X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-binding-api%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fmd%2Fsal%2Fbinding%2Fapi%2FReadTransaction.java;h=c1efcce02c12dbaa0606a8d3482fe405b50ab499;hp=cc85d4337b93d5b1a2322af009052b7c26091bd8;hb=aa1c4a51361239aeaa064eb11eb935be194b6eeb;hpb=753af6de42f98637e83bc26b4b058f47840863a8

diff --git a/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/md/sal/binding/api/ReadTransaction.java b/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/md/sal/binding/api/ReadTransaction.java
index cc85d4337b..c1efcce02c 100644
--- a/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/md/sal/binding/api/ReadTransaction.java
+++ b/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/md/sal/binding/api/ReadTransaction.java
@@ -7,40 +7,76 @@
  */
 package org.opendaylight.controller.md.sal.binding.api;
 
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.MoreExecutors;
+import org.opendaylight.controller.md.sal.common.api.MappingCheckedFuture;
 import org.opendaylight.controller.md.sal.common.api.data.AsyncReadTransaction;
 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
-import com.google.common.base.Optional;
-import com.google.common.util.concurrent.ListenableFuture;
-
 /**
  * A transaction that provides read access to a logical data store.
+ *
  * <p>
  * For more information on usage and examples, please see the documentation in {@link AsyncReadTransaction}.
+ *
+ * @deprecated Use {@link org.opendaylight.mdsal.binding.api.ReadTransaction} instead.
  */
+@Deprecated
 public interface ReadTransaction extends AsyncReadTransaction<InstanceIdentifier<?>, DataObject> {
-
     /**
      * Reads data from the provided logical data store located at the provided path.
-     *<p>
-     * If the target is a subtree, then the whole subtree is read (and will be
-     * accessible from the returned data object).
      *
-     * @param store
-     *            Logical data store from which read should occur.
-     * @param path
-     *            Path which uniquely identifies subtree which client want to
-     *            read
-     * @return Listenable Future which contains read result
+     * <p>
+     * If the target is a subtree, then the whole subtree is read (and will be accessible from the returned data
+     * object).
+     *
+     * @param store Logical data store from which read should occur.
+     * @param path Path which uniquely identifies subtree which client want to read
+     * @return a CheckFuture containing the result of the read. The Future blocks until the
+     *         commit operation is complete. Once complete:
+     *         <ul>
+     *         <li>If the data at the supplied path exists, the Future returns an Optional object
+     *         containing the data.</li>
+     *         <li>If the data at the supplied path does not exist, the Future returns
+     *         Optional#absent().</li>
+     *         <li>If the read of the data fails, the Future will fail with a
+     *         {@link ReadFailedException} or an exception derived from ReadFailedException.</li>
+     *         </ul>
+     */
+    <T extends DataObject> CheckedFuture<Optional<T>, ReadFailedException> read(
+            LogicalDatastoreType store, InstanceIdentifier<T> path);
+
+    /**
+     * Checks if data is available in the logical data store located at provided path.
+     *
+     * <p>
+     * Note: a successful result from this method makes no guarantee that a subsequent call to {@link #read}
+     * will succeed. It is possible that the data resides in a data store on a remote node and, if that
+     * node goes down or a network failure occurs, a subsequent read would fail. Another scenario is if
+     * the data is deleted in between the calls to <code>exists</code> and <code>read</code>
+     *
+     * <p>
+     * Default implementation delegates to {@link #read(LogicalDatastoreType, InstanceIdentifier)}, implementations
+     * are advised to provide a more efficient override.
+     *
+     * @param store Logical data store from which read should occur.
+     * @param path Path which uniquely identifies subtree which client want to check existence of
+     * @return a CheckFuture containing the result of the check.
      *         <ul>
-     *         <li>If data at supplied path exists the
-     *         {@link ListeblaFuture#get()} returns Optional object containing
-     *         data once read is done.
-     *         <li>If data at supplied path does not exists the
-     *         {@link ListenbleFuture#get()} returns {@link Optional#absent()}.
+     *         <li>If the data at the supplied path exists, the Future returns a Boolean
+     *         whose value is true, false otherwise</li>
+     *         <li>If checking for the data fails, the Future will fail with a
+     *         {@link ReadFailedException} or an exception derived from ReadFailedException.</li>
      *         </ul>
      */
-    <T extends DataObject> ListenableFuture<Optional<T>> read(LogicalDatastoreType store, InstanceIdentifier<T> path);
+    default CheckedFuture<Boolean, ReadFailedException> exists(final LogicalDatastoreType store,
+            final InstanceIdentifier<?> path) {
+        return MappingCheckedFuture.create(Futures.transform(read(store, path), Optional::isPresent,
+            MoreExecutors.directExecutor()), ReadFailedException.MAPPER);
+    }
 }