repository instance is a clone of the registered repository instance. It is not registered
+     * and not initialized. References are not updated.
+     *
+     * @param repositoryConfiguration the repository configuration
+     * @param configuration the configuration instance
+     * @return the repository instance that was created or updated
+     * @throws RepositoryException if the update or creation failed
+     */
+    R put( C repositoryConfiguration, Configuration configuration ) throws RepositoryException;
+
+    /**
+     * Adds or updates a repository from the given configuration data. The resulting repository is
+     * checked by the repository checker and the result is returned.
+     * If the checker returns a valid result, the registry is updated and configuration is saved.
+     *
+     * @param repositoryConfiguration the repository configuration
+     * @param checker the checker that validates the repository data
+     * @return the repository and the check result
+     * @throws RepositoryException if the creation or update failed
+     */
+    <D> CheckedResult<R, D>
+    putWithCheck( C repositoryConfiguration, RepositoryChecker<R, D> checker) throws RepositoryException;
+
+    /**
+     * Removes the given repository from the registry and updates references and saves the new configuration.
+     *
+     * @param id The repository identifier
+     * @throws RepositoryException if the repository could not be removed
+     */
+    void remove( final String id ) throws RepositoryException;
+
+    /**
+     * Removes the given repository from the registry and updates only the given configuration instance.
+     * The archiva registry is not updated
+     *
+     * @param id the repository identifier
+     * @param configuration the configuration to update
+     * @throws RepositoryException if the repository could not be removed
+     */
+    void remove( String id, Configuration configuration ) throws RepositoryException;
+
+    /**
+     * Returns the repository with the given identifier or <code>null</code>, if it is not registered.
+     *
+     * @param id the repository id
+     * @return if the retrieval failed
+     */
+    R get( String id );
+
+    /**
+     * Clones a given repository without registering.
+     *
+     * @param repo the repository that should be cloned
+     * @return a newly created instance with the same repository data
+     */
+    R clone(R repo) throws RepositoryException;
+
+    /**
+     * Updates the references and stores updates in the given <code>configuration</code> instance.
+     * The references that are updated depend on the concrete repository subclass <code>R</code>.
+     * This method may register/unregister repositories depending on the implementation. That means there is no simple
+     * way to roll back, if an error occurs.
+     *
+     * @param repo the repository for which references are updated
+     * @param repositoryConfiguration the repository configuration
+     */
+    void updateReferences( R repo, C repositoryConfiguration ) throws RepositoryException;
+
+    /**
+     * Returns all registered repositories.
+     *
+     * @return the list of repositories
+     */
+    Collection<R> getAll();
+
+    /**
+     * Returns <code>true</code>, if the repository is registered with the given id, otherwise <code>false</code>
+     * @param id the repository identifier
+     * @return <code>true</code>, if it is registered, otherwise <code>false</code>
+     */
+    boolean has(String id);
+
+    /**
+     * Initializes
+     */
+    void init();
+
+    /**
+     * Closes the handler
+     */
+    void close();
+
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryRegistry.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryRegistry.java
index bb6bbc98b..2a5210666 100644
--- a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryRegistry.java
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryRegistry.java
@@ -29,23 +29,31 @@ import org.apache.archiva.indexer.ArchivaIndexManager;
 import org.apache.archiva.indexer.IndexUpdateFailedException;
 import org.apache.archiva.repository.metadata.MetadataReader;
 import org.apache.archiva.repository.storage.StorageAsset;
+import org.apache.archiva.repository.validation.ValidationError;
+import org.apache.archiva.repository.validation.ValidationResponse;
 
 import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 
 /**
  *  Registry for repositories. This is the central entry point for repositories. It provides methods for
  *  retrieving, adding and removing repositories.
  *  <p>
- *  The modification methods addXX and removeXX persist the changes immediately to the configuration. If the
+ *  The modification methods putXX and removeXX without configuration object persist the changes immediately to the archiva configuration. If the
  *  configuration save fails the changes are rolled back.
+ *  </p>
  *  <p>
+ *    The modification methods with configuration object do only update the given configuration. The configuration is not saved.
+ *  </p>
  * @author Martin Stockhammer <martin_s@apache.org>
  */
+@SuppressWarnings( "UnusedReturnValue" )
 public interface RepositoryRegistry extends EventSource
 {
     /**
      * Set the configuration for the registry
-     * @param archivaConfiguration
+     * @param archivaConfiguration the archiva configuration instance
      */
     void setArchivaConfiguration( ArchivaConfiguration archivaConfiguration );
 
