@maxgraph/core/lib/esm/serialization/ObjectCodec.d.ts

maxGraph is a fully client side JavaScript diagramming library that uses SVG and HTML for rendering.

import type Codec from './Codec.js';
/**
 * Generic codec for JavaScript objects that implements a mapping between
 * JavaScript objects and XML nodes that maps each field or element to an
 * attribute or child node, and vice versa.
 *
 * ### Atomic Values
 *
 * Consider the following example.
 *
 * ```javascript
 * const obj = new Object();
 * obj.foo = "Foo";
 * obj.bar = "Bar";
 * ```
 *
 * This object is encoded into an XML node using the following.
 *
 * ```javascript
 * const enc = new Codec();
 * const node = enc.encode(obj);
 * ```
 *
 * The output of the encoding may be viewed using {@link GlobalConfig.logger} as follows.
 *
 * ```javascript
 * GlobalConfig.logger.show();
 * GlobalConfig.logger.debug(mxUtils.getPrettyXml(node));
 * ```
 *
 * Finally, the result of the encoding looks as follows.
 *
 * ```javascript
 * <Object foo="Foo" bar="Bar"/>
 * ```
 *
 * In the above output, the foo and bar fields have been mapped to attributes
 * with the same names, and the name of the constructor was used for the
 * node name.
 *
 * ### Booleans
 *
 * Since booleans are numbers in JavaScript, all boolean values are encoded
 * into 1 for true and 0 for false. The decoder also accepts the string true
 * and false for boolean values.
 *
 * ### Objects
 *
 * The above scheme is applied to all atomic fields, that is, to all non-object
 * fields of an object. For object fields, a child node is created with a
 * special attribute that contains the field name. This special attribute is
 * called "as" and hence, as is a reserved word that should not be used for a
 * field name.
 *
 * Consider the following example where foo is an object and bar is an atomic
 * property of foo.
 *
 * ```javascript
 * const obj = {foo: {bar: "Bar"}};
 * ```
 *
 * This will be mapped to the following XML structure by ObjectCodec.
 *
 * ```javascript
 * <Object>
 *   <Object bar="Bar" as="foo"/>
 * </Object>
 * ```
 *
 * In the above output, the inner Object node contains the as-attribute that
 * specifies the field name in the enclosing object. That is, the field foo was
 * mapped to a child node with an as-attribute that has the value foo.
 *
 * ### Arrays
 *
 * Arrays are special objects that are either associative, in which case each
 * key, value pair is treated like a field where the key is the field name, or
 * they are a sequence of atomic values and objects, which is mapped to a
 * sequence of child nodes. For object elements, the above scheme is applied
 * without the use of the special as-attribute for creating each child. For
 * atomic elements, a special add-node is created with the value stored in the
 * value-attribute.
 *
 * For example, the following array contains one atomic value and one object
 * with a field called bar. Furthermore, it contains two associative entries
 * called bar with an atomic value, and foo with an object value.
 *
 * ```javascript
 * const obj = ["Bar", {bar: "Bar"}];
 * obj["bar"] = "Bar";
 * obj["foo"] = {bar: "Bar"};
 * ```
 *
 * This array is represented by the following XML nodes.
 *
 * ```javascript
 * <Array bar="Bar">
 *   <add value="Bar"/>
 *   <Object bar="Bar"/>
 *   <Object bar="Bar" as="foo"/>
 * </Array>
 * ```
 *
 * The Array node name is the name of the constructor. The additional
 * as-attribute in the last child contains the key of the associative entry,
 * whereas the second last child is part of the array sequence and does not
 * have an as-attribute.
 *
 * ### References
 *
 * Objects may be represented as child nodes or attributes with ID values,
 * which are used to look up the object in a table within {@link Codec}. The
 * {@link isReference} function is in charge of deciding if a specific field should
 * be encoded as a reference or not. Its default implementation returns true if
 * the field name is in {@link idrefs}, an array of strings that is used to configure
 * the {@link ObjectCodec}.
 *
 * Using this approach, the mapping does not guarantee that the referenced
 * object itself exists in the document. The fields that are encoded as
 * references must be carefully chosen to make sure all referenced objects
 * exist in the document, or may be resolved by some other means if necessary.
 *
 * For example, in the case of the graph model all cells are stored in a tree
 * whose root is referenced by the model's root field. A tree is a structure
 * that is well suited for an XML representation, however, the additional edges
 * in the graph model have a reference to a source and target cell, which are
 * also contained in the tree. To handle this case, the source and target cell
 * of an edge are treated as references, whereas the children are treated as
 * objects. Since all cells are contained in the tree and no edge references a
 * source or target outside the tree, this setup makes sure all referenced
 * objects are contained in the document.
