org.das2.util.filesystem

Class ExpensiveOpCache

java.lang.Object

org.das2.util.filesystem.ExpensiveOpCache

public class ExpensiveOpCache
extends java.lang.Object

This simply reduces invocations of an expensive operation by caching the result for a given number of milliseconds. This was introduced to remove the number of HEAD requests to the server for a given file.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ExpensiveOpCache.Op

Constructor Summary

Constructors

Constructor and Description
ExpensiveOpCache(ExpensiveOpCache.Op op, int limitMs) Cache the result of op for no more than limitMs milliseconds.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	doOp(java.lang.String key) Do the operation if it has not been done, or if it has not been done recently.
void	reset()

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpensiveOpCache

public ExpensiveOpCache(ExpensiveOpCache.Op op,
                        int limitMs)

Cache the result of op for no more than limitMs milliseconds.

Parameters:

op -

limitMs -

Method Detail

doOp

public java.lang.Object doOp(java.lang.String key)
                      throws java.lang.Exception

Do the operation if it has not been done, or if it has not been done recently.

Parameters:

key -

Returns:

the result of the operation

Throws:

Exception, - see the given op.

java.lang.Exception

reset

public void reset()