Package org.apache.cayenne.query

Class QueryChain

java.lang.Object

org.apache.cayenne.query.QueryChain

All Implemented Interfaces:

Serializable, Query

public class QueryChain
extends Object
implements Query

A Query decorator for a collection of other queries. Note that QueryChain will always return DataRows (that is if it returns data), as it has no way of knowing how to convert the results to objects.

Since:

1.2

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected Collection<Query>	chain

Constructor Summary

Constructors

Constructor	Description
QueryChain()	Creates an empty QueryChain.
QueryChain(Collection<? extends Query> queries)	Creates a new QueryChain with a collection of Queries.
QueryChain(Query[] queries)	Creates a new QueryChain out of an array of queries.

Method Summary

Modifier and Type	Method	Description
void	addQuery(Query query)	Adds a query to the chain.
SQLAction	createSQLAction(SQLActionVisitor visitor)	Throws an exception as execution should've been delegated to the queries contained in the chain.
QueryMetadata	getMetaData(EntityResolver resolver)	Returns default metadata.
boolean	isEmpty()
boolean	removeQuery(Query query)	Removes a query from the chain, returning true if the query was indeed present in the chain and was removed.
void	route(QueryRouter router, EntityResolver resolver, Query substitutedQuery)	Delegates routing to each individual query in the chain.

Methods inherited from class java.lang.Object

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

Field Details

chain

protected Collection<Query> chain

Constructor Details

QueryChain

public QueryChain()

Creates an empty QueryChain.

QueryChain

public QueryChain(Query[] queries)

Creates a new QueryChain out of an array of queries.

QueryChain

public QueryChain(Collection<? extends Query> queries)

Creates a new QueryChain with a collection of Queries.

Method Details

addQuery

public void addQuery(Query query)

Adds a query to the chain.

removeQuery

public boolean removeQuery(Query query)

Removes a query from the chain, returning true if the query was indeed present in the chain and was removed.

isEmpty

public boolean isEmpty()

route

public void route(QueryRouter router,
 EntityResolver resolver,
 Query substitutedQuery)

Delegates routing to each individual query in the chain. If there is no queries, this method does nothing.

Specified by:

route in interface Query

createSQLAction

public SQLAction createSQLAction(SQLActionVisitor visitor)

Throws an exception as execution should've been delegated to the queries contained in the chain.

Specified by:

createSQLAction in interface Query

getMetaData

public QueryMetadata getMetaData(EntityResolver resolver)

Returns default metadata.

Specified by:

getMetaData in interface Query