 *
 * In the case of a tree structure we must further avoid infinite recursion by
 * ignoring the parent reference of each child. This is done by returning true
 * in {@link isExcluded}, whose default implementation uses the array of excluded
 * field names passed to the ObjectCodec constructor.
 *
 * References are only used for cells in mxGraph. For defining other
 * referencable object types, the codec must be able to work out the ID of an
 * object. This is done by implementing {@link Codec.reference}. For decoding a
 * reference, the XML node with the respective id-attribute is fetched from the
 * document, decoded, and stored in a lookup table for later reference. For
 * looking up external objects, {@link Codec.lookup} may be implemented.
 *
 * ### Expressions
 *
 * For decoding JavaScript expressions, the add-node may be used with a text
 * content that contains the JavaScript expression. For example, the following
 * creates a field called foo in the enclosing object and assigns it the value
 * of `MyConstant.PROP`.
 *
 * ```javascript
 * <Object>
 *   <add as="foo">MyConstant.PROP</add>
 * </Object>
 * ```
 *
 * The resulting object has a field called foo with the value "myValue" (assuming that `MyConstant.PROP=myValue`).
 * Its XML representation looks as follows.
 *
 * ```javascript
 * <Object foo="left"/>
 * ```
 *
 * This means the expression is evaluated at decoding time and the result of
 * the evaluation is stored in the respective field. Valid expressions are all
 * JavaScript expressions, including function definitions, which are mapped to
 * functions on the resulting object.
 *
 * Expressions are only evaluated if {@link allowEval} is true.
 *
 * @category Serialization with Codecs
 */
declare class ObjectCodec {
    private name?;
    constructor(template: any, exclude?: string[], idrefs?: string[], mapping?: {
        [key: string]: string;
    });
    /**
     * Static global switch that specifies if expressions in arrays are allowed.
     *
     * **WARNING**: Enabling this switch carries a possible security risk.
     *
     * @default false
     */
    static allowEval: boolean;
    /**
     * Holds the template object associated with this codec.
     */
    template: any;
    /**
     * Array containing the variable names that should be ignored by the codec.
     */
    exclude: string[];
    /**
     * Array containing the variable names that should be
     * turned into or converted from references. See
     * {@link Codec.getId} and {@link Codec.getObject}.
     */
    idrefs: string[];
    /**
     * Maps from field names to XML attribute names.
     */
    mapping: {
        [key: string]: string;
    };
    /**
     * Maps from XML attribute names to fieldnames.
     */
    reverse: {
        [key: string]: string;
    };
    /**
     * Returns the name used for the node names and lookup of the codec when
     * classes are encoded and nodes are decoded. For classes to work with
     * this the codec registry automatically adds an alias for the classname
     * if that is different from what this returns.
     *
     * The default implementation returns the classname of the template class if no name is set.
     */
    getName(): string;
    setName(name: string): void;
    /**
     * Returns a new instance of the template for this codec.
     */
    cloneTemplate(): any;
    /**
     * Returns the field name for the given attribute name.
     * Looks up the value in the {@link reverse} mapping or returns
     * the input if there is no reverse mapping for the
     * given name.
     */
    getFieldName(attributename: string): string;
    /**
     * Returns the attribute name for the given field name.
     * Looks up the value in the {@link mapping} or returns
     * the input if there is no mapping for the
     * given name.
     */
    getAttributeName(fieldname: string | null): string | null;
    /**
     * Returns true if the given attribute is to be ignored by the codec. This
     * implementation returns true if the given field name is in {@link exclude} or
     * if the field name equals {@link ObjectIdentity.FIELD_NAME}.
     *
     * @param obj Object instance that contains the field.
     * @param attr Fieldname of the field.
     * @param value Value of the field.
     * @param write Boolean indicating if the field is being encoded or decoded.
     * Write is true if the field is being encoded, else it is being decoded.
     */
    isExcluded(obj: any, attr: string, value: any, write?: boolean): boolean;
    /**
     * Returns true if the given field name is to be treated
     * as a textual reference (ID). This implementation returns
     * true if the given field name is in {@link idrefs}.
     *
     * @param obj Object instance that contains the field.
     * @param attr Field name of the field.
     * @param value Value of the field.
     * @param write Boolean indicating if the field is being encoded or decoded.
     * Write is true if the field is being encoded, else it is being decoded.
     */
    isReference(obj: any, attr: string | null, value: any, write?: boolean): boolean;
    /**
     * Encodes the specified object and returns a node
     * representing then given object. Calls {@link beforeEncode}
     * after creating the node and {@link afterEncode} with the
     * resulting node after processing.
     *
     * Enc is a reference to the calling encoder. It is used
     * to encode complex objects and create references.
     *
     * This implementation encodes all variables of an
     * object according to the following rules:
     *
     * - If the variable name is in {@link exclude} then it is ignored.
