com.helger.photon.basic.app.dao

Interface IDAODataProvider

@MustImplementEqualsAndHashcode
public interface IDAODataProvider

The external data provider for a DAO

Author:

Philip Helger

Method Summary

Modifier and Type	Method and Description
void	fillStringBuilderForSaving(StringBuilder aSB) Is called to fill the data to be written to the file.
Charset	getCharset()
com.helger.commons.state.EChange	initForFirstTimeUsage() Prepare the data structure for an initial save.
boolean	isContentValidForSaving(String sContent) Perform an additional check to ensure that only valid data is saved.
com.helger.commons.state.EChange	readFromStream(InputStream aIS) Initially fill the DAO from an input stream.

Method Detail

getCharset

@Nonnull
Charset getCharset()

Returns:

The name of the character set to use. May not be null.

initForFirstTimeUsage

@Nonnull
com.helger.commons.state.EChange initForFirstTimeUsage()
                                                          throws Exception

Prepare the data structure for an initial save. This is only called if no file was found to be read from.

Returns:

EChange.CHANGED if reading the document changed the content and so a call to the save action should be performed. Never null.

Throws:

Exception - Any error that may occur on initialization.

readFromStream

@Nonnull
com.helger.commons.state.EChange readFromStream(@Nonnull
                                                          InputStream aIS)
                                                   throws Exception

Initially fill the DAO from an input stream. This is only called if the underlying data is resolvable.

Parameters:

aIS - The input stream to read from. Is never null.

Returns:

EChange.CHANGED if reading the document changed the content and so a call to the save action should be performed. Never null.

Throws:

Exception - In case something goes wrong.

fillStringBuilderForSaving

void fillStringBuilderForSaving(@Nonnull
                                StringBuilder aSB)
                         throws Exception

Is called to fill the data to be written to the file. Just add your text to the passed StringBuilder.

Parameters:

aSB - The string builder to be filled. Is never null.

Throws:

Exception - In case something goes wrong.

isContentValidForSaving

boolean isContentValidForSaving(@Nullable
                                String sContent)

Perform an additional check to ensure that only valid data is saved. It is called with the data previously created via fillStringBuilderForSaving(StringBuilder).

Parameters:

sContent - The content that would be written to the file.

Returns:

true if the content is valid, false if the content is invalid and should not be saved.