Add transaction detach/attach methods.

5 files changed, 114 insertions, 39 deletions

diff --git a/src/main/java/com/amazon/carbonado/Transaction.java b/src/main/java/com/amazon/carbonado/Transaction.java
index 5c8203f..1c2c06d 100644
--- a/src/main/java/com/amazon/carbonado/Transaction.java
+++ b/src/main/java/com/amazon/carbonado/Transaction.java
@@ -117,4 +117,30 @@ public interface Transaction {
      * Returns the isolation level of this transaction.

      */

     IsolationLevel getIsolationLevel();

+

+    /**

+     * Detaches this transaction from the current thread. It can be attached

+     * later, and to any thread which currently has no thread-local

+     * transaction.

+     *

+     * <p>Detaching a transaction also detaches any parent and nested child

+     * transactions. Attaching any of them achieves the same result as

+     * attaching this transaction.

+     *

+     * @throws IllegalStateException if transaction is attached to a different

+     * thread

+     * @since 1.2

+     */

+    void detach();

+

+    /**

+     * Attaches this transaction to the current thread, if it has been

+     * detached. Attaching a transaction also attaches any parent and nested

+     * child transactions.

+     *

+     * @throws IllegalStateException if current thread has a different

+     * transaction already attached

+     * @since 1.2

+     */

+    void attach();

 }

diff --git a/src/main/java/com/amazon/carbonado/repo/logging/LoggingTransaction.java b/src/main/java/com/amazon/carbonado/repo/logging/LoggingTransaction.java
index fd88f35..dd2a4f5 100644
--- a/src/main/java/com/amazon/carbonado/repo/logging/LoggingTransaction.java
+++ b/src/main/java/com/amazon/carbonado/repo/logging/LoggingTransaction.java
@@ -83,6 +83,20 @@ class LoggingTransaction implements Transaction {
         return mTxn.getIsolationLevel();

     }

 

+    public void detach() {

+        if (mLog.isEnabled()) {

+            mLog.write("Transaction.detach() on " + idChain());

+        }

+        mTxn.detach();

+    }

+

+    public void attach() {

+        if (mLog.isEnabled()) {

+            mLog.write("Transaction.attach() on " + idChain());

+        }

+        mTxn.attach();

+    }

+

     private String idChain() {

         if (mParent == null) {

             return String.valueOf(mID);

diff --git a/src/main/java/com/amazon/carbonado/spi/TransactionManager.java b/src/main/java/com/amazon/carbonado/spi/TransactionManager.java
index 4a28d24..a2b1375 100644
--- a/src/main/java/com/amazon/carbonado/spi/TransactionManager.java
+++ b/src/main/java/com/amazon/carbonado/spi/TransactionManager.java
@@ -74,32 +74,36 @@ public abstract class TransactionManager<Txn> {
      * which does not currently have a TransactionScope.

      *

      * @return detached thread-local TransactionScope or null if none

+     * @since 1.2

      */

-    /*

     public TransactionScope<Txn> detachLocalScope() {

         TransactionScope<Txn> scope = mLocalScope.get();

         if (scope != null) {

-            if (!scope.detach()) {

-                scope = null;

-            } else {

-                mLocalScope.remove();

-            }

+            scope.markDetached();

+            mLocalScope.remove();

         }

         return scope;

     }

-    */

 

     // Called by TransactionScope.

-    /*

-    void attach(TransactionScope<Txn> scope) {

+    boolean removeLocalScope(TransactionScope<Txn> scope) {

+        TransactionScope<Txn> existing = mLocalScope.get();

+        if (existing == null || existing == scope) {

+            mLocalScope.remove();

+            return true;

+        }

+        return false;

+    }

+

+    // Called by TransactionScope.

+    boolean setLocalScope(TransactionScope<Txn> scope) {

         TransactionScope<Txn> existing = mLocalScope.get();

         if (existing == null || existing == scope) {

             mLocalScope.set(scope);

-        } else {

-            throw new IllegalStateException("Current thread already has a transaction scope");

+            return true;

         }

+        return false;

     }

-    */

 

     /**

      * Closes all transaction scopes. Should be called only when repository is

diff --git a/src/main/java/com/amazon/carbonado/spi/TransactionPair.java b/src/main/java/com/amazon/carbonado/spi/TransactionPair.java
index d97aef4..ff07bc2 100644
--- a/src/main/java/com/amazon/carbonado/spi/TransactionPair.java
+++ b/src/main/java/com/amazon/carbonado/spi/TransactionPair.java
@@ -86,4 +86,24 @@ public class TransactionPair implements Transaction {
         return mPrimaryTransaction.getIsolationLevel()

             .lowestCommon(mSecondaryTransaction.getIsolationLevel());

     }

+

+    public void detach() {

+        mPrimaryTransaction.detach();

+        try {

+            mSecondaryTransaction.detach();

+        } catch (IllegalStateException e) {

+            mPrimaryTransaction.attach();

+            throw e;

+        }

+    }

+

+    public void attach() {

+        mPrimaryTransaction.attach();

