From 4911919473cf6511fbd193c95cf0db81e5ebae07 Mon Sep 17 00:00:00 2001
From: Jon Marius Venstad <venstad@gmail.com>
Date: Wed, 10 Jun 2020 16:22:03 +0200
Subject: Add draft LocalVisitorSession

---
 .../documentapi/local/LocalVisitorSession.java     | 141 +++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 documentapi/src/main/java/com/yahoo/documentapi/local/LocalVisitorSession.java

(limited to 'documentapi')

diff --git a/documentapi/src/main/java/com/yahoo/documentapi/local/LocalVisitorSession.java b/documentapi/src/main/java/com/yahoo/documentapi/local/LocalVisitorSession.java
new file mode 100644
index 00000000000..4a11d8ae8bc
--- /dev/null
+++ b/documentapi/src/main/java/com/yahoo/documentapi/local/LocalVisitorSession.java
@@ -0,0 +1,141 @@
+package com.yahoo.documentapi.local;
+
+import com.yahoo.document.Document;
+import com.yahoo.document.DocumentId;
+import com.yahoo.document.DocumentPut;
+import com.yahoo.documentapi.AckToken;
+import com.yahoo.documentapi.ProgressToken;
+import com.yahoo.documentapi.VisitorControlHandler;
+import com.yahoo.documentapi.VisitorDataHandler;
+import com.yahoo.documentapi.VisitorDataQueue;
+import com.yahoo.documentapi.VisitorParameters;
+import com.yahoo.documentapi.VisitorResponse;
+import com.yahoo.documentapi.VisitorSession;
+import com.yahoo.documentapi.messagebus.protocol.PutDocumentMessage;
+import com.yahoo.messagebus.Trace;
+import com.yahoo.yolean.Exceptions;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Local visitor session that copies and iterates through all items in the local document access.
+ * Each document must be ack'ed for the session to be done visiting.
+ * Only document puts are sent by this session, and this is done from a separate thread.
+ *
+ * @author jonmv
+ */
+public class LocalVisitorSession implements VisitorSession {
+
+    private enum State { RUNNING, FAILURE, ABORTED, SUCCESS }
+
+    private final VisitorDataHandler data;
+    private final VisitorControlHandler control;
+    private final Map<DocumentId, Document> outstanding;
+    private final AtomicReference<State> state;
+
+    public LocalVisitorSession(LocalDocumentAccess access, VisitorParameters parameters) {
+        if (parameters.getResumeToken() != null)
+            throw new UnsupportedOperationException("Continuation via progress tokens is not supported");
+
+        if (parameters.getRemoteDataHandler() != null)
+            throw new UnsupportedOperationException("Remote data handlers are not supported");
+
+        this.data = parameters.getLocalDataHandler() == null ? new VisitorDataQueue() : parameters.getLocalDataHandler();
+        this.data.reset();
+        this.data.setSession(this);
+
+        this.control = parameters.getControlHandler() == null ? new VisitorControlHandler() : parameters.getControlHandler();
+        this.control.reset();
+        this.control.setSession(this);
+
+        this.outstanding = new ConcurrentSkipListMap<>(access.documents);
+        this.state = new AtomicReference<>(State.RUNNING);
+
+        start();
+    }
+
+    void start() {
+        new Thread(() -> {
+            try {
+                // Iterate through all documents and pass on to data handler
+                outstanding.forEach((id, document) -> {
+                    data.onMessage(new PutDocumentMessage(new DocumentPut(document)),
+                                                               new AckToken(id));
+                });
+                // Transition to a terminal state when done
+                state.updateAndGet(current -> {
+                    switch (current) {
+                        case RUNNING:
+                            control.onDone(VisitorControlHandler.CompletionCode.SUCCESS, "Success");
+                            return State.SUCCESS;
+                        case ABORTED:
+                            control.onDone(VisitorControlHandler.CompletionCode.ABORTED, "Aborted by user");
+                            return State.ABORTED;
+                        default:
+                            control.onDone(VisitorControlHandler.CompletionCode.FAILURE, "Unexpected state '" + current + "'");;
+                            return State.FAILURE;
+                    }
+                });
+            }
+            // Transition to failure terminal state on error
+            catch (Exception e) {
+                state.set(State.FAILURE);
+                outstanding.clear();
+                control.onDone(VisitorControlHandler.CompletionCode.FAILURE, Exceptions.toMessageString(e));
+            }
+            finally {
+                data.onDone();
+            }
+        }).start();
+    }
+
+    @Override
+    public boolean isDone() {
+        return outstanding.isEmpty();
+    }
+
+    @Override
+    public ProgressToken getProgress() {
+        throw new UnsupportedOperationException("Progress tokens are not supported");
+    }
+
+    @Override
+    public Trace getTrace() {
+        throw new UnsupportedOperationException("Traces are not supported");
+    }
+
+    @Override
+    public boolean waitUntilDone(long timeoutMs) throws InterruptedException {
+        return control.waitUntilDone(timeoutMs);
+    }
+
+    @Override
+    public void ack(AckToken token) {
+        outstanding.remove((DocumentId) token.ackObject);
+    }
+
+    @Override
+    public void abort() {
+        state.updateAndGet(current -> current == State.RUNNING ? State.ABORTED : current);
+        outstanding.clear();
+    }
+
+    @Override
+    public VisitorResponse getNext() {
+        return data.getNext();
+    }
+
+    @Override
+    public VisitorResponse getNext(int timeoutMilliseconds) throws InterruptedException {
+        return data.getNext(timeoutMilliseconds);
+    }
+
+    @Override
+    public void destroy() {
+        if ( ! isDone())
+            abort();
+    }
+
+}
-- 
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