Java tutorial
/** * * Copyright (c) 2014 Kerby Martino and others. 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. * * __ __ __ * | |_.--.--.--|__.-----| |_ * | _| | | | |__ --| _| * |____|________|__|_____|____| * :: Twist :: Object Mapping :: * */ package com.pastekit.twist.gae; import com.google.appengine.api.datastore.*; import com.google.appengine.api.datastore.Blob; import com.google.appengine.api.datastore.Entity; import com.google.appengine.api.datastore.Key; import com.pastekit.twist.annotations.Embedded; import com.pastekit.twist.annotations.Flat; import com.pastekit.twist.annotations.Id; import com.pastekit.twist.annotations.Volatile; import com.pastekit.twist.common.AutoGenerateStringIdException; import com.pastekit.twist.common.TwistException; import com.pastekit.twist.util.MapHelper; import com.pastekit.twist.util.StringHelper; import com.pastekit.twist.common.TwistException; import com.google.appengine.api.users.User; import com.pastekit.twist.GaeObjectStore; import com.pastekit.twist.Marshaller; import com.pastekit.twist.annotations.*; import com.pastekit.twist.common.AutoGenerateStringIdException; import com.pastekit.twist.object.KeyStructure; import com.pastekit.twist.util.AnnotationUtil; import com.pastekit.twist.util.MapHelper; import com.pastekit.twist.util.StringHelper; import org.apache.commons.lang3.ArrayUtils; import org.apache.log4j.LogManager; import org.apache.log4j.Logger; import org.boon.Maps; import java.lang.reflect.Field; import java.text.SimpleDateFormat; import java.util.*; /** * Mapping Objects into Entities and vice versa */ public class GaeMarshaller implements Marshaller { private IdentityHashMap<Object, Entity> stack = new IdentityHashMap<Object, Entity>(); /** * GAE Datastore supported types. */ protected static final Set<Class<?>> GAE_SUPPORTED_TYPES = DataTypeUtils.getSupportedTypes(); protected static Logger LOG = LogManager.getLogger(GaeMarshaller.class.getName()); public GaeMarshaller() { stack.clear(); } /** * * Create entity objects that can be persisted into the GAE Datastore, * including its Parent-Child relationships (if necessary). * * @param parent parent of the generated entity or Entities * @param instance to marshall * @return */ @Override public IdentityHashMap marshall(Key parent, Object instance) { if (instance == null) { throw new RuntimeException("Object cannot be null"); } Entity e = null; // Its possible that a Entity to be saved without id and just a parent key if (parent != null && hasNoIdField(instance)) { String kind = getKindOf(instance); e = new Entity(kind, parent); } else { Key key = createKeyFrom(parent, instance); // inspect kind and create key e = new Entity(key); } boolean indexed = !AnnotationUtil.isClassAnnotated(GaeObjectStore.unIndexed(), instance); Map<String, Object> props = new LinkedHashMap<String, Object>(); List<Entity> target = null; // Marshall java.util.Map if (instance instanceof Map) { Map map = (Map) instance; if (String.class.getName().equals(MapHelper.getKeyType(map))) { Iterator<Map.Entry<String, Object>> it = map.entrySet().iterator(); while (it.hasNext()) { Map.Entry<String, Object> entry = it.next(); String entryKey = entry.getKey(); Object entryVal = entry.getValue(); if (!entryKey.equals(GaeObjectStore.KEY_RESERVED_PROPERTY) && !entryKey.equals(GaeObjectStore.KIND_RESERVED_PROPERTY) && !entryKey.equals(GaeObjectStore.NAMESPACE_RESERVED_PROPERTY)) { if (entryVal instanceof Map) { setProperty(e, entryKey, createEmbeddedEntityFromMap((Map) entryVal), indexed); } else if (entryVal instanceof List) { setProperty(e, entryKey, createEmbeddedEntityFromList((List) entryVal), indexed); } else { setProperty(e, entryKey, entryVal, indexed); } } } } else { throw new RuntimeException( String.class.getName() + " is the only supported " + Map.class.getName() + " key"); } } else { // Marshall all other object types Field[] fields = instance.getClass().getDeclaredFields(); GeoPt geoPt = null; for (Field field : fields) { if (target == null) { target = new LinkedList<Entity>(); } if ((field.getModifiers() & java.lang.reflect.Modifier.FINAL) == java.lang.reflect.Modifier.FINAL) { // do nothing for a final field // usually static UID fields continue; } String fieldName = field.getName(); if (field.isAnnotationPresent(GaeObjectStore.key())) { // skip continue; } else if (field.isAnnotationPresent(GaeObjectStore.kind())) { continue; } else if (field.isAnnotationPresent(Volatile.class)) { // skip continue; } try { boolean isAccessible = field.isAccessible(); field.setAccessible(true); Class<?