Package org.apache.axiom.ext.activation
Interface SizeAwareDataSource
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- All Superinterfaces:
DataSource
- All Known Implementing Classes:
BlobDataSource
,ByteArrayDataSource
,CachedFileDataSource
,EmptyDataSource
public interface SizeAwareDataSource extends DataSource
Optional extension interface that can be implemented by data sources that support a getSize method. Code working with data sources can use this this information to optimize certain operations. Note however that instead of checking of this interface directly, this kind of code should useDataSourceUtils.getSize(DataSource)
because this method is able to determine the size of other types of data sources as well.Code using this interface should be aware that some implementations may be unable to guarantee 100% accuracy when determining the size of the data source. Situations where this can occur include:
- The data source uses a network protocol that allows to get the size of the data but that doesn't guarantee accurateness.
- Reading the data involves a decoding operation and the length of the resulting stream can't be determined precisely without performing the decoding operation. In this case the implementation of this interface may return a value based on an estimation.
read
methods of theInputStream
class). It must be prepared to reach the end of the stream after a number of bytes that is lower or higher than the value returned bygetSize()
.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description long
getSize()
Get the size of the data source.-
Methods inherited from interface javax.activation.DataSource
getContentType, getInputStream, getName, getOutputStream
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Method Detail
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getSize
long getSize()
Get the size of the data source. Implementations must return the number of bytes that can be read from the input stream returned byDataSource.getInputStream()
before reaching the end of the stream. If the implementation is unable to determine the size, it must return -1.- Returns:
- the size of the data source or -1 if the size is not known
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