Hello I have a query and I want the result into list of objects, not entity. But the result is actualy a object which I should transfer to my object. Is there a way to map it directly to my custom object?
Maybe this will help you :
public interface ObjRepository extends JpaRepository<MyObject, Long> {
#Query(value = "FROM MyObject WHERE objname = ?1")
public List<MyObject> findByName(String name);
}
Approach-1: using List of object array.
When using native query, we get list of Object array i.e each row in list is array. Elements in array represent column values.
In repo interface:
#Query(value = "select col1, col2, col3 from table1 where col1 = :key", nativeQuery = true)
List<Object[]> findByKey(#Param("key") String key);
In caller
List<Object[]> objectList = new ArrayList<Object[]>();
objectList = repo.findByKey(key);
List<CustomObject> customObjectList = new ArrayList<>();
for (Object[] tuple : objectList) {
String col1 = (String) tuple[0];
String col2 = (String) tuple[1];
String col3 = (String) tuple[2];
CustomObject obj = new CustomObject();
obj.setCol1(col1);
obj.setCol2(col2);
obj.setCol3(col3);
customObjectList.add(obj);
}
return customObjectList;
Approach-2: using custom dto that represents columns in each row.
Refer https://stackoverflow.com/a/42905382/1358551
final List<MyCustomDTO> statuses = myRepository
.findStatuses(marketId, campaignId, stationIds).stream()
.map(o -> new MyCustomDTO(((BigInteger) o[0]), (Boolean) o[1], (Timestamp) o[2]))
.collect(toList());
public class StationStatusDTO {
private long id;
private boolean isSomething;
private LocalDateTime date;
public MyCustomDTO(BigInteger id, Boolean isSomething, Timestamp date) {
this(id.longValue(),
isSomething,
(date == null) ? null : LocalDateTime
.ofInstant(Instant.ofEpochMilli(date.getTime()),
TimeZone.getDefault().toZoneId()));
}
Related
I'm trying to develop music player, I've made a loader and adapter for my data retreiving from mediastore, but when I call query from my app it only returns one row, I don't know wat's wrong with my code, would u help me fixing that problem?
That's my loader which should return a list I'll use in another place
public static List<Song> getAllArtistSongs(Context context, long artist_id){
List<Song> ArtistSongList = new ArrayList<>();
Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
String[] projection = new String[]{
"_id",
"title",
"album_id",
"album",
"artist",
"duration",
"track"
};
String sortorder = MediaStore.Audio.Media.DEFAULT_SORT_ORDER;
String selection = "is_music=1 and artist_id="+artist_id;
Cursor cursor = context.getContentResolver().query(uri, projection, selection, null, sortorder);
assert cursor != null;
if (cursor.moveToFirst()) {
do {
int trackNumber = cursor.getInt(6);
while (trackNumber >= 1000) {
trackNumber -= 1000;
}
Long id = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media._ID));
String title = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE));
Long albumid = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM_ID));
String albumname = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM));
String artistname = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST));
int duration = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION));
ArtistSongList.add(new Song(id, title, albumid, albumname, artist_id, artistname, duration, trackNumber));
} while (cursor.moveToNext());
cursor.close();
}
return ArtistSongList;
}
And this is the adapter which I use to bind to a recyclerview
public void onBindViewHolder(#NonNull VH holder, int position) {
Song song = artistSongList.get(position);
if(song!=null){
holder.ttv.setText(song.title);
holder.dtv.setText(song.artistName);
int trackN = song.trackNumber;
if(trackN==0){
holder.ntv.setText("_");
}else holder.ntv.setText(String.valueOf(trackN));
}
}
And this is where I call the query func
private void setupAlbumList() {
System.out.println(artistId);
songList = ArtistSongLoader.getAllArtistSongs(getActivity(), artistId);
adapter = new ArtistSongAdapter(getActivity(), songList);
recy.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL));
recy.setAdapter(new ArtistSongAdapter(getActivity(), songList));
}
Thx in advance for helping
My example to retrieve all tracks:
private final String track_id = MediaStore.Audio.Media._ID;
private final String track_no = MediaStore.Audio.Media.TRACK;
private final String track_name = MediaStore.Audio.Media.TITLE;
private final String artist = MediaStore.Audio.Media.ARTIST;
private final String artist_id = MediaStore.Audio.Media.ARTIST_ID;
private final String duration = MediaStore.Audio.Media.DURATION;
private final String album = MediaStore.Audio.Media.ALBUM;
private final String composer = MediaStore.Audio.Media.COMPOSER;
private final String year = MediaStore.Audio.Media.YEAR;
private final String path = MediaStore.Audio.Media.DATA;
private final String date_added = MediaStore.Audio.Media.DATE_ADDED;
public Cursor getAllTracks(Context context) {
// gets all tracks
if (context != null) {
ContentResolver cr = context.getContentResolver();
final String[] columns = {track_id, track_no, artist, track_name,
album, duration, path, year, composer};
return cr.query(uri, columns, null, null, null);
} else {
return null;
}
}
then you have
String selection = "is_music=1"
first, you do not need is_music=1. For multiple tracks you of course need more than 1 track by the same artist
The adapter is irrelevant, the query does the selection
To return albums for an artist
public Cursor getArtistsAlbumcursor(Context context, String artistId) {
ContentResolver cr = context.getContentResolver();
final String _id = MediaStore.Audio.Media._ID;
final String album_id = MediaStore.Audio.Media.ALBUM_ID;
final String artistid = MediaStore.Audio.Media.ARTIST_ID;
final String[] columns = {_id, album_id, artistid};
if (artistId != null) {
String where = artistid + " =?";
String[] aId = {artistId};
return cr.query(uri, columns, where, aId, null);
} else {
return null;
}
}
I am trying to collect 2 data fields from the list object.