@@ -57,7 +65,7 @@ public interface RepositoryRegistry extends EventSource
     ArchivaIndexManager getIndexManager( RepositoryType type );
 
     /**
-     * Returns the metadatareader for the given repository type
+     * Returns the metadata reader for the given repository type
      * @param type the repository type
      * @return the metadata reader instance
      */
@@ -75,63 +83,305 @@ public interface RepositoryRegistry extends EventSource
      */
     Collection<ManagedRepository> getManagedRepositories( );
 
+    /**
+     * Returns a collection of all registered remote repositories
+     * @return the collection of remote repositories
+     */
     Collection<RemoteRepository> getRemoteRepositories( );
 
+    /**
+     * Returns a collection of all registered repository groups.
+     *
+     * @return the collection of repository groups
+     */
     Collection<RepositoryGroup> getRepositoryGroups( );
 
+    /**
+     * Returns the repository (managed, remote, group) with the given id
+     * @param repoId the id of the repository
+     * @return the repository or <code>null</code> if no repository with this ID is registered.
+     */
     Repository getRepository( String repoId );
 
+    /**
+     * Returns the managed repository with the given id
+     * @param repoId the id of the repository
+     * @return the managed repository instance or <code>null</code>, if no managed repository with this ID is registered.
+     */
     ManagedRepository getManagedRepository( String repoId );
 
+    /**
+     * Returns the remote repository with the given id
+     * @param repoId the id of the repository
+     * @return the remote repository instance or <code>null</code>, if no remote repository with this ID is registered.
+     */
     RemoteRepository getRemoteRepository( String repoId );
 
+    /**
+     * Returns the repository group with the given id
+     * @param groupId the id of the repository group
+     * @return the repository group instance or <code>null</code>, if no repository group with this ID is registered.
+     */
     RepositoryGroup getRepositoryGroup( String groupId );
 
+    /**
+     * Returns <code>true</code>, if a repository with the given ID is registered, otherwise <code>false</code>
+     * @param repoId the ID of the repository
+     * @return <code>true</code>, if a repository with the given ID is registered, otherwise <code>false</code>
+     */
+    boolean hasRepository(String repoId);
+
+    /**
+     * Returns <code>true</code>, if a managed repository with the given ID is registered, otherwise <code>false</code>
+     * @param repoId the id of the managed repository
+     * @return <code>true</code>, if a managed repository with the given ID is registered, otherwise <code>false</code>
+     */
+    boolean hasManagedRepository(String repoId);
+
+    /**
+     * Returns <code>true</code>, if a remote repository with the given ID is registered, otherwise <code>false</code>
+     * @param repoId the id of the remote repository
+     * @return <code>true</code>, if a remote repository with the given ID is registered, otherwise <code>false</code>
+     */
+    boolean hasRemoteRepository(String repoId);
+
+    /**
+     * Returns <code>true</code>, if a repository group with the given ID is registered, otherwise <code>false</code>
+     * @param groupId the id of the repository group
+     * @return <code>true</code>, if a repository group with the given ID is registered, otherwise <code>false</code>
+     */
+    boolean hasRepositoryGroup( String groupId );
+
+    /**
+     * Adds or updates the given managed repository. If a managed repository with the given id exists already, it is updated
+     * from the data of the given instance. Otherwise a new repository is created and updated by the data of the given instance.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param managedRepository the managed repository
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     ManagedRepository putRepository( ManagedRepository managedRepository ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given managed repository. If a managed repository with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param managedRepositoryConfiguration the managed repository configuration
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     ManagedRepository putRepository( ManagedRepositoryConfiguration managedRepositoryConfiguration ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given managed repository. If a managed repository with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * This method can be used, if the archiva configuration should not be saved. It will only update the given configuration object.
+     *
+     * @param managedRepositoryConfiguration the managed repository configuration
+     * @param configuration the archiva configuration that is updated
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     ManagedRepository putRepository( ManagedRepositoryConfiguration managedRepositoryConfiguration, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given repository group. If a repository group with the given id exists already, it is updated
+     * from the data of the given instance. Otherwise a new repository is created and updated by the data of the given instance.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param repositoryGroup the repository group
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RepositoryGroup putRepositoryGroup( RepositoryGroup repositoryGroup ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given repository group. If a repository group with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param repositoryGroupConfiguration the repository group configuration
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RepositoryGroup putRepositoryGroup( RepositoryGroupConfiguration repositoryGroupConfiguration ) throws RepositoryException;
 
