Getting an element by id in Google App Engine's JDO - google-app-engine

I have a problem when trying to find a single element
by id. The entity class is this:
#PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Test{
#PrimaryKey
private String name;
//..and so on.
In this case, the value "name" is acting like an id. I'm using this
query to find the element:
PersistenceManager pm = PMF.get().getPersistenceManager();
Query q = pm.newQuery(Test.class);
q.setFilter("name == " + id);
//String query = "SELECT FROM " + Test.class.getName() + "WHERE name == " + id;
Test test = (Test) q.execute();
return category;
Assuming id is a string value sent as a parameter by other method.
But it doesn't retrieve any data. Also, it throws an exception:
java.lang.ClassCastException:
org.datanucleus.store.appengine.query.StreamingQueryResult cannot be
cast to com.santiagopoli.gapptest.domain.Test
The commented query also doesn't work.
I hope anyone can help me. Is a shame that something that basic is
difficult to achieve. In other sql implementations, it will be easy as
typing "select * from Test where id=". Thanks!

I just fixed it.
Try this...
Test t = pm.getObjectById(Test.class, id);
reference...
http://code.google.com/intl/us/appengine/docs/java/datastore/jdo/creatinggettinganddeletingdata.html

Related

Salesforce : Apex test class for the getting trending articles of Knowledge from Community

I need to get trending articles from the community. I created a apex class for that by using ConnectApi.Knowledge.getTrendingArticles(communityId, maxResult).
I need to create a test class for that. I am using test class method provided by Salesforce for that. setTestGetTrendingArticles(communityId, maxResults, result) but I am getting this error "System.AssertException: Assertion Failed: No matching test result found for Knowledge.getTrendingArticles(String communityId, Integer maxResults). Before calling this, call Knowledge.setTestGetTrendingArticles(String communityId, Integer maxResults, ConnectApi.KnowledgeArticleVersionCollection result) to set the expected test result."
public without sharing class ConnectTopicCatalogController {
#AuraEnabled(cacheable=true)
public static List<ConnectApi.KnowledgeArticleVersion> getAllTrendingArticles(){
string commId = [Select Id from Network where Name = 'Customer Community v5'].Id;
ConnectApi.KnowledgeArticleVersionCollection mtCollection = ConnectApi.Knowledge.getTrendingArticles(commId, 12);
System.debug('getAllTrendingTopics '+JSON.serializePretty(mtCollection.items));
List<ConnectApi.KnowledgeArticleVersion> topicList = new List<ConnectApi.KnowledgeArticleVersion>();
for(ConnectApi.KnowledgeArticleVersion mtopic : mtCollection.items)
{
topicList.add(mtopic);
}
return topicList;
}
}
Test class that I am using for this
public class ConnectTopicCatalogControllerTest {
public static final string communityId = [Select Id from Network where Name = 'Customer Community v5'].Id;
#isTest
static void getTrendingArticles(){
ConnectApi.KnowledgeArticleVersionCollection knowledgeResult = new ConnectApi.KnowledgeArticleVersionCollection();
List<ConnectApi.KnowledgeArticleVersion> know = new List<ConnectApi.KnowledgeArticleVersion>();
know.add(new ConnectApi.KnowledgeArticleVersion());
know.add(new ConnectApi.KnowledgeArticleVersion());
system.debug('know '+know);
knowledgeResult.items = know;
// Set the test data
ConnectApi.Knowledge.setTestGetTrendingArticles(null, 12, knowledgeResult);
List<ConnectApi.KnowledgeArticleVersion> res = ConnectTopicCatalogController.getAllTrendingArticles();
// The method returns the test page, which we know has two items in it.
Test.startTest();
System.assertEquals(12, res.size());
Test.stopTest();
}
}
I need help to solve the test class
Thanks.
Your controller expects the articles to be inside the 'Customer Community v5' community, but you are passing the communityId parameter as null to the setTestGetTrendingArticles method.

