I am trying to implement a data model where row keys are Strings, column names are Longs and column values are DynamicComposites. Using Hector, an example of the stored procedure looks like this:
// create the value
DynamicComposite colVal = new DynamicComposite();
colVal.add(0, "someString");
colVal.setComparatorByPosition(0, "org.apache.cassandra.db.marshal.UTF8Type");
colVal.setSerializerByPosition(0, StringSerializer.get());
// create the column
HColumnImpl<Long, DynamicComposite> newCol = new
HColumnImpl<Long, DynamicComposite>(longSerializer,
dynamicCompositeSerializer);
newCol.setName(longValue);
newCol.setValue(colVal);
newCol.setClock(keySpace.createClock());
// insert the new column
Mutator<String> mutator = HFactory.createMutator(keySpace,stringSerializer);
mutator.addInsertion("rowKey","columnFamilyName",newCol);
mutator.execute();
Now, when I try to retrieve the data:
// create the query
SliceQuery<String,Long,DynamicComposite> sq =
HFactory.createSliceQuery(keySpace, stringSerializer, longSerializer,
dynamicCompositeSerializer);
// set the query
sq.setColumnFamily("columnFamilyName");
sq.setKey("rowKey");
sq.setColumnNames(longValue);
// execute the query
QueryResult<ColumnSlice<Long, DynamicComposite>> qr = sq.execute();
// get the data
qr.get().getColumnByName(longValue).getValue();
or when I just try to get plain byes:
// get the data
dynamicSerializer.fromByteBuffer(qr.get().
getColumnByName(longValue).getValueBytes());
I run into an exception:
Exception in thread "main" java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:191)
at com.google.common.collect.ImmutableClassToInstanceMap.getInstance(ImmutableClassToInstanceMap.java:147)
at me.prettyprint.hector.api.beans.AbstractComposite.serializerForComparator(AbstractComposite.java:321)
at me.prettyprint.hector.api.beans.AbstractComposite.getSerializer(AbstractComposite.java:344)
at me.prettyprint.hector.api.beans.AbstractComposite.deserialize(AbstractComposite.java:713)
at me.prettyprint.hector.api.beans.DynamicComposite.fromByteBuffer(DynamicComposite.java:25)
at me.prettyprint.cassandra.serializers.DynamicCompositeSerializer.fromByteBuffer(DynamicCompositeSerializer.java:35)
As far as I have understood from all the tutorials I read, it should be possible to use DynamicComposite as column value. Therefore I want to ask: what am I doing wrong? From the exception it seems I am just forgetting to set something somewhere.
Radovan,
Its probably due to compatibility issues of the Guava library used in conjuction with the Hector version.
See also : https://github.com/hector-client/hector/pull/591
I am on Hector-core-1.1-1.jar, in combination with the Guava-14.0.jar I get the same error as you. When I use it with the Guava-12.0.1.jar however it works fine for me.
Related
I have a Insert object created as follows:
Insert insert = QueryBuilder.insertInto("demo", "users");
insert.value("name", name);
insert.value("sport", "test");
insert.value("years", 2);
insert.value("vegetarian", true);
Somewhere else in my code, I need to get the list of names and values associated with this INSERT object. When I debug the code I can see two "values" and "names" ArrayLists that contain the information I need, however they are private and I cannot access them.
While insert.getObject(0); gets the object from the values ArrayList, I can't map the value to a column name. Furthermore insert.getValues(ProtocolVersion.V4, CodecRegistry.DEFAULT_INSTANCE); seems to serialize the objects and put them into a ByteBuffer which is not desirable.
I recommend to use the PreparedStatement & BoundStatement instead of simple Insert. First, you can get better performance if you're inserting a lot of data. And second - you'll be able to get a list of variables defined in prepared statement, together with associated values
I have been using dynamic query for a project.
Here is an scenario for which I am facing problem.
For a table xyz the column version is stored as varchar (I know it's a poor design, but it's too late to change now) and has values as 9,12.
For the query :
select max(version)
from xyz
where something = 'abc';
I am getting the output as 9 instead of 12.
The dynamic query for the same is:
ClassLoader classLoader = PortletBeanLocatorUtil.getBeanLocator(ClpSerializer.getServletContextName()).getClassLoader();
DynamicQuery dynamicQuery = DynamicQueryFactoryUtil.forClass(xyz.class, classLoader);
dynamicQuery.setProjection(ProjectionFactoryUtil.max("version"));
dynamicQuery.add(PropertyFactoryUtil.forName("something").eq("abc"));
List<Object> list = xyzLocalServiceUtil.dynamicQuery(dynamicQuery);
The query which is giving the correct value is :
select max(cast(version as signed))
from xyz
where something = 'abc';
Now, I want it to be in the dynamic query, how can I do that?
