com.opensymphony.module.sitemesh.scalability.secondarystorage

Interface SecondaryStorage

All Known Implementing Classes:

NoopSecondaryStorage, TempDirSecondaryStorage

public interface SecondaryStorage

This is a mechanism that allows large SiteMesh requests to be spilled out of memory and into secondary storage. This means that a fixed amount of memory can be used for a SiteMesh request instead of filling till memory is exhausted.
An implementation of this interface should be LAZY. It should not open its secondary storage until the first char has been written to it. This will ensure its as cheap as possible IF there is no need to spill into it.
And implementation MUST also assume that it lives for the life of a request. A new one will be constructed on every request, another reason to be LAZY on file creation say.

Method Summary

Modifier and Type	Method and Description
void	cleanUp() This allows you to ask the secondary storage to clean up after itself.
long	getMemoryLimitBeforeUse() Returns the number of characters that should be stored in memory before this secondary storage.
void	write(char[] chars, int off, int len)
void	write(int c)
void	write(java.lang.String str)
void	write(java.lang.String str, int off, int len)
void	writeTo(java.io.Writer out) This method will close the "secondary storage" and write the captured output to the specified output writer.

Method Detail

getMemoryLimitBeforeUse

long getMemoryLimitBeforeUse()

Returns the number of characters that should be stored in memory before this secondary storage. If this value is 0 or below then it is in fact disabled.

Returns:

the memory limits in force

write

void write(int c)
    throws java.io.IOException

Throws:

java.io.IOException

See Also:

Writer.write(int)

write

void write(char[] chars,
           int off,
           int len)
    throws java.io.IOException

Throws:

java.io.IOException

See Also:

Writer.write(char[], int, int)

write

void write(java.lang.String str,
           int off,
           int len)
    throws java.io.IOException

Throws:

java.io.IOException

See Also:

Writer.write(String, int, int)

write

void write(java.lang.String str)
    throws java.io.IOException

Throws:

java.io.IOException

See Also:

Writer.write(String)

writeTo

void writeTo(java.io.Writer out)
      throws java.io.IOException

This method will close the "secondary storage" and write the captured output to the specified output writer.

Parameters:

out - the output writer to send the stored data

Throws:

java.io.IOException - if the data cant be written

cleanUp

void cleanUp()

This allows you to ask the secondary storage to clean up after itself. A try / finally would be a good place to put this.
This should be able to be called multiple times because we want to be able to always cleanup in case of exceptions as well an blue sky paths.
Really no exceptions should be propagated from this method.