1 files changed, 33 insertions, 0 deletions
diff --git a/android/guava/src/com/google/common/collect/ImmutableMultiset.java b/android/guava/src/com/google/common/collect/ImmutableMultiset.java
index ecb8ae45b..b5e2e347e 100644
--- a/android/guava/src/com/google/common/collect/ImmutableMultiset.java
+++ b/android/guava/src/com/google/common/collect/ImmutableMultiset.java
@@ -33,6 +33,9 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.function.Function;
+import java.util.function.ToIntFunction;
+import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
@@ -56,6 +59,34 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 @ElementTypesAreNonnullByDefault
 public abstract class ImmutableMultiset<E> extends ImmutableMultisetGwtSerializationDependencies<E>
     implements Multiset<E> {
+
+  /**
+   * Returns a {@code Collector} that accumulates the input elements into a new {@code
+   * ImmutableMultiset}. Elements iterate in order by the <i>first</i> appearance of that element in
+   * encounter order.
+   */
+  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
+  @IgnoreJRERequirement // Users will use this only if they're already using streams.
+  static <E> Collector<E, ?, ImmutableMultiset<E>> toImmutableMultiset() {
+    return CollectCollectors.toImmutableMultiset(Function.identity(), e -> 1);
+  }
+
+  /**
+   * Returns a {@code Collector} that accumulates elements into an {@code ImmutableMultiset} whose
+   * elements are the result of applying {@code elementFunction} to the inputs, with counts equal to
+   * the result of applying {@code countFunction} to the inputs.
+   *
+   * <p>If the mapped elements contain duplicates (according to {@link Object#equals}), the first
+   * occurrence in encounter order appears in the resulting multiset, with count equal to the sum of
+   * the outputs of {@code countFunction.applyAsInt(t)} for each {@code t} mapped to that element.
+   */
+  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
+  @IgnoreJRERequirement // Users will use this only if they're already using streams.
+  static <T extends @Nullable Object, E> Collector<T, ?, ImmutableMultiset<E>> toImmutableMultiset(
+      Function<? super T, ? extends E> elementFunction, ToIntFunction<? super T> countFunction) {
+    return CollectCollectors.toImmutableMultiset(elementFunction, countFunction);
+  }
+
   /**
    * Returns the empty immutable multiset.
    *
@@ -636,4 +667,6 @@ public abstract class ImmutableMultiset<E> extends ImmutableMultisetGwtSerializa
       return new RegularImmutableMultiset<E>(contents);
     }
   }
+
+  private static final long serialVersionUID = 0xdecaf;
 }