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/*
* 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.android.car.internal;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* Represent listeners for a property grouped by their rate.
* T is a type of EventListener such as CarPropertyEventListener
* in {@link android.car.hardware.property.CarPropertyManager}
* @param <T>
* @hide
*/
public class CarRatedFloatListeners<T> {
private final Map<T, Float> mListenersToRate = new HashMap<>(4);
private float mUpdateRate;
protected long mLastUpdateTime = -1;
protected CarRatedFloatListeners(float rate) {
mUpdateRate = rate;
}
/** Check listener */
public boolean contains(T listener) {
return mListenersToRate.containsKey(listener);
}
/** Return current rate after updating */
public float getRate() {
return mUpdateRate;
}
/**
* Remove given listener from the list and update rate if necessary.
*
* @param listener
* @return true if rate was updated. Otherwise, returns false.
*/
public boolean remove(T listener) {
mListenersToRate.remove(listener);
if (mListenersToRate.isEmpty()) {
return false;
}
Float updateRate = Collections.max(mListenersToRate.values());
if (updateRate != mUpdateRate) {
mUpdateRate = updateRate;
return true;
}
return false;
}
public boolean isEmpty() {
return mListenersToRate.isEmpty();
}
/**
* Add given listener to the list and update rate if necessary.
*
* @param listener if null, add part is skipped.
* @param updateRate
* @return true if rate was updated. Otherwise, returns false.
*/
public boolean addAndUpdateRate(T listener, float updateRate) {
Float oldUpdateRate = mListenersToRate.put(listener, updateRate);
if (mUpdateRate < updateRate) {
mUpdateRate = updateRate;
return true;
} else if (oldUpdateRate != null && oldUpdateRate == mUpdateRate) {
mUpdateRate = Collections.max(mListenersToRate.values());
}
return false;
}
public Collection<T> getListeners() {
return mListenersToRate.keySet();
}
}