added ArangoDatabase.cursor() (issue #116)

Author: mpv1989

ChangeLog

@@ -1,3 +1,7 @@
+v4.1.12 (2017-04-xx)
+---------------------------
+* added ArangoDatabase.cursor() (issue #116)
+
 v4.1.11 (2017-03-24)
 ---------------------------
 * fixed exception handling in Connection (issue #110)

src/main/java/com/arangodb/ArangoCursor.java

@@ -44,19 +44,13 @@ public class ArangoCursor<T> implements Iterator<T>, Closeable {
 	private final Class<T> type;
 	protected final ArangoCursorIterator<T> iterator;
 	private final String id;
-	private final Integer count;
-	private final Extras extra;
-	private final boolean cached;
 	private final ArangoCursorExecute execute;
 
 	protected ArangoCursor(final InternalArangoDatabase<?, ?, ?, ?> db, final ArangoCursorExecute execute,
 		final Class<T> type, final CursorEntity result) {
 		super();
 		this.execute = execute;
 		this.type = type;
-		count = result.getCount();
-		extra = result.getExtra();
-		cached = result.getCached().booleanValue();
 		iterator = new ArangoCursorIterator<T>(this, execute, db, result);
 		id = result.getId();
 	}
@@ -77,22 +71,25 @@ public Class<T> getType() {
 	 *         attribute set)
 	 */
 	public Integer getCount() {
-		return count;
+		return iterator.getResult().getCount();
 	}
 
 	public Stats getStats() {
+		final Extras extra = iterator.getResult().getExtra();
 		return extra != null ? extra.getStats() : null;
 	}
 
 	public Collection<Warning> getWarnings() {
+		final Extras extra = iterator.getResult().getExtra();
 		return extra != null ? extra.getWarnings() : null;
 	}
 
 	/**
 	 * @return indicating whether the query result was served from the query cache or not
 	 */
 	public boolean isCached() {
-		return cached;
+		final Boolean cached = iterator.getResult().getCached();
+		return cached != null && cached.booleanValue();
 	}
 
 	@Override

src/main/java/com/arangodb/ArangoDatabase.java

@@ -262,6 +262,28 @@ public <T> ArangoCursor<T> query(
 		final Class<T> type) throws ArangoDBException {
 		final Request request = queryRequest(query, bindVars, options);
 		final CursorEntity result = executor.execute(request, CursorEntity.class);
+		return createCursor(result, type);
+	}
+
+	/**
+	 * Return an cursor from the given cursor-ID if still existing
+	 * 
+	 * @see <a href=
+	 *      "https://docs.arangodb.com/current/HTTP/AqlQueryCursor/AccessingCursors.html#read-next-batch-from-cursor">API
+	 *      Documentation</a>
+	 * @param cursorId
+	 *            The ID of the cursor
+	 * @param type
+	 *            The type of the result (POJO class, VPackSlice, String for Json, or Collection/List/Map)
+	 * @return cursor of the results
+	 * @throws ArangoDBException
+	 */
+	public <T> ArangoCursor<T> cursor(final String cursorId, final Class<T> type) throws ArangoDBException {
+		final CursorEntity result = executor.execute(queryNextRequest(cursorId), CursorEntity.class);
+		return createCursor(result, type);
+	}
+
+	private <T> ArangoCursor<T> createCursor(final CursorEntity result, final Class<T> type) {
 		return new ArangoCursor<T>(this, new ArangoCursorExecute() {
 			@Override
 			public CursorEntity next(final String id) {

src/main/java/com/arangodb/internal/ArangoCursorIterator.java

@@ -50,6 +50,10 @@ public ArangoCursorIterator(final ArangoCursor<T> cursor, final ArangoCursorExec
 		pos = 0;
 	}
 
+	public CursorEntity getResult() {
+		return result;
+	}
+
 	@Override
 	public boolean hasNext() {
 		return pos < result.getResult().size() || result.getHasMore();

src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -477,6 +477,34 @@ public void queryWithCache() throws InterruptedException {
 		}
 	}
 
+	@Test
+	public void queryCursor() {
+		try {
+			db.createCollection(COLLECTION_NAME, null);
+			final int numbDocs = 10;
+			for (int i = 0; i < numbDocs; i++) {
+				db.collection(COLLECTION_NAME).insertDocument(new BaseDocument(), null);
+			}
+
+			final int batchSize = 5;
+			final ArangoCursor<String> cursor = db.query("for i in db_test return i._id", null,
+				new AqlQueryOptions().batchSize(batchSize).count(true), String.class);
+			assertThat(cursor, is(notNullValue()));
+			assertThat(cursor.getCount(), is(numbDocs));
+
+			final ArangoCursor<String> cursor2 = db.cursor(cursor.getId(), String.class);
+			assertThat(cursor2, is(notNullValue()));
+			assertThat(cursor2.getCount(), is(numbDocs));
+			assertThat(cursor2.hasNext(), is(true));
+
+			for (int i = 0; i < batchSize; i++, cursor.next()) {
+				assertThat(cursor.hasNext(), is(i != batchSize));
+			}
+		} finally {
+			db.collection(COLLECTION_NAME).drop();
+		}
+	}
+
 	@Test
 	public void changeQueryTrackingProperties() {
 		try {