+
+    /**
+     * This method creates or updates a repository by the given configuration. It uses the <code>validator</code> to check the
+     * result. If the validation is not successful, the repository will not be saved.
+     *
+     * @param configuration the repository configuration
+     * @return the result
+     */
+    CheckedResult<RepositoryGroup, Map<String, List<ValidationError>>> putRepositoryGroupAndValidate( RepositoryGroupConfiguration configuration) throws RepositoryException;
+
+    /**
+     * Adds or updates the given repository group. If a repository group with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * This method can be used, if the archiva configuration should not be saved. It will only update the given configuration object.
+     *
+     * @param repositoryGroupConfiguration the repository group configuration
+     * @param configuration the archiva configuration that is updated
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RepositoryGroup putRepositoryGroup( RepositoryGroupConfiguration repositoryGroupConfiguration, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given remote repository. If a remote repository with the given id exists already, it is updated
+     * from the data of the given instance. Otherwise a new repository is created and updated by the data of the given instance.
+     *
+     * This method can be used, if the archiva configuration should not be saved. It will only update the given configuration object.
+     *
+     * @param remoteRepository the remote repository
+     * @param configuration the configuration that is updated
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RemoteRepository putRepository( RemoteRepository remoteRepository, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given remote repository. If a remote repository with the given id exists already, it is updated
+     * from the data of the given instance. Otherwise a new repository is created and updated by the data of the given instance.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param remoteRepository the remote repository
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RemoteRepository putRepository( RemoteRepository remoteRepository ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given remote repository. If a remote repository with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * The archiva configuration is updated and saved after updating the registered repository instance.
+     *
+     * @param remoteRepositoryConfiguration the remote repository configuration
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RemoteRepository putRepository( RemoteRepositoryConfiguration remoteRepositoryConfiguration ) throws RepositoryException;
 
+    /**
+     * Adds or updates the given remote repository. If a remote repository with the given id exists already, it is updated
+     * from the data of the given configuration. Otherwise a new repository is created and updated by the data of the given configuration.
+     *
+     * This method can be used, if the archiva configuration should not be saved. It will only update the given configuration object.
+     *
+     * @param remoteRepositoryConfiguration the remote repository configuration
+     * @param configuration the archiva configuration where the updated data is stored into
+     * @return the repository instance, that was created or updated
+     * @throws RepositoryException if an error occurred while creating or updating the instance
+     */
     RemoteRepository putRepository( RemoteRepositoryConfiguration remoteRepositoryConfiguration, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Removes the repository or repository group with the given id, if it exists. Otherwise, it will do nothing.
+     *
+     * The configuration is updated and saved, if the deletion was successful
+     *
+     * @param repoId the id of the repository or repository group to delete
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( String repoId ) throws RepositoryException;
 
+    /**
+     * Removes the given repository.
+     *
+     * The configuration is updated and saved, if the deletion was successful
+     *
+     * @param repo the repository instance that should be deleted
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( Repository repo ) throws RepositoryException;
 
+    /**
+     * Removes the given managed repository.
+     *
+     * The configuration is updated and saved, if the deletion was successful
+     *
+     * @param managedRepository the managed repository to remove
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( ManagedRepository managedRepository ) throws RepositoryException;
 
+    /**
+     * Removes the given managed repository. The given configuration instance is updated, but the
+     * archiva configuration is not saved.
+     *
+     * @param managedRepository the managed repository to remove
+     * @param configuration the configuration instance to update
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( ManagedRepository managedRepository, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Removes the given repository group.
+     *
+     * The configuration is updated and saved, if the deletion was successful
+     *
+     * @param repositoryGroup the repository group to remove
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepositoryGroup( RepositoryGroup repositoryGroup ) throws RepositoryException;
 
+    /**
+     * Removes the given repository group. The given configuration instance is updated, but the
+     * archiva configuration is not saved.
+     *
+     * @param repositoryGroup the repository group to remove
+     * @param configuration the configuration instance to update
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepositoryGroup( RepositoryGroup repositoryGroup, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Removes the given remote repository.
+     *
+     * The configuration is updated and saved, if the deletion was successful
+     *
+     * @param remoteRepository the remote repository to remove
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( RemoteRepository remoteRepository ) throws RepositoryException;
 
