ScalarSelectOperation (sormula)

java.lang.Object
- org.sormula.operation.SqlOperation<R>
- - org.sormula.operation.ScalarSelectOperation<R>

Type Parameters:

R - class type which contains members for columns of a row in a table

All Implemented Interfaces:

java.lang.AutoCloseable, java.lang.Iterable<R>

Direct Known Subclasses:

SelectAggregateOperation, SelectOperation
```
public class ScalarSelectOperation<R>
extends SqlOperation<R>
implements java.lang.Iterable<R>
```
Select operation that reads one value at a time. It does not have any methods that use Collection objects.

Since:

1.0

Author:

Jeff Miller

Constructor Summary

Constructors
Constructor and Description
`ScalarSelectOperation(Table<R> table)` Constructs standard sql select by primary key as: SELECT c1, c2, c3, ...
`ScalarSelectOperation(Table<R> table, java.lang.String whereConditionName)` Constructs standard sql select by primary key as: SELECT c1, c2, c3, ...

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`<F> void`	`addFilter(java.lang.Class<F> rowClass, java.util.function.BiPredicate<F,java.lang.Boolean> filterPredicate)` Adds a filter to use for a row type.
`void`	`close()` Cleans up after operation is no longer needed.
`void`	`execute()` Performs query.
`java.util.Map<java.lang.Class<?>,java.util.function.BiPredicate<?,java.lang.Boolean>>`	`getFilterPredicateMap()` Gets all filters defined for this operation.
`int`	`getMaximumRowsRead()` Gets the maximum number of rows to read from result set.
`java.lang.String`	`getOrderByName()` Gets order by name that was set with `setOrderBy(String)`.
`protected OrderByTranslator<R>`	`getOrderByTranslator()` Gets the `OrderByTranslator`.
`protected java.sql.ResultSet`	`getResultSet()` Gets the result set of the most recent select.
`int`	`getRowsReadCount()` Gets the count of rows that were read since the most recent `execute()`.
`protected java.lang.String`	`getSql()` Gets full sql statement to prepare.
`protected void`	`initBaseSql()` Sets the base sql with `SqlOperation.setBaseSql(String)`.
`boolean`	`isExecuted()` Indicates if `execute()` has been invoked.
`boolean`	`isLazySelectsCascades()` Reports that operation has at least one field with `SelectCascade.lazy()` true.
`boolean`	`isNotifyLazySelects()` Reports that `isLazySelectsCascades()` is true and row is instance of `LazySelectable`.
`java.util.Iterator<R>`	`iterator()` Creates iterator for results of this operation.
`void`	`positionAbsolute(int rowNumber)` Positions the result set cursor to a specific row.
`void`	`positionRelative(int rowOffset)` Positions the result set cursor to a row relative to the current row.
`protected void`	`postRead(R row)` Invoked after reading columns into row.
`protected void`	`postReadCascade(R row)` Invoked after reading row.
`protected java.util.List<CascadeOperation<R,?>>`	`prepareCascades(java.lang.reflect.Field field)` Creates and prepares cascade operations based upon cascade annotations for a field.
`protected void`	`preRead(R row)` Invoked prior to reading columns into row.
`protected void`	`preReadCascade(R row)` Invoked prior to reading row.
`R`	`readNext()` Reads next row from current result set.
`<F> void`	`removeFilter(java.lang.Class<F> rowClass)` Removes a filter that was previously added with `addFilter(Class, BiPredicate)`.
`void`	`resetRowsReadCount()` Sets the number of rows read to zero.
`R`	`select(java.lang.Object... parameters)` Set parameters, executes, reads one row, closes.
`R`	`select(R whereParameters)` Set parameters, executes, reads one row, closes.
`void`	`setFilterPredicateMap(java.util.Map<java.lang.Class<?>,java.util.function.BiPredicate<?,java.lang.Boolean>> filterPredicateMap)` Sets all filters defined for this operation and lower level cascades.
`void`	`setMaximumRowsRead(int maximumRowsRead)` Sets the maximum number of rows to read from result set.
`void`	`setOrderBy(java.lang.String orderByName)` Sets order of results in list.
`protected void`	`setOrderByTranslator(OrderByTranslator<R> orderByTranslator)` Sets the `OrderByTranslator` that creates the sql "order by" phrase based upon the `OrderBy` annotations.
`void`	`setParameters(java.lang.Object... parameters)` Sets any parameters to be used by operation.
`void`	`setRowParameters(R rowParameters)` Set parameters using values from a row object.
`protected boolean`	`updateActiveFilterPredicate(java.lang.Class<?> rowClass, java.util.function.BiPredicate<?,java.lang.Boolean> filterPredicate)` Tests if filterPredicate parameter is to be used for this operation.

