Class SelectQuery<T>

    • Field Detail

      • distinct

        protected boolean distinct
      • havingQualifier

        protected Expression havingQualifier
        Since:
        4.0
      • canReturnScalarValue

        protected boolean canReturnScalarValue

        Flag that indicates whether this query can return single value or it should always return some complex data (Object[] for now)

        Default value is true

        Since:
        4.0
    • Constructor Detail

      • SelectQuery

        public SelectQuery()
        Creates an empty SelectQuery.
      • SelectQuery

        public SelectQuery​(ObjEntity root)
        Creates a SelectQuery with null qualifier, for the specifed ObjEntity
        Parameters:
        root - the ObjEntity this SelectQuery is for.
      • SelectQuery

        public SelectQuery​(ObjEntity root,
                           Expression qualifier)
        Creates a SelectQuery for the specified ObjEntity with the given qualifier.
        Parameters:
        root - the ObjEntity this SelectQuery is for.
        qualifier - an Expression indicating which objects should be fetched
      • SelectQuery

        public SelectQuery​(ObjEntity root,
                           Expression qualifier,
                           List<? extends Ordering> orderings)
        Creates a SelectQuery for the specified ObjEntity with the given qualifier and orderings.
        Parameters:
        root - the ObjEntity this SelectQuery is for.
        qualifier - an Expression indicating which objects should be fetched.
        orderings - defines how to order the results, may be null.
        Since:
        3.1
      • SelectQuery

        public SelectQuery​(Class<T> rootClass)
        Creates a SelectQuery that selects all objects of a given persistent class.
        Parameters:
        rootClass - the Class of objects fetched by this query.
      • SelectQuery

        public SelectQuery​(Class<T> rootClass,
                           Expression qualifier)
        Creates a SelectQuery that selects objects of a given persistent class that match supplied qualifier.
        Parameters:
        rootClass - the Class of objects fetched by this query.
        qualifier - an Expression indicating which objects should be fetched.
      • SelectQuery

        public SelectQuery​(Class<T> rootClass,
                           Expression qualifier,
                           List<? extends Ordering> orderings)
        Creates a SelectQuery that selects objects of a given persistent class that match supplied qualifier.
        Parameters:
        rootClass - the Class of objects fetched by this query.
        qualifier - an Expression indicating which objects should be fetched.
        orderings - defines how to order the results, may be null.
        Since:
        3.1
      • SelectQuery

        public SelectQuery​(DbEntity root)
        Creates a SelectQuery for the specified DbEntity.
        Parameters:
        root - the DbEntity this SelectQuery is for.
        Since:
        1.1
      • SelectQuery

        public SelectQuery​(DbEntity root,
                           Expression qualifier)
        Creates a SelectQuery for the specified DbEntity with the given qualifier.
        Parameters:
        root - the DbEntity this SelectQuery is for.
        qualifier - an Expression indicating which objects should be fetched.
        Since:
        1.1
      • SelectQuery

        public SelectQuery​(DbEntity root,
                           Expression qualifier,
                           List<? extends Ordering> orderings)
        Creates a SelectQuery for the specified DbEntity with the given qualifier and orderings.
        Parameters:
        root - the DbEntity this SelectQuery is for.
        qualifier - an Expression indicating which objects should be fetched.
        orderings - defines how to order the results, may be null.
        Since:
        3.1
      • SelectQuery

        public SelectQuery​(String objEntityName)
        Creates SelectQuery with objEntityName parameter.
      • SelectQuery

        public SelectQuery​(String objEntityName,
                           Expression qualifier)
        Creates SelectQuery with objEntityName and qualifier parameters.
      • SelectQuery

        public SelectQuery​(String objEntityName,
                           Expression qualifier,
                           List<? extends Ordering> orderings)
        Creates a SelectQuery that selects objects of a given persistent class that match supplied qualifier.
        Parameters:
        objEntityName - the name of the ObjEntity to fetch from.
        qualifier - an Expression indicating which objects should be fetched.
        orderings - defines how to order the results, may be null.
        Since:
        3.1
    • Method Detail

      • query

        public static <T> SelectQuery<T> query​(Class<T> rootClass)
        Creates a SelectQuery that selects objects of a given persistent class.
        Parameters:
        rootClass - the Class of objects fetched by this query.
        Since:
        4.0
      • query

        public static <T> SelectQuery<T> query​(Class<T> rootClass,
                                               Expression qualifier)
        Creates a SelectQuery that selects objects of a given persistent class that match supplied qualifier.
        Parameters:
        rootClass - the Class of objects fetched by this query.
        qualifier - an Expression indicating which objects should be fetched.
        Since:
        4.0
      • query

        public static <T> SelectQuery<T> query​(Class<T> rootClass,
                                               Expression qualifier,
                                               List<? extends Ordering> orderings)
        Creates a SelectQuery that selects objects of a given persistent class that match supplied qualifier.
        Parameters:
        rootClass - the Class of objects fetched by this query.
        qualifier - an Expression indicating which objects should be fetched.
        orderings - defines how to order the results, may be null.
        Since:
        4.0
      • dataRowQuery

        public static SelectQuery<DataRow> dataRowQuery​(Class<?> rootClass,
                                                        Expression qualifier)
        Creates a SelectQuery that selects DataRows that correspond to a given persistent class that match supplied qualifier.
        Parameters:
        rootClass - the Class of objects that correspond to DataRows entity.
        qualifier - an Expression indicating which objects should be fetched.
        Since:
        4.0
      • select

        public List<T> select​(ObjectContext context)
        Description copied from interface: Select
        Selects objects using provided context.

        Essentially the inversion of "ObjectContext.select(Select)".

        Specified by:
        select in interface Select<T>
      • selectOne

        public T selectOne​(ObjectContext context)
        Description copied from interface: Select
        Selects a single object using provided context. The query is expected to match zero or one object. It returns null if no objects were matched. If query matched more than one object, CayenneRuntimeException is thrown.

        Essentially the inversion of "ObjectContext.selectOne(Select)".

        Specified by:
        selectOne in interface Select<T>
      • selectFirst

        public T selectFirst​(ObjectContext context)
        Description copied from interface: Select
        Selects a single object using provided context. The query itself can match any number of objects, but will return only the first one. It returns null if no objects were matched.

        If it matched more than one object, the first object from the list is returned. This makes 'selectFirst' different from Select.selectOne(ObjectContext), which would throw in this situation. 'selectFirst' is useful e.g. when the query is ordered and we only want to see the first object (e.g. "most recent news article"), etc.

        Selecting the first object via "Select.selectFirst(ObjectContext)" is more comprehensible than selecting via "ObjectContext.selectFirst(Select)", because implementations of "Select" set fetch size limit to one.

        Specified by:
        selectFirst in interface Select<T>
      • iterate

        public void iterate​(ObjectContext context,
                            ResultIteratorCallback<T> callback)
        Description copied from interface: Select
        Creates a ResultIterator based on the provided context and passes it to a callback for processing. The caller does not need to worry about closing the iterator. This method takes care of it.

        Essentially the inversion of "ObjectContext.iterate(Select, ResultIteratorCallback)".

        Specified by:
        iterate in interface Select<T>
      • iterator

        public ResultIterator<T> iterator​(ObjectContext context)
        Description copied from interface: Select
        Creates a ResultIterator based on the provided context. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultIterator explicitly. Or use Select.iterate(ObjectContext, ResultIteratorCallback) as an alternative.

        Essentially the inversion of "ObjectContext.iterator(Select)".

        Specified by:
        iterator in interface Select<T>
      • batchIterator

        public ResultBatchIterator<T> batchIterator​(ObjectContext context,
                                                    int size)
        Description copied from interface: Select
        Creates a ResultBatchIterator based on the provided context and batch size. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultBatchIterator explicitly.
        Specified by:
        batchIterator in interface Select<T>
      • route

        public void route​(QueryRouter router,
                          EntityResolver resolver,
                          Query substitutedQuery)
        Routes itself and if there are any prefetches configured, creates prefetch queries and routes them as well.
        Specified by:
        route in interface Query
        Overrides:
        route in class AbstractQuery
        Since:
        1.2
      • initWithProperties

        public void initWithProperties​(Map<String,​?> properties)
        Initializes query parameters using a set of properties.
        Since:
        1.1
      • queryWithParameters

        public SelectQuery<T> queryWithParameters​(Map<String,​?> parameters,
                                                  boolean pruneMissing)
        Returns a query built using this query as a prototype, using a set of parameters to build the qualifier.
        See Also:
        parameter substitution.
      • createQuery

        public SelectQuery<T> createQuery​(Map<String,​?> parameters)
        Creates and returns a new SelectQuery built using this query as a prototype and substituting qualifier parameters with the values from the map.
        Specified by:
        createQuery in interface ParameterizedQuery
        Since:
        1.1
      • addOrdering

        public void addOrdering​(Ordering ordering)
        Adds ordering specification to this query orderings.
      • addOrderings

        public void addOrderings​(Collection<? extends Ordering> orderings)
        Adds a list of orderings.
      • addOrdering

        public void addOrdering​(String sortPathSpec,
                                SortOrder order)
        Adds ordering specification to this query orderings.
        Since:
        3.0
      • removeOrdering

        public void removeOrdering​(Ordering ordering)
        Removes ordering.
        Since:
        1.1
      • getOrderings

        public List<Ordering> getOrderings()
        Returns a list of orderings used by this query.
      • clearOrderings

        public void clearOrderings()
        Clears all configured orderings.
      • isDistinct

        public boolean isDistinct()
        Returns true if this query returns distinct rows.
      • setDistinct

        public void setDistinct​(boolean distinct)
        Sets distinct property that determines whether this query returns distinct row.
      • setSuppressDistinct

        public void setSuppressDistinct​(boolean suppressDistinct)
        Sets distinct property that determines whether this query returns distinct row.
      • aliasPathSplits

