Make cursors more resilient against concurrent close, preventing NoSuchElementException from being thrown inappropriately.

10 files changed, 39 insertions, 18 deletions

diff --git a/src/main/java/com/amazon/carbonado/cursor/DifferenceCursor.java b/src/main/java/com/amazon/carbonado/cursor/DifferenceCursor.java
index a04aec0..867f2f0 100644
--- a/src/main/java/com/amazon/carbonado/cursor/DifferenceCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/DifferenceCursor.java
@@ -108,6 +108,8 @@ public class DifferenceCursor<S> extends AbstractCursor<S> {
                     }

                 }

             }

+        } catch (NoSuchElementException e) {

+            return false;

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/IntersectionCursor.java b/src/main/java/com/amazon/carbonado/cursor/IntersectionCursor.java
index 6eb3179..4d542e9 100644
--- a/src/main/java/com/amazon/carbonado/cursor/IntersectionCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/IntersectionCursor.java
@@ -106,6 +106,8 @@ public class IntersectionCursor<S> extends AbstractCursor<S> {
                     return true;

                 }

             }

+        } catch (NoSuchElementException e) {

+            return false;

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/LimitCursor.java b/src/main/java/com/amazon/carbonado/cursor/LimitCursor.java
index 925c582..1dc50be 100644
--- a/src/main/java/com/amazon/carbonado/cursor/LimitCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/LimitCursor.java
@@ -50,11 +50,14 @@ public class LimitCursor<S> extends AbstractCursor<S> {
     }

 

     public boolean hasNext() throws FetchException {

-        if (mSource.hasNext()) {

-            if (mRemaining > 0) {

-                return true;

+        try {

+            if (mSource.hasNext()) {

+                if (mRemaining > 0) {

+                    return true;

+                }

+                mSource.close();

             }

-            mSource.close();

+        } catch (NoSuchElementException e) {

         }

         return false;

     }

diff --git a/src/main/java/com/amazon/carbonado/cursor/MultiTransformedCursor.java b/src/main/java/com/amazon/carbonado/cursor/MultiTransformedCursor.java
index fafb55f..fdeb941 100644
--- a/src/main/java/com/amazon/carbonado/cursor/MultiTransformedCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/MultiTransformedCursor.java
@@ -72,21 +72,19 @@ public abstract class MultiTransformedCursor<S, T> extends AbstractCursor<T> {
                 mNextCursor.close();

                 mNextCursor = null;

             }

-            try {

-                int count = 0;

-                while (mCursor.hasNext()) {

-                    Cursor<T> nextCursor = transform(mCursor.next());

-                    if (nextCursor != null) {

-                        if (nextCursor.hasNext()) {

-                            mNextCursor = nextCursor;

-                            return true;

-                        }

-                        nextCursor.close();

+            int count = 0;

+            while (mCursor.hasNext()) {

+                Cursor<T> nextCursor = transform(mCursor.next());

+                if (nextCursor != null) {

+                    if (nextCursor.hasNext()) {

+                        mNextCursor = nextCursor;

+                        return true;

                     }

-                    interruptCheck(++count);

+                    nextCursor.close();

                 }

-            } catch (NoSuchElementException e) {

+                interruptCheck(++count);

             }

+        } catch (NoSuchElementException e) {

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/SkipCursor.java b/src/main/java/com/amazon/carbonado/cursor/SkipCursor.java
index c991933..c770751 100644
--- a/src/main/java/com/amazon/carbonado/cursor/SkipCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/SkipCursor.java
@@ -18,6 +18,8 @@
 

 package com.amazon.carbonado.cursor;

 

+import java.util.NoSuchElementException;

+

 import com.amazon.carbonado.Cursor;

 import com.amazon.carbonado.FetchException;

 

@@ -48,8 +50,12 @@ public class SkipCursor<S> extends AbstractCursor<S> {
     }

 

     public boolean hasNext() throws FetchException {

-        doSkip();

-        return mSource.hasNext();

+        try {

+            doSkip();

+            return mSource.hasNext();

+        } catch (NoSuchElementException e) {

+            return false;

+        }

     }

 

     public S next() throws FetchException {

diff --git a/src/main/java/com/amazon/carbonado/cursor/SortedCursor.java b/src/main/java/com/amazon/carbonado/cursor/SortedCursor.java
index 8de527d..d3bf24b 100644
--- a/src/main/java/com/amazon/carbonado/cursor/SortedCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/SortedCursor.java
@@ -306,6 +306,7 @@ public class SortedCursor<S> extends AbstractCursor<S> {
             } catch (UndeclaredThrowableException e) {

                 throw toFetchException(e);

             }

+        } catch (NoSuchElementException e) {

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/SymmetricDifferenceCursor.java b/src/main/java/com/amazon/carbonado/cursor/SymmetricDifferenceCursor.java
index b78cf79..4dc8700 100644
--- a/src/main/java/com/amazon/carbonado/cursor/SymmetricDifferenceCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/SymmetricDifferenceCursor.java
@@ -113,6 +113,8 @@ public class SymmetricDifferenceCursor<S> extends AbstractCursor<S> {
                     return mCompareResult;

                 }

             }

+        } catch (NoSuchElementException e) {

+            return 0;

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/ThrottledCursor.java b/src/main/java/com/amazon/carbonado/cursor/ThrottledCursor.java
index a349782..0a40570 100644
--- a/src/main/java/com/amazon/carbonado/cursor/ThrottledCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/ThrottledCursor.java
@@ -18,6 +18,8 @@
 

 package com.amazon.carbonado.cursor;

 

+import java.util.NoSuchElementException;

+

 import com.amazon.carbonado.Cursor;

 import com.amazon.carbonado.FetchException;

 import com.amazon.carbonado.FetchInterruptedException;

@@ -63,6 +65,8 @@ public class ThrottledCursor<S> extends AbstractCursor<S> {
     public boolean hasNext() throws FetchException {

         try {

             return mCursor.hasNext();

+        } catch (NoSuchElementException e) {

+            return false;

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/cursor/UnionCursor.java b/src/main/java/com/amazon/carbonado/cursor/UnionCursor.java
index c2bdd19..5f0e326 100644
--- a/src/main/java/com/amazon/carbonado/cursor/UnionCursor.java
+++ b/src/main/java/com/amazon/carbonado/cursor/UnionCursor.java
@@ -74,6 +74,8 @@ public class UnionCursor<S> extends AbstractCursor<S> {
             if (mNextRight == null && mRightCursor.hasNext()) {

                 mNextRight = mRightCursor.next();

             }

+        } catch (NoSuchElementException e) {

+            return false;

         } catch (FetchException e) {

             try {

                 close();

diff --git a/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java b/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
index de105cc..872b5b4 100644
--- a/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
+++ b/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
@@ -152,6 +152,7 @@ class IndexedCursor<S extends Storable> extends AbstractCursor<S> {
                     }

                 }

             }

+        } catch (NoSuchElementException e) {

         } catch (FetchException e) {

             try {

                 close();