> fieldType = field.getType(); Object fieldValue = field.get(instance); if (fieldValue == null) { e.setProperty(fieldName, null); } else if (fieldValue instanceof String) { setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof Number || fieldValue instanceof Long || fieldValue instanceof Integer || fieldValue instanceof Short) { setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof Boolean) { setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof Date) { setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof User) { // GAE support this type setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof List) { LOG.debug("Processing List valueType"); if (field.isAnnotationPresent(Embedded.class)) { setProperty(e, fieldName, createEmbeddedEntityFromList((List) fieldValue), indexed); } else { boolean supported = true; List list = (List) fieldValue; for (Object item : list) { if (!GAE_SUPPORTED_TYPES.contains(item.getClass())) { supported = false; } } if (supported) { setProperty(e, fieldName, fieldValue, indexed); } else { throw new RuntimeException("List should only include GAE supported types " + GAE_SUPPORTED_TYPES + " otherwise annotate the List with @Embedded"); } } } else if (fieldValue instanceof GeoPt) { setProperty(e, fieldName, fieldValue, indexed); } else if (fieldValue instanceof Map) { LOG.debug("Processing Map valueType"); if (field.isAnnotationPresent(Embedded.class)) { setProperty(e, fieldName, createEmbeddedEntityFromMap((Map) fieldValue), indexed); } else if (field.isAnnotationPresent(Flat.class)) { Map<String, Object> flat = (Map) fieldValue; Iterator<Map.Entry<String, Object>> it = flat.entrySet().iterator(); if (!it.hasNext()) { LOG.debug("Iterator is empty"); } while (it.hasNext()) { Object entry = it.next(); try { Map.Entry<Object, Object> mapEntry = (Map.Entry<Object, Object>) entry; Object entryKey = mapEntry.getKey(); Object entryVal = mapEntry.getValue(); if (entryVal == null) { setProperty(e, (String) entryKey, null, indexed); } else if (entryVal instanceof Map) { setProperty(e, (String) entryKey, createEmbeddedEntityFromMap((Map) entryVal), indexed); } else if (entryVal instanceof List) { throw new RuntimeException("List values are not yet supported"); } else if (entryVal instanceof String || entryVal instanceof Number || entryVal instanceof Boolean || entryVal instanceof Date || entryVal instanceof User) { setProperty(e, (String) entryKey, entryVal, indexed); } else { throw new RuntimeException( "Unsupported GAE property type: " + entryVal.getClass().getName()); } if (e == null) { throw new RuntimeException("Entity is null"); } } catch (ClassCastException ex) { // Something is wrong here ex.printStackTrace(); } catch (Exception ex) { ex.printStackTrace(); } } } else { throw new TwistException("Map type should be annotated with @Embedded or @Flat"); } } else { // For primitives if (fieldType.equals(int.class)) { int i = (Integer) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(boolean.class)) { boolean i = (Boolean) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(byte.class)) { byte i = (Byte) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(short.class)) { short i = (Short) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(long.class)) { long i = (Long) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(float.class)) { float i = (Float) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(double.class)) { double i = (Double) fieldValue; setProperty(e, fieldName, i, indexed); } else if (fieldType.equals(byte.class)) { byte b = (byte) fieldValue; Blob blob = new Blob(new byte[b]); setProperty(e, fieldName, blob, indexed); } else