@sap/odata-v4/lib/edm/EdmNavigationProperty.js

OData V4.0 server library

'use strict';

const EdmAnnotation = require('./EdmAnnotation');
const EdmReferentialConstraint = require('./EdmReferentialConstraint');
const validateThat = require('../validator/ParameterValidator').validateThat;

/**
 * A navigation property allows navigation to related entities.
 *
 * <a href="../ODataSpecification/odata-v4.0-errata03-os/complete/part3-csdl/odata-v4.0-errata03-os-part3-csdl-complete.html#_Toc453752537">
 *  OData CSDL # 7.1 Element edm:NavigationProperty
 * </a>
 * @hideconstructor
 */
class EdmNavigationProperty {

    /**
     * Creates an instance of EdmNavigationProperty.
     *
     * @param {Edm} edm The edm itself
     * @param {CsdlNavigationProperty} navigationProperty The navigation property structure
     */
    constructor(edm, navigationProperty) {
        validateThat('edm', edm).truthy();
        validateThat('navigationProperty', navigationProperty).truthy();

        /**
         * @type {Edm}
         * @private
         */
        this._edm = edm;

        /**
         * @type {string}
         * @private
         */
        this._name = navigationProperty.name;

        /**
         * @type {CsdlNavigationProperty}
         * @private
         */
        this._navigationProperty = navigationProperty;

        /**
         * @type {EdmReferentialConstraint[]}
         * @private
         */
        this._referentialConstraints = null;

        /**
         * @type {EdmEntityType}
         * @private
         */
        this._entityType = null;

        /**
         * @type {EdmNavigationProperty}
         * @private
         */
        this._partnerNavigationProperty = null;

        /**
         * @type {EdmAnnotation[]}
         * @private
         */
        this._annotations = null;
    }

    /**
     * Return true if this navigation property's target is a collection, else false.
     *
     * @returns {boolean} True if this navigation property's target is a collection, else false
     */
    isCollection() {
        return this._navigationProperty.isCollection;
    }

    /**
     * Returns true if the navigation property is nullable, otherwise false
     *
     * @returns {boolean} True if this navigation property is nullable, else false
     */
    isNullable() {
        return this._navigationProperty.isNullable;
    }

    /**
     * True if this navigation property contains target, else false
     *
     * @returns {boolean}
     */
    containsTarget() {
        return this._navigationProperty.containsTarget;
    }

    /**
     * Returns the corresponding entity type.
     *
     * @returns {EdmEntityType}
     */
    getEntityType() {
        if (!this._entityType) {
            this._entityType = this._edm.getEntityType(this._navigationProperty.type);
        }
        return this._entityType;
    }

    /**
     * Returns the name of this navigation property
     *
     * @returns {string} The name of the property
     */
    getName() {
        return this._name;
    }

    /**
     * Returns the partner navigation property
     *
     * @returns {EdmNavigationProperty}
     */
    getPartner() {
        if (!this._navigationProperty.partner) {
            return null;
        }

        if (this._partnerNavigationProperty) {
            return this._partnerNavigationProperty;
        }

        let partner = this._navigationProperty.partner;
        let currentType = this.getEntityType();

        partner.split('/').forEach(name => {
            this._partnerNavigationProperty = currentType.getNavigationProperty(name);
            currentType = this._partnerNavigationProperty.getEntityType();
        });

        return this._partnerNavigationProperty;
    }

    /**
     * Returns the list of referential constraints.
     *
     * @returns {Map.<string, EdmReferentialConstraint>} The collection of referential constraints
     */
    getReferentialConstraints() {
        if (!this._referentialConstraints) {
            this._referentialConstraints = new Map();

            let providerConstraints = this._navigationProperty.referentialConstraints;
            if (providerConstraints && providerConstraints.length > 0) {
                // constraint --> CsdlReferentialConstraint
                for (const constraint of providerConstraints) {
                    this._referentialConstraints.set(
                        constraint.property,
                        new EdmReferentialConstraint(this._edm, constraint)
                    );
                }
            }
        }
        return this._referentialConstraints;
    }

    /**
     * Returns the annotations for this object
     *
     * @returns {EdmAnnotation[]}
     */
    getAnnotations() {
        if (!this._annotations) {
            this._annotations = this._navigationProperty.annotations.map(item => new EdmAnnotation(this._edm, item));
        }
        return this._annotations;
    }
}

module.exports = EdmNavigationProperty;