/* * 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.car.oem.focus; import static android.media.AudioManager.AUDIOFOCUS_FLAG_DELAY_OK; import static android.media.AudioManager.AUDIOFOCUS_GAIN; import static android.media.AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK; import static android.media.AudioManager.AUDIOFOCUS_REQUEST_DELAYED; import static android.media.AudioManager.AUDIOFOCUS_REQUEST_FAILED; import static android.media.AudioManager.AUDIOFOCUS_REQUEST_GRANTED; import static com.android.car.oem.utils.AudioUtils.getAudioAttributeFromUsage; import android.car.oem.AudioFocusEntry; import android.car.oem.OemCarAudioFocusEvaluationRequest; import android.car.oem.OemCarAudioFocusResult; import android.media.AudioAttributes; import android.media.AudioFocusInfo; import android.media.AudioManager; import android.util.ArrayMap; import android.util.Log; import android.util.Slog; import com.android.car.oem.utils.AudioAttributesWrapper; import com.android.car.oem.utils.AudioUtils; import java.io.PrintWriter; import java.util.ArrayList; import java.util.List; import java.util.Set; /** * FocusInteraction is responsible for evaluating how incoming focus requests should be handled * based on pre-defined interaction behaviors for each incoming {@link AudioAttributes} * in relation to a {@link AudioAttributes} that is currently holding focus. */ public final class FocusInteraction { private static final String TAG = FocusInteraction.class.getSimpleName(); // Values for the internal interaction matrix we use to make focus decisions private static final int INTERACTION_INVALID = -2; // Focus not granted /** * Value for the interaction matrix for rejecting incoming focus request. Focus not granted. */ public static final int INTERACTION_REJECT = -1; /** * Value for the interaction matrix for granting exclusive access to incoming focus request. * Focus granted, others lose focus */ public static final int INTERACTION_EXCLUSIVE = 1; /** * Value for the interaction matrix for concurrent focus, incoming focus request and current * focus holders will concurrently hold focus. Focus granted, others keep focus. */ public static final int INTERACTION_CONCURRENT = 2; static final AudioAttributes[] MUSIC_ATTRIBUTES = new AudioAttributes[] { getAudioAttributeFromUsage(AudioAttributes.USAGE_UNKNOWN), getAudioAttributeFromUsage(AudioAttributes.USAGE_GAME), getAudioAttributeFromUsage(AudioAttributes.USAGE_MEDIA) }; static final AudioAttributes[] NAVIGATION_ATTRIBUTES = new AudioAttributes[] { getAudioAttributeFromUsage(AudioAttributes .USAGE_ASSISTANCE_NAVIGATION_GUIDANCE) }; static final AudioAttributes[] VOICE_COMMAND_ATTRIBUTES = new AudioAttributes[] { getAudioAttributeFromUsage(AudioAttributes.USAGE_ASSISTANCE_ACCESSIBILITY), getAudioAttributeFromUsage(AudioAttributes.USAGE_ASSISTANT) }; static final AudioAttributes[] CALL_RING_ATTRIBUTES = new AudioAttributes[] { getAudioAttributeFromUsage(AudioAttributes.USAGE_NOTIFICATION_RINGTONE), }; static final AudioAttributes[] CALL_ATTRIBUTES = new AudioAttributes[] { getAudioAttributeFromUsage(AudioAttributes.USAGE_VOICE_COMMUNICATION), getAudioAttributeFromUsage(AudioAttributes.USAGE_CALL_ASSISTANT), getAudioAttributeFromUsage(AudioAttributes .USAGE_VOICE_COMMUNICATION_SIGNALLING) }; static final AudioAttributes[] ALARM_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_ALARM) }; static final AudioAttributes[] NOTIFICATION_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_NOTIFICATION), getAudioAttributeFromUsage(AudioAttributes.USAGE_NOTIFICATION_EVENT) }; static final AudioAttributes[] SYSTEM_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_ASSISTANCE_SONIFICATION) }; static final AudioAttributes[] EMERGENCY_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_EMERGENCY) }; static final AudioAttributes[] SAFETY_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_SAFETY) }; static final AudioAttributes[] VEHICLE_STATUS_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_VEHICLE_STATUS) }; static final AudioAttributes[] ANNOUNCEMENT_ATTRIBUTES = new AudioAttributes[]{ getAudioAttributeFromUsage(AudioAttributes.USAGE_ANNOUNCEMENT) }; private static final int[][] INTERACTION_MATRIX = { // Each Row represents audio group of current focus holder // Each Column represents audio group of incoming