+    /**
+     * Removes the given remote repository. The given configuration instance is updated, but the
+     * archiva configuration is not saved.
+     *
+     * @param remoteRepository the remote repository to remove
+     * @param configuration the configuration instance to update
+     * @throws RepositoryException if the repository deletion failed
+     */
     void removeRepository( RemoteRepository remoteRepository, Configuration configuration ) throws RepositoryException;
 
+    /**
+     * Reloads all repositories and groups from the configuration
+     */
     void reload( );
 
     void resetIndexingContext( Repository repository ) throws IndexUpdateFailedException;
 
-    ManagedRepository clone( ManagedRepository repo, String newId ) throws RepositoryException;
-
-    <T extends Repository> Repository clone( T repo, String newId ) throws RepositoryException;
-
-    RemoteRepository clone( RemoteRepository repo, String newId ) throws RepositoryException;
+    /**
+     * Creates a new repository based on the given repository and with the given new id.
+     * @param repo the repository to copy from
+     * @param newId the new repository id
+     * @param <T> the type of the repository (Manage, Remote or RepositoryGroup)
+     * @return the newly created repository
+     * @throws RepositoryException if the repository could not be created
+     */
+    <T extends Repository> T clone( T repo, String newId ) throws RepositoryException;
 
     /**
      * Return the repository that stores the given asset.
@@ -139,4 +389,25 @@ public interface RepositoryRegistry extends EventSource
      * @return the repository or <code>null</code> if no matching repository is found
      */
     Repository getRepositoryOfAsset( StorageAsset asset );
+
+    /**
+     * Validates the set attributes of the given repository instance and returns the validation result.
+     * The repository registry uses all available validators and applies their validateRepository method to the given
+     * repository. Validation results will be merged per field.
+     *
+     * @param repository the repository to validate against
+     * @return the result of the validation.
+     */
+    <R extends Repository> ValidationResponse<R> validateRepository( R repository);
+
+    /**
+     * Validates the set attributes of the given repository instance for a repository update and returns the validation result.
+     * The repository registry uses all available validators and applies their validateRepositoryForUpdate method to the given
+     * repository. Validation results will be merged per field.
+     *
+     * @param repository the repository to validate against
+     * @return the result of the validation.
+     */
+    <R extends Repository> ValidationResponse<R> validateRepositoryForUpdate( R repository);
+
 }
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryType.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryType.java
index f60c65787..b5e8385c1 100644
--- a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryType.java
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/RepositoryType.java
@@ -25,5 +25,5 @@ package org.apache.archiva.repository;
  */
 public enum RepositoryType {
 
