WIP: still working toward a solid caching scheme, progress but far from done.

NOTES

@@ -1,3 +1,13 @@
+--- Cache
+
+cache entites (2 methods) marked @Cacheable
+cache entites in txn context
+cache results when .cache() chained before .{a}sync() call, return a EvictableCacheItem<E> that has an .evict() method
+fix txn .andThen() chains
+
+
+
+
 primitive types have default values, (e.g. boolean, int, ...) but primative wrapper classes do not and can be null (e.g. Boolean, Integer, ...)
 
 create table wal {

src/main/java/net/helenus/core/AbstractSessionOperations.java

@@ -22,6 +22,10 @@ import com.datastax.driver.core.querybuilder.BuiltStatement;
 import com.google.common.util.concurrent.ListenableFuture;
 import java.io.PrintStream;
 import java.util.concurrent.Executor;
+
+import net.helenus.core.operation.AbstractCache;
+import net.helenus.core.operation.CacheManager;
+import net.helenus.mapping.HelenusEntity;
 import net.helenus.mapping.value.ColumnValuePreparer;
 import net.helenus.mapping.value.ColumnValueProvider;
 import net.helenus.support.HelenusException;
@@ -111,7 +115,7 @@ public abstract class AbstractSessionOperations {
     return null;
   }
 
-  public void cache(String key, Object value) {}
+  public AbstractCache cacheFor(CacheManager.Type type) { return null; }
 
   RuntimeException translateException(RuntimeException e) {
     if (e instanceof HelenusException) {

src/main/java/net/helenus/core/HelenusSession.java

@@ -60,7 +60,7 @@ public final class HelenusSession extends AbstractSessionOperations implements C
   private final RowColumnValueProvider valueProvider;
   private final StatementColumnValuePreparer valuePreparer;
   private final Metadata metadata;
-  private final Cache<String, Object> sessionCache;
+  private final CacheManager cacheManager;
   private UnitOfWork currentUnitOfWork;
 
   HelenusSession(
@@ -92,13 +92,8 @@ public final class HelenusSession extends AbstractSessionOperations implements C
     this.valueProvider = new RowColumnValueProvider(this.sessionRepository);
     this.valuePreparer = new StatementColumnValuePreparer(this.sessionRepository);
     this.metadata = session.getCluster().getMetadata();
-    this.sessionCache =
-        CacheBuilder.newBuilder()
-            .maximumSize(MAX_CACHE_SIZE)
-            .expireAfterAccess(MAX_CACHE_EXPIRE_SECONDS, TimeUnit.SECONDS)
-            .recordStats()
-            .build();
     this.currentUnitOfWork = null;
+    this.cacheManager = new CacheManager(this);
   }
 
   @Override
@@ -200,16 +195,13 @@ public final class HelenusSession extends AbstractSessionOperations implements C
     }
   }
 
-  public void cache(String key, Object value) {
-    sessionCache.put(key, value); // ttl
-  }
-
   public <E> SelectOperation<E> select(Class<E> entityClass) {
 
     Objects.requireNonNull(entityClass, "entityClass is empty");
     ColumnValueProvider valueProvider = getValueProvider();
     HelenusEntity entity = Helenus.entity(entityClass);
 
+      //TODO cache entity
     return new SelectOperation<E>(
         this,
         entity,
@@ -453,6 +445,11 @@ public final class HelenusSession extends AbstractSessionOperations implements C
     return new DeleteOperation(this, Helenus.resolve(dsl));
   }
 
