Ticket #354 (closed enhancement: fixed)

This functionality will allow applications to more easily write image data to non-file destinations, such as output streams, by providing an alternative subclass of loci.common.IRandomAccess.

For example, an RAOutputStream class could (trivially) implement all of the java.io.DataOutput methods while throwing an "unsupported" exception for the java.io.DataInput and random access (i.e., seek) methods. Then any writer that uses only the allowed method calls would be easily streamable using an RAOutputStream with loci.common.Location.mapFile(String, IRandomAccess).

For another theoretical example, see: source:trunk/utils/ReadWriteInMemory.java

One other change would be useful to facilitate this support. Currently, loci.common.RandomAccessStream has logic to decide which type of IRandomAccess object to create from the id string. This logic should be refactored into a loci.common.Location.getHandle(String) method or similar that returns an IRandomAccess object. This method would take care of the work of checking getMappedId, getMappedFile and string formatting (e.g., using RAUrl if the string starts with "http:"). Then, both RandomAccessStream and the format writers could call Location.getHandle(String) to easily leverage the mapping functionality.

See r4900; Location.getHandle(String) was added, and most format writers were modified to use an IRandomAccess instead of a RandomAccessFile.

As of r4913, all writers except for loci.formats.out.LegacyQTWriter use loci.common.RandomAccessOutputStream to write files. As far as I know, QT Java only allows movies to be written to a file on disk, so it's probably not feasible to have LegacyQTWriter use RandomAccessOutputStream.

In my opinion, this ticket will be solved once the commented out code at the bottom of source:trunk/utils/ReadWriteInMemory.java works as expected, even if it does not work with LegacyQTWriter, as long as unsupported formats throw a FormatException, IllegalStateException or something similar.

(In [4919]) * Changed TiffTools.overwriteIFDValue to accept a String filename instead of a RandomAccessFile.

• Updated loci.ome.editor.MetadataPane to use TiffTools.overwriteComment(String, String) instead of TiffTools.overwriteIFDValue.
• Updated ReadWriteInMemory utility to take advantage of the loci.common.RABytes fixes in r4917.

Reading from/writing to files in memory should work now. Closes #354.