Reading in all docs (doc id only if possible) from Solr without searching

I know Solr is meant to be used for searching.
However, I am doing some benchmarking and I wonder if there is a way to retrieve doc id of every document indexed.
The best option is retrieving without searching (if there exist a way).
I guess the alternative is to query all documents but only asks for doc id.
I will be using SolrJ, so operations of SolrJ would be useful
Use the /export end point: Exporting result sets.
It supports using the same fl parameter as regular search (although searching for just *:* will probably behave quite similar when you're using SolrJ).
In SolrJ you'll have to use the CloudSolrStream class instead to properly stream the results (as compared to the regular behavior when searching for *:*).
From Joel Bernstein's example when introducing the feature:
import org.apache.solr.client.solrj.io.*;
import java.util.*;
public class StreamingClient {
public static void main(String args[]) throws IOException {
String zkHost = args[0];
String collection = args[1];
Map props = new HashMap();
props.put("q", "*:*");
props.put("qt", "/export");
props.put("sort", "fieldA asc");
props.put("fl", "fieldA,fieldB,fieldC");
CloudSolrStream cstream = new CloudSolrStream(zkHost,
collection,
props);
try {
cstream.open();
while(true) {
Tuple tuple = cstream.read();
if(tuple.EOF) {
break;
}
String fieldA = tuple.getString("fieldA");
String fieldB = tuple.getString("fieldB");
String fieldC = tuple.getString("fieldC");
System.out.println(fieldA + ", " + fieldB + ", " + fieldC);
}
} finally {
cstream.close();
}
}
}

Why Spring is turning my object into an array of attributes? [duplicate]