+  @Override
+  public AbstractCache cacheFor(CacheManager.Type type) {
+      return cacheManager.of(type);
+  }
+
   public Session getSession() {
     return session;
   }

src/main/java/net/helenus/core/operation/AbstractCache.java

@@ -0,0 +1,38 @@
+package net.helenus.core.operation;
+
+import java.util.concurrent.ExecutionException;
+
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Statement;
+import com.google.common.cache.Cache;
+
+public abstract class AbstractCache {
+    protected CacheManager.Type type;
+    protected Cache<String, ResultSet> cache;
+
+    public AbstractCache(CacheManager.Type type, Cache<String, ResultSet> cache) {
+        this.type = type;
+        this.cache = cache;
+    }
+
+    protected abstract ResultSet fetch(Statement statement, OperationsDelegate delegate, ResultSetFuture resultSetFuture)
+            throws InterruptedException, ExecutionException;
+    protected abstract ResultSet mutate(Statement statement, OperationsDelegate delegate, ResultSetFuture resultSetFuture)
+            throws InterruptedException, ExecutionException;
+
+    public ResultSet apply(Statement statement, OperationsDelegate delegate, ResultSetFuture futureResultSet)
+            throws InterruptedException, ExecutionException {
+        ResultSet resultSet = null;
+        switch (type) {
+        case FETCH:
+            resultSet = fetch(statement, delegate, futureResultSet);
+            break;
+        case MUTATE:
+            resultSet = mutate(statement, delegate, futureResultSet);
+            break;
+        }
+        return resultSet;
+    }
+
+}

src/main/java/net/helenus/core/operation/AbstractOperation.java

@@ -24,7 +24,7 @@ public abstract class AbstractOperation<E, O extends AbstractOperation<E, O>>
 
   public abstract E transform(ResultSet resultSet);
 
-  protected CacheManager getCacheManager() { return null; }
+  protected AbstractCache getCache() { return null; }
 
   public boolean cacheable() {
     return false;
@@ -42,11 +42,11 @@ public abstract class AbstractOperation<E, O extends AbstractOperation<E, O>>
 
   public E sync() {
     return Executioner.INSTANCE.<E>sync(
-        sessionOps, options(buildStatement()), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 
   public CompletableFuture<E> async() {
     return Executioner.INSTANCE.<E>async(
-        sessionOps, options(buildStatement()), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 }

src/main/java/net/helenus/core/operation/AbstractOptionalOperation.java

@@ -33,7 +33,7 @@ public abstract class AbstractOptionalOperation<E, O extends AbstractOptionalOpe
 
   public abstract Optional<E> transform(ResultSet resultSet);
 
-  protected CacheManager getCacheManager() { return null; }
+  protected AbstractCache getCache() { return null; }
 
   public CacheKey getCacheKey() { return null; }
 
@@ -56,11 +56,11 @@ public abstract class AbstractOptionalOperation<E, O extends AbstractOptionalOpe
   public Optional<E> sync() {
 
     return Executioner.INSTANCE.<Optional<E>>sync(
-        sessionOps, options(buildStatement()), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 
   public CompletableFuture<Optional<E>> async() {
     return Executioner.INSTANCE.<Optional<E>>async(
-        sessionOps, options(buildStatement()), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 }

src/main/java/net/helenus/core/operation/AbstractStreamOperation.java

@@ -33,7 +33,7 @@ public abstract class AbstractStreamOperation<E, O extends AbstractStreamOperati
 
   public abstract Stream<E> transform(ResultSet resultSet);
 
-  protected CacheManager getCacheManager() { return null; }
+  protected AbstractCache getCache() { return null; }
 
   public CacheKey getCacheKey() { return null; }
 
@@ -55,11 +55,11 @@ public abstract class AbstractStreamOperation<E, O extends AbstractStreamOperati
 
   public Stream<E> sync() {
     return Executioner.INSTANCE.<Stream<E>>sync(
-        sessionOps, options(buildStatement()), getCacheManager(), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 
   public CompletableFuture<Stream<E>> async() {
     return Executioner.INSTANCE.<Stream<E>>async(
-        sessionOps, options(buildStatement()), getCacheManager(), traceContext, this, showValues);
+        sessionOps, options(buildStatement()), getCache(), traceContext, this, showValues);
   }
 }

src/main/java/net/helenus/core/operation/BoundOptionalOperation.java

@@ -38,6 +38,9 @@ public final class BoundOptionalOperation<E>
     return delegate.transform(resultSet);
   }
 
