Add a compatibility utility class for TextInfo

This is a groundwork for enabling LocaleSpan support in spell
checker service. TextInfo#getCharSequence is supposed to be
available in API Level 21 and later. We need some abstraction
layer as usual.

BUG: 16029304
Change-Id: Iafbf2877db393dbd040295c21d429334e3a13a5f

1 files changed, 59 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/compat/TextInfoCompatUtils.java b/java/src/com/android/inputmethod/compat/TextInfoCompatUtils.java
new file mode 100644
index 000000000..8bd919749
--- /dev/null
+++ b/java/src/com/android/inputmethod/compat/TextInfoCompatUtils.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2014 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.inputmethod.compat;
+
+import android.view.textservice.TextInfo;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.util.Locale;
+
+@UsedForTesting
+public final class TextInfoCompatUtils {
+    // Note that TextInfo.getCharSequence() is supposed to be available in API level 21 and later.
+    private static final Method TEXT_INFO_GET_CHAR_SEQUENCE =
+            CompatUtils.getMethod(TextInfo.class, "getCharSequence");
+    private static final Constructor<?> TEXT_INFO_CONSTRUCTOR_FOR_CHAR_SEQUENCE =
+            CompatUtils.getConstructor(TextInfo.class, CharSequence.class, int.class, int.class,
+                    int.class, int.class);
+
+    @UsedForTesting
+    public static boolean isCharSequenceSupported() {
+        return TEXT_INFO_GET_CHAR_SEQUENCE != null &&
+                TEXT_INFO_CONSTRUCTOR_FOR_CHAR_SEQUENCE != null;
+    }
+
+    @UsedForTesting
+    public static TextInfo newInstance(CharSequence charSequence, int start, int end, int cookie,
+            int sequenceNumber) {
+        if (TEXT_INFO_CONSTRUCTOR_FOR_CHAR_SEQUENCE != null) {
+            return (TextInfo) CompatUtils.newInstance(TEXT_INFO_CONSTRUCTOR_FOR_CHAR_SEQUENCE,
+                    charSequence, start, end, cookie, sequenceNumber);
+        }
+        return new TextInfo(charSequence.subSequence(start, end).toString(), cookie,
+                sequenceNumber);
+    }
+
+    @UsedForTesting
+    public static CharSequence getCharSequence(final TextInfo textInfo,
+            final CharSequence defaultValue) {
+        return (CharSequence) CompatUtils.invoke(textInfo, defaultValue,
+                TEXT_INFO_GET_CHAR_SEQUENCE);
+    }
+}