I'm developing a Spring Boot application with Spring Data JPA. I'm using a custom JPQL query to group by some field and get the count. Following is my repository method.
#Query(value = "select count(v) as cnt, v.answer from Survey v group by v.answer")
public List<?> findSurveyCount();
It's working and result is obtained as follows:
[
[1, "a1"],
[2, "a2"]
]
I would like to get something like this:
[
{ "cnt":1, "answer":"a1" },
{ "cnt":2, "answer":"a2" }
]
How can I achieve this?
Solution for JPQL queries
This is supported for JPQL queries within the JPA specification.
Step 1: Declare a simple bean class
package com.path.to;
public class SurveyAnswerStatistics {
private String answer;
private Long cnt;
public SurveyAnswerStatistics(String answer, Long cnt) {
this.answer = answer;
this.count = cnt;
}
}
Step 2: Return bean instances from the repository method
public interface SurveyRepository extends CrudRepository<Survey, Long> {
#Query("SELECT " +
" new com.path.to.SurveyAnswerStatistics(v.answer, COUNT(v)) " +
"FROM " +
" Survey v " +
"GROUP BY " +
" v.answer")
List<SurveyAnswerStatistics> findSurveyCount();
}
Important notes
Make sure to provide the fully-qualified path to the bean class, including the package name. For example, if the bean class is called MyBean and it is in package com.path.to, the fully-qualified path to the bean will be com.path.to.MyBean. Simply providing MyBean will not work (unless the bean class is in the default package).
Make sure to call the bean class constructor using the new keyword. SELECT new com.path.to.MyBean(...) will work, whereas SELECT com.path.to.MyBean(...) will not.
Make sure to pass attributes in exactly the same order as that expected in the bean constructor. Attempting to pass attributes in a different order will lead to an exception.
Make sure the query is a valid JPA query, that is, it is not a native query. #Query("SELECT ..."), or #Query(value = "SELECT ..."), or #Query(value = "SELECT ...", nativeQuery = false) will work, whereas #Query(value = "SELECT ...", nativeQuery = true) will not work. This is because native queries are passed without modifications to the JPA provider, and are executed against the underlying RDBMS as such. Since new and com.path.to.MyBean are not valid SQL keywords, the RDBMS then throws an exception.
Solution for native queries
As noted above, the new ... syntax is a JPA-supported mechanism and works with all JPA providers. However, if the query itself is not a JPA query, that is, it is a native query, the new ... syntax will not work as the query is passed on directly to the underlying RDBMS, which does not understand the new keyword since it is not part of the SQL standard.
In situations like these, bean classes need to be replaced with Spring Data Projection interfaces.
Step 1: Declare a projection interface
package com.path.to;
public interface SurveyAnswerStatistics {
String getAnswer();
int getCnt();
}
Step 2: Return projected properties from the query
public interface SurveyRepository extends CrudRepository<Survey, Long> {
#Query(nativeQuery = true, value =
"SELECT " +
" v.answer AS answer, COUNT(v) AS cnt " +
"FROM " +
" Survey v " +
"GROUP BY " +
" v.answer")
List<SurveyAnswerStatistics> findSurveyCount();
}
Use the SQL AS keyword to map result fields to projection properties for unambiguous mapping.
This SQL query return List< Object[] > would.
You can do it this way:
#RestController
#RequestMapping("/survey")
public class SurveyController {
#Autowired
private SurveyRepository surveyRepository;
#RequestMapping(value = "/find", method = RequestMethod.GET)
public Map<Long,String> findSurvey(){
List<Object[]> result = surveyRepository.findSurveyCount();
Map<Long,String> map = null;
if(result != null && !result.isEmpty()){
map = new HashMap<Long,String>();
for (Object[] object : result) {
map.put(((Long)object[0]),object[1]);
}
}
return map;
}
}
I know this is an old question and it has already been answered, but here's another approach:
#Query("select new map(count(v) as cnt, v.answer) from Survey v group by v.answer")
public List<?> findSurveyCount();
define a custom pojo class say sureveyQueryAnalytics and store the query returned value in your custom pojo class
#Query(value = "select new com.xxx.xxx.class.SureveyQueryAnalytics(s.answer, count(sv)) from Survey s group by s.answer")
List<SureveyQueryAnalytics> calculateSurveyCount();
I do not like java type names in query strings and handle it with a specific constructor.
Spring JPA implicitly calls constructor with query result in HashMap parameter:
#Getter
public class SurveyAnswerStatistics {
public static final String PROP_ANSWER = "answer";
public static final String PROP_CNT = "cnt";
private String answer;
private Long cnt;
public SurveyAnswerStatistics(HashMap<String, Object> values) {
this.answer = (String) values.get(PROP_ANSWER);
this.count = (Long) values.get(PROP_CNT);
}
}
#Query("SELECT v.answer as "+PROP_ANSWER+", count(v) as "+PROP_CNT+" FROM Survey v GROUP BY v.answer")
List<SurveyAnswerStatistics> findSurveyCount();
Code needs Lombok for resolving #Getter
#Repository
public interface ExpenseRepo extends JpaRepository<Expense,Long> {
List<Expense> findByCategoryId(Long categoryId);
#Query(value = "select category.name,SUM(expense.amount) from expense JOIN category ON expense.category_id=category.id GROUP BY expense.category_id",nativeQuery = true)
List<?> getAmountByCategory();
}
The above code worked for me.
I used custom DTO (interface) to map a native query to - the most flexible approach and refactoring-safe.
The problem I had with this - that surprisingly, the order of fields in the interface and the columns in the query matters. I got it working by ordering interface getters alphabetically and then ordering the columns in the query the same way.
I just solved this problem :
Class-based Projections doesn't work with query native(#Query(value = "SELECT ...", nativeQuery = true)) so I recommend to define custom DTO using interface .
Before using DTO should verify the query syntatically correct or not
Get data with column name and its values (in key-value pair) using JDBC:
/*Template class with a basic set of JDBC operations, allowing the use
of named parameters rather than traditional '?' placeholders.
This class delegates to a wrapped {#link #getJdbcOperations() JdbcTemplate}
once the substitution from named parameters to JDBC style '?' placeholders is
done at execution time. It also allows for expanding a {#link java.util.List}
of values to the appropriate number of placeholders.
The underlying {#link org.springframework.jdbc.core.JdbcTemplate} is
exposed to allow for convenient access to the traditional
{#link org.springframework.jdbc.core.JdbcTemplate} methods.*/
#Autowired
protected NamedParameterJdbcTemplate jdbc;
#GetMapping("/showDataUsingQuery/{Query}")
public List<Map<String,Object>> ShowColumNameAndValue(#PathVariable("Query")String Query) throws SQLException {
/* MapSqlParameterSource class is intended for passing in a simple Map of parameter values
to the methods of the {#link NamedParameterJdbcTemplate} class*/
MapSqlParameterSource msp = new MapSqlParameterSource();
// this query used for show column name and columnvalues....
List<Map<String,Object>> css = jdbc.queryForList(Query,msp);
return css;
}
//in Service
`
public List<DevicesPerCustomer> findDevicesPerCustomer() {
LOGGER.info(TAG_NAME + " :: inside findDevicesPerCustomer : ");
List<Object[]> list = iDeviceRegistrationRepo.findDevicesPerCustomer();
List<DevicesPerCustomer> out = new ArrayList<>();
if (list != null && !list.isEmpty()) {
DevicesPerCustomer mDevicesPerCustomer = null;
for (Object[] object : list) {
mDevicesPerCustomer = new DevicesPerCustomer();
mDevicesPerCustomer.setCustomerId(object[0].toString());
mDevicesPerCustomer.setCount(Integer.parseInt(object[1].toString()));
out.add(mDevicesPerCustomer);
}
}
return out;
}`
//In Repo
` #Query(value = "SELECT d.customerId,count(*) FROM senseer.DEVICE_REGISTRATION d where d.customerId is not null group by d.customerId", nativeQuery=true)
List<Object[]> findDevicesPerCustomer();`

