Lane.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.car.app.navigation.model;
import static java.util.Objects.requireNonNull;
import androidx.annotation.Keep;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.car.app.utils.CollectionUtils;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
/**
* Configuration of a single lane of a road at a particular point in the navigation.
*
* <p>A {@link Lane} object describes all possible directions the driver could go from this lane,
* and indicates which directions the driver could take to stay on the navigation route.
*/
public final class Lane {
@Keep
private final List<LaneDirection> mDirections;
/**
* Returns the list of directions a driver can take from this {@link Lane}.
*
* @see Builder#addDirection(LaneDirection)
*/
@NonNull
public List<LaneDirection> getDirections() {
return CollectionUtils.emptyIfNull(mDirections);
}
@Override
@NonNull
public String toString() {
return "[direction count: " + (mDirections != null ? mDirections.size() : 0) + "]";
}
@Override
public int hashCode() {
return Objects.hashCode(mDirections);
}
@Override
public boolean equals(@Nullable Object other) {
if (this == other) {
return true;
}
if (!(other instanceof Lane)) {
return false;
}
Lane otherLane = (Lane) other;
return Objects.equals(mDirections, otherLane.mDirections);
}
Lane(List<LaneDirection> directions) {
mDirections = CollectionUtils.unmodifiableCopy(directions);
}
/** Constructs an empty instance, used by serialization code. */
private Lane() {
mDirections = Collections.emptyList();
}
/** A builder of {@link Lane}. */
public static final class Builder {
private final List<LaneDirection> mDirections = new ArrayList<>();
/**
* Adds a direction a driver can take from this lane.
*
* @throws NullPointerException if {@code direction} is {@code null}
*/
@NonNull
public Builder addDirection(@NonNull LaneDirection direction) {
mDirections.add(requireNonNull(direction));
return this;
}
/** Constructs the {@link Lane} defined by this builder. */
@NonNull
public Lane build() {
return new Lane(mDirections);
}
/** Returns an empty {@link Builder} instance. */
public Builder() {
}
}
}