From: Tony Tkacik <ttkacik@cisco.com>
Date: Mon, 16 Jun 2014 16:33:40 +0000 (+0200)
Subject: Bug 629: Introduction of Configuration Commit Handler
X-Git-Tag: release/helium~648^2
X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=commitdiff_plain;h=5b322ec52a079aa43615637705e5ebcf8308c17d

Bug 629: Introduction of Configuration Commit Handler

One piece of functionality which was not-well defined
in original APIs and was missing in new APIs is
user-submitted commit handlers.

Contract of Commit Handlers was updated to reflect
more existing concept of three-phase commit and
to allow commit handlers only for configuration
subtree.

Access to proposed data is done via read-only
transaction instead of data change event,
since commit handlers may want to cross-reference
data with other and we need to capture this reads
as preconditions for later commit phases.

Change-Id: Id2049c05384dd74792f3cfbbb9f77bf684223be2
Signed-off-by: Tony Tkacik <ttkacik@cisco.com>
---

diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCohort.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCohort.java
new file mode 100644
index 0000000000..9fb350b7c0
--- /dev/null
+++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCohort.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.common.api.data;
+
+import org.opendaylight.yangtools.concepts.Path;
+
+import com.google.common.util.concurrent.ListenableFuture;
+
+/**
+ *
+ * Three phase Commit Cohort for subtree, which is
+ * uniquely associated with user submitted transcation.
+ *
+ * @param <P>
+ *            Type of path (subtree identifier), which represents location in
+ *            tree
+ * @param <D>
+ *            Type of data (payload), which represents data payload
+ */
+public interface AsyncConfigurationCommitCohort<P extends Path<P>, D> {
+
+    /**
+     * Initiates a pre-commit of associated request
+     *
+     * Implementation MUST NOT do any blocking calls during this callback, all
+     * pre-commit preparation SHOULD happen asynchronously and MUST result in
+     * completing returned future object.
+     *
+     * @param rebasedTransaction
+     *            Read-only view of transaction as if happened on top of actual
+     *            data store
+     * @return Future which is completed once pre-commit phase for this request
+     *         is finished.
+     */
+    ListenableFuture<Void> preCommit(AsyncReadTransaction<P, D> rebasedTransaction);
+
+    /**
+     *
+     * Initiates a commit phase of associated request
+     *
+     * Implementation MUST NOT do any blocking calls during this callback, all
+     * commit finalization SHOULD happen asynchronously and MUST result in
+     * completing returned future object.
+     *
+     * @return Future which is completed once commit phase for associated
+     *         request is finished.
+     */
+    ListenableFuture<Void> commit();
+
+    /**
+     *
+     * Initiates abort phase of associated request
+     *
+     * Implementation MUST NOT do any blocking calls during this callback, all
+     * commit finalization SHOULD happen asynchronously and MUST result in
+     * completing returned future object.
+     *
+     * @return Future which is completed once commit phase for associated
+     *         request is finished.
+     */
+    ListenableFuture<Void> abort();
+
+}
diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCoordinator.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCoordinator.java
new file mode 100644
index 0000000000..6d669ab9df
--- /dev/null
+++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitCoordinator.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.common.api.data;
+
+import org.opendaylight.yangtools.concepts.ObjectRegistration;
+import org.opendaylight.yangtools.concepts.Path;
+
+/**
+ * Three Phase Commit Coordinator with support of user-supplied commit cohorts
+ * which participates in three-phase commit protocols
+ *
+ * @param <P>
+ *            Type of path (subtree identifier), which represents location in
+ *            tree
+ * @param <D>
+ *            Type of data (payload), which represents data payload
+ */
+public interface AsyncConfigurationCommitCoordinator<P extends Path<P>, D> {
+
+    /**
+     * Register configuration commit handler for particular subtree
+     *
+     * Configuration commit handler is invoked for all write transactions
+     * which modifies <code>subtree</code>
+     *
+     * @param subtree Subtree which configuration commit handler is interested it
+     * @param commitHandler Instance of user-provided commit handler
+     * @return Registration object representing this registration. Invoking {@link ObjectRegistration#close()}
+     *   will unregister configuration commit handler.
+     */
+    <C extends AsyncConfigurationCommitCohort<P, D>> ObjectRegistration<C> registerConfigurationCommitHandler(
+            P subtree, C commitHandler);
+}
diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitHandler.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitHandler.java
new file mode 100644
index 0000000000..6025e139ab
--- /dev/null
+++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/AsyncConfigurationCommitHandler.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.common.api.data;
+
+import org.opendaylight.yangtools.concepts.Path;
+
+import com.google.common.util.concurrent.CheckedFuture;
+
+/**
+ * User-supplied participant in three-phase commit of transaction for configuration data tree
+ *
+ * Client-supplied implementation of commit handler for subtree, which
+ * is responsible for processing CAN-COMMIT phase of three-phase commit protocol
+ * and return CommitCohort, which provides access to additional transitions
+ * such as PRE-COMMIT, COMMIT and ABORT.
+ *
+ * @param <P>
+ *            Type of path (subtree identifier), which represents location in
+ *            tree
+ * @param <D>
+ *            Type of data (payload), which represents data payload