JPA query return List<org.datanucleus.store.types.sco.backed.ArrayList> instead List<T>

I'm using JPA on GAE and this query return a List containing 1 element.
This element is a org.datanucleus.store.types.sco.backed.ArrayList (and it's finally containing my results) while I'm expecting a List of Products. What I'm doing wrong?
Thanx in advance!
Query query = entityManager.createQuery
("select p.products from Place p where p.id = :Id" );
query.setParameter("Id",id);
List<Product> resultList = query.getResultList();
//for debugging purpose
assert (resultList.get(0) instanceof Product);
if (resultList.size() > 0)
{
//raise a cast exception here
Product p = resultList.get(0);
}
#Entity
public class Place {
private Collection<Product> products;
#OneToMany(cascade = CascadeType.ALL)
public Collection<Product> getProducts() {
return products;
}
public void setProducts(Collection<Product> products) {
this.products = products;
}
private String id;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true")
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
Selecting a multi-valued field from a JPQL query is illegal when the JPQL spec says the select item should be
"single_valued_path_expression | scalar_expression | aggregate_expression |
identification_variable | OBJECT(identification_variable) | constructor_expression"
so answers saying this query is correct are wrong. If you want the "products" for a Place then you retrieve the Place and it has the products.
I am not much familiar with DataNucleus, so haven't executed. But with JPA, the query should work fine. You can try the below code to build query, which returns results according to the specified class.
entityManager.createQuery("SELECT p.products FROM Place p WHERE p.id = :Id", Product.class);
From Documentation :
<T> TypedQuery<T> createQuery(java.lang.String qlString,
java.lang.Class<T> resultClass)
Create an instance of TypedQuery for executing a Java Persistence
query language statement. The select list of the query must contain
only a single item, which must be assignable to the type specified by
the resultClass argument.
Parameters:
qlString - a Java Persistence query string
resultClass - the type of the query result
Edit :
You can try the following code.
Place place = entityManager.createQuery("SELECT p FROM Place p WHERE p.id = :Id", Place.class).getSingleResult();
List<Products> products = place.getProducts();
Also as a side-note, you are using JPA, but #Extension seems to be JDO specific annotation.
That class javadoc tells that it implements java.util.List, so it is a valid return type.
Remember that the specification says that you get a List as a return type, not a java.util.ArrayList, so any class that implements List is as valid as any other.
UPDATE:
Try:
SELECT pr FROM Place pl INNER JOIN pl.products pr WHERE pl.id = :Id

