com.conveyal.gtfs

Class BaseGTFSCache<T>

java.lang.Object

com.conveyal.gtfs.BaseGTFSCache<T>

Direct Known Subclasses:

GTFSCache

public abstract class BaseGTFSCache<T>
extends Object

Fast cache for GTFS feeds stored on S3. Depending on the application, we often want to store additional data with a GTFS feed. Thus, you can subclass this class and override the processFeed function with a function that transforms a GTFSFeed object into whatever objects you need. If you just need to store GTFSFeeds without any additional data, see the GTFSCache class. This uses a soft-values cache because (it is assumed) you do not want to have multiple copies of the same GTFS feed in memory. When you are storing a reference to the original GTFS feed, it may be retrieved from the cache and held by the caller for some finite amount of time. If, during that time, it is removed from the cache and requested again, we would connect another GTFSFeed to the same mapdb, which seems like an ideal way to corrupt mapdbs. SoftReferences prevent this as it cannot be removed if it is referenced elsewhere.

Field Summary

Fields

Modifier and Type	Field and Description
String	bucket
String	bucketFolder
File	cacheDir

Constructor Summary

Constructors

Constructor and Description
BaseGTFSCache(String bucket, File cacheDir)
BaseGTFSCache(String bucket, String bucketFolder, File cacheDir) If bucket is null, work offline and do not use S3

Method Summary

Modifier and Type	Method and Description
static String	cleanId(String id)
boolean	containsId(String id)
T	get(String id)
long	getCurrentCacheSize()
abstract GTFSFeed	getFeed(String id)
protected abstract T	processFeed(GTFSFeed feed) Convert a GTFSFeed into whatever this cache holds.
T	put(Function<GTFSFeed,String> idGenerator, File feedFile) Add a GTFS feed to this cache where the ID is calculated from the feed itself
T	put(String id, File feedFile) Add a GTFS feed to this cache with the given ID.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

bucket

public final String bucket

bucketFolder

public final String bucketFolder

cacheDir

public final File cacheDir

Constructor Detail

BaseGTFSCache

public BaseGTFSCache(String bucket,
                     File cacheDir)

BaseGTFSCache

public BaseGTFSCache(String bucket,
                     String bucketFolder,
                     File cacheDir)

If bucket is null, work offline and do not use S3

Method Detail

getCurrentCacheSize

public long getCurrentCacheSize()

put

public T put(String id,
             File feedFile)
      throws Exception

Add a GTFS feed to this cache with the given ID. NB this is not the feed ID, because feed IDs are not unique when you load multiple versions of the same feed.

Throws:

Exception

put

public T put(Function<GTFSFeed,String> idGenerator,
             File feedFile)
      throws Exception

Add a GTFS feed to this cache where the ID is calculated from the feed itself

Throws:

Exception

get

public T get(String id)

containsId

public boolean containsId(String id)

processFeed

protected abstract T processFeed(GTFSFeed feed)

Convert a GTFSFeed into whatever this cache holds.

getFeed

public abstract GTFSFeed getFeed(String id)

cleanId

public static String cleanId(String id)