+ */
+public interface AsyncConfigurationCommitHandler<P extends Path<P>, D> {
+
+    /**
+     *
+     * Requests a can commit phase
+     *
+     * Implementations SHOULD NOT do any blocking operation during
+     * processing this callback.
+     *
+     * <b>Implementation Notes</b>
+     * <ul>
+     * <li>Implementation are REQUIRED to use <code>request</code> object for any data related access</li>
+     * <li>Implementations SHOULD NOT use any other state stored outside configuration subtree for validation</li>
+     * <li>Validation should happen asynchronously, outside callback call by updating returned {@link CheckedFuture}
+     *     object.</li>
+     * <li>If validation (CAN_COMMIT) phase:
+     * <ul>
+     * <li><b>is successful</b> - invocation of {@link CheckedFuture#checkedGet()} on returned future MUST
+     *     return {@link AsyncConfigurationCommitCohort} associated with request.</li>
+     * <li><b>is unsuccessful</b> - invocation of {@link CheckedFuture#checkedGet()} must throw instance of {@link DataValidationFailedException}
+     * with human readable explanaition of error condition.
+     * </li>
+     * </ul>
+     * </li>
+     * @param request
+     *            Commit Request submitted by client, which contains
+     *            information about modifications and read-only view as
+     *            if transaction happened.
+     * @return CheckedFuture which contains client-supplied implementation of {@link AsyncConfigurationCommitCohort}
+     *         associated with submitted request, if can commit phase is
+     *         successful, if can commit was unsuccessful, future must fail with
+     *         {@link TransactionCommitFailedException} exception.
+     */
+    CheckedFuture<AsyncConfigurationCommitCohort<P, D>, DataValidationFailedException> canCommit(
+            ConfigurationCommitRequest<P, D> request);
+
+    /**
+     *
+     * Commit Request as was submitted by client code
+     *
+     * Commit Request contains list view of created / updated / removed
+     * path and read-only view of proposed client transaction,
+     * which may be used to retrieve modified or referenced data.
+     *
+     *
+     * @param <P>
+     *            Type of path (subtree identifier), which represents location
+     *            in tree
+     * @param <D>
+     *            Type of data (payload), which represents data payload
+     */
+    static interface ConfigurationCommitRequest<P extends Path<P>, D> {
+
+        /**
+         *
+         * Read-only transaction which provides access only to configuration
+         * data tree as if submitted transaction successfully happened and
+         * no other concurrent modifications happened between allocation
+         * of client transactions and write of client transactions.
+         *
+         * Implementations of Commit Handlers are REQUIRED to use this
+         * read-only view to access any data from configuration data tree,
+         * in order to capture them as preconditions for this transaction.
+         *
+         * @return Read-only transaction which provides access only to configuration
+         * data tree as if submitted transaction successfully happened
+         */
+        AsyncReadTransaction<P, D> getReadOnlyView();
+
+        /**
+         *
+         * Returns iteration of paths, to data which was introduced by this transaction.
+         *
+         * @return Iteration of paths, which was introduced by this transaction.
+         */
+        Iterable<P> getCreatedPaths();
+        /**
+         *
+         * Returns iteration of paths, to data which was updated by this transaction.
+         *
+         * @return Iteration of paths, which was updated by this transaction.
+         */
+        Iterable<P> getUpdatedPaths();
+
+        /**
+         *
+         * Returns iteration of paths, to data which was removed by this transaction.
+         *
+         * @return Iteration of paths, which was removed by this transaction.
+         */
+        Iterable<P> getRemovedPaths();
+    }
+
+}
diff --git a/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/DataValidationFailedException.java b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/DataValidationFailedException.java
new file mode 100644
index 0000000000..c59c12ec5c
--- /dev/null
+++ b/opendaylight/md-sal/sal-common-api/src/main/java/org/opendaylight/controller/md/sal/common/api/data/DataValidationFailedException.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.common.api.data;
+
+import org.opendaylight.yangtools.concepts.Path;
+
+import com.google.common.base.Preconditions;
+
+/**
+ *
+ * Failure of asynchronous transaction commit caused by invalid data.
+ *
+ * This exception is raised and returned when transaction commit
+ * failed, because other data submitted via transactions
+ *
+ *  Clients usually are not able recover from this error condition by
+ *  retrieving same transaction, since data introduced by this transaction
+ *  are invalid.
+ *
+ */
+public class DataValidationFailedException extends TransactionCommitFailedException {
+
+    private static final long serialVersionUID = 1L;
+
+    private Path<?> path;
+
+    private Class<? extends Path<?>> pathType;
+
+    public <P extends Path<P>> DataValidationFailedException(final Class<P> pathType,final P path, final String message, final Throwable cause) {
+        super(message, cause);
+        this.pathType = Preconditions.checkNotNull(pathType, "path type must not be null");
+        this.path = Preconditions.checkNotNull(path,"path must not be null.");
+    }
+
+    public  <P extends Path<P>> DataValidationFailedException(final Class<P> pathType,final P path,final String message) {
+        this(pathType,path,message,null);
+    }
+
+    public final Path<?> getPath() {
+        return path;
+    }
+
+    public final Class<? extends Path<?>> getPathType() {
+        return pathType;
+    }
+
+}