Initial implementation of the new Save APIs.

Test: manual verification with sample app (CTS tests coming later)

Bug: 62534917

Change-Id: I085a9c933bb5e8316d673976e059e13abd7098e5
diff --git a/core/java/android/service/autofill/RequiredValidators.java b/core/java/android/service/autofill/RequiredValidators.java
new file mode 100644
index 0000000..f2b7db8
--- /dev/null
+++ b/core/java/android/service/autofill/RequiredValidators.java
@@ -0,0 +1,94 @@
+/*
+ * 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 static android.view.autofill.Helper.sDebug;
+
+import android.annotation.NonNull;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import com.android.internal.util.Preconditions;
+
+/**
+ * Compound validator that only returns {@code true} on {@link #isValid(ValueFinder)} if all
+ * of its subvalidators return {@code true} as well.
+ *
+ * <p>Used to implement an {@code AND} logical operation.
+ *
+ * @hide
+ */
+final class RequiredValidators extends InternalValidator {
+
+    private final InternalValidator[] mValidators;
+
+    RequiredValidators(@NonNull InternalValidator[] validators) {
+        mValidators = Preconditions.checkArrayElementsNotNull(validators, "validators");
+    }
+
+    @Override
+    public boolean isValid(@NonNull ValueFinder finder) {
+        if (mValidators == null) {
+            return true;
+        }
+        // TODO(b/62534917): handle errors, like not finding the ID
+        for (InternalValidator validator : mValidators) {
+            final boolean valid = validator.isValid(finder);
+            if (!valid) return false;
+        }
+        return true;
+    }
+
+    /////////////////////////////////////
+    // Object "contract" methods. //
+    /////////////////////////////////////
+    @Override
+    public String toString() {
+        if (!sDebug) return super.toString();
+
+        return new StringBuilder("RequiredValidators: [validators=").append(mValidators)
+                .append("]")
+                .toString();
+    }
+
+    /////////////////////////////////////
+    // Parcelable "contract" methods. //
+    /////////////////////////////////////
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeParcelableArray(mValidators, flags);
+    }
+
+    public static final Parcelable.Creator<RequiredValidators> CREATOR =
+            new Parcelable.Creator<RequiredValidators>() {
+        @Override
+        public RequiredValidators createFromParcel(Parcel parcel) {
+            return new RequiredValidators(parcel
+                .readParcelableArray(null, InternalValidator.class));
+        }
+
+        @Override
+        public RequiredValidators[] newArray(int size) {
+            return new RequiredValidators[size];
+        }
+    };
+}