UseCaseGroup.java
/*
* Copyright 2020 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 androidx.camera.core;
import static androidx.camera.core.CameraEffect.IMAGE_CAPTURE;
import static androidx.camera.core.CameraEffect.PREVIEW;
import static androidx.camera.core.CameraEffect.VIDEO_CAPTURE;
import static androidx.core.util.Preconditions.checkArgument;
import static java.util.Objects.requireNonNull;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.lifecycle.Lifecycle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
/**
* Represents a collection of {@link UseCase}.
*
* When the {@link UseCaseGroup} is bound to {@link Lifecycle}, it binds all the
* {@link UseCase}s to the same {@link Lifecycle}. {@link UseCase}s inside of a
* {@link UseCaseGroup} usually share some common properties like the FOV defined by
* {@link ViewPort}.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public final class UseCaseGroup {
@Nullable
private final ViewPort mViewPort;
@NonNull
private final List<UseCase> mUseCases;
@NonNull
private final List<CameraEffect> mEffects;
UseCaseGroup(@Nullable ViewPort viewPort, @NonNull List<UseCase> useCases,
@NonNull List<CameraEffect> effects) {
mViewPort = viewPort;
mUseCases = useCases;
mEffects = effects;
}
/**
* Gets the {@link ViewPort} shared by the {@link UseCase} collection.
*/
@Nullable
public ViewPort getViewPort() {
return mViewPort;
}
/**
* Gets the {@link UseCase}s.
*/
@NonNull
public List<UseCase> getUseCases() {
return mUseCases;
}
/**
* Gets the {@link CameraEffect}s.
*/
@NonNull
public List<CameraEffect> getEffects() {
return mEffects;
}
/**
* A builder for generating {@link UseCaseGroup}.
*/
public static final class Builder {
// Allow-list effect targets supported by CameraX.
private static final List<Integer> SUPPORTED_TARGETS = Arrays.asList(
PREVIEW,
IMAGE_CAPTURE);
private ViewPort mViewPort;
private final List<UseCase> mUseCases;
private final List<CameraEffect> mEffects;
public Builder() {
mUseCases = new ArrayList<>();
mEffects = new ArrayList<>();
}
/**
* Sets {@link ViewPort} shared by the {@link UseCase}s.
*/
@NonNull
public Builder setViewPort(@NonNull ViewPort viewPort) {
mViewPort = viewPort;
return this;
}
/**
* Adds a {@link CameraEffect} to the collection.
*
* <p>The value of {@link CameraEffect#getTargets()} must be unique and must be one of
* the supported values below:
* <ul>
* <li>{@link CameraEffect#PREVIEW}
* </ul>
*
* <p>Once added, CameraX will use the {@link CameraEffect}s to process the outputs of
* the {@link UseCase}s.
*/
@NonNull
public Builder addEffect(@NonNull CameraEffect cameraEffect) {
mEffects.add(cameraEffect);
return this;
}
/**
* Checks effect targets and throw {@link IllegalArgumentException}.
*
* <p>Throws exception if the effects 1) contains duplicate targets or 2) contains
* effects that is not in the allowlist.
*/
private void checkEffectTargets() {
Map<Integer, CameraEffect> targetEffectMap = new HashMap<>();
for (CameraEffect effect : mEffects) {
int targets = effect.getTargets();
if (!SUPPORTED_TARGETS.contains(targets)) {
throw new IllegalArgumentException(String.format(Locale.US,
"Target %s is not in the supported list %s.",
getHumanReadableTargets(targets),
getHumanReadableSupportedTargets()));
}
if (targetEffectMap.containsKey(effect.getTargets())) {
throw new IllegalArgumentException(String.format(Locale.US,
"%s and %s contain duplicate targets %s.",
requireNonNull(
targetEffectMap.get(effect.getTargets())).getClass().getName(),
effect.getClass().getName(),
getHumanReadableTargets(targets)));
}
targetEffectMap.put(effect.getTargets(), effect);
}
}
static String getHumanReadableSupportedTargets() {
List<String> targetNameList = new ArrayList<>();
for (Integer targets : SUPPORTED_TARGETS) {
targetNameList.add(getHumanReadableTargets(targets));
}
return "[" + String.join(", ", targetNameList) + "]";
}
static String getHumanReadableTargets(int targets) {
List<String> names = new ArrayList<>();
if ((targets & IMAGE_CAPTURE) != 0) {
names.add("IMAGE_CAPTURE");
}
if ((targets & PREVIEW) != 0) {
names.add("PREVIEW");
}
if ((targets & VIDEO_CAPTURE) != 0) {
names.add("VIDEO_CAPTURE");
}
return String.join("|", names);
}
/**
* Adds {@link UseCase} to the collection.
*/
@NonNull
public Builder addUseCase(@NonNull UseCase useCase) {
mUseCases.add(useCase);
return this;
}
/**
* Builds a {@link UseCaseGroup} from the current state.
*/
@NonNull
public UseCaseGroup build() {
checkArgument(!mUseCases.isEmpty(), "UseCase must not be empty.");
checkEffectTargets();
return new UseCaseGroup(mViewPort, mUseCases, mEffects);
}
}
}