src/com/android/quicksearchbox/util/AsyncDataSetObservable.kt

/*
 * Copyright (C) 2022 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.quicksearchbox.util

import android.database.DataSetObservable
import android.os.Handler

/**
 * A version of [DataSetObservable] that performs callbacks on given [Handler].
 */
class AsyncDataSetObservable(handler: Handler?) : DataSetObservable() {
    private val mHandler: Handler?
    private val mChangedRunnable: Runnable = object : Runnable() {
        fun run() {
            super@AsyncDataSetObservable.notifyChanged()
        }
    }
    private val mInvalidatedRunnable: Runnable = object : Runnable() {
        fun run() {
            super@AsyncDataSetObservable.notifyInvalidated()
        }
    }

    @Override
    fun notifyChanged() {
        if (mHandler == null) {
            super.notifyChanged()
        } else {
            mHandler.post(mChangedRunnable)
        }
    }

    @Override
    fun notifyInvalidated() {
        if (mHandler == null) {
            super.notifyInvalidated()
        } else {
            mHandler.post(mInvalidatedRunnable)
        }
    }

    /**
     * @param handler Handler to run callbacks on.
     */
    init {
        mHandler = handler
    }
}