Avoid storing Iterable<Blob> in BlobListResult

googleapis · Sep 23, 2015 · c1f018c · c1f018c
1 parent 44cefb0
commit c1f018c
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Showing 2 changed files with 34 additions and 27 deletions.
diff --git a/gcloud-java-storage/src/main/java/com/google/gcloud/storage/BlobListResult.java b/gcloud-java-storage/src/main/java/com/google/gcloud/storage/BlobListResult.java
@@ -16,9 +16,9 @@
 
 package com.google.gcloud.storage;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
 import java.util.Objects;
 
 /**
@@ -27,13 +27,35 @@
 public class BlobListResult implements ListResult<Blob> {
 
   private final ListResult<BlobInfo> infoList;
-  private final transient Storage storage;
-  private transient List<Blob> results;
+  private final Storage storage;
+
+  private class BlobListIterator implements Iterator<Blob> {
+
+    private final Iterator<BlobInfo> blobInfoIterator;
+
+    public BlobListIterator() {
+      this.blobInfoIterator = infoList.iterator();
+    }
+
+    @Override
+    public boolean hasNext() {
+      return blobInfoIterator.hasNext();
+    }
+
+    @Override
+    public Blob next() {
+      return new Blob(storage, blobInfoIterator.next());
+    }
+
+    @Override
+    public void remove() {
+      blobInfoIterator.remove();
+    }
+  }
 
   public BlobListResult(Storage storage, ListResult<BlobInfo> infoList) {
-    this.storage = storage;
-    this.infoList = infoList;
-    this.results = null;
+    this.storage = checkNotNull(storage);
+    this.infoList = checkNotNull(infoList);
   }
 
   @Override
@@ -52,13 +74,7 @@ public ListResult<Blob> nextPage() {
 
   @Override
   public Iterator<Blob> iterator() {
-    if (results == null) {
-      this.results = new LinkedList<>();
-      for (Iterator<BlobInfo> it = infoList.iterator(); it.hasNext();) {
-        results.add(new Blob(storage, it.next()));
-      }
-    }
-    return results.iterator();
+    return new BlobListIterator();
   }
 
   @Override

diff --git a/gcloud-java-storage/src/main/java/com/google/gcloud/storage/ListResult.java b/gcloud-java-storage/src/main/java/com/google/gcloud/storage/ListResult.java
@@ -16,28 +16,19 @@
 
 package com.google.gcloud.storage;
 
-import java.util.Iterator;
-
 /**
  * Interface for Google Cloud storage list result.
  */
 public interface ListResult<T> extends Iterable<T> {
 
   /**
-   * Returns the cursor for the nextPage or {@code null} if no more results.
-   * 
-   * @return the string cursor for next page
+   * Return the cursor for the nextPage or {@code null} if no more results.
    */
-  public String nextPageCursor();
+  String nextPageCursor();
 
   /**
-   * Returns the results of the nextPage or {@code null} if no more result.
-   * 
-   * @return the {@code ListResult} object for the next page
+   * Return the results of the nextPage or {@code null} if no more result.
    */
-  public ListResult<T> nextPage();
-
-  @Override
-  public Iterator<T> iterator();
+  ListResult<T> nextPage();
 
 }