+        try {

+            mSecondaryTransaction.attach();

+        } catch (IllegalStateException e) {

+            mPrimaryTransaction.detach();

+            throw e;

+        }

+    }

 }

diff --git a/src/main/java/com/amazon/carbonado/spi/TransactionScope.java b/src/main/java/com/amazon/carbonado/spi/TransactionScope.java
index 0ac2cee..82a20eb 100644
--- a/src/main/java/com/amazon/carbonado/spi/TransactionScope.java
+++ b/src/main/java/com/amazon/carbonado/spi/TransactionScope.java
@@ -41,8 +41,6 @@ import com.amazon.carbonado.Transaction;
  * @see TransactionManager

  */

 public class TransactionScope<Txn> {

-    private static final int OPEN = 0, DETACHED = 1, CLOSED = 2;

-

     final TransactionManager<Txn> mTxnMgr;

     final Lock mLock;

 

@@ -51,12 +49,12 @@ public class TransactionScope<Txn> {
     // Tracks all registered cursors by storage type.

     private Map<Class<?>, CursorList<TransactionImpl<Txn>>> mCursors;

 

-    private int mState;

+    private boolean mClosed;

+    private boolean mDetached;

 

     TransactionScope(TransactionManager<Txn> txnMgr, boolean closed) {

         mTxnMgr = txnMgr;

         mLock = new ReentrantLock(true);

-        mState = closed ? CLOSED : OPEN;

     }

 

     /**

@@ -192,7 +190,7 @@ public class TransactionScope<Txn> {
     public boolean isForUpdate() {

         mLock.lock();

         try {

-            return (mState == CLOSED || mActive == null) ? false : mActive.isForUpdate();

+            return (mClosed || mActive == null) ? false : mActive.isForUpdate();

         } finally {

             mLock.unlock();

         }

@@ -205,7 +203,7 @@ public class TransactionScope<Txn> {
     public IsolationLevel getIsolationLevel() {

         mLock.lock();

         try {

-            return (mState == CLOSED || mActive == null) ? null : mActive.getIsolationLevel();

+            return (mClosed || mActive == null) ? null : mActive.getIsolationLevel();

         } finally {

             mLock.unlock();

         }

@@ -215,41 +213,46 @@ public class TransactionScope<Txn> {
      * Attach this scope to the current thread, if it has been {@link

      * TransactionManager#detachLocalScope detached}.

      *

-     * @throws IllegalStateException if scope is not detached or if current

-     * thread already has a transaction scope

+     * @throws IllegalStateException if current thread has a different

+     * transaction already attached

      */

-    /*

     public void attach() {

         mLock.lock();

         try {

-            if (mState != DETACHED) {

-                throw new IllegalStateException("Transaction scope is not detached");

+            if (mTxnMgr.setLocalScope(this)) {

+                mDetached = false;

+            } else {

+                throw new IllegalStateException

+                    ("Current thread has a different transaction already attached");

             }

-            mState = OPEN;

         } finally {

             mLock.unlock();

         }

-        mTxnMgr.attach(this);

     }

-    */

 

-    /**

-     * @return false if closed

-     */

-    /*

-    boolean detach() {

+    // Called by TransactionImpl.

+    void detach() {

         mLock.lock();

         try {

-            if (mState == CLOSED) {

-                return false;

+            if (mTxnMgr.removeLocalScope(this)) {

+                mDetached = true;

+            } else {

+                throw new IllegalStateException("Transaction is attached to a different thread");

             }

-            mState = DETACHED;

-            return true;

         } finally {

             mLock.unlock();

         }

     }

-    */

+

+    // Called by TransactionManager.

+    void markDetached() {

+        mLock.lock();

+        try {

+            mDetached = true;

+        } finally {

+            mLock.unlock();

+        }

+    }

 

     /**

      * Exits all transactions and closes all cursors. Should be called only

@@ -258,7 +261,7 @@ public class TransactionScope<Txn> {
     void close() throws RepositoryException {

         mLock.lock();

         try {

-            if (mState != CLOSED) {

+            if (!mClosed) {

                 while (mActive != null) {

                     mActive.exit();

                 }

@@ -269,7 +272,7 @@ public class TransactionScope<Txn> {
                 }

             }

         } finally {

-            mState = CLOSED;

+            mClosed = true;

             mLock.unlock();

         }

     }

@@ -278,7 +281,7 @@ public class TransactionScope<Txn> {
      * Caller must hold mLock.

      */

     private void checkClosed() {

-        if (mState == CLOSED) {

+        if (mClosed) {

             throw new IllegalStateException("Repository is closed");

         }

     }

@@ -409,6 +412,14 @@ public class TransactionScope<Txn> {
             return mLevel;

         }

 

+        public void detach() {

+            mScope.detach();

+        }

+

+        public void attach() {

+            mScope.attach();

+        }

+

         // Caller must hold mLock.

         <S extends Storable> void register(Cursor<S> cursor) {

             if (mCursorList == null) {