request (labels along the right) // Cell value is one of INTERACTION_REJECT, INTERACTION_EXCLUSIVE, // or INTERACTION_CONCURRENT // Focus holder: MUSIC { INTERACTION_EXCLUSIVE, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_EXCLUSIVE, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_EXCLUSIVE, // ANNOUNCEMENT }, // Focus holder: NAVIGATION { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_CONCURRENT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_CONCURRENT, // ANNOUNCEMENT }, // Focus holder: VOICE_COMMAND { INTERACTION_CONCURRENT, // MUSIC INTERACTION_REJECT, // NAVIGATION INTERACTION_CONCURRENT, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_REJECT, // ALARM INTERACTION_REJECT, // NOTIFICATION INTERACTION_REJECT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_REJECT, // ANNOUNCEMENT }, // Focus holder: CALL_RING { INTERACTION_REJECT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_CONCURRENT, // VOICE_COMMAND INTERACTION_CONCURRENT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_REJECT, // ALARM INTERACTION_REJECT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_REJECT, // ANNOUNCEMENT }, // Focus holder: CALL { INTERACTION_REJECT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_REJECT, // VOICE_COMMAND INTERACTION_CONCURRENT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_REJECT, // SYSTEM_SOUND INTERACTION_CONCURRENT, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_REJECT, // ANNOUNCEMENT }, // Focus holder: ALARM { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_REJECT, // ANNOUNCEMENT }, // Focus holder: NOTIFICATION { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_CONCURRENT, // ANNOUNCEMENT }, // Focus holder: SYSTEM_SOUND { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_CONCURRENT, // ANNOUNCEMENT }, // Focus holder: EMERGENCY { INTERACTION_REJECT, // MUSIC INTERACTION_REJECT, // NAVIGATION INTERACTION_REJECT, // VOICE_COMMAND INTERACTION_REJECT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_REJECT, // ALARM INTERACTION_REJECT, // NOTIFICATION INTERACTION_REJECT, // SYSTEM_SOUND INTERACTION_CONCURRENT, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_REJECT, // VEHICLE_STATUS INTERACTION_REJECT, // ANNOUNCEMENT }, // Focus holder: SAFETY { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_CONCURRENT, // VOICE_COMMAND INTERACTION_CONCURRENT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_CONCURRENT, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_CONCURRENT, // ANNOUNCEMENT }, // Focus holder: VEHICLE_STATUS { INTERACTION_CONCURRENT, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_CONCURRENT, // VOICE_COMMAND INTERACTION_CONCURRENT, // CALL_RING INTERACTION_CONCURRENT, // CALL INTERACTION_CONCURRENT, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_CONCURRENT, // ANNOUNCEMENT }, // Focus holder: ANNOUNCEMENT { INTERACTION_EXCLUSIVE, // MUSIC INTERACTION_CONCURRENT, // NAVIGATION INTERACTION_EXCLUSIVE, // VOICE_COMMAND INTERACTION_EXCLUSIVE, // CALL_RING INTERACTION_EXCLUSIVE, // CALL INTERACTION_EXCLUSIVE, // ALARM INTERACTION_CONCURRENT, // NOTIFICATION INTERACTION_CONCURRENT, // SYSTEM_SOUND INTERACTION_EXCLUSIVE, // EMERGENCY INTERACTION_CONCURRENT, // SAFETY INTERACTION_CONCURRENT, // VEHICLE_STATUS INTERACTION_EXCLUSIVE, // ANNOUNCEMENT }, }; /** * Attributes interaction resembling default interaction in car audio service. * *

The key are the audio attribute for current focus holder. The value is another map for * the possible interactions for the incoming focus request. The latter map has the * incoming audio attribute as the key, its value is the actual interaction * {@code INTERACTION_REJECT}, {@code INTERACTION_EXCLUSIVE}, or {@code INTERACTION_CONCURRENT}. */ public static final ArrayMap> ATTRIBUTES_INTERACTIONS = new ArrayMap<>(); private final ArrayMap> mHolderToIncomingAttributesInteractions; static { List interactionsGroups = List.of( MUSIC_ATTRIBUTES, NAVIGATION_ATTRIBUTES, VOICE_COMMAND_ATTRIBUTES, CALL_RING_ATTRIBUTES, CALL_ATTRIBUTES, ALARM_ATTRIBUTES, NOTIFICATION_ATTRIBUTES, SYSTEM_ATTRIBUTES, EMERGENCY_ATTRIBUTES, SAFETY_ATTRIBUTES, VEHICLE_STATUS_ATTRIBUTES, ANNOUNCEMENT_ATTRIBUTES ); for (int group = 0; group < interactionsGroups.size(); group++) { AudioAttributes[] holderAttributes = interactionsGroups.get(group); for (int index = 0; index < holderAttributes.length; index++) { ArrayMap attributeInteractions = getAudioAttributesInteractions(interactionsGroups, group); ATTRIBUTES_INTERACTIONS.put(holderAttributes[index], attributeInteractions); } } } private static ArrayMap getAudioAttributesInteractions( List interactionsGroups, int group) { ArrayMap attributeInteractions = new ArrayMap<>(); for (int incomingGroup = 0; incomingGroup < interactionsGroups.size(); incomingGroup++) { AudioAttributes[] incomingAttributes = interactionsGroups.get(incomingGroup); Integer interaction = INTERACTION_MATRIX[group][incomingGroup]; for (int index = 0; index < incomingAttributes.length; index++) { attributeInteractions.put(incomingAttributes[index], interaction); } } return attributeInteractions; } /** * Constructs a focus interaction instance. */ public FocusInteraction(ArrayMap> audioAttributesInteractions) { mHolderToIncomingAttributesInteractions = new ArrayMap<>(); for (int holderIndex = 0; holderIndex < audioAttributesInteractions.size(); holderIndex++) { ArrayMap interactions = audioAttributesInteractions.valueAt(holderIndex); AudioAttributesWrapper holderWrapper = new AudioAttributesWrapper(audioAttributesInteractions.keyAt(holderIndex)); ArrayMap wrappedInteractions = new ArrayMap<>(); for (int incomingIndex = 0; incomingIndex < interactions.size(); incomingIndex++) { wrappedInteractions .put(new AudioAttributesWrapper(interactions.keyAt(incomingIndex)), interactions.valueAt(incomingIndex)); } mHolderToIncomingAttributesInteractions.put(holderWrapper, wrappedInteractions); } } /** * Evaluates interaction between incoming focus {@link OemCarAudioFocusEvaluationRequest} * and the current focus request based on interaction matrix. */ public OemCarAudioFocusResult evaluateFocusRequest(OemCarAudioFocusEvaluationRequest request) { FocusEvaluation holdersEvaluation = evaluateAgainstFocusList(request.getAudioFocusRequest(), request.getFocusHolders(), /* evalTag= */ "holders"); if (holdersEvaluation.equals(FocusEvaluation.FOCUS_EVALUATION_FAILED)) { return OemCarAudioFocusResult.EMPTY_OEM_CAR_AUDIO_FOCUS_RESULTS; } FocusEvaluation losersEvaluation = evaluateAgainstFocusList(request.getAudioFocusRequest(), request.getFocusLosers(), /* evalTag= */ "losers"); if (losersEvaluation.equals(FocusEvaluation.FOCUS_EVALUATION_FAILED)) { return OemCarAudioFocusResult.EMPTY_OEM_CAR_AUDIO_FOCUS_RESULTS; } boolean delayFocus = holdersEvaluation.mAudioFocusEvalResults == AUDIOFOCUS_REQUEST_DELAYED || losersEvaluation.mAudioFocusEvalResults == AUDIOFOCUS_REQUEST_DELAYED; int results = delayFocus ? AUDIOFOCUS_REQUEST_DELAYED : AUDIOFOCUS_REQUEST_GRANTED; AudioFocusEntry currenRequest = request.getAudioFocusRequest(); AudioFocusEntry focusEntry = new AudioFocusEntry.Builder(currenRequest.getAudioFocusInfo(), currenRequest.getAudioContextId(), currenRequest.getAudioVolumeGroupId(), AUDIOFOCUS_GAIN).build(); return new OemCarAudioFocusResult.Builder(holdersEvaluation.mChangedEntries, losersEvaluation.mChangedEntries, results).setAudioFocusEntry(focusEntry) .build(); } private FocusEvaluation evaluateAgainstFocusList(AudioFocusEntry request, List focusEntries, String evalTag) { boolean delayFocusForCurrentRequest = false; if (Log.isLoggable(TAG, Log.DEBUG)) { Slog.d(TAG, "Scanning focus " + evalTag); } ArrayList changed = new ArrayList(); for (int index = 0; index < focusEntries.size(); index++) { AudioFocusEntry entry = focusEntries.get(index); if (Log.isLoggable(TAG, Log.DEBUG)) { Slog.d(TAG, "Evaluating focus entry: " + entry); } int interactionResult = evaluateRequest(request, entry, changed); switch (interactionResult) { case AUDIOFOCUS_REQUEST_FAILED: return FocusEvaluation.FOCUS_EVALUATION_FAILED; case AUDIOFOCUS_REQUEST_DELAYED: delayFocusForCurrentRequest = true; // fall through case AUDIOFOCUS_REQUEST_GRANTED: // fall through default: continue; } } int results = delayFocusForCurrentRequest ? AUDIOFOCUS_REQUEST_DELAYED : AUDIOFOCUS_REQUEST_GRANTED; return new FocusEvaluation(changed, results); } /** * Evaluates interaction between incoming focus {@link AudioFocusEntry} and the current focus * request based on interaction matrix. * *