Methods inherited from class org.sormula.operation.SqlOperation
cancel, cascade, closeCascades, closeStatement, createRowField, getBaseSql, getCascadeDepth, getConnection, getCustomSql, getNamedParameterMap, getNextParameter, getOperationTime, getParameter, getParameters, getPreparedSql, getPreparedStatement, getQueryTimeout, getRequiredCascades, getTable, getTargetTable, getTimingId, getWhereAnnotation, getWhereConditionName, getWhereTranslator, initOperationTime, isCached, isCascade, isCascading, isIncludeIdentityColumns, isPrimaryKey, isReadOnly, isRequiredCascade, isTimings, logTimings, prepare, prepareCascades, prepareCheck, prepareStatement, setBaseSql, setCached, setCascade, setCascadeDepth, setCustomSql, setIncludeIdentityColumns, setNamedParameterMap, setNextParameter, setParameter, setQueryTimeout, setReadOnly, setRequiredCascades, setTimingId, setTimings, setWhere, setWhereTranslator, writeColumns, writeParameter, writeParameters, writeWhere

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Constructor Detail
  - ScalarSelectOperation
```
public ScalarSelectOperation(Table<R> table)
                      throws OperationException
```
    Constructs standard sql select by primary key as:
    SELECT c1, c2, c3, ... FROM table WHERE primary key clause
    
    Parameters:
    
    table - select from this table
    
    Throws:
    
    OperationException - if error
  - ScalarSelectOperation
```
public ScalarSelectOperation(Table<R> table,
                             java.lang.String whereConditionName)
                      throws OperationException
```
    Constructs standard sql select by primary key as:
    SELECT c1, c2, c3, ... FROM table WHERE ...
    
    Parameters:
    
    table - select from this table
    
    whereConditionName - name of where condition to use ("primaryKey" to select by primary key; empty string to select all rows in table)
    
    Throws:
    
    OperationException - if error
- Method Detail
  - iterator
```
public java.util.Iterator<R> iterator()
```
    Creates iterator for results of this operation.
    
    Specified by:
    
    iterator in interface java.lang.Iterable<R>
    
    Returns:
    
    SelectIterator
    
    Since:
    
    3.0
  - getMaximumRowsRead
```
public int getMaximumRowsRead()
```
    Gets the maximum number of rows to read from result set. The default is Integer.MAX_VALUE.
    
    Returns:
    
    0..Integer.MAX_VALUE
    
    Since:
    
    1.4
  - setMaximumRowsRead
```
public void setMaximumRowsRead(int maximumRowsRead)
```
    Sets the maximum number of rows to read from result set. This method does NOT alter SQL to contain anything to limit query but only limits the number of rows read by readNext() and SelectOperation.readAll(). Limiting rows read is useful to avoid reading too many rows and thus creating memory or display problems.
    
    Parameters:
    
    maximumRowsRead - 0..Integer.MAX_VALUE
    
    Since:
    
    1.4
  - getRowsReadCount
```
public int getRowsReadCount()
```
    Gets the count of rows that were read since the most recent execute().
    
    Returns:
    
    number of rows read
    
    Since:
    
    1.4
  - resetRowsReadCount
```
public void resetRowsReadCount()
```
    Sets the number of rows read to zero. Use this method if setMaximumRowsRead(int) has been used to limit the number of rows, some rows have already been read, and you would like to reset the counting of maximum number of rows. For example, after a page of rows is read.
    
    Since:
    
    4.3
  - setRowParameters
```
public void setRowParameters(R rowParameters)
```
    Set parameters using values from a row object. Use this instead of setParameters(Object...).
    
    Parameters:
    
    rowParameters - where parameters are read from this object using fields defined by Where or the primary key defined by Column.primaryKey(), Column.identity(), or Row.primaryKeyFields().
  - setParameters
```
public void setParameters(java.lang.Object... parameters)
```
    Sets any parameters to be used by operation. Parameters must be in the same order as defined by Column.primaryKey() or Where annotation or Row.primaryKeyFields().
    
    Overrides:
    
    setParameters in class SqlOperation<R>
    
    Parameters:
    
    parameters - parameters as objects (not from row fields)
  - execute
```
public void execute()
             throws OperationException
```
    Performs query. Use readNext() to get the next row selected.
    
    Specified by:
    
    execute in class SqlOperation<R>
    
    Throws:
    
    OperationException - if error
  - isExecuted
```
public boolean isExecuted()
```
    Indicates if execute() has been invoked.
    
    Returns:
    
    true if operation has been executed; false if not
    
    Since:
    
    3.0
  - close
```
public void close()
           throws OperationException
```
    Cleans up after operation is no longer needed. The connection is not closed but all other objects created by this operations are closed. Prepared statement is closed and close method is invoked on all CascadeOperation objects. This method should be invoked when operation is no longer needed for proper JDBC clean up.
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
    
    Overrides:
    
    close in class SqlOperation<R>
    
    Throws:
    
    OperationException - if error
  - positionAbsolute
```
public void positionAbsolute(int rowNumber)
                      throws OperationException
```
    Positions the result set cursor to a specific row.
    
    Parameters:
    
    rowNumber - the number of the row to which the cursor should move. A value of zero indicates that the cursor will be positioned before the first row; a positive number indicates the row number counting from the beginning of the result set; a negative number indicates the row number counting from the end of the result set
    
    Throws:
    
    OperationException - if error
    
    Since:
    
    4.3
    
    See Also:
    
    ResultSet.absolute(int)
  - positionRelative
```
public void positionRelative(int rowOffset)
                      throws OperationException
```
    Positions the result set cursor to a row relative to the current row.
    
    Parameters:
    
    rowOffset - - the number of rows to move from the current row; a positive number moves the cursor forward; a negative number moves the cursor backward
    
    Throws:
    
    OperationException - if error
    
    Since:
    
    4.3
    
    See Also:
    
    ResultSet.relative(int)
  - readNext
```
public R readNext()
           throws OperationException
```
    Reads next row from current result set. If table is cached, and cache indicates that the next row is deleted, this method will continue to read until non deleted row is selected.
    
    Returns:
    
    new instance of row or null if no more row in the current result set
    
    Throws:
    
    OperationException - if error
  - setOrderBy
```
public void setOrderBy(java.lang.String orderByName)
                throws OperationException
```
    Sets order of results in list. Setting the order condition affects the order of the rows are read from database but is only meaningful if the resulting collection type is also ordered.
    
    Parameters:
    
    orderByName - name of order phrase to use as defined in OrderBy.name() in OrderBy annotation on row R; use empty string for no ordering
    
    Throws:
    
    OperationException - if error
  - getOrderByName
```
public java.lang.String getOrderByName()
```
    Gets order by name that was set with setOrderBy(String).
    
    Returns:
    
    order by name
  - select
```
public R select(java.lang.Object... parameters)
         throws OperationException
```
    Set parameters, executes, reads one row, closes.
    Since this class implements AutoCloseable, you may see resource leak warning when you use this method. You can ignore it, add a suppress annotation, explicitly close, or close with a try-with-resources statement. Closing an operation more than once will not cause problems since the close methods are idempotent.
    
    Parameters:
    
    parameters - query parameters as objects (see setParameters(Object...))
    
    Returns:
    
    readNext()
    
    Throws:
    
    OperationException - if error
    
    Since:
    
    1.4
  - select
```
public R select(R whereParameters)
         throws OperationException
```
    Set parameters, executes, reads one row, closes.
    Since this class implements AutoCloseable, you may see resource leak warning when you use this method. You can ignore it, add a suppress annotation, explicitly close, or close with a try-with-resources statement. Closing an operation more than once will not cause problems since the close methods are idempotent.
    
    Parameters:
    
    whereParameters - query parameters are read from an existing row object (see setRowParameters(Object))
    
    Returns:
    
    readNext()
    
    Throws:
    
    OperationException - if error
    
    Since:
    
    1.4
  - isLazySelectsCascades
```
public boolean isLazySelectsCascades()
```
    Reports that operation has at least one field with SelectCascade.lazy() true. This status is set during SqlOperation.prepare().
    
    Returns:
    
    true if there are lazy select cascades annotated
    
    Since:
    
    1.8 and 2.2
  - isNotifyLazySelects
```
public boolean isNotifyLazySelects()
```
    Reports that isLazySelectsCascades() is true and row is instance of LazySelectable. This is set as an optimization so the readNext() only tests a boolean to know when to invoke LazySelectable.pendingLazySelects(org.sormula.Database).
    
    Returns:
    
    true if LazySelectable.pendingLazySelects(org.sormula.Database) will be inovked for each row selected
    
    Since:
    
    1.8 and 2.2
  - addFilter
```
public <F> void addFilter(java.lang.Class<F> rowClass,
                          java.util.function.BiPredicate<F,java.lang.Boolean> filterPredicate)
```
    Adds a filter to use for a row type. Every row of type, rowClass, is is tested as the row is read from the database.
    It is tested up to two times. It is always tested immediately after it is read. It is tested a second time if the row has cascades after all cascades have been performed on the row.
    An example use:
    SelectOperation<Order.class> op = ... op.addFilter(Order.class, (order, cascadesCompleted) -> { if (!cascadesCompleted) { // tests prior to cascades return ... } else { // tests after cascades return ... } });
    All filters that here are automatically added to lower level cascades when the operation is prepared. The purpose of this is so that a top-level select operation can define filters for any/all lower level cascaded row types.
    Type Parameters:
    
    F - row type to filter
    
    Parameters:
    
    rowClass - type of row to test
    
    filterPredicate - predicate to perform the test
    
    Since:
    
    4.0
  - removeFilter
```
public <F> void removeFilter(java.lang.Class<F> rowClass)
```
    Removes a filter that was previously added with addFilter(Class, BiPredicate).
    
    Type Parameters:
    
    F - row type to filter
    
    Parameters:
    
    rowClass - remove filter defined for this row class
    
    Since:
    
    4.0
  - getFilterPredicateMap
```
public java.util.Map<java.lang.Class<?>,java.util.function.BiPredicate<?,java.lang.Boolean>> getFilterPredicateMap()
```
    Gets all filters defined for this operation. Typically this method is used internally by cascade operations.
    
    Returns:
    
    map of row class to filter
    
    Since:
    
    4.0
  - setFilterPredicateMap
```
public void setFilterPredicateMap(java.util.Map<java.lang.Class<?>,java.util.function.BiPredicate<?,java.lang.Boolean>> filterPredicateMap)
```
    Sets all filters defined for this operation and lower level cascades. Typically this method is used internally by when preparing cascade operations.
    
    Parameters:
    
    filterPredicateMap - map of row class to filter
    
    Since:
    
    4.0
  - updateActiveFilterPredicate
```
protected boolean updateActiveFilterPredicate(java.lang.Class<?> rowClass,
                                              java.util.function.BiPredicate<?,java.lang.Boolean> filterPredicate)
```
    Tests if filterPredicate parameter is to be used for this operation. If true is returned then #filterPredicate member is set to filterPredicate parameter.
    
    Parameters:
    
    rowClass - row class that is to use filterPredicate
    
    filterPredicate - filter
    
    Returns:
    
    true if rowClass parameter is same as the row class of row translator (rowTranslator) or if rowClass is Object.class (indicates that filter is to be used for all row types)
    
    Since:
    
    4.0
  - getOrderByTranslator
```
protected OrderByTranslator<R> getOrderByTranslator()
```
    Gets the OrderByTranslator. See setOrderByTranslator(OrderByTranslator) for details.
    
    Returns:
    
    order translator or null if no ordering desired
  - setOrderByTranslator
```
protected void setOrderByTranslator(OrderByTranslator<R> orderByTranslator)
```
    Sets the OrderByTranslator that creates the sql "order by" phrase based upon the OrderBy annotations. Default is null. Set by setOrderBy(String).
    
    Parameters:
    
    orderByTranslator - order translator or null if no ordering desired
  - getSql
```
protected java.lang.String getSql()
```
    Gets full sql statement to prepare. Default implementation is to use base sql + custom sql + where sql. Subclasses may override to create more detailed sql. Order by clause is appended to supergetSql().
    
    Overrides:
    
    getSql in class SqlOperation<R>
    
    Returns:
    
    sql to use in SqlOperation.prepare()
  - getResultSet
```
protected java.sql.ResultSet getResultSet()
```
    Gets the result set of the most recent select.
    
    Returns:
    
    JDBC result set
  - initBaseSql
```
protected void initBaseSql()
```
    Sets the base sql with SqlOperation.setBaseSql(String).
  - preRead
```
protected void preRead(R row)
```
    Invoked prior to reading columns into row. Override to modify the row prior to JDBC reads. Default implementation does nothing.
    
    Parameters:
    
    row - row that will get column values from table
  - postRead
```
protected void postRead(R row)
```
    Invoked after reading columns into row. Override to modify the row after to JDBC reads. Default implementation does nothing.
    
    Parameters:
    
    row - row that got column values from table
  - preReadCascade
```
protected void preReadCascade(R row)
                       throws OperationException
```
    Invoked prior to reading row. Performs all select cascade operations where SelectCascade.post() is false.
    
    Parameters:
    
    row - row that will get column values from table
    
    Throws:
    
    OperationException - if error
  - postReadCascade
```
protected void postReadCascade(R row)
                        throws OperationException
```
    Invoked after reading row. Performs all select cascade operations where SelectCascade.post() is true.
    
    Parameters:
    
    row - row that got column values from table
    
    Throws:
    
    OperationException - if error
  - prepareCascades
```
protected java.util.List<CascadeOperation<R,?>> prepareCascades(java.lang.reflect.Field field)
                                                         throws OperationException
```
    Creates and prepares cascade operations based upon cascade annotations for a field.
    
    Specified by:
    
    prepareCascades in class SqlOperation<R>
    
    Parameters:
    
    field - annotation is for this field of row class R
    
    Returns:
    
    list of cascade operations; empty list for none
    
    Throws:
    
    OperationException - if error

Class ScalarSelectOperation<R>

Constructor Summary

Method Summary

Methods inherited from class org.sormula.operation.SqlOperation

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Constructor Detail

ScalarSelectOperation

ScalarSelectOperation

Method Detail

iterator

getMaximumRowsRead

setMaximumRowsRead

getRowsReadCount

resetRowsReadCount

setRowParameters

setParameters

execute

isExecuted

close

positionAbsolute

positionRelative

readNext

setOrderBy

getOrderByName

select

select

isLazySelectsCascades

isNotifyLazySelects

addFilter

removeFilter

getFilterPredicateMap

setFilterPredicateMap

updateActiveFilterPredicate

getOrderByTranslator

setOrderByTranslator

getSql

getResultSet

initBaseSql

preRead

postRead

preReadCascade

postReadCascade

prepareCascades