diff options
Diffstat (limited to 'src/main/java')
4 files changed, 56 insertions, 77 deletions
diff --git a/src/main/java/com/amazon/carbonado/Query.java b/src/main/java/com/amazon/carbonado/Query.java index d1cebca..36a8117 100644 --- a/src/main/java/com/amazon/carbonado/Query.java +++ b/src/main/java/com/amazon/carbonado/Query.java @@ -255,6 +255,25 @@ public interface Query<S extends Storable> { Query<S> orderBy(String... properties) throws FetchException;
/**
+ * Returns a query which fetches results for this query after a given
+ * starting point, which is useful for re-opening a cursor. This is only
+ * effective when query has been given an explicit {@link #orderBy
+ * ordering}. If not a total ordering, then query may start at an earlier
+ * position.
+ *
+ * <p>Note: The returned query can be very expensive to fetch from
+ * repeatedly, if the query needs to perform a sort operation. Ideally, the
+ * query ordering should match the natural ordering of an index or key.
+ *
+ * @param start storable to attempt to start after; if null, this query is
+ * returned
+ * @throws IllegalStateException if any blank parameters in this query
+ * @throws FetchException if storage layer throws an exception
+ * @since 1.2
+ */
+ Query<S> after(S start) throws FetchException;
+
+ /**
* Fetches results for this query. If any updates or deletes might be
* performed on the results, consider enclosing the fetch in a
* transaction. This allows the isolation level and "for update" mode to be
@@ -288,7 +307,7 @@ public interface Query<S extends Storable> { * Fetches results for this query after a given starting point, which is
* useful for re-opening a cursor. This is only effective when query has
* been given an explicit {@link #orderBy ordering}. If not a total
- * ordering, then returned cursor may start at an earlier position.
+ * ordering, then cursor may start at an earlier position.
*
* <p>Note: This method can be very expensive to call repeatedly, if the
* query needs to perform a sort operation. Ideally, the query ordering
@@ -299,35 +318,11 @@ public interface Query<S extends Storable> { * @throws IllegalStateException if any blank parameters in this query
* @throws FetchException if storage layer throws an exception
* @see Repository#enterTransaction(IsolationLevel)
+ * @see #after
*/
Cursor<S> fetchAfter(S start) throws FetchException;
/**
- * Fetches a slice of results for this query after a given starting point,
- * which is useful for re-opening a cursor. This is only effective when
- * query has been given an explicit {@link #orderBy ordering}. If not a
- * total ordering, then returned cursor may start at an earlier position.
- * It is strongly recommended that the query be given a total ordering in
- * order for the slice results to be deterministic.
- *
- * <p>Note: This method can be very expensive to call repeatedly, if the
- * query needs to perform a sort operation. Ideally, the query ordering
- * should match the natural ordering of an index or key.
- *
- * @param start storable to attempt to start after; if null, fetch all results
- * @param from zero-based {@code from} record number, inclusive
- * @param to optional zero-based {@code to} record number, exclusive
- * @return fetch results
- * @throws IllegalStateException if any blank parameters in this query
- * @throws IllegalArgumentException if {@code from} is negative or if
- * {@code from} is more than {@code to}
- * @throws FetchException if storage layer throws an exception
- * @see Repository#enterTransaction(IsolationLevel)
- * @since 1.2
- */
- Cursor<S> fetchAfter(S start, long from, Long to) throws FetchException;
-
- /**
* Attempts to load exactly one matching object. If the number of matching
* records is zero or exceeds one, then an exception is thrown instead.
*
diff --git a/src/main/java/com/amazon/carbonado/qe/EmptyQuery.java b/src/main/java/com/amazon/carbonado/qe/EmptyQuery.java index 9754019..83c09a6 100644 --- a/src/main/java/com/amazon/carbonado/qe/EmptyQuery.java +++ b/src/main/java/com/amazon/carbonado/qe/EmptyQuery.java @@ -205,6 +205,10 @@ public final class EmptyQuery<S extends Storable> extends AbstractQuery<S> { return new EmptyQuery<S>(mFactory, properties);
}
+ public Query<S> after(S start) {
+ return this;
+ }
+
/**
* Always returns an {@link EmptyCursor}.
*/
@@ -228,14 +232,6 @@ public final class EmptyQuery<S extends Storable> extends AbstractQuery<S> { }
/**
- * Always returns an {@link EmptyCursor}.
- */
- public Cursor<S> fetchAfter(S start, long from, Long to) {
- checkSliceArguments(from, to);
- return EmptyCursor.the();
- }
-
- /**
* Always throws {@link PersistNoneException}.
