com.google.cloud.firestore.BasePath.java Source code

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Here is the source code for com.google.cloud.firestore.BasePath.java

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/*
 * Copyright 2017 Google LLC
 *
 * 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.google.cloud.firestore;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;

/**
 * BasePath represents a path sequence in the Firestore database. It is composed of an ordered
 * sequence of string segments.
 */
abstract class BasePath<B extends BasePath<B>> implements Comparable<B> {

    /**
     * Returns the segments that make up this path.
     *
     * @return The path segments.
     */
    abstract ImmutableList<String> getSegments();

    /**
     * Returns the path of the parent element.
     *
     * @return The new Path or null if we are already at the root.
     */
    @Nullable
    B getParent() {
        ImmutableList<String> parts = getSegments();
        if (parts.isEmpty()) {
            return null;
        }
        return createPathWithSegments(parts.subList(0, parts.size() - 1));
    }

    /**
     * Returns a new path pointing to a child of this Path.
     *
     * @param path A relative path
     */
    B append(String path) {
        Preconditions.checkArgument(path != null && !path.isEmpty(), "'path' must be a non-empty String");
        ImmutableList.Builder<String> components = ImmutableList.builder();
        components.addAll(this.getSegments());
        components.add(splitChildPath(path));
        return createPathWithSegments(components.build());
    }

    /**
     * Returns a new path pointing to a child of this Path.
     *
     * @param path A relative path
     */
    B append(BasePath<B> path) {
        ImmutableList.Builder<String> components = ImmutableList.builder();
        components.addAll(this.getSegments());
        components.addAll(path.getSegments());
        return createPathWithSegments(components.build());
    }

    /**
     * Checks to see if this path is a prefix of (or equals) another path.
     *
     * @param path the path to check against
     * @return true if current path is a prefix of the other path.
     */
    boolean isPrefixOf(BasePath<B> path) {
        ImmutableList<String> prefixSegments = getSegments();
        ImmutableList<String> childSegments = path.getSegments();
        if (prefixSegments.size() > path.getSegments().size()) {
            return false;
        }
        for (int i = 0; i < prefixSegments.size(); i++) {
            if (!prefixSegments.get(i).equals(childSegments.get(i))) {
                return false;
            }
        }
        return true;
    }

    /**
     * Compare the current path lexicographically against another Path object.
     *
     * @param other The path to compare to.
     * @return -1 if current is less than other, 1 if current greater than other, 0 if equal
     */
    @Override
    public int compareTo(@Nonnull B other) {
        int length = Math.min(this.getSegments().size(), other.getSegments().size());
        for (int i = 0; i < length; i++) {
            int cmp = this.getSegments().get(i).compareTo(other.getSegments().get(i));
            if (cmp != 0) {
                return cmp;
            }
        }
        return Integer.compare(this.getSegments().size(), other.getSegments().size());
    }

    /** Returns the number of path components. */
    int size() {
        return this.getSegments().size();
    }

    abstract String[] splitChildPath(String path);

    abstract B createPathWithSegments(ImmutableList<String> segments);
}