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- /*
- * Copyright 2011 Vaadin Ltd.
- *
- * 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.vaadin.client.communication;
-
- import java.util.Collection;
- import java.util.List;
- import java.util.Map;
- import java.util.Map.Entry;
- import java.util.Set;
-
- import com.google.gwt.json.client.JSONArray;
- import com.google.gwt.json.client.JSONBoolean;
- import com.google.gwt.json.client.JSONNull;
- import com.google.gwt.json.client.JSONNumber;
- import com.google.gwt.json.client.JSONObject;
- import com.google.gwt.json.client.JSONString;
- import com.google.gwt.json.client.JSONValue;
- import com.vaadin.client.ApplicationConnection;
- import com.vaadin.client.metadata.NoDataException;
- import com.vaadin.client.metadata.Property;
- import com.vaadin.client.metadata.Type;
- import com.vaadin.shared.Connector;
- import com.vaadin.shared.JsonConstants;
- import com.vaadin.shared.communication.UidlValue;
-
- /**
- * Encoder for converting RPC parameters and other values to JSON for transfer
- * between the client and the server.
- *
- * Currently, basic data types as well as Map, String[] and Object[] are
- * supported, where maps and Object[] can contain other supported data types.
- *
- * TODO extensible type support
- *
- * @since 7.0
- */
- public class JsonEncoder {
-
- /**
- * Encode a value to a JSON representation for transport from the client to
- * the server.
- *
- * @param value
- * value to convert
- * @param connection
- * @return JSON representation of the value
- */
- public static JSONValue encode(Object value,
- boolean restrictToInternalTypes, ApplicationConnection connection) {
- if (null == value) {
- return JSONNull.getInstance();
- } else if (value instanceof JSONValue) {
- return (JSONValue) value;
- } else if (value instanceof String[]) {
- String[] array = (String[]) value;
- JSONArray jsonArray = new JSONArray();
- for (int i = 0; i < array.length; ++i) {
- jsonArray.set(i, new JSONString(array[i]));
- }
- return jsonArray;
- } else if (value instanceof String) {
- return new JSONString((String) value);
- } else if (value instanceof Boolean) {
- return JSONBoolean.getInstance((Boolean) value);
- } else if (value instanceof Byte) {
- return new JSONNumber((Byte) value);
- } else if (value instanceof Character) {
- return new JSONString(String.valueOf(value));
- } else if (value instanceof Object[]) {
- return encodeObjectArray((Object[]) value, restrictToInternalTypes,
- connection);
- } else if (value instanceof Enum) {
- return encodeEnum((Enum<?>) value, connection);
- } else if (value instanceof Map) {
- return encodeMap((Map) value, restrictToInternalTypes, connection);
- } else if (value instanceof Connector) {
- Connector connector = (Connector) value;
- return new JSONString(connector.getConnectorId());
- } else if (value instanceof Collection) {
- return encodeCollection((Collection) value,
- restrictToInternalTypes, connection);
- } else if (value instanceof UidlValue) {
- return encodeVariableChange((UidlValue) value, connection);
- } else {
- String transportType = getTransportType(value);
- if (transportType != null) {
- return new JSONString(String.valueOf(value));
- } else {
- // Try to find a generated serializer object, class name is the
- // type
- Type type = new Type(value.getClass());
-
- JSONSerializer<Object> serializer = (JSONSerializer<Object>) type
- .findSerializer();
- if (serializer != null) {
- return serializer.serialize(value, connection);
- } else {
- try {
- Collection<Property> properties = type.getProperties();
-
- JSONObject jsonObject = new JSONObject();
- for (Property property : properties) {
- Object propertyValue = property.getValue(value);
- JSONValue encodedPropertyValue = encode(
- propertyValue, restrictToInternalTypes,
- connection);
- jsonObject.put(property.getName(),
- encodedPropertyValue);
- }
- return jsonObject;
-
- } catch (NoDataException e) {
- throw new RuntimeException("Can not encode "
- + type.getSignature(), e);
- }
- }
-
- }
- }
- }
-
- private static JSONValue encodeVariableChange(UidlValue uidlValue,
- ApplicationConnection connection) {
- Object value = uidlValue.getValue();
-
- JSONArray jsonArray = new JSONArray();
- jsonArray.set(0, new JSONString(getTransportType(value)));
- jsonArray.set(1, encode(value, true, connection));
-
- return jsonArray;
- }
-
- private static JSONValue encodeMap(Map<Object, Object> map,
- boolean restrictToInternalTypes, ApplicationConnection connection) {
- /*
- * As we have no info about declared types, we instead select encoding
- * scheme based on actual type of first key. We can't do this if there's
- * no first key, so instead we send some special value that the
- * server-side decoding must check for. (see #8906)
- */
