1 files changed, 183 insertions, 0 deletions
diff --git a/java/com/google/android/libraries/mobiledatadownload/internal/DownloadGroupState.java b/java/com/google/android/libraries/mobiledatadownload/internal/DownloadGroupState.java
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+++ b/java/com/google/android/libraries/mobiledatadownload/internal/DownloadGroupState.java
@@ -0,0 +1,183 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.libraries.mobiledatadownload.internal;
+
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.mobiledatadownload.ClientConfigProto.ClientFileGroup;
+import com.google.mobiledatadownload.internal.MetadataProto.DataFileGroupInternal;
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+/** A helper class that includes information about the state of a file group download. */
+@Immutable
+public abstract class DownloadGroupState {
+  /** The kind of {@link DownloadGroupState}. */
+  public enum Kind {
+    /** A pending that hasn't been downloaded yet. */
+    PENDING_GROUP,
+
+    /** A pending group whose download has already stated. */
+    IN_PROGRESS_FUTURE,
+
+    /** A group that has already been downloaded. */
+    DOWNLOADED_GROUP,
+  }
+
+  public abstract Kind getKind();
+
+  public abstract DataFileGroupInternal pendingGroup();
+
+  public abstract ListenableFuture<ClientFileGroup> inProgressFuture();
+
+  public abstract ClientFileGroup downloadedGroup();
+
+  public static DownloadGroupState ofPendingGroup(DataFileGroupInternal dataFileGroup) {
+    return new ImplPendingGroup(dataFileGroup);
+  }
+
+  public static DownloadGroupState ofInProgressFuture(
+      ListenableFuture<ClientFileGroup> clientFileGroupFuture) {
+    return new ImplInProgressFuture(clientFileGroupFuture);
+  }
+
+  public static DownloadGroupState ofDownloadedGroup(ClientFileGroup clientFileGroup) {
+    return new ImplDownloadedGroup(clientFileGroup);
+  }
+
+  private DownloadGroupState() {}
+
+  // Parent class that each implementation will inherit from.
+  private abstract static class Parent extends DownloadGroupState {
+    @Override
+    public DataFileGroupInternal pendingGroup() {
+      throw new UnsupportedOperationException(getKind().toString());
+    }
+
+    @Override
+    public ListenableFuture<ClientFileGroup> inProgressFuture() {
+      throw new UnsupportedOperationException(getKind().toString());
+    }
+
+    @Override
+    public ClientFileGroup downloadedGroup() {
+      throw new UnsupportedOperationException(getKind().toString());
+    }
+  }
+
+  // Implementation when the contained property is "pendingGroup".
+  private static final class ImplPendingGroup extends Parent {
+    private final DataFileGroupInternal pendingGroup;
+
+    ImplPendingGroup(DataFileGroupInternal pendingGroup) {
+      this.pendingGroup = pendingGroup;
+    }
+
+    @Override
+    public DataFileGroupInternal pendingGroup() {
+      return pendingGroup;
+    }
+
+    @Override
+    public DownloadGroupState.Kind getKind() {
+      return DownloadGroupState.Kind.PENDING_GROUP;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object x) {
+      if (x instanceof DownloadGroupState) {
+        DownloadGroupState that = (DownloadGroupState) x;
+        return this.getKind() == that.getKind() && this.pendingGroup.equals(that.pendingGroup());
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public int hashCode() {
+      return pendingGroup.hashCode();
+    }
+  }
+
+  // Implementation when the contained property is "inProgressFuture".
+  private static final class ImplInProgressFuture extends Parent {
+    private final ListenableFuture<ClientFileGroup> inProgressFuture;
+
+    ImplInProgressFuture(ListenableFuture<ClientFileGroup> inProgressFuture) {
+      this.inProgressFuture = inProgressFuture;
+    }
+
+    @Override
+    public ListenableFuture<ClientFileGroup> inProgressFuture() {
+      return inProgressFuture;
+    }
+
+    @Override
+    public DownloadGroupState.Kind getKind() {
+      return DownloadGroupState.Kind.IN_PROGRESS_FUTURE;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object x) {
+      if (x instanceof DownloadGroupState) {
+        DownloadGroupState that = (DownloadGroupState) x;
+        return this.getKind() == that.getKind()
+            && this.inProgressFuture.equals(that.inProgressFuture());
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public int hashCode() {
+      return inProgressFuture.hashCode();
+    }
+  }
+
+  // Implementation when the contained property is "downloadedGroup".
+  private static final class ImplDownloadedGroup extends Parent {
+    private final ClientFileGroup downloadedGroup;
+
+    ImplDownloadedGroup(ClientFileGroup downloadedGroup) {
+      this.downloadedGroup = downloadedGroup;
+    }
+
+    @Override
+    public ClientFileGroup downloadedGroup() {
+      return downloadedGroup;
+    }
+
+    @Override
+    public DownloadGroupState.Kind getKind() {
+      return DownloadGroupState.Kind.DOWNLOADED_GROUP;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object x) {
+      if (x instanceof DownloadGroupState) {
+        DownloadGroupState that = (DownloadGroupState) x;
+        return this.getKind() == that.getKind()
+            && this.downloadedGroup.equals(that.downloadedGroup());
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public int hashCode() {
+      return downloadedGroup.hashCode();
+    }
+  }
+}