I am using liferay-6.2-ce
Try using ProjectionFactoryUtil.sqlProjection method.
That method allows using functions that are executed by SQL engine.
For example, I am using following code in order to get the max length of a string column called 'content':
Projection maxSizeProjection = ProjectionFactoryUtil.sqlProjection(
"max(length(content)) as maxSize", new String[] {"maxSize"},
new Type[] {Type.BIG_DECIMAL});
The same thing can be done with dynamic query criterions using RestrictionsFactoryUtil.sqlRestriction in case you want to use a SQL function in a condition.
In your case try following code:
import com.liferay.portal.kernel.dao.orm.ProjectionFactoryUtil;
import com.liferay.portal.kernel.dao.orm.Type;
...
Projection maxSizeProjection = ProjectionFactoryUtil.sqlProjection(
"max(cast(version as signed)) as maxVersion",
new String[] {"maxVersion"}, new Type[] {Type.BIG_DECIMAL});
dynamicQuery.setProjection(maxSizeProjection);
I have a Paginated List displayed on the visual force page and in the backend I was using a StandardSetController to control the pagination. However, one column on the table is an aggregated field whose calculation is done in a wrapper class. Recently, I want to sort the paginated list against the calculated field. And unfortunately the calculated result cannot be done on the data model(SObject) level.
So I am thinking to passed a sorted list of SObject to the StandardSetController constructor. That is to sort the record before it has been pass into the StandardSetController.
The code is like below:
List<Job__c> jobs = new List<Job__c>();
List<Job__c> tempJobs = Database.Query(basicQuery + filterExpression);
//sort with values
List<JobWrapper> jws = createJobWrappers(tempJobs);
JobWrapper.sortBy = JobWrapper.SORTBY_CALCULATEDFIELD_ASC;
jws.sort();
for(JobWrapper jw : jws){
jobs.add(jw.JobRecord);
}
jobs = jobs.deepClone(true, true, true);
StandardSetController con = new ApexPages.StandardSetController(jobs);
con.setPageSize(10);
However after executing the last line system throw exception:Modified rows exist in the records collection!
I did not modify any rows in the controller. Could anyone help me understanding the exception?
today I migrated to Astyanax 1.56.42 and discovered, that withValues() on prepared statements doesn't seem to work properly with SQL SELECT...WHERE...IN ().
ArrayList<ByteBuffer> uids = new ArrayList<ByteBuffer>(fileUids.size());
for (int i = 0; i < fileUids.size(); i++) {
uids.add(ByteBuffer.wrap(UUIDtoByteArray(fileUids.get(i)), 0, 16));
}
result = KEYSPACE.prepareQuery(CF_FILESYSTEM)
.withCql("SELECT * from files where file_uid in (?);")
.asPreparedStatement()
.withValues(uids)
.execute();
If my ArrayList contains more than one entry, this results in error
SEVERE: com.netflix.astyanax.connectionpool.exceptions.BadRequestException: BadRequestException: [host=hostname(hostname):9160, latency=5(5), attempts=1]InvalidRequestException(why:there were 1 markers(?) in CQL but 2 bound variables)
What am I doing wrong? Is there any other way to handle a SQL SELECT...WHERE...IN () - statement or did I find a bug?
Best regards
Chris
As you mentioned because you are supplying a collection (ArrayList) to a single ? Astyanax throws an exception. I think you need to add a ? for each element you want to have inside the IN clause.
Say you want to have 2 ints stored in an ArrayList called arrayListObj the where clause, your statement looks like this:
SELECT & FROM users WHERE somevalue IN (arrayListObj);
Because you are suppling a collection, this cant work, so you will need multiple ?'s. I.e. you want :
SELECT name, occupation FROM users WHERE userid IN (arrayListObj.get(0), arrayListObj.get(1));
I couldn't find anything on the Astyanax wiki about using the IN clause with prepared statements.
Using SubSonic 2.2, I have this query:
string q = #"SELECT Media.Id, Media.Title FROM Media WHERE Media.UserId = 7"
DAL.MediumCollection matches = new InlineQuery().ExecuteAsCollection<DAL.MediumCollection>(q).Load();
Looping through "matches" results in every single entry in the "Media" table.
However, when I do this:
IDataReader reader = new InlineQuery().ExecuteReader(q);
It returns the correct rows. Why is ExecuteAsCollection returning something completely different from ExecuteReader? Has anyone else experience this strange behavior?
I think it's because you're calling .Load(). That's overwriting your original query.
ExecuteAsCollection() should do it.
When you call the Load() method it's just like doing new DAL.MediumCollection().Load() that returns all the data in the table.