FileAttributeProvider (NetBeans VCS API) - NetBeans API Javadoc 4.1.0

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org.netbeans.modules.vcscore.turbo.local
Interface FileAttributeProvider

public interface FileAttributeProvider

SPI, extension point allowing third parties to redefine attribute reading and writing. Must be registered in default Lookup.

It must generally deternime that they support given FileObject and attribute pair and if so then perform action.

Two providers can theoreticaly clash and support the same attribute for the same fileobject. The key point is that attribute meaning must be precisely defined guaranteeing that two independent providers respond with exactly same value hence making irrelevant which one is actually choosen.

Providers are not required to cache results. Any speculative results (per folder batching) can be implemented using FileAttributeQuery.writeAttribute() ignoring this self-initiated write.

Nested Class Summary

static class FileAttributeProvider.MemoryCache
          Provides direct access to memory layer without delegating to providers layer.

Method Summary

Object readAttribute(FileObject fo, String name, FileAttributeProvider.MemoryCache memoryCache)
          Reads given attribute for given fileobject.

boolean recognizesAttribute(String name)
          Reports if an attribute is supported by the implementation.

boolean recognizesFileObject(FileObject fo)
          Reports if the file object is supported by the implementation.

boolean writeAttribute(FileObject fo, String name, Object value)
          Writes given attribute.

Method Detail

recognizesAttribute

public boolean recognizesAttribute(String name)

Reports if an attribute is supported by the implementation.

recognizesFileObject

public boolean recognizesFileObject(FileObject fo)

Reports if the file object is supported by the implementation.

readAttribute

public Object readAttribute(FileObject fo,
                            String name,
                            FileAttributeProvider.MemoryCache memoryCache)

Reads given attribute for given fileobject. No method parameter may be referenced after method execution finishes.

Parameters:: fo - identifies source FileObject, never null; name - identifies requested attribute, never null; memoryCache - can store speculative results
Returns:: attribute value or null if it does not exist.

writeAttribute

public boolean writeAttribute(FileObject fo,
                              String name,
                              Object value)

Writes given attribute. No method parameter may be referenced after method execution finishes.

Parameters:: fo - identifies target file object, never null; name - identifies attribute, never null; value - actual attribute value that should be stored or null for removing it
Returns:: false on write failure if provider denies the value. On I/O error it returns true.