     * - If the variable name is in {@link idrefs} then {@link Codec.getId}
     * is used to replace the object with its ID.
     * - The variable name is mapped using {@link mapping}.
     * - If obj is an array and the variable name is numeric
     * (ie. an index) then it is not encoded.
     * - If the value is an object, then the codec is used to
     * create a child node with the variable name encoded into
     * the "as" attribute.
     * - Else, if {@link encodeDefaults} is true or the value differs
     * from the template value, then ...
     * - ... if obj is not an array, then the value is mapped to
     * an attribute.
     * - ... else if obj is an array, the value is mapped to an
     * add child with a value attribute or a text child node,
     * if the value is a function.
     *
     * If no ID exists for a variable in {@link idrefs} or if an object
     * cannot be encoded, a warning is issued using {@link GlobalConfig.logger}.
     *
     * Returns the resulting XML node that represents the given
     * object.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object to be encoded.
     */
    encode(enc: Codec, obj: any): Element | null;
    /**
     * Encodes the value of each member in then given obj into the given node using
     * {@link encodeValue}.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object to be encoded.
     * @param node XML node that contains the encoded object.
     */
    encodeObject(enc: Codec, obj: any, node: Element): void;
    /**
     * Converts the given value according to the mappings
     * and id-refs in this codec and uses {@link writeAttribute}
     * to write the attribute into the given node.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object whose property is going to be encoded.
     * @param name XML node that contains the encoded object.
     * @param value Value of the property to be encoded.
     * @param node XML node that contains the encoded object.
     */
    encodeValue(enc: Codec, obj: any, name: string | null, value: any, node: Element): void;
    /**
     * Writes the given value into node using {@link writePrimitiveAttribute}
     * or {@link writeComplexAttribute} depending on the type of the value.
     */
    writeAttribute(enc: Codec, obj: any, name: string | null, value: any, node: Element): void;
    /**
     * Writes the given value as an attribute of the given node.
     */
    writePrimitiveAttribute(enc: Codec, obj: any, name: string | null, value: any, node: Element): void;
    /**
     * Writes the given value as a child node of the given node.
     */
    writeComplexAttribute(enc: Codec, obj: any, name: string | null, value: any, node: Element): void;
    /**
     * Converts true to "1" and false to "0" is {@link isBooleanAttribute} returns true.
     * All other values are not converted.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Objec to convert the attribute for.
     * @param name Name of the attribute to be converted.
     * @param value Value to be converted.
     */
    convertAttributeToXml(enc: Codec, obj: any, name: string | null, value: any, node: Element): any;
    /**
     * Returns true if the given object attribute is a boolean value.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object to convert the attribute for.
     * @param name Name of the attribute to be converted.
     * @param value Value of the attribute to be converted.
     */
    isBooleanAttribute(enc: Codec, obj: any, name: string | null, value: any): boolean;
    /**
     * Converts booleans and numeric values to the respective types. Values are
     * numeric if {@link isNumericAttribute} returns true.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param attr XML attribute to be converted.
     * @param obj Objec to convert the attribute for.
     */
    convertAttributeFromXml(dec: Codec, attr: any, obj: any): any;
    /**
     * Returns true if the given XML attribute is or should be a numeric value.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param attr XML attribute to be converted.
     * @param obj Object to convert the attribute for.
     */
    isNumericAttribute(dec: Codec, attr: any, obj: any): boolean;
    /**
     * Hook for subclassers to pre-process the object before
     * encoding. This returns the input object. The return
     * value of this function is used in {@link encode} to perform
     * the default encoding into the given node.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object to be encoded.
     * @param node XML node to encode the object into.
     */
    beforeEncode(enc: Codec, obj: any, node?: Element): any;
    /**
     * Hook for subclassers to post-process the node
     * for the given object after encoding and return the
     * post-processed node. This implementation returns
     * the input node. The return value of this method
     * is returned to the encoder from {@link encode}.
     *
     * @param enc {@link Codec} that controls the encoding process.
     * @param obj Object to be encoded.
     * @param node XML node that represents the default encoding.
     */
    afterEncode(enc: Codec, obj: any, node: Element): Element;
    /**
     * Parses the given node into the object or returns a new object
     * representing the given node.
     *
     * Dec is a reference to the calling decoder. It is used to decode
     * complex objects and resolve references.
     *
     * If a node has an id attribute then the object cache is checked for the
     * object. If the object is not yet in the cache then it is constructed
     * using the constructor of {@link template} and cached in {@link Codec.objects}.
     *
     * This implementation decodes all attributes and childs of a node
     * according to the following rules:
     *
     * - If the variable name is in {@link exclude} or if the attribute name is "id"
     * or "as" then it is ignored.