Note: In addition to returning the request results * for the incoming request based on this interaction, this method also adds the current {@code * focusHolder} to the {@code focusLosers} list when appropriate. * * @param request {@link AudioFocusEntry} to evaluate * @param focusHolder {@link AudioFocusEntry} for current focus holder * @param focusLosers Mutable array to add focusHolder to if it should lose focus * @return result of focus interaction, can be any of {@code AUDIOFOCUS_REQUEST_DELAYED}, * {@code AUDIOFOCUS_REQUEST_FAILED}, or {@code AUDIOFOCUS_REQUEST_GRANTED} */ private int evaluateRequest(AudioFocusEntry request, AudioFocusEntry focusHolder, List focusLosers) { boolean allowDucking = canReceiveDucking(request.getAudioFocusInfo()); boolean allowsDelayedFocus = canReceiveDelayedFocus(request.getAudioFocusInfo()); AudioAttributesWrapper holderAttribute = new AudioAttributesWrapper(focusHolder.getAudioFocusInfo().getAttributes()); AudioAttributesWrapper requestAttribute = new AudioAttributesWrapper(request.getAudioFocusInfo().getAttributes()); int interaction = mHolderToIncomingAttributesInteractions .get(holderAttribute).getOrDefault(requestAttribute, INTERACTION_INVALID); switch (interaction) { case INTERACTION_REJECT: return allowsDelayedFocus ? AUDIOFOCUS_REQUEST_DELAYED : AUDIOFOCUS_REQUEST_FAILED; case INTERACTION_EXCLUSIVE: focusLosers.add(focusHolder); return AUDIOFOCUS_REQUEST_GRANTED; case INTERACTION_CONCURRENT: // If ducking isn't allowed by the focus requester, then everybody else // must get a LOSS. // If a focus holder has set the AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS flag, // they must get a LOSS message even if ducking would otherwise be allowed. // If a focus holder holds the RECEIVE_CAR_AUDIO_DUCKING_EVENTS permission, // they must receive all audio focus losses. if (!allowDucking || wantsPauseInsteadOfDucking(focusHolder.getAudioFocusInfo())) { focusLosers.add(focusHolder); } return AUDIOFOCUS_REQUEST_GRANTED; default: Slog.e(TAG, "Unsupported attributes " + request + " - rejecting request"); return AUDIOFOCUS_REQUEST_FAILED; } } private boolean canReceiveDucking(AudioFocusInfo audioFocusInfo) { return (audioFocusInfo.getGainRequest() == AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK); } private boolean canReceiveDelayedFocus(AudioFocusInfo audioFocusInfo) { if (audioFocusInfo.getGainRequest() != AUDIOFOCUS_GAIN) { return false; } return (audioFocusInfo.getFlags() & AUDIOFOCUS_FLAG_DELAY_OK) == AUDIOFOCUS_FLAG_DELAY_OK; } private boolean wantsPauseInsteadOfDucking(AudioFocusInfo focusHolder) { return (focusHolder.getFlags() & AudioManager.AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS) != 0; } public void dump(PrintWriter writer, String indent) { writer.printf("%sInteractions: \n", indent); Set audioAttributesWrapperSet = mHolderToIncomingAttributesInteractions.keySet(); for (AudioAttributesWrapper holder : audioAttributesWrapperSet) { String holderUsageString = AudioUtils.getUsageString(holder.getAudioAttributes()); writer.printf("%s%sHolder: %s\n", indent, indent, holderUsageString); for (AudioAttributesWrapper incoming : audioAttributesWrapperSet) { String incomingUsageString = AudioUtils.getUsageString(incoming .getAudioAttributes()); String interaction = getInteractionString( mHolderToIncomingAttributesInteractions.get(holder).get(incoming)); writer.printf("%s%s%sIncoming: %s interaction %s\n", indent, indent, indent, incomingUsageString, interaction); } writer.flush(); } } private static String getInteractionString(int interaction) { switch (interaction) { case INTERACTION_CONCURRENT: return "CONCURRENT"; case INTERACTION_EXCLUSIVE: return "EXCLUSIVE"; case INTERACTION_REJECT: return "REJECT"; case INTERACTION_INVALID: // fall through default: return "INVALID"; } } private static final class FocusEvaluation { private static final FocusEvaluation FOCUS_EVALUATION_FAILED = new FocusEvaluation(/* changedEntries= */ new ArrayList<>(/* initialCap= */ 0), AUDIOFOCUS_REQUEST_FAILED); private final List mChangedEntries; private final int mAudioFocusEvalResults; FocusEvaluation(List changedEntries, int audioFocusEvalResults) { mChangedEntries = changedEntries; mAudioFocusEvalResults = audioFocusEvalResults; } @Override public String toString() { return new StringBuilder().append("{Changed Entries: ").append(mChangedEntries) .append(", Results: ").append(mAudioFocusEvalResults) .append(" }").toString(); } } }