com.couchbase.lite.Select Maven / Gradle / Ivy

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//
// Copyright (c) 2020, 2017 Couchbase, Inc All rights reserved.
//
// 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.couchbase.lite;

import android.support.annotation.NonNull;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import com.couchbase.lite.internal.utils.Preconditions;


/**
 * Select represents the SELECT clause of the query for specifying the returning properties in each
 * query result row.
 */
public final class Select extends AbstractQuery implements FromRouter {
    //---------------------------------------------
    // Member variables
    //---------------------------------------------
    private final boolean distinct;                 // DISTINCT
    private final List selectResults; // result-columns

    //---------------------------------------------
    // Constructor
    //---------------------------------------------

    Select(boolean distinct, SelectResult... selectResults) {
        this.distinct = distinct;
        this.selectResults = Arrays.asList(selectResults);
        setSelect(this);
    }

    //---------------------------------------------
    // implementation of FromRouter
    //---------------------------------------------

    /**
     * Create and chain a FROM component for specifying the data source of the query.
     *
     * @param dataSource the data source.
     * @return the From component.
     */
    @NonNull
    @Override
    public From from(@NonNull DataSource dataSource) {
        Preconditions.assertNotNull(dataSource, "dataSource");
        return new From(this, dataSource);
    }

    //---------------------------------------------
    // Package level access
    //---------------------------------------------

    List getSelectResults() { return selectResults; }

    boolean isDistinct() { return distinct; }

    boolean hasSelectResults() { return !selectResults.isEmpty(); }

    Object asJSON() {
        final List