widebase.io.table.FileTableFind.scala Maven / Gradle / Ivy
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package widebase.io.table
import java.io. { File, RandomAccessFile }
import widebase.data.Datatype
import widebase.io.VariantReader
import widebase.io.column.FileColumnFinder
import widebase.io.filter. { MagicId, StreamFilter }
/** Finds tables within database.
*
* @param path of database
*
* @author myst3r10n
*/
abstract class FileTableFind(path: String) {
import widebase.io.filter.StreamFilter.StreamFilter
/** Checks whether table exists.
*
* @param name of table
* @param filter self-explanatory
* @param segmented path of segment
*
* @return true if exists, else false
*/
def apply(
name: String,
filter: StreamFilter = props.filters.finder)
(implicit segmented: File = null): Boolean = {
val fileExtension =
filter match {
case StreamFilter.Gzip => ".gz"
case StreamFilter.Zlib => ".zip"
case _ => ""
}
var dir =
if(segmented == null)
path
else
segmented.getPath
val file = new File(dir + "/" + name + fileExtension)
if(!file.exists)
return false
val magicLength =
MagicId.Column.toString.getBytes(props.charsets.finder).size
val channel = new RandomAccessFile(file.getPath, "r").getChannel
val reader = new VariantReader(channel, filter) {
override val charset = props.charsets.finder
override def capacity = magicLength
override def order = props.orders.finder
}
// Read magic
reader.mode = Datatype.String
val magic = reader.readString(magicLength)
try {
if(magic.isEmpty)
return false
if(MagicId.withName(magic) != MagicId.Column)
return false
} catch {
case e: NoSuchElementException => return false
} finally {
reader.close
}
true
}
/** Checks whether directory table exists.
*
* @note Supports optional partitioned tables.
*
* @param name of table
* @param parted partition name
* @param segmented path of segment
*
* @return true if exists, else false
*/
def dir(name: String)
(implicit parted: String = null, segmented: File = null): Boolean =
(new FileColumnFinder(path)).find(name)(parted, segmented)
}