com.builtamont.cassandra.migration.internal.resolver.java.JavaMigrationResolver.kt Maven / Gradle / Ivy
/**
* File : JavaMigrationResolver.kt
* License :
* Original - Copyright (c) 2015 - 2016 Contrast Security
* 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.java
import com.builtamont.cassandra.migration.api.CassandraMigrationException
import com.builtamont.cassandra.migration.api.MigrationType
import com.builtamont.cassandra.migration.api.MigrationVersion
import com.builtamont.cassandra.migration.api.migration.MigrationChecksumProvider
import com.builtamont.cassandra.migration.api.migration.MigrationInfoProvider
import com.builtamont.cassandra.migration.api.migration.java.JavaMigration
import com.builtamont.cassandra.migration.api.resolver.MigrationResolver
import com.builtamont.cassandra.migration.api.resolver.ResolvedMigration
import com.builtamont.cassandra.migration.internal.resolver.MigrationInfoHelper
import com.builtamont.cassandra.migration.internal.resolver.ResolvedMigrationComparator
import com.builtamont.cassandra.migration.internal.resolver.ResolvedMigrationImpl
import com.builtamont.cassandra.migration.internal.util.ClassUtils
import com.builtamont.cassandra.migration.internal.util.ScriptsLocation
import com.builtamont.cassandra.migration.internal.util.StringUtils
import com.builtamont.cassandra.migration.internal.util.scanner.Scanner
import java.util.*
/**
* Migration resolver for Java migrations.
* The classes must have a name like V1 or V1_1_3 or V1__Description or V1_1_3__Description.
*
* @param classLoader The ClassLoader for loading migrations on the classpath.
* @param location The base package on the classpath where to migrations are located.
*/
class JavaMigrationResolver(
private val classLoader: ClassLoader,
private val location: ScriptsLocation?
) : MigrationResolver {
/**
* Resolves the available migrations.
*
* @return The available migrations.
* @throws CassandraMigrationException when unable to resolve JavaMigrator with the given location.
*/
@Throws(CassandraMigrationException::class)
override fun resolveMigrations(): List {
// Guard: If location is not defined and not a classpath,
// then return an empty JavaMigration resolvers
if (location != null && !location.isClassPath) {
return ArrayList()
}
try {
val classes = Scanner(classLoader).scanForClasses(location, JavaMigration::class.java)
return classes.map { clazz ->
val javaMigration = ClassUtils.instantiate(clazz.name, classLoader)
val resolvedMigration = extractMigrationInfo(javaMigration)
resolvedMigration.physicalLocation = ClassUtils.getLocationOnDisk(clazz)
resolvedMigration.executor = JavaMigrationExecutor(javaMigration)
resolvedMigration
}.sortedWith(ResolvedMigrationComparator())
} catch (e: Exception) {
throw CassandraMigrationException("Unable to resolve Java migrations in location: " + location, e)
}
}
/**
* Extracts the migration info from this migration.
*
* @param javaMigration The migration to analyse.
* @return The migration info.
* @throws CassandraMigrationException when JavaMigration is missing its description.
*/
@Throws(CassandraMigrationException::class)
fun extractMigrationInfo(javaMigration: JavaMigration): ResolvedMigration {
val checksum: Int?
if (javaMigration is MigrationChecksumProvider) {
checksum = javaMigration.checksum
} else {
checksum = 0
}
val version: MigrationVersion
val description: String
if (javaMigration is MigrationInfoProvider) {
version = javaMigration.version
description = javaMigration.description
if (!StringUtils.hasText(description)) {
throw CassandraMigrationException("Missing description for migration " + version)
}
} else {
val className = ClassUtils.getShortName(javaMigration.javaClass)
val info = MigrationInfoHelper.extractVersionAndDescription(className, "V", "__", "")
version = info.left
description = info.right
}
val script = javaMigration.javaClass.name
val resolvedMigration = ResolvedMigrationImpl()
resolvedMigration.version = version
resolvedMigration.description = description
resolvedMigration.script = script
resolvedMigration.checksum = checksum
resolvedMigration.type = MigrationType.JAVA_DRIVER
return resolvedMigration
}
}