+  @Override
+  protected AbstractCache getCache() { return delegate.getCache(); }
+
   @Override
   public CacheKey getCacheKey() { return delegate.getCacheKey(); }
 

src/main/java/net/helenus/core/operation/BoundStreamOperation.java

@@ -36,7 +36,7 @@ public final class BoundStreamOperation<E>
   }
 
   @Override
-  protected CacheManager getCacheManager() { return delegate.getCacheManager(); }
+  protected AbstractCache getCache() { return delegate.getCache(); }
 
   @Override
   public Stream<E> transform(ResultSet resultSet) {

src/main/java/net/helenus/core/operation/CacheKey.java

@@ -1,9 +1,15 @@
 package net.helenus.core.operation;
 
+import com.datastax.driver.core.Statement;
+
 public class CacheKey {
 
     private String key;
 
+    static String of(Statement statement) {
+      return "use " + statement.getKeyspace() + "; " + statement.toString();
+    }
+
     CacheKey() {}
 
     CacheKey(String key) { this.key = key; }

src/main/java/net/helenus/core/operation/CacheManager.java

@@ -3,47 +3,52 @@ package net.helenus.core.operation;
 import com.datastax.driver.core.ResultSet;
 import com.datastax.driver.core.ResultSetFuture;
 import com.datastax.driver.core.Statement;
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
+import net.helenus.core.HelenusSession;
 import net.helenus.mapping.HelenusEntity;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
 
-
+public class CacheManager {
-public abstract class CacheManager {
     public enum Type { FETCH, MUTATE }
 
-    private static CacheManager sessionFetch = new SessionCacheManager(Type.FETCH);
+    final Logger logger = LoggerFactory.getLogger(getClass());
+    final HelenusSession session;
 
-    protected CacheManager.Type type;
+    private AbstractCache sessionFetch;
 
+    public CacheManager(HelenusSession session) {
+        this.session = session;
 
-    public static CacheManager of(Type type, HelenusEntity entity) {
+        RemovalListener<String, ResultSet> listener = new RemovalListener<String, ResultSet>() {
-        if (entity != null && entity.isCacheable()) {
+            @Override
+            public void onRemoval(RemovalNotification<String, ResultSet> n){
+                if (n.wasEvicted()) {
+                    String cause = n.getCause().name();
+                    logger.info(cause);
+                }
+            }
+        };
+
+        Cache<String, ResultSet> cache = CacheBuilder.newBuilder()
+                .maximumSize(10_000)
+                .expireAfterAccess(20, TimeUnit.MINUTES)
+                .weakKeys()
+                .softValues()
+                .removalListener(listener)
+                .build();
+
+        sessionFetch = new SessionCache(Type.FETCH, this, cache);
+    }
+
+    public AbstractCache of(CacheManager.Type type) {
         return sessionFetch;
     }
-        return null;
-    }
-
-    public CacheManager(Type type) {
-        this.type = type;
-    }
-
-    protected abstract ResultSet fetch(Statement statement, OperationsDelegate delegate, ResultSetFuture resultSetFuture)
-            throws InterruptedException, ExecutionException;
-    protected abstract ResultSet mutate(Statement statement, OperationsDelegate delegate, ResultSetFuture resultSetFuture)
-            throws InterruptedException, ExecutionException;
-
-    public ResultSet apply(Statement statement, OperationsDelegate delegate, ResultSetFuture futureResultSet)
-            throws InterruptedException, ExecutionException {
-        ResultSet resultSet = null;
-        switch (type) {
-            case FETCH:
-                 resultSet = fetch(statement, delegate, futureResultSet);
-                break;
-            case MUTATE:
-                resultSet = mutate(statement, delegate, futureResultSet);
-                break;
-        }
-        return resultSet;
-    }
 