- if (map.isEmpty()) {
- return new JSONArray();
- }
-
- Object firstKey = map.keySet().iterator().next();
- if (firstKey instanceof String) {
- return encodeStringMap(map, restrictToInternalTypes, connection);
- } else if (restrictToInternalTypes) {
- throw new IllegalStateException(
- "Only string keys supported for legacy maps");
- } else if (firstKey instanceof Connector) {
- return encodeConenctorMap(map, connection);
- } else {
- return encodeObjectMap(map, connection);
- }
- }
-
- private static JSONValue encodeObjectMap(Map<Object, Object> map,
- ApplicationConnection connection) {
- JSONArray keys = new JSONArray();
- JSONArray values = new JSONArray();
- for (Entry<?, ?> entry : map.entrySet()) {
- // restrictToInternalTypes always false if we end up here
- keys.set(keys.size(), encode(entry.getKey(), false, connection));
- values.set(values.size(),
- encode(entry.getValue(), false, connection));
- }
-
- JSONArray keysAndValues = new JSONArray();
- keysAndValues.set(0, keys);
- keysAndValues.set(1, values);
-
- return keysAndValues;
- }
-
- private static JSONValue encodeConenctorMap(Map<Object, Object> map,
- ApplicationConnection connection) {
- JSONObject jsonMap = new JSONObject();
-
- for (Entry<?, ?> entry : map.entrySet()) {
- Connector connector = (Connector) entry.getKey();
-
- // restrictToInternalTypes always false if we end up here
- JSONValue encodedValue = encode(entry.getValue(), false, connection);
-
- jsonMap.put(connector.getConnectorId(), encodedValue);
- }
-
- return jsonMap;
- }
-
- private static JSONValue encodeStringMap(Map<Object, Object> map,
- boolean restrictToInternalTypes, ApplicationConnection connection) {
- JSONObject jsonMap = new JSONObject();
-
- for (Entry<?, ?> entry : map.entrySet()) {
- String key = (String) entry.getKey();
- Object value = entry.getValue();
-
- if (restrictToInternalTypes) {
- value = new UidlValue(value);
- }
-
- JSONValue encodedValue = encode(value, restrictToInternalTypes,
- connection);
-
- jsonMap.put(key, encodedValue);
- }
-
- return jsonMap;
- }
-
- private static JSONValue encodeEnum(Enum<?> e,
- ApplicationConnection connection) {
- return new JSONString(e.toString());
- }
-
- private static JSONValue encodeObjectArray(Object[] array,
- boolean restrictToInternalTypes, ApplicationConnection connection) {
- JSONArray jsonArray = new JSONArray();
- for (int i = 0; i < array.length; ++i) {
- // TODO handle object graph loops?
- Object value = array[i];
- if (restrictToInternalTypes) {
- value = new UidlValue(value);
- }
- jsonArray
- .set(i, encode(value, restrictToInternalTypes, connection));
- }
- return jsonArray;
- }
-
- private static JSONValue encodeCollection(Collection collection,
- boolean restrictToInternalTypes, ApplicationConnection connection) {
- JSONArray jsonArray = new JSONArray();
- int idx = 0;
- for (Object o : collection) {
- JSONValue encodedObject = encode(o, restrictToInternalTypes,
- connection);
- jsonArray.set(idx++, encodedObject);
- }
- if (collection instanceof Set) {
- return jsonArray;
- } else if (collection instanceof List) {
- return jsonArray;
- } else {
- throw new RuntimeException("Unsupport collection type: "
- + collection.getClass().getName());
- }
-
- }
-
- /**
- * Returns the transport type for the given value. Only returns a transport
- * type for internally handled values.
- *
- * @param value
- * The value that should be transported
- * @return One of the JsonEncode.VTYPE_ constants or null if the value
- * cannot be transported using an internally handled type.
- */
- private static String getTransportType(Object value) {
- if (value == null) {
- return JsonConstants.VTYPE_NULL;
- } else if (value instanceof String) {
- return JsonConstants.VTYPE_STRING;
- } else if (value instanceof Connector) {
- return JsonConstants.VTYPE_CONNECTOR;
- } else if (value instanceof Boolean) {
- return JsonConstants.VTYPE_BOOLEAN;
- } else if (value instanceof Integer) {
- return JsonConstants.VTYPE_INTEGER;
- } else if (value instanceof Float) {
- return JsonConstants.VTYPE_FLOAT;
- } else if (value instanceof Double) {
- return JsonConstants.VTYPE_DOUBLE;
- } else if (value instanceof Long) {
- return JsonConstants.VTYPE_LONG;
- } else if (value instanceof List) {
- return JsonConstants.VTYPE_LIST;
- } else if (value instanceof Set) {
- return JsonConstants.VTYPE_SET;
- } else if (value instanceof String[]) {
- return JsonConstants.VTYPE_STRINGARRAY;
- } else if (value instanceof Object[]) {
- return JsonConstants.VTYPE_ARRAY;
- } else if (value instanceof Map) {
- return JsonConstants.VTYPE_MAP;
- } else if (value instanceof Enum<?>) {
- // Enum value is processed as a string
- return JsonConstants.VTYPE_STRING;
- }
- return null;
- }
- }
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