I am using Employee object:
public class Employee
{
private long id;
private Source source;
private String name;
private String gender;
// getters
private Builder toBuilder(Builder builder)
{
builder.id = this.summaryDataId;
builder.name = this.name;
builder.gender = this.gender;
builder.source = this.source;
return builder;
}
getting employee data into a list in a service class
final List<Employee> employeeData = employeeDao.retrieveEmployeeData(emp.getID());
and then trying to create a list with employeeId and sourceid (Ex: 1234:3). for this I am trying to use collectors.toList
List<String> employeeCollector = employeeData.stream()
.filter(s -> s.getId != null)
.filter(s -> s.getSource() != null && s.getSource().getId() != null)
.collect(Collectors.toList());
how do i get employeeid:souceid format using collectors.toLis()
You just need an intermediate operation map to extract the employee id and source id
List<String> employeeCollector = employeeData.stream()
.filter(s -> s.getId != null)
.filter(s -> s.getSource() != null && s.getSource().getId() != null)
.map(s-> String.format("%s:%s",s.getId(),s.getSource().getId()))
.collect(Collectors.toList());
I have an arraylist of event
var approvedEvents = ArrayList<Event>()
the class of Event is like this
class Event() {
var eventID : String = ""
var createdBy: String = "" // uid of user creator
var creatorFullName: String = ""
var creatorIsVerified : Boolean = false
var creatorProfilePictureImagePath = ""
var createdAt : Date = Calendar.getInstance().time
var hasBeenApproved : Boolean = false
var title : String = ""
var speaker : String? = null
var coordinate : GeoPoint = City.defaultCityCoordinate
var address : String = ""
var city : String = ""
var venue : String = ""
}
so I want to find an index in approvedEvents arraylist that its eventID match selectedEvent.eventID how to do that in Kotlin ? is there specific method that I can use ?
Use indexOfFirst or indexOfLast to find the index of an item in an ArrayList based on your own criteria like below:
val index = approvedEvents.indexOfFirst{
it.eventID == selectedEvent.eventID
}
First of all, you have to override equals function in your Event class like
------
------
var city : String = ""
var venue : String = ""
override fun equals(other: Any?): Boolean{
if(other is Event){
return eventID.equals(other.eventID)
}
return false;
}
}
Now when you want to search for an Event object with eventId in a list, first create a temporary event object with that eventId which you want to search like
val temp=Event()
temp.eventID="102"
and simply get the index
print(events.indexOf(temp))
spring data jpa 1.4.3 with Oracle 11g.
I have an entity like this:
class LinkRecord {
String value;
int linkType;
...
}
I am using (value, linkType) as a composite index.
For a given list of (v, t) tuples, we need to select all the records in the DB so that value = v, linkType = t.
Basically, I want to build this query:
SELECT * FROM LINK_RECORD WHERE (VALUE, LINK_TYPE) IN (('value1', 0), ('value2', 25), ...)
where the list in the IN clause is passed in as a param.
Since we're working with a large volume of data, it would be very undesirable to query for the tuples one by one.
In my repository I've tried this:
#Query("select r from LinkRecord r where (r.value, r.linkType) in :keys")
List<LinkRecord> findByValueAndType(#Param("keys")List<List<Object>> keys);
where keys is a list of (lists of length 2). This gets me ORA_00920: invalid relational operator.
Is there any way to make this work using a named query? Or do I have to resort to native sql?
The answer is too late, but maybe some1 else has the same problem. This is one of my working examples. Here I need to search for all entries that match a given composite key:
The entity....