 }

src/main/java/net/helenus/core/operation/Executioner.java

@@ -27,15 +27,12 @@ public enum Executioner {
     <E> E sync(
             AbstractSessionOperations session,
             Statement statement,
-            CacheManager cacheManager,
+            AbstractCache cache,
             TraceContext traceContext,
             OperationsDelegate<E> delegate,
             boolean showValues) {
-    try {
+    ResultSetFuture futureResultSet = session.executeAsync(statement, showValues);
-      return this.<E>async(session, statement, cacheManager, traceContext, delegate, showValues).get();
+    return this.<E>execute(futureResultSet, session, statement, cache, traceContext, delegate, showValues);
-    } catch (InterruptedException | ExecutionException e) {
-        throw new HelenusException(e);
-    }
   }
 
   public <E> CompletableFuture<E> async(
@@ -50,24 +47,43 @@ public enum Executioner {
   public <E> CompletableFuture<E> async(
           AbstractSessionOperations session,
           Statement statement,
-            CacheManager cacheManager,
+          AbstractCache cache,
+          TraceContext traceContext,
+          OperationsDelegate<E> delegate,
+          boolean showValues) {
+
+    ResultSetFuture futureResultSet = session.executeAsync(statement, showValues);
+    return CompletableFuture.<E>supplyAsync(() ->
+            execute(futureResultSet, session, statement, cache, traceContext, delegate, showValues));
+  }
+
+  public <E> E execute(ResultSetFuture futureResultSet,
+          AbstractSessionOperations session,
+          Statement statement,
+          AbstractCache cache,
           TraceContext traceContext,
           OperationsDelegate<E> delegate,
           boolean showValues) {
-    ResultSetFuture futureResultSet = session.executeAsync(statement, showValues);
 
-    return CompletableFuture.<E>supplyAsync(
-        () -> {
       Tracer tracer = session.getZipkinTracer();
-          final Span span =
+      Span span = null;
-              (tracer != null && traceContext != null) ? tracer.newChild(traceContext) : null;
+      if (tracer != null && traceContext != null) {
+          span = tracer.newChild(traceContext);
+      }
+
       try {
           if (span != null) {
               span.name("cassandra");
               span.start();
           }
-            ResultSet resultSet = cacheManager != null ? cacheManager.apply(statement, delegate, futureResultSet) :
+
-                    futureResultSet.get();
+          ResultSet resultSet;
+          if (cache != null) {
+              resultSet = cache.apply(statement, delegate, futureResultSet);
+          } else {
+              resultSet = futureResultSet.get();
+          }
+
           E result = delegate.transform(resultSet);
 
           return result;
@@ -78,6 +94,6 @@ public enum Executioner {
               span.finish();
           }
       }
-        });
   }
+
 }

src/main/java/net/helenus/core/operation/SelectOperation.java

@@ -46,7 +46,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
   protected Integer limit = null;
   protected boolean allowFiltering = false;
 
-  protected CacheManager cacheManager;
 
   public SelectOperation(AbstractSessionOperations sessionOperations) {
     super(sessionOperations);
@@ -70,7 +69,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
               }
             };
 
-    this.cacheManager = CacheManager.of(CacheManager.Type.FETCH, null) ;
   }
 
   public SelectOperation(AbstractSessionOperations sessionOperations, HelenusEntity entity) {
@@ -83,7 +81,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
             .map(p -> new HelenusPropertyNode(p, Optional.empty()))
             .forEach(p -> this.props.add(p));
 
-    this.cacheManager = CacheManager.of(CacheManager.Type.FETCH, entity) ;
   }
 
   public SelectOperation(
@@ -100,7 +97,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
             .map(p -> new HelenusPropertyNode(p, Optional.empty()))
             .forEach(p -> this.props.add(p));
 
-    this.cacheManager = CacheManager.of(CacheManager.Type.FETCH, entity) ;
   }
 
   public SelectOperation(
@@ -112,7 +108,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
     this.rowMapper = rowMapper;
     Collections.addAll(this.props, props);
 
-    this.cacheManager = CacheManager.of(CacheManager.Type.FETCH, null) ;
   }
 
   public CountOperation count() {
@@ -262,10 +257,6 @@ public final class SelectOperation<E> extends AbstractFilterStreamOperation<E, S
     }
   }
 