-    MAVEN, NPM
+    ALL, MAVEN, NPM
 }
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/AbstractRepositoryValidator.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/AbstractRepositoryValidator.java
new file mode 100644
index 000000000..319fc50db
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/AbstractRepositoryValidator.java
@@ -0,0 +1,50 @@
+package org.apache.archiva.repository.validation;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.CheckedResult;
+import org.apache.archiva.repository.Repository;
+import org.apache.archiva.repository.RepositoryRegistry;
+
+/**
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public abstract class AbstractRepositoryValidator<R extends Repository> implements RepositoryValidator<R>
+{
+    protected RepositoryRegistry repositoryRegistry;
+
+    @Override
+    public void setRepositoryRegistry( RepositoryRegistry repositoryRegistry )
+    {
+        this.repositoryRegistry = repositoryRegistry;
+    }
+
+    protected abstract ValidationResponse<R> apply( R repo, boolean update );
+
+    @Override
+    public ValidationResponse<R> apply( R r )
+    {
+        return apply( r, false );
+    }
+
+    @Override
+    public ValidationResponse<R> applyForUpdate( R repo )
+    {
+        return apply( repo, true );
+    }
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryChecker.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryChecker.java
new file mode 100644
index 000000000..f208d10fe
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryChecker.java
@@ -0,0 +1,36 @@
+package org.apache.archiva.repository.validation;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.CheckedResult;
+import org.apache.archiva.repository.Repository;
+
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+/**
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface RepositoryChecker<R extends Repository, D> extends Function<R, CheckedResult<R,D>>
+{
+
+    @Override
+    CheckedResult<R,D> apply( R r );
+
+    CheckedResult<R,D> applyForUpdate( R repo );
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryValidator.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryValidator.java
new file mode 100644
index 000000000..041fe8a48
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/RepositoryValidator.java
@@ -0,0 +1,85 @@
+package org.apache.archiva.repository.validation;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.Repository;
+import org.apache.archiva.repository.RepositoryRegistry;
+import org.apache.archiva.repository.RepositoryType;
+
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * A repository validator validates given repository data against certain rules.
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public interface RepositoryValidator<R extends Repository> extends RepositoryChecker<R, Map<String, List<ValidationError>>>, Comparable<RepositoryValidator<R>>
+{
+
+    int DEFAULT_PRIORITY=1000;
+
+    /**
+     * Returns the repository type for which this validator can be used. If the validator is applicable
+     * to all types, it should return {@link RepositoryType#ALL}
+     *
+     * @return the repository type for which this validator is applicable
+     */
+    default RepositoryType getType() {
+        return RepositoryType.ALL;
+    }
+
+    /**
+     * Returns the priority of this validator. Smaller values mean higher priority.
+     * All common validators have priority {@link #DEFAULT_PRIORITY}
+     *
+     * Validators are called in numerical order of their priority.
+     *
+     * @return
+     */
+    default int getPriority() {
+        return DEFAULT_PRIORITY;
+    }
+
+
+    /**
+     * Orders by priority
+     *
+     * @see Comparable#compareTo(Object)
+     */
+    @Override
+    default int compareTo( RepositoryValidator o ) {
+        if (o==null) {
+            return 1;
+        } else
+        {
+            return this.getPriority( ) - o.getPriority( );
+        }
+    }
+
+    /**
+     * Sets the repository registry to the given instance.
+     * @param repositoryRegistry the repository registry
+     */
+    void setRepositoryRegistry( RepositoryRegistry repositoryRegistry );
+
+    Class<R> getFlavour();
+
+    boolean isFlavour(Class<?> clazz);
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationError.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationError.java
new file mode 100644
index 000000000..22594fbfa
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationError.java
@@ -0,0 +1,186 @@
+package org.apache.archiva.repository.validation;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Represents a single validation error. A error is defined by a global unique key and has a optional number
+ * of arguments.
+ * <p>
+ * The unique key should represent a category, the attribute and a generic type, separated by '.'
+ * E.g. repository_group.id.empty
+ * </p>
+ * <p>
+ * Categories normally separate errors for different domain types, like managed repository, repository group, maven repository.
+ * <p>
+ * Types define a certain type of error that can be handled similar independent of the attribute or category
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public class ValidationError
+{
+    public static final String UNSPECIFIED = "unspecified";
+
+    final String errorKey;
+    final String attribute;
+    final String category;
+    final String type;
+    final List<Object> arguments = new ArrayList<>();
+
+
+    public static ValidationError ofKey( final String errorKey, Object... arguments )
+    {
+        return new ValidationError( errorKey, getCategoryFromKey( errorKey ), getTypeFromKey( errorKey ), getAttributeFromKey( errorKey ),
+            Arrays.asList( arguments ) );
+    }
+
+    public static ValidationError ofKey( String errorKey, List<Object> arguments )
+    {
+        return new ValidationError( errorKey, getCategoryFromKey( errorKey ), getTypeFromKey( errorKey ), getAttributeFromKey( errorKey ),
+            arguments );
+    }
+
+    public ValidationError( String errorKey, String category, String type, String attribute, List<Object> arguments )
+    {
+        if ( StringUtils.isEmpty( errorKey ) )
+        {
+            throw new IllegalArgumentException( "The key of a validation error cannot be empty" );