     * - If the variable name is in {@link idrefs} then {@link Codec.getObject} is used
     * to replace the reference with an object.
     * - The variable name is mapped using a reverse {@link mapping}.
     * - If the value has a child node, then the codec is used to create a
     * child object with the variable name taken from the "as" attribute.
     * - If the object is an array and the variable name is empty then the
     * value or child object is appended to the array.
     * - If an add child has no value or the object is not an array then
     * the child text content is evaluated using {@link eval}.
     *
     * For add nodes where the object is not an array and the variable name
     * is defined, the default mechanism is used, allowing to override/add
     * methods as follows:
     *
     * ```javascript
     * <Object>
     *   <add as="hello"><![CDATA[
     *     function(arg1) {
     *       mxUtils.alert('Hello '+arg1);
     *     }
     *   ]]></add>
     * </Object>
     * ```
     *
     * If no object exists for an ID in {@link idrefs} a warning is issued
     * using {@link GlobalConfig.logger}.
     *
     * Returns the resulting object that represents the given XML node
     * or the object given to the method as the into parameter.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param node XML node to be decoded.
     * @param into Optional object to encode the node into.
     */
    decode(dec: Codec, node: Element, into?: any): any;
    /**
     * Calls {@link decodeAttributes} and {@link decodeChildren} for the given node.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param node XML node to be decoded.
     * @param obj Object to encode the node into.
     */
    decodeNode(dec: Codec, node: Element | null, obj: any): void;
    /**
     * Decodes all attributes of the given node using {@link decodeAttribute}.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param node XML node to be decoded.
     * @param obj Object to encode the node into.
     */
    decodeAttributes(dec: Codec, node: Element, obj: any): void;
    /**
     * Returns true if the given attribute should be ignored. This implementation
     * returns true if the attribute name is "as" or "id".
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param attr XML attribute to be decoded.
     * @param obj Objec to encode the attribute into.
     */
    isIgnoredAttribute(dec: Codec, attr: any, obj?: any): boolean;
    /**
     * Reads the given attribute into the specified object.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param attr XML attribute to be decoded.
     * @param obj Objec to encode the attribute into.
     */
    decodeAttribute(dec: Codec, attr: any, obj?: any): void;
    /**
     * Decodes all children of the given node using {@link decodeChild}.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param node XML node to be decoded.
     * @param obj Objec to encode the node into.
     */
    decodeChildren(dec: Codec, node: Element, obj?: any): void;
    /**
     * Reads the specified child into the given object.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param child XML child element to be decoded.
     * @param obj Objec to encode the node into.
     */
    decodeChild(dec: Codec, child: Element, obj: any): void;
    /**
     * Returns the template instance for the given field. This returns the
     * value of the field, null if the value is an array or an empty collection
     * if the value is a collection. The value is then used to populate the
     * field for a new instance. For strongly typed languages it may be
     * required to override this to return the correct collection instance
     * based on the encoded child.
     */
    getFieldTemplate(obj: any, fieldname: string, child: Element): any;
    /**
     * Sets the decoded child node as a value of the given object. If the
     * object is a map, then the value is added with the given field name as a
     * key. If the field name is not empty, then setFieldValue is called or
     * else, if the object is a collection, the value is added to the
     * collection. For strongly typed languages it may be required to
     * override this with the correct code to add an entry to an object.
     */
    addObjectValue(obj: any, fieldname: string, value: any, template: any): void;
    /**
     * Returns true if the given node is an include directive and
     * executes the include by decoding the XML document. Returns
     * false if the given node is not an include directive.
     *
     * @param dec {@link Codec} that controls the encoding/decoding process.
     * @param node XML node to be checked.
     * @param into Optional object to pass-thru to the codec.
     */
    processInclude(dec: Codec, node: Element, into?: any): boolean;
    /**
     * Hook for subclassers to pre-process the node for
     * the specified object and return the node to be
     * used for further processing by {@link decode}.
     * The object is created based on the template in the
     * calling method and is never null. This implementation
     * returns the input node. The return value of this
     * function is used in {@link decode} to perform
     * the default decoding into the given object.
     *
     * @param dec {@link Codec} that controls the decoding process.
     * @param node XML node to be decoded.
     * @param obj Object to encode the node into.
     */
    beforeDecode(dec: Codec, node: Element, obj: any): Element | null;
    /**
     * Hook for subclassers to post-process the object after
     * decoding. This implementation returns the given object
     * without any changes. The return value of this method
     * is returned to the decoder from {@link decode}.
     *
     * @param dec {@link Codec} that controls the encoding process.
     * @param node XML node to be decoded.
     * @param obj Object that represents the default decoding.
     */
    afterDecode(dec: Codec, node: Element | null, obj?: any): any;
}
export default ObjectCodec;