From 7bb2ef6f61fb8f180c70e854344550a13bdb3361 Mon Sep 17 00:00:00 2001
From: "Brian S. O'Neill" <bronee@gmail.com>
Date: Sat, 24 Jul 2010 23:14:20 +0000
Subject: Allow new layouts if BDB is read-only.

---
 .../java/com/amazon/carbonado/layout/Layout.java    |  6 +++++-
 .../com/amazon/carbonado/layout/LayoutFactory.java  | 21 ++++++++++++++++++---
 .../carbonado/repo/sleepycat/BDBRepository.java     |  2 +-
 .../amazon/carbonado/repo/sleepycat/BDBStorage.java |  8 +++++---
 4 files changed, 29 insertions(+), 8 deletions(-)

(limited to 'src/main')

diff --git a/src/main/java/com/amazon/carbonado/layout/Layout.java b/src/main/java/com/amazon/carbonado/layout/Layout.java
index 0c7ab83..98df22c 100644
--- a/src/main/java/com/amazon/carbonado/layout/Layout.java
+++ b/src/main/java/com/amazon/carbonado/layout/Layout.java
@@ -518,13 +518,17 @@ public class Layout {
     }
 
     // Assumes caller is in a transaction.
-    void insert(int generation) throws PersistException {
+    void insert(boolean readOnly, int generation) throws PersistException {
         if (mAllProperties == null) {
             throw new IllegalStateException();
         }
 
         mStoredLayout.setGeneration(generation);
 
+        if (readOnly) {
+            return;
+        }
+
         try {
             mStoredLayout.insert();
         } catch (UniqueConstraintException e) {
diff --git a/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java b/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java
index 92099dd..7b7953b 100644
--- a/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java
+++ b/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java
@@ -101,6 +101,21 @@ public class LayoutFactory implements LayoutCapability {
      */
     public Layout layoutFor(Class<? extends Storable> type, LayoutOptions options)
         throws FetchException, PersistException
+    {
+        return layoutFor(false, type, options);
+    }
+
+    /**
+     * Returns the layout matching the current definition of the given type.
+     *
+     * @param readOnly if true, don't attempt to persist new generation because
+     * underlying repository is read-only
+     * @throws PersistException if type represents a new generation, but
+     * persisting this information failed
+     */
+    public Layout layoutFor(boolean readOnly,
+                            Class<? extends Storable> type, LayoutOptions options)
+        throws FetchException, PersistException
     {
         if (options != null) {
             // Make side-effect consistently applied.
@@ -132,7 +147,7 @@ public class LayoutFactory implements LayoutCapability {
                     txn = mRepository.enterTransaction(IsolationLevel.READ_COMMITTED);
                 }
 
-                txn.setForUpdate(true);
+                txn.setForUpdate(!readOnly);
                 try {
                     // If type represents a new generation, then a new layout needs to
                     // be inserted.
@@ -207,7 +222,7 @@ public class LayoutFactory implements LayoutCapability {
                         cursor.close();
                     }
 
-                    newLayout.insert(generation);
+                    newLayout.insert(readOnly, generation);
                     layout = newLayout;
 
                     txn.commit();
@@ -247,7 +262,7 @@ public class LayoutFactory implements LayoutCapability {
             }
         }
 
-        if (resyncCap != null) {
+        if (!readOnly && resyncCap != null) {
             // Make sure that all layout records are sync'd.
             try {
                 resyncCap.resync(StoredLayoutProperty.class, 1.0, null);
diff --git a/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBRepository.java b/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBRepository.java
index b423ab9..eb10042 100644
--- a/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBRepository.java
+++ b/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBRepository.java
@@ -354,7 +354,7 @@ abstract class BDBRepository<Txn> extends AbstractRepository<Txn>
         throws FetchException, PersistException
     {
         try {
-            return ((BDBStorage) storageFor(type)).getLayout(mStorableCodecFactory);
+            return ((BDBStorage) storageFor(type)).getLayout(true, mStorableCodecFactory);
         } catch (PersistException e) {
             throw e;
         } catch (RepositoryException e) {
diff --git a/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBStorage.java b/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBStorage.java
index 66e8475..f4d8f24 100644
--- a/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBStorage.java
+++ b/src/main/java/com/amazon/carbonado/repo/sleepycat/BDBStorage.java
@@ -419,7 +419,7 @@ abstract class BDBStorage<Txn, S extends Storable> implements Storage<S>, Storag
     {
         StorableInfo<S> info = StorableIntrospector.examine(getStorableType());
         StorableCodecFactory codecFactory = mRepository.getStorableCodecFactory();
-        final Layout layout = getLayout(codecFactory);
+        final Layout layout = getLayout(readOnly, codecFactory);
 
         // Open primary database.
         Object primaryDatabase;
@@ -766,7 +766,9 @@ abstract class BDBStorage<Txn, S extends Storable> implements Storage<S>, Storag
         }
     }
 
-    Layout getLayout(StorableCodecFactory codecFactory) throws RepositoryException {
+    Layout getLayout(boolean readOnly, StorableCodecFactory codecFactory)
+        throws RepositoryException
+    {
         if (Unevolvable.class.isAssignableFrom(getStorableType())) {
             // Don't record generation for storables marked as unevolvable.
             return null;
@@ -782,7 +784,7 @@ abstract class BDBStorage<Txn, S extends Storable> implements Storage<S>, Storag
         }
 
         Class<S> type = getStorableType();
-        return factory.layoutFor(type, codecFactory.getLayoutOptions(type));
+        return factory.layoutFor(readOnly, type, codecFactory.getLayoutOptions(type));
     }
 
     /**
-- 
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