+        }
+        this.errorKey = errorKey;
+        if ( arguments != null )
+        {
+            this.arguments.addAll( arguments );
+        }
+        this.type = type;
+        this.category = category;
+        this.attribute = attribute;
+    }
+
+    private static String getTypeFromKey( final String errorKey )
+    {
+        return errorKey.contains( "." ) ?
+            StringUtils.substringAfterLast( errorKey, "." ) :
+            UNSPECIFIED;
+    }
+
+    private static String getCategoryFromKey( final String errorKey )
+    {
+        return errorKey.contains( "." ) ?
+            StringUtils.substringBefore( errorKey, "." ) :
+            UNSPECIFIED;
+    }
+
+    private static String getAttributeFromKey( final String errorKey )
+    {
+        return StringUtils.countMatches( errorKey, "." ) >= 2 ?
+            StringUtils.substringBetween( errorKey, "." ) : UNSPECIFIED;
+    }
+
+    /**
+     * Returns the unique key of this validation error. It is best practice for keys to contain the
+     * validation source, the attribute and a unique error definition.
+     * E.g. repository_group.id.empty
+     *
+     * @return
+     */
+    public String getErrorKey( )
+    {
+        return errorKey;
+    }
+
+    /**
+     * Returns the list of arguments stored for this error
+     * @return the list of arguments
+     */
+    public List<Object> getArguments( )
+    {
+        return arguments;
+    }
+
+    /**
+     * Adds the given argument to the list
+     * @param argument the argument to add
+     */
+    public void addArgument( Object argument )
+    {
+        this.arguments.add( argument );
+    }
+
+    /**
+     * Returns the generic error type, this error represents.
+     *
+     * @return the error type or {@link #UNSPECIFIED} if not explicitly set.
+     */
+    public String getType( )
+    {
+        return type;
+    }
+
+    /**
+     * Returns the category of the error.
+     *
+     * @return the category or {@link #UNSPECIFIED} if not explicitly set
+     */
+    public String getCategory( )
+    {
+        return category;
+    }
+
+    /**
+     * Returns the attribute name
+     * @return the attribute name or {@link #UNSPECIFIED} if not explicitly set
+     */
+    public String getAttribute( )
+    {
+        return attribute;
+    }
+
+    @Override
+    public String toString( )
+    {
+        final StringBuilder sb = new StringBuilder( "ValidationError{" );
+        sb.append( "errorKey='" ).append( errorKey ).append( '\'' );
+        sb.append( '}' );
+        return sb.toString( );
+    }
+
+    @Override
+    public boolean equals( Object o )
+    {
+        if ( this == o ) return true;
+        if ( o == null || getClass( ) != o.getClass( ) ) return false;
+
+        ValidationError that = (ValidationError) o;
+
+        if ( !errorKey.equals( that.errorKey ) ) return false;
+        return arguments.equals( that.arguments );
+    }
+
+    @Override
+    public int hashCode( )
+    {
+        int result = errorKey.hashCode( );
+        result = 31 * result + arguments.hashCode( );
+        return result;
+    }
+}
diff --git a/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationResponse.java b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationResponse.java
new file mode 100644
index 000000000..377a3ccb2
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-repository-api/src/main/java/org/apache/archiva/repository/validation/ValidationResponse.java
@@ -0,0 +1,110 @@
+package org.apache.archiva.repository.validation;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.apache.archiva.repository.CheckedResult;
+import org.apache.archiva.repository.Repository;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * A validation response gives information about the validation status for certain attributes.
+ *
+ *
+ * @author Martin Stockhammer <martin_s@apache.org>
+ */
+public class ValidationResponse<R extends Repository> implements CheckedResult<R, Map<String, List<ValidationError>>>
+{
+    final boolean valid;
+    final R repository;
+    final Map<String, List<ValidationError>> validationErrors = new HashMap<>( );
+
+
+    public ValidationResponse( R repo, Map<String, List<ValidationError>> errors)
+    {
+        if( errors==null || errors.size()==0 ) {
+            this.valid = true;
+        } else {
+            this.valid = false;
+            validationErrors.putAll( errors );
+        }
+        this.repository = repo;
+    }
+
+    public static <S extends Repository> ValidationResponse<S> getValid( S repository )
+    {
+        return new ValidationResponse<>( repository, null );
+    }
+
+    @Override
+    public R getRepository( )
+    {
+        return repository;
+    }
+
+    /**
+     * Returns true, if the validation was successful and there are not validation errors.
+     * @return <code>true</code>, if the validation was successful, otherwise <code>false</code>
+     */
+    @Override
+    public boolean isValid( )
+    {
+        return valid;
+    }
+
+    @Override
+    public Map<String, List<ValidationError>> getResult( )
+    {
+        return validationErrors;
+    }
+
+
+    /**
+     * Add the given validation error to the list for the given attribute.
+     *
+     * @param attribute the name of the attribute
+     * @param error the error that is added to the list
+     */
+    public void addValidationError(String attribute, ValidationError error) {
+        if (!validationErrors.containsKey( attribute )) {
+            validationErrors.put( attribute, new ArrayList<>( ) );
+        }
+        validationErrors.get( attribute ).add( error );
+    }
+
+    /**
+     * Returns a list of validation errors that are stored for the given attribute. If there are no
+     * errors stored for this attribute, a empty list is returned.
+     *
+     * @param attribute the name of the attribute
+     * @return the list of validation errors
+     */
+    public List<ValidationError> getValidationErrors(String attribute) {
+        if (validationErrors.containsKey( attribute )) {
+            return validationErrors.get( attribute );
+        } else {
+            return Collections.emptyList( );
+        }
+    }
+
+}