#Entity
#NamedQueries({
#NamedQuery(name = "Article.findByIdAndAccessId", query = "SELECT a FROM Article a WHERE a.articlePk IN (:articlePks) ORDER BY a.articlePk.article")
})
#Table(name = "ARTICLE")
public class Article implements Serializable
{
private static final long serialVersionUID = 1L;
#EmbeddedId
private ArticlePk articlePk = new ArticlePk();
#Column(name = "art_amount")
private Float amount;
#Column(name = "art_unit")
private String unit;
public Article()
{
}
//more code
}
The PK class....
#Embeddable
public class ArticlePk implements Serializable
{
private static final long serialVersionUID = 1L;
#Column(name = "art_article")
private String article;
#Column(name = "art_acc_identifier")
private Long identifier;
public ArticlePk()
{
}
public ArticlePk(String article, Long identifier)
{
this.article = article;
this.identifier = identifier;
}
#Override
public boolean equals(Object other)
{
if (this == other)
{
return true;
}
if (!(other instanceof ArticlePk))
{
return false;
}
ArticlePk castOther = (ArticlePk)other;
return this.article.equals(castOther.article) && this.identifier.equals(castOther.identifier);
}
#Override
public int hashCode()
{
final int prime = 31;
int hash = 17;
hash = hash * prime + this.article.hashCode();
hash = hash * prime + this.identifier.hashCode();
return hash;
}
//more code
}
Invocation by....
TypedQuery<Article> queryArticle = entityManager.createNamedQuery("Article.findByIdAndAccessId", Article.class);
queryArticle.setParameter("articlePks", articlePks);
List<Article> articles = queryArticle.getResultList();
where....
articlePks is List<ArticlePk>.
I spent a lot of time on this problem. I am able to do simple Group By LINQ queries (on one property) but for multiple fields I'm a little stuck...
Here is a LINQPad sample of what I want to do :
dim lFinal={new with {.Year=2010, .Month=6, .Value1=0, .Value2=0},
new with {.Year=2010, .Month=6, .Value1=2, .Value2=1},
new with {.Year=2010, .Month=7, .Value1=3, .Value2=4},
new with {.Year=2010, .Month=8, .Value1=0, .Value2=1},
new with {.Year=2011, .Month=1, .Value1=2, .Value2=2},
new with {.Year=2011, .Month=1, .Value1=0, .Value2=0}}
Dim lFinal2 = From el In lFinal
Group el By Key = new with {el.Year,el.Month}
Into Group
Select New With {.Year = Key.Year, .Month=Key.Month, .Value1 = Group.Sum(Function(x) x.Value1), .Value2 = Group.Sum(Function(x) x.Value2)}
lFinal.Dump()
lFinal2.Dump()
The lFinal list has 6 items, I want the lFinal2 to have 4 items : 2010-6 and 2011-1 should group.
Thanks in advance.
Make the properties in the anonymous type immutable using the Key keyword and then they will be used for comparisons
Dim lFinal2 = From el In lFinal
Group el By Key = new with {key el.Year, key el.Month}
Into Group
Select New With {
.Year = Key.Year,
.Month = Key.Month,
.Value1 = Group.Sum(Function(x) x.Value1),
.Value2 = Group.Sum(Function(x) x.Value2)
}
Thanks !
But I noticed I needed to also write the GetHashCode function to make it works. I provide the VB.Net translation of the final class + LINQ GroupBy :
Class :
Public Class YearMonth
Implements IEquatable(Of YearMonth)
Public Property Year As Integer
Public Property Month As Integer
Public Function Equals1(other As YearMonth) As Boolean Implements System.IEquatable(Of YearMonth).Equals
Return other.Year = Me.Year And other.Month = Me.Month
End Function
Public Overrides Function GetHashCode() As Integer
Return Me.Year * 1000 + Me.Month * 100
End Function
End Class
And the LINQ query :
Dim lFinal2 = From el In lFinal
Group el By Key = New YearMonth With {.Year = el.Year, .Month = el.Month}
Into Group
Select New ItemsByDates With {.Year = Key.Year,
.Month = Key.Month,
.Value1 = Group.Sum(Function(x) x.Value1),
.Value2 = Group.Sum(Function(x) x.Value2)}
Not 100% sure but group by probably uses the Equals() and/or GetHashCode implementation, so when you do the implicit creation:
= Group el By Key = new with {el.Year,el.Month}
the implicit object doesn't know to check both year and month (just because it has the properties doesn't mean it checks them when comparing to other objects).
So you'll probably need to do something more like this:
= Group el By Key = new CustomKey() { Year = el.Year, Month = el.Month };
public class CustomKey{
int Year { get; set; }
int Month { get; set; }
public override bool Equals(obj A) {
var key (CustomKey)A;
return key.Year == this.Year && key.Month == this.Month;
}
}