Timestamp Store Invalidator plus basic tests.

timestamp-api/build.gradle

@@ -2,6 +2,8 @@ apply from: "../gradle/publish-jars.gradle"
 apply from: "../gradle/shared.gradle"
 
 dependencies {
- compile 'javax.ws.rs:javax.ws.rs-api:2.0.1'
- compile group: 'com.fasterxml.jackson.core', name: 'jackson-annotations'
+ compile 'javax.ws.rs:javax.ws.rs-api:2.0.1'
+ compile group: 'com.fasterxml.jackson.core', name: 'jackson-annotations'
+
+ testCompile group: 'org.assertj', name: 'assertj-core'
 }

timestamp-api/src/main/java/com/palantir/timestamp/TimestampStoreInvalidator.java

@@ -0,0 +1,42 @@
+/**
+ * Copyright 2017 Palantir Technologies
+ *
+ * Licensed under the BSD-3 License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.palantir.timestamp;
+
+public interface TimestampStoreInvalidator {
+ /**
+ * This method corrupts the data in an underlying timestamp bound store. This is important for the safety of
+ * timestamp store migrations; if one migrates AtlasDB to a different timestamp bound store, then the
+ * original timestamp bound store must not be used again if it is not updated with information about what
+ * timestamps the new store has given out.
+ *
+ * As this method performs corruption, it should only be called *after* the migration of the existing timestamp
+ * bound to the new timestamp bound store has been carried out successfully.
+ *
+ * Of course, this is not strictly needed if no one ever uses the original timestamp bound store again.
+ * However, we find this to be a safety precaution worth taking, especially if AtlasDB is subsequently downgraded.
+ */
+ void invalidateTimestampStore();
+
+ /**
+ * This method performs the inverse of invalidateTimestampStore().
+ *
+ * It is not safe to use a revalidated timestamp store directly, *unless* we can guarantee that no timestamps
+ * have been taken out for the relevant data since invalidation.
+ */
+ default void revalidateTimestampStore() {
+ throw new UnsupportedOperationException("This timestamp store does not support revalidation!");
+ }
+}

timestamp-api/src/test/java/com/palantir/timestamp/TimestampStoreInvalidatorTest.java

@@ -0,0 +1,28 @@
+/**
+ * Copyright 2017 Palantir Technologies
+ *
+ * Licensed under the BSD-3 License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.palantir.timestamp;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.Test;
+
+public class TimestampStoreInvalidatorTest {
+ @Test
+ public void revalidateTimestampStoreThrowsByDefault() {
+ TimestampStoreInvalidator nopInvalidator = () -> {};
+ assertThatThrownBy(nopInvalidator::revalidateTimestampStore).isInstanceOf(UnsupportedOperationException.class);
+ }
+}