org.apache.derby.client.am.stmtcache
Class JDBCStatementCache.BoundedLinkedHashMap

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap<K,V>
          java.util.LinkedHashMap<StatementKey,java.sql.PreparedStatement>
              org.apache.derby.client.am.stmtcache.JDBCStatementCache.BoundedLinkedHashMap

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map<StatementKey,java.sql.PreparedStatement>

Enclosing class:

JDBCStatementCache

private static class JDBCStatementCache.BoundedLinkedHashMap
extends java.util.LinkedHashMap<StatementKey,java.sql.PreparedStatement>

A LinkedHashMap with an upper bound on the number of entries.

If the maximum size is exceeded, the oldest entry is automatically removed after the new entry has been inserted.

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>

Field Summary

private int

maxSize Maximum number of entries.

Constructor Summary

JDBCStatementCache.BoundedLinkedHashMap(int maxCapacity)
Creates a bounded LinkedHashMap with the specified maximum size.

Method Summary

protected boolean

removeEldestEntry(java.util.Map.Entry<StatementKey,java.sql.PreparedStatement> eldest) Tells if an entry should be removed from the map.

Methods inherited from class java.util.LinkedHashMap

clear, containsValue, get

Methods inherited from class java.util.HashMap

clone, containsKey, entrySet, isEmpty, keySet, put, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

containsKey, entrySet, equals, hashCode, isEmpty, keySet, put, putAll, remove, size, values

Field Detail

maxSize

private final int maxSize

Maximum number of entries.

Constructor Detail

JDBCStatementCache.BoundedLinkedHashMap

public JDBCStatementCache.BoundedLinkedHashMap(int maxCapacity)

Creates a bounded LinkedHashMap with the specified maximum size.

Iteration is by insertion-order.

Parameters:

maxCapacity - maximum size of the map

Method Detail

removeEldestEntry

protected boolean removeEldestEntry(java.util.Map.Entry<StatementKey,java.sql.PreparedStatement> eldest)

Tells if an entry should be removed from the map.

If the cache has exceeded its maximum size, the oldest element will be marked for removal. The oldest element will be removed after the new element has been inserted.

Overrides:

removeEldestEntry in class java.util.LinkedHashMap<StatementKey,java.sql.PreparedStatement>

Parameters:

eldest - the element picked out for removal

Returns:

true if the element is to be removed, false if not.