1 files changed, 92 insertions, 0 deletions
diff --git a/src/main/java/org/openslx/imagemaster/serverconnection/AbstractTransfer.java b/src/main/java/org/openslx/imagemaster/serverconnection/AbstractTransfer.java
new file mode 100644
index 0000000..3acac5b
--- /dev/null
+++ b/src/main/java/org/openslx/imagemaster/serverconnection/AbstractTransfer.java
@@ -0,0 +1,92 @@
+package org.openslx.imagemaster.serverconnection;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+
+public abstract class AbstractTransfer {
+
+	/**
+	 * How long to keep this transfer information when the transfer is
+	 * (potentially) done
+	 */
+	private static final long FINISH_TIMEOUT = TimeUnit.MINUTES.toMillis(5);
+
+	/**
+	 * How long to keep this transfer information when there are no active
+	 * connections and the transfer seems unfinished
+	 */
+	private static final long IDLE_TIMEOUT = TimeUnit.HOURS.toMillis(4);
+
+	/**
+	 * Time stamp of when (we think) the transfer finished. Clients can/might
+	 * not tell us they're done, and simply taking "no active connection" as a
+	 * sign the download is done might have unwanted effects if the user's
+	 * connection drops for a minute. If this time stamp (plus a FINISH_TIMEOUT)
+	 * passed,
+	 * we consider the download done and flag it for removal.
+	 * If set to zero, the transfer is not finished, or not assumed to have
+	 * finished.
+	 */
+	protected final AtomicLong potentialFinishTime = new AtomicLong(0);
+
+	/**
+	 * Time of last activity on this transfer.
+	 */
+	protected final AtomicLong lastActivityTime = new AtomicLong(System.currentTimeMillis());
+
+	private final String transferId;
+
+	public AbstractTransfer(String transferId) {
+		this.transferId = transferId;
+	}
+
+	/**
+	 * Returns true if the transfer is considered completed.
+	 * 
+	 * @param now pass System.currentTimeMillis()
+	 * @return true if the transfer is considered completed
+	 */
+	public boolean isComplete(long now) {
+		long val = potentialFinishTime.get();
+		return val != 0 && val + FINISH_TIMEOUT < now;
+	}
+
+	/**
+	 * Returns true if there has been no activity on this transfer for a certain
+	 * amount of time.
+	 * 
+	 * @param now pass System.currentTimeMillis()
+	 * @return true if the transfer reached its idle timeout
+	 */
+	public final boolean hasReachedIdleTimeout(long now) {
+		return getActiveConnectionCount() == 0 && lastActivityTime.get() + IDLE_TIMEOUT < now;
+	}
+
+	public final String getId() {
+		return transferId;
+	}
+
+	/**
+	 * Returns true if this transfer would potentially accept new connections.
+	 * This should NOT return false if there are too many concurrent
+	 * connections, as this is used to signal the client whether to keep trying
+	 * to connect.
+	 * 
+	 * @return true if this transfer would potentially accept new connections
+	 */
+	public abstract boolean isActive();
+
+	/**
+	 * Cancel this transfer, aborting all active connections and rejecting
+	 * further incoming ones.
+	 */
+	public abstract void cancel();
+
+	/**
+	 * Returns number of active transfer connections.
+	 * 
+	 * @return number of active transfer connections
+	 */
+	public abstract int getActiveConnectionCount();
+
+}