1 files changed, 53 insertions, 0 deletions
diff --git a/java/com/android/dialer/calllog/datasources/util/RowCombiner.java b/java/com/android/dialer/calllog/datasources/util/RowCombiner.java
new file mode 100644
index 000000000..0c7be1e27
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+++ b/java/com/android/dialer/calllog/datasources/util/RowCombiner.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * 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.android.dialer.calllog.datasources.util;
+
+import android.content.ContentValues;
+import com.android.dialer.common.Assert;
+import java.util.Iterator;
+import java.util.List;
+
+/** Convenience class for aggregating row values. */
+public class RowCombiner {
+  private final List<ContentValues> individualRowsSortedByTimestampDesc;
+  private final ContentValues combinedRow = new ContentValues();
+
+  public RowCombiner(List<ContentValues> individualRowsSortedByTimestampDesc) {
+    Assert.checkArgument(!individualRowsSortedByTimestampDesc.isEmpty());
+    this.individualRowsSortedByTimestampDesc = individualRowsSortedByTimestampDesc;
+  }
+
+  /** Use the most recent value for the specified column. */
+  public RowCombiner useMostRecentLong(String columnName) {
+    combinedRow.put(columnName, individualRowsSortedByTimestampDesc.get(0).getAsLong(columnName));
+    return this;
+  }
+
+  /** Asserts that all column values for the given column name are the same, and uses it. */
+  public RowCombiner useSingleValueString(String columnName) {
+    Iterator<ContentValues> iterator = individualRowsSortedByTimestampDesc.iterator();
+    String singleValue = iterator.next().getAsString(columnName);
+    while (iterator.hasNext()) {
+      Assert.checkState(iterator.next().getAsString(columnName).equals(singleValue));
+    }
+    combinedRow.put(columnName, singleValue);
+    return this;
+  }
+
+  public ContentValues combine() {
+    return combinedRow;
+  }
+}