Query

public class Query implements QueryInterface, ToElementable, EntityTransactionInterface

This class represents a single, complete Query execution from the parsing of the query string to the resulting list of entity ids.

This class handles caching of queries and checking retrieve permissions as well. It does not, however, retrieve the resulting entities; this is handled by the Retrieve class.

Author:

Timm Fitschen

Fields

resultSet

List<IdVersionAclTriplet> resultSet

Constructors

Query

public Query(String query)

Query

public Query(String query, Subject user)

Query

public Query(String query, Transaction<? extends TransactionContainer> transaction)

Query

public Query(String query, Subject user, TransactionContainer container, EntityTransactionInterface transaction, Access access)

Methods

addBenchmark

public void addBenchmark(String str, long time)

addToElement

public void addToElement(Element parent)

applyQueryTemplates

public void applyQueryTemplates(QueryInterface query, String resultSet)

Finds all QueryTemplates in the resultSet and applies them to the same resultSet. The IDs of the QueryTemplates themselves are then removed from the resultSet. If the current user doesn’t have the RETRIEVE:ENTITY permission for a particular QueryTemplate it will be ignored.

Parameters:

• resultSet –

Throws:

• QueryException –

clearCache

public static void clearCache()

Remove all cached queries from the cache.

execute

public void execute()

Execute the query.

First try the cache and only then use the back-end.

Throws:

• ParsingException, – QueryException

executeQueryInBackend

protected void executeQueryInBackend(Access access)

filterIntermediateResult

public void filterIntermediateResult(String tabname)

Filter out all entities which may not be retrieved by this user due to a missing RETRIEVE permission. This function is also designed for filtering of intermediate results.

Parameters:

• tabname –

Throws:

• SQLException –

getAccess

public Access getAccess()

getCacheKey

String getCacheKey(boolean addUser)

Return a key for the query cache. The key should describe the query with all the filters but without the FIND, COUNT and SELECT … FROM parts.

Returns:

A Cache key.

getConnection

public Connection getConnection()

getCount

public int getCount()

getETag

public static String getETag()

Return the ETag.

The ETag tags the query cache and is renewed each time the cache is being cleared, i.e. each time the database is being updated.

Returns:

The ETag

getEntity

public Pattern getEntity()

getQuery

public Query getQuery()

getRole

public Role getRole()

getSelections

public List<Selection> getSelections()

getSourceSet

public String getSourceSet()

getTargetSet

public String getTargetSet()

getTargetSetCount

public int getTargetSetCount()

Returns:

the number of entities in the resultset. Might be updated by the filters.

getTimestamp

public UTCDateTime getTimestamp()

getTransactionBenchmark

public TransactionBenchmark getTransactionBenchmark()

getType

public Type getType()

getUser

public Subject getUser()

isVersioned

public boolean isVersioned()

matchIdPattern

public boolean matchIdPattern(String id)

optimize

public void optimize()

Optimize the query after parsing. The optimization is purely based on formal rules.

Implemented rules:

1. FIND * -> FIND ENTITY (which basically prevents to copy the complete entity table just to read out the IDs immediately).

parse

public void parse(boolean optimize)

Parse the query and run optimize() if the parameter optimize is true.

Parameters:

• optimize – whether to run optimize() immediately.

Throws:

• ParsingException –

parse

public void parse()

Parse the query and run optimize() immediately.

Throws:

• ParsingException –

setTargetSetCount

public void setTargetSetCount(Integer c)

toString

public String toString()