# Class QueryMetadataProxy

java.lang.Object
org.apache.cayenne.query.QueryMetadataProxy

All Implemented Interfaces:
  `QueryMetadata`

public class QueryMetadataProxy extends Object implements QueryMetadata

Since:
  4.0

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected QueryMetadata`
  `mdDelegate`

  ### Fields inherited from interface QueryMetadata

  `CACHE_GROUPS_PROPERTY, CACHE_STRATEGY_PROPERTY, FETCH_LIMIT_DEFAULT, FETCH_LIMIT_PROPERTY, FETCH_OFFSET_DEFAULT, FETCH_OFFSET_PROPERTY, FETCHING_DATA_ROWS_DEFAULT, FETCHING_DATA_ROWS_PROPERTY, PAGE_SIZE_DEFAULT, PAGE_SIZE_PROPERTY, QUERY_TIMEOUT_DEFAULT, STATEMENT_FETCH_SIZE_DEFAULT, STATEMENT_FETCH_SIZE_PROPERTY`

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `QueryMetadataProxy(QueryMetadata mdDelegate)`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `String`
  `getCacheGroup()`
  Returns an optional cache "group".
  `String`
  `getCacheKey()`
  Returns a String that uniquely identifies this query for the purposes of result caching.
  `QueryCacheStrategy`
  `getCacheStrategy()`
  Returns a caching strategy for this query.
  `ClassDescriptor`
  `getClassDescriptor()`
  `DataMap`
  `getDataMap()`
  Returns a DataMap associated with a query or null if no such DataMap exists.
  `DbEntity`
  `getDbEntity()`
  Returns a DbEntity associated with a query or null if no such entity exists.
  `int`
  `getFetchLimit()`
  Returns the limit on the maximum number of records that can be returned by this query.
  `int`
  `getFetchOffset()`
  Specifies a start of a range when fetching a subset of records.
  `ObjEntity`
  `getObjEntity()`
  Returns an ObjEntity associated with a query or null if no such entity exists.
  `Query`
  `getOriginatingQuery()`
  Returns a query that originated this query.
  `int`
  `getPageSize()`
  Returns query page size.
  `Map<String,String>`
  `getPathSplitAliases()`
  Returns a map of aliases vs. expression subpaths that is used to build split joins.
  `PrefetchTreeNode`
  `getPrefetchTree()`
  Returns a root node of prefetch tree used by this query, or null of no prefetches are configured.
  `Procedure`
  `getProcedure()`
  Returns a Procedure associated with a query or null if no such procedure exists.
  `int`
  `getQueryTimeout()`
  `List<Object>`
  `getResultSetMapping()`
  Returns an optional list of result set mapping hints.
  `int`
  `getStatementFetchSize()`
  `boolean`
  `isFetchingDataRows()`
  Returns `true` if this query should produce a list of data rows as opposed to Persistent objects, `false` for Persistent objects.
  `boolean`
  `isReadOnly()`
  Returns true if this is a read-only (selecting) query that does not need to run in its own transaction.
  `boolean`
  `isRefreshingObjects()`
  Returns `true` if the query results should replace any currently cached values, returns `false` otherwise.
  `boolean`
  `isSingleResultSetMapping()`
  `boolean`
  `isSuppressingDistinct()`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

  ### Methods inherited from interface QueryMetadata

  `getResultMapper, setResultSetMapping`

- ## Field Details

  - ### mdDelegate

    protected QueryMetadata mdDelegate

- ## Constructor Details

  - ### QueryMetadataProxy

    protected QueryMetadataProxy(QueryMetadata mdDelegate)

- ## Method Details

  - ### getCacheGroup

    public String getCacheGroup()
    Description copied from interface: `QueryMetadata`
    Returns an optional cache "group". Cache groups allow to invalidate query caches in bulk on different events.
    Specified by:
      `getCacheGroup` in interface `QueryMetadata`

  - ### getCacheKey

    public String getCacheKey()
    Description copied from interface: `QueryMetadata`
    Returns a String that uniquely identifies this query for the purposes of result caching. If null is returned, no caching is performed.
    Specified by:
      `getCacheKey` in interface `QueryMetadata`

  - ### getCacheStrategy

    public QueryCacheStrategy getCacheStrategy()
    Description copied from interface: `QueryMetadata`
    Returns a caching strategy for this query.
    Specified by:
      `getCacheStrategy` in interface `QueryMetadata`

  - ### getClassDescriptor

    public ClassDescriptor getClassDescriptor()
    Specified by:
      `getClassDescriptor` in interface `QueryMetadata`

  - ### getDataMap

    public DataMap getDataMap()
    Description copied from interface: `QueryMetadata`
    Returns a DataMap associated with a query or null if no such DataMap exists.
    Specified by:
      `getDataMap` in interface `QueryMetadata`

  - ### getDbEntity

    public DbEntity getDbEntity()
    Description copied from interface: `QueryMetadata`
    Returns a DbEntity associated with a query or null if no such entity exists.
    Specified by:
      `getDbEntity` in interface `QueryMetadata`

