Made CorpusBasedExporter's buffer configurable

src/main/java/info/textgrid/services/aggregator/CorpusBasedExporter.java

@@ -8,8 +8,12 @@
 import info.textgrid.namespaces.middleware.tgcrud.services.tgcrudservice.ProtocolNotImplementedFault;
 import info.textgrid.services.aggregator.teicorpus.TEICorpusSerializer;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.text.MessageFormat;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -22,19 +26,61 @@
 
 import com.google.common.io.ByteStreams;
 import com.google.common.io.FileBackedOutputStream;
+import com.google.common.io.Files;
 import com.google.common.io.InputSupplier;
 
 public abstract class CorpusBasedExporter extends AbstractExporter {
 
 	private static final Logger logger = Logger.getLogger(CorpusBasedExporter.class.getCanonicalName());
 	protected boolean readStylesheetPI = false;
-	private InputSupplier<InputStream> sourceBuffer = null;
+	private InputSupplier<? extends InputStream> sourceBuffer = null;
+	private IBufferFactory bufferFactory = new FBBAOSBufferFactory();
 
 	public CorpusBasedExporter(final ITextGridRep repository,
 			final Request request, final String uriList) {
 		super(repository, request, uriList);
 	}
 
+	public static interface IBufferFactory {
+		public OutputStream getBufferSink();
+		public InputSupplier<? extends InputStream> getBufferContents();
+	}
+
+	public static final class FBBAOSBufferFactory implements IBufferFactory {
+		private FileBackedOutputStream sink;
+
+		@Override
+		public OutputStream getBufferSink() {
+			this.sink = new FileBackedOutputStream(1024 * 1024, true);
+			return sink;
+		}
+
+		@Override
+		public InputSupplier<InputStream> getBufferContents() {
+			return sink.getSupplier();
+		}
+	}
+
+	public static final class FileBufferFactory implements IBufferFactory {
+		private final File file;
+		private FileOutputStream sink;
+
+		public FileBufferFactory(final File file) throws FileNotFoundException {
+			this.file = file;
+			this.sink = new FileOutputStream(file);
+		}
+
+		@Override
+		public InputSupplier<? extends InputStream> getBufferContents() {
+			return Files.newInputStreamSupplier(file);
+		}
+
+		@Override
+		public OutputStream getBufferSink() {
+			return sink;
+		}
+	}
+
 	/**
 	 * Loads a source for the given document.
 	 *
@@ -83,17 +129,15 @@ protected Source loadSource(final boolean bufferRequired)
 				|| sourceType == SourceType.BASKET) {
 			final TEICorpusSerializer corpusSerializer =
 					new TEICorpusSerializer(getRootObjects(), false, getSid().orNull());
-			final FileBackedOutputStream corpusBuffer = new FileBackedOutputStream(
-					1024 * 1024, true);
+			final OutputStream corpusBuffer = getBufferFactory().getBufferSink();
 			corpusSerializer.write(corpusBuffer);
 			corpusBuffer.close();
-			sourceBuffer = corpusBuffer.getSupplier();
+			sourceBuffer = getBufferFactory().getBufferContents();
 			source = new StreamSource(sourceBuffer.getInput());
 		} else if (sourceType == SourceType.XML && bufferRequired) {
-			final FileBackedOutputStream xmlBuffer = new FileBackedOutputStream(
-					1024 * 1024, true);
+			final OutputStream xmlBuffer = getBufferFactory().getBufferSink();
 			ByteStreams.copy(getContentSimple(), xmlBuffer);
-			sourceBuffer = xmlBuffer.getSupplier();
+			sourceBuffer = getBufferFactory().getBufferContents();
 			source = new StreamSource(sourceBuffer.getInput());
 		} else {
 			source = new StreamSource(getContentSimple().getInput(),
@@ -106,4 +150,12 @@ protected Source loadSource(final boolean bufferRequired)
 		return source;
 	}
 
+	private IBufferFactory getBufferFactory() {
+		return bufferFactory;
+	}
+
+	protected void setBufferFactory(final IBufferFactory bufferFactory) {
+		this.bufferFactory = bufferFactory;
+	}
+
 }
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