Add toMap to Access interface to simplify fast lookups
Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/com/google/gwtorm/client/Access.java b/src/com/google/gwtorm/client/Access.java
index ff8058e..98776ee 100644
--- a/src/com/google/gwtorm/client/Access.java
+++ b/src/com/google/gwtorm/client/Access.java
@@ -14,6 +14,8 @@
package com.google.gwtorm.client;
+import java.util.Map;
+
/**
* Data access interface for an entity type.
* <p>
@@ -55,6 +57,14 @@
K primaryKey(T entity);
/**
+ * Convert a collection of objects into a map, keyed by their primary key.
+ *
+ * @param c the collection
+ * @return a map of the objects, indexed by their primary key.
+ */
+ Map<K, T> toMap(Iterable<T> c);
+
+ /**
* Lookup a single entity via its primary key.
* <p>
* This method is only implemented if the entity's primary key is defined to
diff --git a/src/com/google/gwtorm/client/impl/AbstractAccess.java b/src/com/google/gwtorm/client/impl/AbstractAccess.java
index 237feef..9103773 100644
--- a/src/com/google/gwtorm/client/impl/AbstractAccess.java
+++ b/src/com/google/gwtorm/client/impl/AbstractAccess.java
@@ -21,6 +21,8 @@
import com.google.gwtorm.client.Transaction;
import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
public abstract class AbstractAccess<E, K extends Key<?>, T extends AbstractTransaction>
implements Access<E, K> {
@@ -35,6 +37,20 @@
return new ListResultSet<E>(r);
}
+ public Map<K, E> toMap(final Iterable<E> c) {
+ try {
+ final HashMap<K, E> r = new HashMap<K, E>();
+ for (final E e : c) {
+ r.put(primaryKey(e), e);
+ }
+ return r;
+ } finally {
+ if (c instanceof ResultSet) {
+ ((ResultSet<?>) c).close();
+ }
+ }
+ }
+
public final void insert(final Iterable<E> instances) throws OrmException {
doInsert(instances, null);
}