if (fieldType.equals(byte[].class)) { byte[] bytes = (byte[]) fieldValue; Blob blob = new Blob(bytes); setProperty(e, fieldName, blob, indexed); } else { // POJO if (field.isAnnotationPresent(Embedded.class)) { Map<String, Object> map = createMapFrom(fieldValue); EmbeddedEntity ee = createEmbeddedEntityFromMap(map); setProperty(e, fieldName, ee, indexed); } else if (field.isAnnotationPresent(GaeObjectStore.parent())) { // @Parent first before @Child, don't switch. @Child needs parent Key. if (field.getType().equals(Key.class)) { // skip it continue; } else { if (parent != null) { // Case where a Parent entity is marshalled then during the // iteration process, a @Child entity is found Entity _target = new Entity(createKeyFrom(parent, instance)); _target.setPropertiesFrom(e); e = _target; } else { // Case where a Child entity is first marshalled // at this point this child is not yet in the stack // and the Parent entity is not yet also in the stack // so we will create a Key from the "not yet marshalled" parent instance // or is it not? Let's check. Object parentField = field.get(instance); Entity parentEntity = stack.get(parentField); if (parentEntity != null) { Entity _target = new Entity( createKeyFrom(parentEntity.getKey(), instance)); _target.setPropertiesFrom(e); e = _target; } else { Key generatedParentKey = createKeyFrom(null, parentField); Entity _target = new Entity( createKeyFrom(generatedParentKey, instance)); _target.setPropertiesFrom(e); e = _target; marshall(null, parentField); } } } } else if (field.isAnnotationPresent(GaeObjectStore.child())) { Object childField = field.get(instance); marshall(e.getKey(), childField); Entity childEntity = stack.get(childField); Key childEntityKey = childEntity.getKey(); setProperty(e, fieldName, childEntityKey, indexed); } else if (field.isAnnotationPresent(GaeObjectStore.ancestor())) { // already processed above, skip it } else { throw new RuntimeException( "POJO's must be annotated with @Embedded, @Parent or @Child annotations for field " + fieldName); } } } field.setAccessible(isAccessible); } catch (IllegalAccessException ex) { ex.printStackTrace(); } } } stack.put(instance, e); return stack; } public static <T> T createObjectFrom(Class<T> clazz, Entity source) { T obj = null; Map<String, Object> props = source.getProperties(); Iterator<Map.Entry<String, Object>> it = props.entrySet().iterator(); if (props.size() > 1) { if (clazz == List.class) { throw new RuntimeException("Not yet implemented"); } else if (clazz == Map.class) { throw new RuntimeException("Not yet implemented"); } else { //obj = createPOJOFrom(clazz, createMapFromEntity(source)); } } else if (props.size() == 1) { Map.Entry<String, Object> entry = it.next(); Object value = entry.getValue(); if (clazz.isPrimitive()) { obj = (T) value; } else if (clazz == String.class) { String prop = String.valueOf(value); obj = (T) prop; } else if (clazz == Number.class || clazz == Long.class || clazz == Integer.class) { Long prop = Long.valueOf(String.valueOf(value)); obj = (T) prop; } else if (clazz == Boolean.class) { Boolean prop = Boolean.valueOf(String.valueOf(value)); obj = (T) prop; } } else { // empty } return obj; } /** * * Create a new entity from Java primitive types, String, Number, Boolean * When obj is a primitive type, or String, Number, Boolean, the entity that will be created * is a single property entity with key from {@code target} and a single value of obj * * @param target entity with Key that will be populated * @param obj to get properties from * @return marshalled */ public static Entity createEntityFromBasicTypes(Entity target, Object obj) { if (obj == null) { throw new RuntimeException("Object should not be null"); } Map<String, Object> props = null; try { if (obj.getClass().isPrimitive()) { String key = target.getKey().getName(); // TODO: Must wrap primitives to object representation target.setProperty(key, obj); } else if (obj instanceof String || obj instanceof Number || obj instanceof Boolean) { String key = target.getKey().getName(); target.setProperty(key, obj); } else if (obj instanceof