com.builtamont.cassandra.migration.internal.resolver.CompositeMigrationResolver.kt Maven / Gradle / Ivy
/**
* File : CompositeMigrationResolver.kt
* License :
* Original - Copyright (c) 2010 - 2016 Boxfuse GmbH
* Derivative - Copyright (c) 2016 Citadel Technology Solutions Pte Ltd
*
* Licensed 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.
*/
package com.builtamont.cassandra.migration.internal.resolver
import com.builtamont.cassandra.migration.api.CassandraMigrationException
import com.builtamont.cassandra.migration.api.resolver.MigrationResolver
import com.builtamont.cassandra.migration.api.resolver.ResolvedMigration
import com.builtamont.cassandra.migration.internal.resolver.cql.CqlMigrationResolver
import com.builtamont.cassandra.migration.internal.resolver.java.JavaMigrationResolver
import com.builtamont.cassandra.migration.internal.util.Locations
import java.util.*
/**
* Facility for retrieving and sorting the available migrations from the classpath through the various migration
* resolvers.
*
* @param classLoader The ClassLoader for loading migrations on the classpath.
* @param locations The locations where migrations are located.
* @param encoding The encoding of Cql migrations.
* @param customMigrationResolvers Custom Migration Resolvers.
*/
class CompositeMigrationResolver(
classLoader: ClassLoader,
locations: Locations,
encoding: String,
vararg customMigrationResolvers: MigrationResolver
) : MigrationResolver {
/**
* The migration resolvers to use internally.
*/
private val migrationResolvers = ArrayList()
/**
* The available migrations, sorted by version, newest first. An empty list is returned when no migrations can be
* found.
*/
private var availableMigrations: List? = null
/**
* CompositeMigrationResolver initialization.
*/
init {
locations.getLocations().forEach {
migrationResolvers.add(CqlMigrationResolver(classLoader, it, encoding))
migrationResolvers.add(JavaMigrationResolver(classLoader, it))
}
migrationResolvers.addAll(Arrays.asList(*customMigrationResolvers))
}
/**
* Finds all available migrations using all migration resolvers (CQL, Java, ...).
*
* @return The available migrations, sorted by version, oldest first. An empty list is returned when no migrations
* can be found.
* @throws CassandraMigrationException when the available migrations have overlapping versions.
*/
override fun resolveMigrations(): List {
if (availableMigrations == null) {
availableMigrations = doFindAvailableMigrations()
}
return availableMigrations as List
}
/**
* Finds all available migrations using all migration resolvers (CQL, Java, ...).
*
* @return The available migrations, sorted by version, oldest first. An empty list is returned when no migrations
* can be found.
* @throws CassandraMigrationException when the available migrations have overlapping versions.
*/
@Throws(CassandraMigrationException::class)
private fun doFindAvailableMigrations(): List {
val migrations = ArrayList(collectMigrations(migrationResolvers))
migrations.sortWith(ResolvedMigrationComparator())
checkForIncompatibilities(migrations)
return migrations
}
/**
* CompositeMigrationResolver companion object.
*/
companion object {
/**
* Collects all the migrations for all migration resolvers.
*
* @param migrationResolvers The migration resolvers to check.
* @return All migrations.
*/
fun collectMigrations(migrationResolvers: Collection): Collection {
return migrationResolvers.flatMap { it.resolveMigrations() }.distinct()
}
/**
* Checks for incompatible migrations.
*
* @param migrations The migrations to check.
* @throws CassandraMigrationException when two different migration with the same version number are found.
*/
fun checkForIncompatibilities(migrations: List) {
/**
* Returns incompatible migration error message.
*
* @param current The current migration run.
* @param next The next migration to run.
* @return Incompatible migration error message.
*/
fun incompatibleErrorMsg(current: ResolvedMigration, next: ResolvedMigration): String {
return "Found more than one migration with version ${current.version}\nOffenders:\n-> ${current.physicalLocation} (${current.type})\n-> ${next.physicalLocation} (${next.type})"
}
// Check for more than one migration with same version
for (i in 0..migrations.size - 1 - 1) {
val current = migrations[i]
val next = migrations[i + 1]
if (current.version!!.compareTo(next.version) == 0) {
throw CassandraMigrationException(incompatibleErrorMsg(current, next))
}
}
}
}
}