org.apache.openjpa.datacache
Class QueryKey

java.lang.Object
  org.apache.openjpa.datacache.QueryKey

All Implemented Interfaces:

Externalizable, Serializable

public class QueryKey
extends Object
implements Externalizable

This class stores information about a particular invocation of a query. It contains a reference to the external properties of the query that was executed, as well as any parameters used to execute that query, with one exception: first-class objects used as parameter values are converted to OIDs.

Author:

Patrick Linskey

See Also:

Serialized Form

Constructor Summary

QueryKey()
Public constructor for externalization only.

Method Summary

boolean	changeInvalidatesQuery(Collection changed) Returns true if modifications to any of the classes in changed results in a possible invalidation of this query; otherwise returns false.
boolean	equals(Object ob) Determine equality based on identifying information.
String	getCandidateTypeName() Returns the candidate class name for this query.
int	getTimeout() Return the amount of time this key is good for.
int	hashCode() Define a hashing algorithm corresponding to the equals(java.lang.Object) method defined above.
static QueryKey	newInstance(Query q) Return a key for the given query, or null if it is not cacheable.
static QueryKey	newInstance(Query q, Map args) Return a key for the given query, or null if it is not cacheable.
static QueryKey	newInstance(Query q, Object[] args) Return a key for the given query, or null if it is not cacheable.
void	readExternal(ObjectInput in)
String	toString()
void	writeExternal(ObjectOutput out)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

QueryKey

public QueryKey()

Public constructor for externalization only.

Method Detail

newInstance

public static QueryKey newInstance(Query q)

Return a key for the given query, or null if it is not cacheable.

newInstance

public static QueryKey newInstance(Query q,
                                   Object[] args)

Return a key for the given query, or null if it is not cacheable.

newInstance

public static QueryKey newInstance(Query q,
                                   Map args)

Return a key for the given query, or null if it is not cacheable.

getCandidateTypeName

public String getCandidateTypeName()

Returns the candidate class name for this query.

getTimeout

public int getTimeout()

Return the amount of time this key is good for.

changeInvalidatesQuery

public boolean changeInvalidatesQuery(Collection changed)

Returns true if modifications to any of the classes in changed results in a possible invalidation of this query; otherwise returns false. Invalidation is possible if one or more of the classes in this query key's access path has been changed.

equals

public boolean equals(Object ob)

Determine equality based on identifying information. Keys created for queries that specify a candidate collection are always not equal.

Overrides:

equals in class Object

hashCode

public int hashCode()

Define a hashing algorithm corresponding to the equals(java.lang.Object) method defined above.

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException