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## org.apache.cayenne.access.trans
Class SelectTranslator

    java.lang.Object
      org.apache.cayenne.access.trans.QueryAssembler
          org.apache.cayenne.access.trans.SelectTranslator

Direct Known Subclasses:
  SQLServerSelectTranslator

    public class SelectTranslator

extends QueryAssembler

A builder of JDBC PreparedStatements based on Cayenne SelectQueries. Translates SelectQuery to parameterized SQL string and wraps it in a PreparedStatement. SelectTranslator is stateful and thread-unsafe.

Field Summary
`protected static int[]` | `UNSUPPORTED_DISTINCT_TYPES`

Fields inherited from class org.apache.cayenne.access.trans.QueryAssembler
`adapter, attributes, connection, entityResolver, parameterIndex, query, queryMetadata, values`

Constructor Summary
`SelectTranslator()`

Method Summary
`protected void` | `appendLimitAndOffsetClauses(StringBuilder buffer)` Handles appending optional limit and offset clauses.
`protected List<ColumnDescriptor>` | `buildResultColumns()`
`protected JoinStack` | `createJoinStack()`
`String` | `createSqlString()` Returns query translated to SQL.
`void` | `dbRelationshipAdded(DbRelationship relationship, JoinType joinType, String joinSplitAlias)` Appends a join with given semantics to the query.
`Map<ObjAttribute,ColumnDescriptor>` | `getAttributeOverrides()` Returns a map of ColumnDescriptors keyed by ObjAttribute for columns that may need to be reprocessed manually due to incompatible mappings along the inheritance hierarchy.
`String` | `getCurrentAlias()` Returns an alias of the table which is currently at the top of the join stack.
`JoinStack` | `getJoinStack()`
`ColumnDescriptor[]` | `getResultColumns()` Returns a list of ColumnDescriptors for the query columns.
`boolean` | `isSuppressingDistinct()` Returns true if SelectTranslator determined that a query requiring DISTINCT can't be run with DISTINCT keyword for internal reasons.
`protected static boolean` | `isUnsupportedForDistinct(int type)`
`void` | `resetJoinStack()` A callback invoked by a child qualifier or ordering processor allowing query assembler to reset its join stack.
`boolean` | `supportsTableAliases()` Always returns true.

Methods inherited from class org.apache.cayenne.access.trans.QueryAssembler
`addToParamList, createStatement, getAdapter, getEntityResolver, getPathAliases, getQuery, getQueryMetadata, getRootDbEntity, getRootEntity, getRootInheritanceTree, initStatement, setAdapter, setConnection, setEntityResolver, setQuery`

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

Field Detail

### UNSUPPORTED_DISTINCT_TYPES

    protected static final int[] UNSUPPORTED_DISTINCT_TYPES

Constructor Detail

### SelectTranslator

    public SelectTranslator()

Method Detail

### isUnsupportedForDistinct

    protected static boolean isUnsupportedForDistinct(int type)

### getJoinStack

    public JoinStack getJoinStack()

### createJoinStack

    protected JoinStack createJoinStack()

### createSqlString

    public String createSqlString()
                           throws Exception

  Returns query translated to SQL. This is a main work method of the SelectTranslator.

  Specified by:
    `createSqlString` in class `QueryAssembler`
  Throws:
    `Exception`

### appendLimitAndOffsetClauses

    protected void appendLimitAndOffsetClauses(StringBuilder buffer)

  Handles appending optional limit and offset clauses. This implementation does nothing, deferring to subclasses to define the LIMIT/OFFSET clause syntax.

  Since:
    3.0

### getCurrentAlias

    public String getCurrentAlias()

  Description copied from class: `QueryAssembler`
  Returns an alias of the table which is currently at the top of the join stack.

  Specified by:
    `getCurrentAlias` in class `QueryAssembler`

### getResultColumns

    public ColumnDescriptor[] getResultColumns()

  Returns a list of ColumnDescriptors for the query columns.

  Since:
    1.2

### getAttributeOverrides

    public Map<ObjAttribute,ColumnDescriptor> getAttributeOverrides()

  Returns a map of ColumnDescriptors keyed by ObjAttribute for columns that may need to be reprocessed manually due to incompatible mappings along the inheritance hierarchy.

  Since:
    1.2

### isSuppressingDistinct

    public boolean isSuppressingDistinct()

  Returns true if SelectTranslator determined that a query requiring DISTINCT can't be run with DISTINCT keyword for internal reasons. If this method returns true, DataNode may need to do in-memory distinct filtering.

  Since:
    1.1

### buildResultColumns

    protected List<ColumnDescriptor> buildResultColumns()

### resetJoinStack

    public void resetJoinStack()

  Description copied from class: `QueryAssembler`
  A callback invoked by a child qualifier or ordering processor allowing query assembler to reset its join stack.

  Specified by:
    `resetJoinStack` in class `QueryAssembler`
  Since:
    3.0

### dbRelationshipAdded

    public void dbRelationshipAdded(DbRelationship relationship,
                                    JoinType joinType,
                                    String joinSplitAlias)

  Description copied from class: `QueryAssembler`
  Appends a join with given semantics to the query.

  Specified by:
    `dbRelationshipAdded` in class `QueryAssembler`
  Since:
    3.0

### supportsTableAliases

    public boolean supportsTableAliases()

  Always returns true.

  Overrides:
    `supportsTableAliases` in class `QueryAssembler`

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