*/
public void deleteOne() throws PersistNoneException {
diff --git a/src/main/java/com/amazon/carbonado/qe/StandardQuery.java b/src/main/java/com/amazon/carbonado/qe/StandardQuery.java index 1ee3acb..f8db1df 100644 --- a/src/main/java/com/amazon/carbonado/qe/StandardQuery.java +++ b/src/main/java/com/amazon/carbonado/qe/StandardQuery.java @@ -209,43 +209,12 @@ public abstract class StandardQuery<S extends Storable> extends AbstractQuery<S> OrderingList.get(getStorableType(), properties), mHints);
}
- public Cursor<S> fetch() throws FetchException {
- try {
- return executor().fetch(mValues);
- } catch (RepositoryException e) {
- throw e.toFetchException();
- }
- }
-
- public Cursor<S> fetch(long from, Long to) throws FetchException {
- if (!checkSliceArguments(from, to)) {
- return fetch();
- }
- try {
- QueryHints hints = QueryHints.emptyHints().with(QueryHint.CONSUME_SLICE);
- return executorFactory().executor(mFilter, mOrdering, hints).fetch(mValues, from, to);
- } catch (RepositoryException e) {
- throw e.toFetchException();
- }
- }
-
- public Cursor<S> fetchAfter(S start) throws FetchException {
+ public Query<S> after(S start) throws FetchException {
OrderingList<S> orderings;
if (start == null || (orderings = mOrdering).size() == 0) {
- return fetch();
- }
- return buildAfter(start, orderings).fetch();
- }
-
- public Cursor<S> fetchAfter(S start, long from, Long to) throws FetchException {
- if (!checkSliceArguments(from, to)) {
- return fetchAfter(start);
- }
- OrderingList<S> orderings;
- if (start == null || (orderings = mOrdering).size() == 0) {
- return fetch(from, to);
+ return this;
}
- return buildAfter(start, orderings).fetch(from, to);
+ return buildAfter(start, orderings);
}
private Query<S> buildAfter(S start, OrderingList<S> orderings) throws FetchException {
@@ -271,6 +240,30 @@ public abstract class StandardQuery<S extends Storable> extends AbstractQuery<S> return and(orderFilter);
}
+ public Cursor<S> fetch() throws FetchException {
+ try {
+ return executor().fetch(mValues);
+ } catch (RepositoryException e) {
+ throw e.toFetchException();
+ }
+ }
+
+ public Cursor<S> fetch(long from, Long to) throws FetchException {
+ if (!checkSliceArguments(from, to)) {
+ return fetch();
+ }
+ try {
+ QueryHints hints = QueryHints.emptyHints().with(QueryHint.CONSUME_SLICE);
+ return executorFactory().executor(mFilter, mOrdering, hints).fetch(mValues, from, to);
+ } catch (RepositoryException e) {
+ throw e.toFetchException();
+ }
+ }
+
+ public Cursor<S> fetchAfter(S start) throws FetchException {
+ return after(start).fetch();
+ }
+
public boolean tryDeleteOne() throws PersistException {
Transaction txn = enterTransaction(IsolationLevel.READ_COMMITTED);
try {
diff --git a/src/main/java/com/amazon/carbonado/repo/logging/LoggingQuery.java b/src/main/java/com/amazon/carbonado/repo/logging/LoggingQuery.java index 56e4e33..e737288 100644 --- a/src/main/java/com/amazon/carbonado/repo/logging/LoggingQuery.java +++ b/src/main/java/com/amazon/carbonado/repo/logging/LoggingQuery.java @@ -129,6 +129,10 @@ class LoggingQuery<S extends Storable> implements Query<S> { return newInstance(mQuery.orderBy(strings));
}
+ public Query<S> after(S start) throws FetchException {
+ return newInstance(mQuery.after(start));
+ }
+
public Cursor<S> fetch() throws FetchException {
Log log = mStorage.mLog;
if (log.isEnabled()) {
@@ -154,15 +158,6 @@ class LoggingQuery<S extends Storable> implements Query<S> { return mQuery.fetchAfter(start);
}
- public Cursor<S> fetchAfter(S start, long from, Long to) throws FetchException {
- Log log = mStorage.mLog;
- if (log.isEnabled()) {
- log.write("Query.fetchAfter(start, from, to) on " + this + ", start: " + start +
- ", from: " + from + ", to: " + to);
- }
- return mQuery.fetchAfter(start);
- }
-
public S loadOne() throws FetchException {
Log log = mStorage.mLog;
if (log.isEnabled()) {
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