salesforce SOQL : query to fetch all the fields on the entity

I was going through the SOQL documentation , but couldn't find query to fetch all the field data of an entity say , Account , like
select * from Account [ SQL syntax ]
Is there a syntax like the above in SOQL to fetch all the data of account , or the only way is to list all the fields ( though there are lot of fields to be queried )
Create a map like this:
Map<String, Schema.SObjectField> fldObjMap = schema.SObjectType.Account.fields.getMap();
List<Schema.SObjectField> fldObjMapValues = fldObjMap.values();
Then you can iterate through fldObjMapValues to create a SOQL query string:
String theQuery = 'SELECT ';
for(Schema.SObjectField s : fldObjMapValues)
{
String theLabel = s.getDescribe().getLabel(); // Perhaps store this in another map
String theName = s.getDescribe().getName();
String theType = s.getDescribe().getType(); // Perhaps store this in another map
// Continue building your dynamic query string
theQuery += theName + ',';
}
// Trim last comma
theQuery = theQuery.subString(0, theQuery.length() - 1);
// Finalize query string
theQuery += ' FROM Account WHERE ... AND ... LIMIT ...';
// Make your dynamic call
Account[] accounts = Database.query(theQuery);
superfell is correct, there is no way to directly do a SELECT *. However, this little code recipe will work (well, I haven't tested it but I think it looks ok). Understandably Force.com wants a multi-tenant architecture where resources are only provisioned as explicitly needed - not easily by doing SELECT * when usually only a subset of fields are actually needed.
You have to specify the fields, if you want to build something dynamic the describeSObject call returns the metadata about all the fields for an object, so you can build the query from that.
I use the Force.com Explorer and within the schema filter you can click the checkbox next to the TableName and it will select all the fields and insert into your query window - I use this as a shortcut to typeing it all out - just copy and paste from the query window. Hope this helps.
In case anyone was looking for a C# approach, I was able to use reflection and come up with the following:
public IEnumerable<String> GetColumnsFor<T>()
{
return typeof(T).GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance)
.Where(x => !Attribute.IsDefined(x, typeof(System.Xml.Serialization.XmlIgnoreAttribute))) // Exclude the ignored properties
.Where(x => x.DeclaringType != typeof(sObject)) // & Exclude inherited sObject propert(y/ies)
.Where(x => x.PropertyType.Namespace != typeof(Account).Namespace) // & Exclude properties storing references to other objects
.Select(x => x.Name);
}
It appears to work for the objects I've tested (and matches the columns generated by the API test). From there, it's about creating the query:
/* assume: this.server = new sForceService(); */
public IEnumerable<T> QueryAll<T>(params String[] columns)
where T : sObject
{
String soql = String.Format("SELECT {0} FROM {1}",
String.Join(", ", GetColumnsFor<T>()),
typeof(T).Name
);
this.service.QueryOptionsValue = new QueryOptions
{
batchsize = 250,
batchSizeSpecified = true
};
ICollection<T> results = new HashSet<T>();
try
{
Boolean done = false;
QueryResult queryResult = this.service.queryAll(soql);
while (!finished)
{
sObject[] records = queryResult.records;
foreach (sObject record in records)
{
T entity = entity as T;
if (entity != null)
{
results.Add(entity);
}
}
done &= queryResult.done;
if (!done)
{
queryResult = this.service.queryMode(queryResult.queryLocator);
}
}
}
catch (Exception ex)
{
throw; // your exception handling
}
return results;
}
For me it was the first time with Salesforce today and I came up with this in Java:
/**
* #param o any class that extends {#link SObject}, f.ex. Opportunity.class
* #return a list of all the objects of this type
*/
#SuppressWarnings("unchecked")
public <O extends SObject> List<O> getAll(Class<O> o) throws Exception {
// get the objectName; for example "Opportunity"
String objectName= o.getSimpleName();
// this will give us all the possible fields of this type of object
DescribeSObjectResult describeSObject = connection.describeSObject(objectName);
// making the query
String query = "SELECT ";
for (Field field : describeSObject.getFields()) { // add all the fields in the SELECT
query += field.getName() + ',';
}
// trim last comma
query = query.substring(0, query.length() - 1);
query += " FROM " + objectName;
SObject[] records = connection.query(query).getRecords();
List<O> result = new ArrayList<O>();
for (SObject record : records) {
result.add((O) record);
}
return result;
}
I used following to get complete records-
query_all("Select Id, Name From User_Profile__c")
To get complete fields of record, we have to mention those fields as mentioned here-
https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_select.htm
Hope will help you !!!

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