        public void aliasPathSplits​(String path,
                                    String... aliases)
        Adds one or more aliases for the qualifier expression path. Aliases serve to instruct Cayenne to generate separate sets of joins for overlapping paths, that maybe needed for complex conditions. An example of an implicit splits is this method: ExpressionFactory.matchAllExp(String, Object...).
        Since:
        3.0
      • setPrefetchTree

        public void setPrefetchTree​(PrefetchTreeNode prefetchTree)
        Since:
        1.2
      • addPrefetch

        public void addPrefetch​(PrefetchTreeNode prefetchElement)
        Adds a prefetch with specified relationship path to the query.
        Since:
        4.0
      • addPrefetch

        public PrefetchTreeNode addPrefetch​(String prefetchPath)
        Adds a prefetch with specified relationship path to the query.
        Since:
        1.2 signature changed to return created PrefetchTreeNode.
      • clearPrefetches

        public void clearPrefetches()
        Clears all stored prefetch paths.
      • removePrefetch

        public void removePrefetch​(String prefetchPath)
        Removes prefetch.
        Since:
        1.1
      • isFetchingDataRows

        public boolean isFetchingDataRows()
        Returns true if this query should produce a list of data rows as opposed to DataObjects, false for DataObjects. This is a hint to QueryEngine executing this query.
      • setFetchingDataRows

        public void setFetchingDataRows​(boolean flag)
        Deprecated.
        since 4.0, use dataRowQuery(Class, Expression) to create DataRow query instead.
        Sets query result type. If flag parameter is true, then results will be in the form of data rows.

        Note that if the root of this query is a DbEntity, this setting has no effect, and data rows are always fetched.

      • getFetchOffset

        public int getFetchOffset()
        Returns the fetchOffset.
        Since:
        3.0
      • getFetchLimit

        public int getFetchLimit()
        Returns the fetchLimit.
      • setFetchLimit

        public void setFetchLimit​(int fetchLimit)
        Sets the fetchLimit.
      • setFetchOffset

        public void setFetchOffset​(int fetchOffset)
        Since:
        3.0
      • getPageSize

        public int getPageSize()
        Returns pageSize property. See setPageSize for more details.
      • setPageSize

        public void setPageSize​(int pageSize)
        Sets pageSize property. By setting a page size, the Collection returned by performing a query will return hollow DataObjects. This is considerably faster and uses a tiny fraction of the memory compared to a non-paged query when large numbers of objects are returned in the result. When a hollow DataObject is accessed all DataObjects on the same page will be faulted into memory. There will be a small delay when faulting objects while the data is fetched from the data source, but otherwise you do not need to do anything special to access data in hollow objects. The first page is always faulted into memory immediately.
        Parameters:
        pageSize - The pageSize to set
      • setStatementFetchSize

        public void setStatementFetchSize​(int size)
        Sets statement's fetch size (0 for default size)
        Since:
        3.0
      • getStatementFetchSize

        public int getStatementFetchSize()
        Returns:
        statement's fetch size
        Since:
        3.0
      • setQualifier

        public void setQualifier​(Expression qualifier)
        Sets new query qualifier.
      • getQualifier

        public Expression getQualifier()
        Returns query qualifier.
      • andQualifier

        public void andQualifier​(Expression e)
        Adds specified qualifier to the existing qualifier joining it using "AND".
      • orQualifier

        public void orQualifier​(Expression e)
        Adds specified qualifier to the existing qualifier joining it using "OR".
      • setColumns

        public void setColumns​(Property<?>... columns)
        Since:
        4.0
      • setCanReturnScalarValue

        public void setCanReturnScalarValue​(boolean canReturnScalarValue)

        Flag that indicates whether this query can return single value or it should always return some complex data (Object[] for now)

        Default value is true

        Parameters:
        canReturnScalarValue - can this query return single value
        Since:
        4.0
        See Also:
        setColumns(java.util.Collection<org.apache.cayenne.exp.Property<?>>)
      • canReturnScalarValue

        public boolean canReturnScalarValue()
        Returns:
        can this query return single value
        Since:
        4.0
      • setHavingQualifier

        public void setHavingQualifier​(Expression qualifier)
        Sets new query HAVING qualifier.
        Since:
        4.0
      • getHavingQualifier

        public Expression getHavingQualifier()
        Returns query HAVING qualifier.
        Since:
        4.0
      • andHavingQualifier

        public void andHavingQualifier​(Expression e)
        Adds specified HAVING qualifier to the existing HAVING qualifier joining it using "AND".
        Since:
        4.0
      • orHavingQualifier

        public void orHavingQualifier​(Expression e)
        Adds specified HAVING qualifier to the existing HAVING qualifier joining it using "OR".
        Since:
        4.0
      • getBaseMetaData

        protected org.apache.cayenne.query.BaseQueryMetadata getBaseMetaData()
        Specified by:
        getBaseMetaData in class CacheableQuery