List) { List<Object> list = (List<Object>) obj; } else if (obj instanceof Map) { Map map = (Map) obj; } else { throw new RuntimeException("Method can only process basic types"); } } catch (Exception ex) { target = null; } return target; } /** * Inspect the surface of object * * @param instance key * @return */ private Key inspectObjectAndCreateKey(Object instance) { AnnotationUtil.AnnotatedField parentField = AnnotationUtil.getFieldWithAnnotation(GaeObjectStore.parent(), instance); String fieldName = parentField.getFieldName(); Object fieldValue = parentField.getFieldValue(); return null; } private static String getKindOf(Object instance) { String kind; if (instance instanceof Map) { kind = (String) ((Map) instance).get(GaeObjectStore.KIND_RESERVED_PROPERTY); if (kind == null || kind.isEmpty()) { kind = instance.getClass().getSimpleName(); } return kind; } com.pastekit.twist.annotations.Entity anno = (com.pastekit.twist.annotations.Entity) AnnotationUtil .getClassAnnotation(com.pastekit.twist.annotations.Entity.class, instance); AnnotationUtil.AnnotatedField kindField = AnnotationUtil.getFieldWithAnnotation(Kind.class, instance); if (kindField != null && kindField.getFieldValue() != null) { kind = (String) kindField.getFieldValue(); } else if (anno != null) { // Get the kind if (anno.name() != null && !anno.name().isEmpty()) { kind = anno.name(); } else { kind = StringHelper.getClassNameOf(instance); } } else { kind = StringHelper.getClassNameOf(instance); } return kind; } private static boolean hasNoIdField(Object instance) { AnnotationUtil.AnnotatedField idField = AnnotationUtil.getFieldWithAnnotation(GaeObjectStore.key(), instance); return idField == null ? true : false; } /** * Creates a Key from a object instance, the kind is inspected in * the process. * * @param parent key or null * @param instance String, Long/long key object * @return GAE {@code Key} */ public static Key createKeyFrom(Key parent, Object instance) { Key key = null; Object id = null; String kind = getKindOf(instance); if (instance instanceof Map) { id = ((Map) instance).get(GaeObjectStore.KEY_RESERVED_PROPERTY); if (id != null) { if (id instanceof Long || instance.getClass().equals(long.class)) { key = KeyStructure.createKey(parent, kind, (Long) id); } else if (id instanceof String) { key = KeyStructure.createKey(parent, kind, (String) id); } else { throw new RuntimeException( "Unsupported " + GaeObjectStore.KEY_RESERVED_PROPERTY + ". Use String or Long type"); } } else { // auto-generate "key" when not supplied key = KeyStructure.createKey(parent, kind, KeyStructure.autoLongId(kind)); } return key; } AnnotationUtil.AnnotatedField ancestorField = AnnotationUtil .getFieldWithAnnotation(GaeObjectStore.ancestor(), instance); AnnotationUtil.AnnotatedField parentField = AnnotationUtil.getFieldWithAnnotation(GaeObjectStore.parent(), instance); AnnotationUtil.AnnotatedField idField = AnnotationUtil.getFieldWithAnnotation(GaeObjectStore.key(), instance); if (ancestorField != null) { Class<?> clazz = ancestorField.getFieldType(); if (clazz.equals(Key.class)) { Key ancestor = (Key) ancestorField.getFieldValue(); // TODO: No use use it seems } else { throw new RuntimeException("Only " + Key.class + " is supported to be annoated with @Ancestor"); } } if (idField != null) { if (parentField != null && parentField.getFieldValue() != null) { if (parentField.getFieldValue().getClass().equals(Key.class)) { parent = (Key) parentField.getFieldValue(); } } Class<?> clazz = idField.getFieldType(); id = idField.getFieldValue(); if (clazz.equals(String.class)) { if (id != null) { key = KeyStructure.createKey(parent, kind, (String) id); } else { Id annotation = (Id) idField.annotation(); String prefix = annotation.prefix(); if (prefix != null && !prefix.isEmpty()) { Key auto = KeyStructure.createKey(parent, kind, KeyStructure.autoLongId(kind)); Long autoId = auto.getId(); key = KeyStructure.createKey(parent, kind, prefix + autoId); } else { throw new AutoGenerateStringIdException(); } } } else if (clazz.equals(Long.class)) { if (id != null) { key = KeyStructure.createKey(parent, kind, (Long) id); } else { // auto-generate key = KeyStructure.createKey(parent, kind, KeyStructure.autoLongId(kind)); } } else if (clazz.equals(long.class)) { key = KeyStructure.createKey(parent, kind, (Long) id); } else { throw new RuntimeException("Unsupported @Id type " + id.getClass() + " Use String or Long type"); } } else { throw new RuntimeException( "Object does not have id or key. Must put @Id annotation on " + instance.getClass()); } return key; } /** * Create <code>EmbeddedEntity</code> from List * * @param entity to marshall into {@code EmbeddedEntity} * @return marshalled */ //TODO: This method is quite the most problematic part, since there is no list implementation in the Datastore, unlike with a <code>Map</code>. public EmbeddedEntity createEmbeddedEntityFromList(List entity) { if (entity == null) { throw new RuntimeException("List entity cannot be nulll"); } EmbeddedEntity ee = null; try { int index = 0; ee = new EmbeddedEntity(); // if (parent != null) // ee.setKey(parent); for (Object o : entity) { if (o instanceof String || o instanceof Boolean || o instanceof Number || o instanceof Date || o instanceof User) { ee.setProperty(String.valueOf(index), o); } else if (o instanceof List) { ee.setProperty(String.valueOf(index), createEmbeddedEntityFromList((List) o)); } else if (o instanceof Map) { ee.setProperty(String.valueOf(index), createEmbeddedEntityFromMap((Map) o)); } if (o == null) { ee.setProperty(String.valueOf(index), null); } index++; } } catch (Exception e) { // TODO Handle exception e.printStackTrace(); } return ee; } /** * Creates a <code>EmbeddedEntity</code> from a <code>Map</code> * Which may include inner <code>EmbeddedEntity</code>. * * @param map to marshall into {@code EmbeddedEntity} * @return marshalled */ public EmbeddedEntity createEmbeddedEntityFromMap(Map<String, Object> map) { if (map == null) { throw new RuntimeException("Map entity cannot be null"); } // I think this is not necessary: // Deal with empty map // if (entity.size() == 0){ // EmbeddedEntity ee = new EmbeddedEntity(); // if (parent != null) // ee.setKey(parent); // return ee; // } EmbeddedEntity ee = null; Object oid = map.get(GaeObjectStore.KEY_RESERVED_PROPERTY); // TODO! Iterator<Map.Entry<String, Object>> it = map.entrySet().iterator(); while (it.hasNext()) { if (ee == null) { ee = new EmbeddedEntity(); } Map.Entry<String, Object> entry = it.next(); String key = entry.getKey(); Object value = entry.getValue(); if (value == null) { ee.setProperty(key, null); } else if (value instanceof String) { ee.setProperty(key, value); } else if (value instanceof Number) { ee.setProperty(key, value); } else if (value instanceof Boolean) { ee.setProperty(key, value); } else if (value instanceof Date) { ee.setProperty(key, value); } else if (value instanceof User) { ee.setProperty(key, value); } else if (value instanceof List) { ee.setProperty(key, createEmbeddedEntityFromList((List) value)); } else if (value instanceof Map) { Map<String, Object> newMap = (Map<String, Object>) value; ee.setProperty(key, createEmbeddedEntityFromMap(map)); } } LOG.debug("Warning method is returning null valueType"); return ee; } private static void validateKey(Object key) { throw new IllegalArgumentException("Invalid key"); } /** TODOS **/ /** * * Evaluates whether to return a <code>List</code> or a <code>Map</code> from the * values in the given <code>EmbeddedEntity</code> * <br> * <br> * Since a JSON List or Map is stored in the same type as a <code>EmbeddedEntity</code> * it is needed to analyze the property names of the specified embedded entity to decide whether its * a <code>List</code> or a <code>Map</code> instance. * * An <code>EmbeddedEntity</code> was chosen approach than directly mapping the list into the * parent entity because JSON array can contain arbitrary values and even objects too. * * This method will read all the property names of the entity and if all of its properties have * a dot-number prefix then it will be transformed into a List, otherwise a Map * * @param ee * @return */ public static Object getMapOrList(final