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 androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.core.util.Preconditions;
import androidx.lifecycle.Lifecycle;
import java.util.ArrayList;
import java.util.List;
/**
* 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;
UseCaseGroup(@Nullable ViewPort viewPort, @NonNull List<UseCase> useCases) {
mViewPort = viewPort;
mUseCases = useCases;
}
/**
* 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;
}
/**
* A builder for generating {@link UseCaseGroup}.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public static final class Builder {
private ViewPort mViewPort;
private final List<UseCase> mUseCases;
public Builder() {
mUseCases = new ArrayList<>();
}
/**
* Sets {@link ViewPort} shared by the {@link UseCase}s.
*/
@NonNull
public Builder setViewPort(@NonNull ViewPort viewPort) {
mViewPort = viewPort;
return this;
}
/**
* 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() {
Preconditions.checkArgument(!mUseCases.isEmpty(), "UseCase must not be empty.");
return new UseCaseGroup(mViewPort, mUseCases);
}
}
}