  - ### getFetchLimit

    public int getFetchLimit()
    Description copied from interface: `QueryMetadata`
    Returns the limit on the maximum number of records that can be returned by this query. If the actual number of rows in the result exceeds the fetch limit, they will be discarded. One possible use of fetch limit is using it as a safeguard against large result sets that may lead to the application running out of memory, etc. If a fetch limit is greater or equal to zero, all rows will be returned.
    Specified by:
      `getFetchLimit` in interface `QueryMetadata`
    Returns:
      the limit on the maximum number of records that can be returned by this query

  - ### getFetchOffset

    public int getFetchOffset()
    Description copied from interface: `QueryMetadata`
    Specifies a start of a range when fetching a subset of records.
    Specified by:
      `getFetchOffset` in interface `QueryMetadata`

  - ### getObjEntity

    public ObjEntity getObjEntity()
    Description copied from interface: `QueryMetadata`
    Returns an ObjEntity associated with a query or null if no such entity exists.
    Specified by:
      `getObjEntity` in interface `QueryMetadata`

  - ### getOriginatingQuery

    public Query getOriginatingQuery()
    Description copied from interface: `QueryMetadata`
    Returns a query that originated this query. Originating query is a query whose result is needed to obtain the result of the query owning this metadata. Most often than not the returned value is null. One example of non-null originating query is a query for a range of objects in a previously fetched paginated list. The query that fetched the original paginated list is an "originated" query. It may be used to restore a list that got lost due to a cache overflow, etc.
    Specified by:
      `getOriginatingQuery` in interface `QueryMetadata`

  - ### getPageSize

    public int getPageSize()
    Description copied from interface: `QueryMetadata`
    Returns query page size. Page size is a hint to Cayenne that query should be performed page by page, instead of retrieving all results at once. If the value returned is less than or equal to zero, no paging should occur.
    Specified by:
      `getPageSize` in interface `QueryMetadata`

  - ### getPrefetchTree

    public PrefetchTreeNode getPrefetchTree()
    Description copied from interface: `QueryMetadata`
    Returns a root node of prefetch tree used by this query, or null of no prefetches are configured.
    Specified by:
      `getPrefetchTree` in interface `QueryMetadata`

  - ### getPathSplitAliases

    public Map<String,String> getPathSplitAliases()
    Description copied from interface: `QueryMetadata`
    Returns a map of aliases vs. expression subpaths that is used to build split joins.
    Specified by:
      `getPathSplitAliases` in interface `QueryMetadata`

  - ### getProcedure

    public Procedure getProcedure()
    Description copied from interface: `QueryMetadata`
    Returns a Procedure associated with a query or null if no such procedure exists.
    Specified by:
      `getProcedure` in interface `QueryMetadata`

  - ### getResultSetMapping

    public List<Object> getResultSetMapping()
    Description copied from interface: `QueryMetadata`
    Returns an optional list of result set mapping hints. Elements in the list can be either `EntityResultSegment` or `ScalarResultSegment`. The returned list can be null.
    Specified by:
      `getResultSetMapping` in interface `QueryMetadata`

  - ### isSingleResultSetMapping

    public boolean isSingleResultSetMapping()
    Specified by:
      `isSingleResultSetMapping` in interface `QueryMetadata`
    Returns:
      should the result be mapped to single object (scalar or entity)
    See Also:
      - `QueryMetadata.getResultSetMapping()`

  - ### isFetchingDataRows

    public boolean isFetchingDataRows()
    Description copied from interface: `QueryMetadata`
    Returns `true` if this query should produce a list of data rows as opposed to Persistent objects, `false` for Persistent objects. This is a hint to the DataNode executing this query.
    Specified by:
      `isFetchingDataRows` in interface `QueryMetadata`

  - ### isRefreshingObjects

    public boolean isRefreshingObjects()
    Description copied from interface: `QueryMetadata`
    Returns `true` if the query results should replace any currently cached values, returns `false` otherwise. If `QueryMetadata.isFetchingDataRows()` returns `true`, this setting is not applicable and has no effect.
    Specified by:
      `isRefreshingObjects` in interface `QueryMetadata`

  - ### getStatementFetchSize

    public int getStatementFetchSize()
    Specified by:
      `getStatementFetchSize` in interface `QueryMetadata`
    Returns:
      statement's fetch size

  - ### getQueryTimeout

    public int getQueryTimeout()
    Specified by:
      `getQueryTimeout` in interface `QueryMetadata`
    Returns:
      query timeout

  - ### isSuppressingDistinct

    public boolean isSuppressingDistinct()
    Specified by:
      `isSuppressingDistinct` in interface `QueryMetadata`

  - ### isReadOnly

    public boolean isReadOnly()
    Description copied from interface: `QueryMetadata`
    Returns true if this is a read-only (selecting) query that does not need to run in its own transaction. Defaults to false, so any query not explicitly marked read-only is still wrapped in a transaction.
    Specified by:
      `isReadOnly` in interface `QueryMetadata`