EmbeddedEntity ee) { boolean isList = true; Iterator<String> it = ee.getProperties().keySet().iterator(); while (it.hasNext()) { String propName = it.next(); if (!propName.matches("[0-9]{1,9}")) { isList = false; } } if (isList) { return createListFromEmbeddedEntity(ee); } else { return createMapFromEmbeddedEntity(ee); } } /** * Get the <code>List</code> out of the Embedded entity. * The <code>List</code> is expected to be stored following a dot (.) notation. * E.g. A JSON array with a keyType of "numbers" will be stored as a <code>EmbeddedEntity</code> * with property names: * * <code> * numbers.0 * numbers.1 * numbers.2 * </code> * * And so on. And since it is stored a a <code>EmbeddedEntity</code> then it is ambiguous to a * <code>Map</code> that is also stored in the same Datastore type. * * @param ee {@code EmbeddedEntity} to unmarshall * @return {@code List} of unmarshalled {@code EmbeddedEntity} */ private static List<Object> createListFromEmbeddedEntity(final EmbeddedEntity ee) { List<Object> list = null; Iterator<Map.Entry<String, Object>> it = ee.getProperties().entrySet().iterator(); Object[] arr = new Object[1024]; List<Integer> indexToRemove = new ArrayList<Integer>(); for (int i = 0; i < arr.length; i++) { indexToRemove.add(i); } while (it.hasNext()) { Map.Entry<String, Object> entry = it.next(); try { if (list == null) { list = new LinkedList<Object>(); } Object value = entry.getValue(); Integer i = Integer.valueOf(entry.getKey()); LOG.debug("Value=" + entry.getValue()); if (value instanceof String || value instanceof Boolean || value instanceof Number || value instanceof Date || value instanceof User) // GAE supported type { arr[i] = value; indexToRemove.remove(i); } else if (value instanceof EmbeddedEntity) { arr[i] = getMapOrList((EmbeddedEntity) value); indexToRemove.remove(i); } else { throw new RuntimeException("Invalid JSON field type in embedded list entity"); } } catch (Exception e) { // TODO Handle exception e.printStackTrace(); } } int[] intArray = ArrayUtils.toPrimitive(indexToRemove.toArray(new Integer[indexToRemove.size()])); arr = copyArrayRemove(arr, intArray); return Arrays.asList(arr); } /** * Process <code>EmbeddedEntity</code> and inner <code>EmbeddedEntity</code> * of this entity. * * @param ee {@code EmbeddedEntity} to unmarshall into map * @return unmarshalled */ public static Map<String, Object> createMapFromEmbeddedEntity(final EmbeddedEntity ee) { Map<String, Object> map = null; try { map = new HashMap<String, Object>(); map.putAll(ee.getProperties()); Map<String, Object> newMap = new HashMap<String, Object>(); Iterator<Map.Entry<String, Object>> it = map.entrySet().iterator(); while (it.hasNext()) { Map.Entry<String, Object> entry = it.next(); if (entry.getValue() instanceof EmbeddedEntity) { LOG.debug("Inner embedded entity found with keyType=" + entry.getKey()); // newMap.put(entry.getKey(), createMapFromEmbeddedEntity( (EmbeddedEntity) entry.getValue())); newMap.put(entry.getKey(), getMapOrList((EmbeddedEntity) entry.getValue())); it.remove(); } } map.putAll(newMap); } catch (Exception e) { // TODO Handle exception e.printStackTrace(); LOG.error("Error when processing EmbeddedEntity to Map"); } return map; } /** * Used as a method in the chain of making a {@code EmbeddedEntity} from a given * POJO instance. Should not be used other than for EmbeddedEntity objects. * * @param instance TODO * @return Map */ public Map<String, Object> createMapFrom(Object instance) { Map<String, Object> result = Maps.toMap(instance); return result; } private static Object[] copyArrayRemove(Object[] objects, int[] elemToRemove) { LOG.debug("Removing elements from array=" + elemToRemove); Object[] nobjs = Arrays.copyOf(objects, objects.length - elemToRemove.length); for (int i = 0, j = 0, k = 0; i < objects.length; i++) { if (j < elemToRemove.length && i == elemToRemove[j]) { j++; } else { nobjs[k++] = objects[i]; } } return nobjs; } /** * Helper method to convert a retrieved Date object from the GAE Datastore * to a string format that Google Gson library can map to a Date field on a POJO * * @param map * @return */ private static Map<String, Object> formatDates(Map<String, Object> map) { Iterator<Map.Entry<String, Object>> it = map.entrySet().iterator(); Map<String, Object> dateMap = new HashMap<String, Object>(); while (it.hasNext()) { Map.Entry<String, Object> entry = it.next(); String key = entry.getKey(); Object value = entry.getValue(); if (value instanceof Date) { Date date = (Date) value; String dateString = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssz").format(date); // Causes, Caused by: java.text.ParseException: Unparseable date: "Mon Jul 15 17:17:32 UTC 2013" dateMap.put(key, dateString); } } map.putAll(dateMap); return map; } private static <T> T getAs(Object obj, Class<T> clazz) { if (obj == null) { return null; } if (obj.getClass().equals(clazz)) { return (T) obj; } T newObj = null; try { newObj = (T) obj; } catch (ClassCastException e) { throw new RuntimeException("Invalid object valueType type is being assigned to Object"); } return newObj; } private static void setProperty(Entity entity, String key, Object value, boolean isIndexed) { if (isIndexed) { setIndexedProperty(entity, key, value); } else { setUnindexProperty(entity, key, value); } } private static void setUnindexProperty(Entity entity, String key, Object value) { LOG.debug("Setting unindexed property key: " + key); if (entity == null) { throw new RuntimeException("entity can't be null"); } if (key == null) { throw new RuntimeException("entity property key can't be null"); } if (key.isEmpty()) { throw new IllegalArgumentException("entity property key can't be empty"); } if (value == null) { entity.setUnindexedProperty(key, null); return; } if (!GAE_SUPPORTED_TYPES.contains(value.getClass()) && !(value instanceof Blob) && !(value instanceof EmbeddedEntity) && !(value instanceof List)) { throw new RuntimeException( "Unsupported type[class=" + value.getClass().getName() + "] in GAE repository"); } if (value instanceof String) { final String valueString = (String) value; if (valueString.length() > DataTypeUtils.MAX_STRING_PROPERTY_LENGTH) { final Text text = new Text(valueString); entity.setUnindexedProperty(key, text); } else { entity.setUnindexedProperty(key, value); } } else if (value instanceof Number || value instanceof Date || value instanceof Boolean || GAE_SUPPORTED_TYPES.contains(value.getClass())) { entity.setUnindexedProperty(key, value); } else if (value instanceof EmbeddedEntity) { entity.setUnindexedProperty(key, value); } else if (value instanceof Blob) { final Blob blob = (Blob) value; entity.setUnindexedProperty(key, new com.google.appengine.api.datastore.Blob(blob.getBytes())); } else if (value instanceof List) { entity.setUnindexedProperty(key, value); } } private static void setIndexedProperty(Entity entity, String key, Object value) { if (entity == null) { throw new RuntimeException("entity can't be null"); } if (key == null) { throw new RuntimeException("entity property key can't be null"); } if (key.isEmpty()) { throw new IllegalArgumentException("entity property key can't be empty"); } if (value == null) { entity.setProperty(key, null); return; } if (!GAE_SUPPORTED_TYPES.contains(value.getClass()) && !(value instanceof Blob) && !(value instanceof EmbeddedEntity) && !(value instanceof List)) { throw new RuntimeException( "Unsupported type[class=" + value.getClass().getName() + "] in GAE repository"); } if (value instanceof String) { final String valueString = (String) value; if (valueString.length() > DataTypeUtils.MAX_STRING_PROPERTY_LENGTH) { final Text text = new Text(valueString); entity.setProperty(key, text); } else { entity.setProperty(key, value); } } else if (value instanceof Number || value instanceof Date || value instanceof Boolean || GAE_SUPPORTED_TYPES.contains(value.getClass())) { entity.setProperty(key, value); } else if (value instanceof EmbeddedEntity) { entity.setProperty(key, value); } else if (value instanceof Blob) { final Blob blob = (Blob) value; entity.setProperty(key, new com.google.appengine.api.datastore.Blob(blob.getBytes())); } else if (value instanceof List) { entity.setProperty(key, value); } } }