1 files changed, 97 insertions, 0 deletions
diff --git a/android/service/autofill/EditDistanceScorer.java b/android/service/autofill/EditDistanceScorer.java
new file mode 100644
index 00000000..0706b377
--- /dev/null
+++ b/android/service/autofill/EditDistanceScorer.java
@@ -0,0 +1,97 @@
+/*
+ * 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 android.service.autofill;
+
+import android.annotation.NonNull;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.view.autofill.AutofillValue;
+
+/**
+ * Helper used to calculate the classification score between an actual {@link AutofillValue} filled
+ * by the user and the expected value predicted by an autofill service.
+ */
+// TODO(b/70291841): explain algorithm once it's fully implemented
+public final class EditDistanceScorer extends InternalScorer implements Scorer, Parcelable {
+
+    private static final EditDistanceScorer sInstance = new EditDistanceScorer();
+
+    /**
+     * Gets the singleton instance.
+     */
+    public static EditDistanceScorer getInstance() {
+        return sInstance;
+    }
+
+    private EditDistanceScorer() {
+    }
+
+    /** @hide */
+    @Override
+    public float getScore(@NonNull AutofillValue actualValue, @NonNull String userData) {
+        if (actualValue == null || !actualValue.isText() || userData == null) return 0;
+        // TODO(b/70291841): implement edit distance - currently it's returning either 0, 100%, or
+        // partial match when number of chars match
+        final String textValue = actualValue.getTextValue().toString();
+        final int total = textValue.length();
+        if (total != userData.length()) return 0F;
+
+        int matches = 0;
+        for (int i = 0; i < total; i++) {
+            if (Character.toLowerCase(textValue.charAt(i)) == Character
+                    .toLowerCase(userData.charAt(i))) {
+                matches++;
+            }
+        }
+
+        return ((float) matches) / total;
+    }
+
+    /////////////////////////////////////
+    // Object "contract" methods. //
+    /////////////////////////////////////
+    @Override
+    public String toString() {
+        return "EditDistanceScorer";
+    }
+
+    /////////////////////////////////////
+    // Parcelable "contract" methods. //
+    /////////////////////////////////////
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel parcel, int flags) {
+        // Do nothing
+    }
+
+    public static final Parcelable.Creator<EditDistanceScorer> CREATOR =
+            new Parcelable.Creator<EditDistanceScorer>() {
+        @Override
+        public EditDistanceScorer createFromParcel(Parcel parcel) {
+            return EditDistanceScorer.getInstance();
+        }
+
+        @Override
+        public EditDistanceScorer[] newArray(int size) {
+            return new EditDistanceScorer[size];
+        }
+    };
+}