1 files changed, 82 insertions, 0 deletions
diff --git a/sample_updater/src/com/example/android/systemupdatersample/util/UpdateConfigs.java b/sample_updater/src/com/example/android/systemupdatersample/util/UpdateConfigs.java
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index 000000000..089f8b2f2
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+++ b/sample_updater/src/com/example/android/systemupdatersample/util/UpdateConfigs.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2018 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.example.android.systemupdatersample.util;
+
+import android.content.Context;
+
+import com.example.android.systemupdatersample.UpdateConfig;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Utility class for working with json update configurations.
+ */
+public final class UpdateConfigs {
+
+    private static final String UPDATE_CONFIGS_ROOT = "configs/";
+
+    /**
+     * @param configs update configs
+     * @return list of names
+     */
+    public static String[] configsToNames(List<UpdateConfig> configs) {
+        return configs.stream().map(UpdateConfig::getName).toArray(String[]::new);
+    }
+
+    /**
+     * @param context app context
+     * @return configs root directory
+     */
+    public static String getConfigsRoot(Context context) {
+        return Paths.get(context.getFilesDir().toString(),
+                UPDATE_CONFIGS_ROOT).toString();
+    }
+
+    /**
+     * It parses only {@code .json} files.
+     *
+     * @param context application context
+     * @return list of configs from directory {@link UpdateConfigs#getConfigsRoot}
+     */
+    public static List<UpdateConfig> getUpdateConfigs(Context context) {
+        File root = new File(getConfigsRoot(context));
+        ArrayList<UpdateConfig> configs = new ArrayList<>();
+        if (!root.exists()) {
+            return configs;
+        }
+        for (final File f : root.listFiles()) {
+            if (!f.isDirectory() && f.getName().endsWith(".json")) {
+                try {
+                    String json = new String(Files.readAllBytes(f.toPath()),
+                            StandardCharsets.UTF_8);
+                    configs.add(UpdateConfig.fromJson(json));
+                } catch (Exception e) {
+                    throw new RuntimeException(
+                            "Can't read/parse config file " + f.getName(), e);
+                }
+            }
+        }
+        return configs;
+    }
+
+    private UpdateConfigs() {}
+}