Node JS version

node_modules/cassandra-driver/lib/datastax/graph/graph-serializer.js

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+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you 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.
+ */
+
+/**
+ * @module datastax/graph/tinkerpop/graphSerializers
+ * @ignore
+ */
+
+
+/**
+ * @author Jorge Bay Gondra
+ */
+'use strict';
+
+const typeSerializers = require('./type-serializers');
+
+/**
+ * GraphSON2 writer.
+ */
+class GraphSON2Writer {
+
+  /**
+   * @param {Object} [options]
+   * @param {Object} [options.serializers] An object used as an associative array with GraphSON 2 type name as keys and
+   * serializer instances as values, ie: { 'g:Int64': longSerializer }.
+   * @constructor
+   */
+  constructor(options) {
+    this._options = options || {};
+    // Create instance of the default serializers
+    this._serializers = this.getDefaultSerializers().map(serializerConstructor => {
+      const s = new serializerConstructor();
+      s.writer = this;
+      return s;
+    });
+
+    const customSerializers = this._options.serializers || {};
+
+    Object.keys(customSerializers).forEach(key => {
+      const s = customSerializers[key];
+      if (!s.serialize) {
+        return;
+      }
+      s.writer = this;
+      // Insert custom serializers first
+      this._serializers.unshift(s);
+    });
+  }
+
+  /**
+   * Gets the default serializers to be used.
+   * @returns {Array}
+   */
+  getDefaultSerializers() {
+    return graphSON2Serializers;
+  }
+
+  adaptObject(value) {
+    let s;
+
+    for (let i = 0; i < this._serializers.length; i++) {
+      const currentSerializer = this._serializers[i];
+      if (currentSerializer.canBeUsedFor && currentSerializer.canBeUsedFor(value)) {
+        s = currentSerializer;
+        break;
+      }
+    }
+
+    if (s) {
+      return s.serialize(value);
+    }
+
+    if (Array.isArray(value)) {
+      // We need to handle arrays when there is no serializer
+      // for older versions of GraphSON
+      return value.map(item => this.adaptObject(item));
+    }
+
+    // Default (strings / objects / ...)
+    return value;
+  }
+
+  /**
+   * Returns the GraphSON representation of the provided object instance.
+   * @param {Object} obj
+   * @returns {String}
+   */
+  write(obj) {
+    return JSON.stringify(this.adaptObject(obj));
+  }
+}
+
+/**
+ * GraphSON3 writer.
+ */
+class GraphSON3Writer extends GraphSON2Writer {
+  getDefaultSerializers() {
+    return graphSON3Serializers;
+  }
+}
+
+/**
+ * GraphSON2 reader.
+ */
+class GraphSON2Reader {
+  /**
+   * GraphSON Reader
+   * @param {Object} [options]
+   * @param {Object} [options.serializers] An object used as an associative array with GraphSON 2 type name as keys and
+   * deserializer instances as values, ie: { 'g:Int64': longSerializer }.
+   * @constructor
+   */
+  constructor(options) {
+    this._options = options || {};
+    this._deserializers = {};
+
+    const defaultDeserializers = this.getDefaultDeserializers();
+    Object.keys(defaultDeserializers).forEach(typeName => {
+      const serializerConstructor = defaultDeserializers[typeName];
+      const s = new serializerConstructor();
+      s.reader = this;
+      this._deserializers[typeName] = s;
+    });
+
+    if (this._options.serializers) {
+      const customSerializers = this._options.serializers || {};
+      Object.keys(customSerializers).forEach(key => {
+        const s = customSerializers[key];
+        if (!s.deserialize) {
+          return;
+        }
+        s.reader = this;
+        this._deserializers[key] = s;
+      });
+    }
+  }
+
+  /**
+   * Gets the default deserializers as an associative array.
+   * @returns {Object}
+   */
+  getDefaultDeserializers() {
+    return graphSON2Deserializers;
+  }
+
+  read(obj) {
+    if (obj === undefined) {
+      return undefined;
+    }
+    if (obj === null) {
+      return null;
+    }
+    if (Array.isArray(obj)) {
+      return obj.map(item => this.read(item));
+    }
+    const type = obj[typeSerializers.typeKey];
+    if (type) {
+      const d = this._deserializers[type];
+      if (d) {
+        // Use type serializer
+        return d.deserialize(obj);
+      }
+      return obj[typeSerializers.valueKey];
+    }
+    if (obj && typeof obj === 'object' && obj.constructor === Object) {
+      return this._deserializeObject(obj);
+    }
+    // Default (for boolean, number and other scalars)
+    return obj;
+  }
+
+  _deserializeObject(obj) {
+    const keys = Object.keys(obj);
+    const result = {};
+    for (let i = 0; i < keys.length; i++) {
+      result[keys[i]] = this.read(obj[keys[i]]);
+    }
+    return result;
+  }
+}
+
+/**
+ * GraphSON3 reader.
+ */
+class GraphSON3Reader extends GraphSON2Reader {
+  getDefaultDeserializers() {
+    return graphSON3Deserializers;
+  }
+}
+
+const graphSON2Deserializers = {
+  'g:Traverser': typeSerializers.TraverserSerializer,
+  'g:TraversalStrategy': typeSerializers.TraversalStrategySerializer,
+  'g:Int32':  typeSerializers.NumberSerializer,
+  'g:Int64':  typeSerializers.NumberSerializer,
+  'g:Float':  typeSerializers.NumberSerializer,
+  'g:Double': typeSerializers.NumberSerializer,
+  'g:Date': typeSerializers.DateSerializer,
+  'g:Direction': typeSerializers.DirectionSerializer,
+  'g:Vertex': typeSerializers.VertexSerializer,
+  'g:Edge': typeSerializers.EdgeSerializer,
+  'g:VertexProperty': typeSerializers.VertexPropertySerializer,
+  'g:Property': typeSerializers.PropertySerializer,
+  'g:Path': typeSerializers.Path3Serializer,
+  'g:TextP': typeSerializers.TextPSerializer,
+  'g:T': typeSerializers.TSerializer,
+  'g:BulkSet': typeSerializers.BulkSetSerializer
+};
+
+const graphSON3Deserializers = Object.assign({}, graphSON2Deserializers, {
+  'g:List': typeSerializers.ListSerializer,
+  'g:Set': typeSerializers.SetSerializer,
+  'g:Map': typeSerializers.MapSerializer
+});
+
+const graphSON2Serializers = [
+  typeSerializers.NumberSerializer,
+  typeSerializers.DateSerializer,
+  typeSerializers.BytecodeSerializer,
+  typeSerializers.TraverserSerializer,
+  typeSerializers.TraversalStrategySerializer,
+  typeSerializers.PSerializer,
+  typeSerializers.TextPSerializer,
+  typeSerializers.LambdaSerializer,
+  typeSerializers.EnumSerializer,
+  typeSerializers.VertexSerializer,
+  typeSerializers.EdgeSerializer,
+  typeSerializers.LongSerializer
+];
+
+const graphSON3Serializers = graphSON2Serializers.concat([
+  typeSerializers.ListSerializer,
+  typeSerializers.SetSerializer,
+  typeSerializers.MapSerializer
+]);
+
+module.exports = {
+  GraphSON3Writer,
+  GraphSON3Reader,
+  GraphSON2Writer,
+  GraphSON2Reader,
+  GraphSONWriter: GraphSON3Writer,
+  GraphSONReader: GraphSON3Reader
+};