-  protected CacheManager getCacheManager() {
-    return cacheManager;
-  }
-
   private List<Ordering> getOrCreateOrdering() {
     if (ordering == null) {
       ordering = new ArrayList<Ordering>();

src/main/java/net/helenus/core/operation/SelectTransformingOperation.java

@@ -40,6 +40,9 @@ public final class SelectTransformingOperation<R, E>
     return src.buildStatement();
   }
 
+  @Override
+  protected AbstractCache getCache() { return src.getCache(); }
+
   @Override
   public Stream<R> transform(ResultSet resultSet) {
     return src.transform(resultSet).map(fn);

src/main/java/net/helenus/core/operation/SessionCache.java

@@ -1,48 +1,27 @@
 package net.helenus.core.operation;
 
+import java.util.concurrent.ExecutionException;
+
 import com.datastax.driver.core.ResultSet;
 import com.datastax.driver.core.ResultSetFuture;
 import com.datastax.driver.core.Statement;
-import com.google.common.cache.*;
+import com.datastax.driver.core.querybuilder.Select;
-import org.slf4j.Logger;
+import com.google.common.cache.Cache;
-import org.slf4j.LoggerFactory;
-
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.TimeUnit;
 
 
-public class SessionCacheManager extends CacheManager {
+public class SessionCache extends AbstractCache {
-    final Logger logger = LoggerFactory.getLogger(getClass());
 
-    private Cache<String, ResultSet> cache;
+    private final CacheManager manager;
 
-    SessionCacheManager(CacheManager.Type type) {
+    SessionCache(CacheManager.Type type, CacheManager manager, Cache<String, ResultSet> cache) {
-        super(type);
+        super(type, cache);
-
+        this.manager = manager;
-        RemovalListener<String, ResultSet> listener;
-        listener = new RemovalListener<String, ResultSet>() {
-            @Override
-            public void onRemoval(RemovalNotification<String, ResultSet> n){
-                if (n.wasEvicted()) {
-                    String cause = n.getCause().name();
-                    logger.info(cause);
-                }
-            }
-        };
-
-        cache = CacheBuilder.newBuilder()
-                .maximumSize(10_000)
-                .expireAfterAccess(20, TimeUnit.MINUTES)
-                .weakKeys()
-                .softValues()
-                .removalListener(listener)
-                .build();
     }
 
     protected ResultSet fetch(Statement statement, OperationsDelegate delegate, ResultSetFuture resultSetFuture)
             throws InterruptedException, ExecutionException {
-        CacheKey key = delegate.getCacheKey();
+        final CacheKey key = delegate.getCacheKey();
-        final String cacheKey = key == null ? statement.toString() : key.toString();
+        final String cacheKey = (key == null) ? CacheKey.of(statement) : key.toString();
         ResultSet resultSet = null;
         if (cacheKey == null) {
             resultSet = resultSetFuture.get();
@@ -51,6 +30,7 @@ public class SessionCacheManager extends CacheManager {
             if (resultSet == null) {
                 resultSet = resultSetFuture.get();
                 if (resultSet != null) {
+                    planEvictionFor(statement);
                     cache.put(cacheKey, resultSet);
                 }
             }
@@ -64,9 +44,22 @@ public class SessionCacheManager extends CacheManager {
         final String cacheKey = key == null ? statement.toString() : key.toString();
         ResultSet resultSet = resultSetFuture.get();
         if (cacheKey != null && resultSet != null) {
+            planEvictionFor(statement);
+            //manager.evictIfNecessary(statement, delegate);
             cache.put(cacheKey, resultSet);
         }
         return resultSet;
     }
 
+    private void planEvictionFor(Statement statement) {
+        //((Select)statement).table + statement.where.clauses.length == 0
+        //TTL for rows read
+    }
+
+    public ResultSet get(Statement statement, OperationsDelegate delegate) {
+        final CacheKey key = delegate.getCacheKey();
+        final String cacheKey = (key == null) ? CacheKey.of(statement) : key.toString();
+        return cache.getIfPresent(cacheKey);
+    }
+
 }