Bug 56437 - [PATCH] Streaming write support in NPOIFS

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1588887 13f79535-47bb-0310-9956-ffa450edef68

6 files changed, 262 insertions, 111 deletions

diff --git a/src/java/org/apache/poi/poifs/filesystem/DirectoryNode.java b/src/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
index b9b7a51b5d..cb705ff073 100644
--- a/src/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
+++ b/src/java/org/apache/poi/poifs/filesystem/DirectoryNode.java
@@ -412,7 +412,11 @@ public class DirectoryNode
                                         final POIFSWriterListener writer)
         throws IOException
     {
-        return createDocument(new POIFSDocument(name, size, _path, writer));
+        if(_nfilesystem != null) {
+            return createDocument(new NPOIFSDocument(name, size, _nfilesystem, writer));
+         } else {
+            return createDocument(new POIFSDocument(name, size, _path, writer));
+         }
     }
 
     /**
diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
index f7de415942..a61c7dc655 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSDocument.java
@@ -17,10 +17,11 @@
 
 package org.apache.poi.poifs.filesystem;
 
-import java.io.ByteArrayInputStream;
+import java.io.BufferedInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.Iterator;
@@ -30,7 +31,6 @@ import org.apache.poi.poifs.common.POIFSConstants;
 import org.apache.poi.poifs.dev.POIFSViewable;
 import org.apache.poi.poifs.property.DocumentProperty;
 import org.apache.poi.util.HexDump;
-import org.apache.poi.util.IOUtils;
 
 /**
  * This class manages a document in the NIO POIFS filesystem.
@@ -72,21 +72,12 @@ public final class NPOIFSDocument implements POIFSViewable {
    {
       this._filesystem = filesystem;
 
-      // Buffer the contents into memory. This is a bit icky...
-      // TODO Replace with a buffer up to the mini stream size, then streaming write
-      byte[] contents;
-      if(stream instanceof ByteArrayInputStream) {
-         ByteArrayInputStream bais = (ByteArrayInputStream)stream;
-         contents = new byte[bais.available()];
-         bais.read(contents);
-      } else {
-         ByteArrayOutputStream baos = new ByteArrayOutputStream();
-         IOUtils.copy(stream, baos);
-         contents = baos.toByteArray();
-      }
+      final int bigBlockSize = POIFSConstants.BIG_BLOCK_MINIMUM_DOCUMENT_SIZE;
+      BufferedInputStream bis = new BufferedInputStream(stream, bigBlockSize+1);
+      bis.mark(bigBlockSize);
 
       // Do we need to store as a mini stream or a full one?
-      if(contents.length <= POIFSConstants.BIG_BLOCK_MINIMUM_DOCUMENT_SIZE) {
+      if(bis.skip(bigBlockSize) < bigBlockSize) {
          _stream = new NPOIFSStream(filesystem.getMiniStore());
          _block_size = _filesystem.getMiniStore().getBlockStoreBlockSize();
       } else {
@@ -94,14 +85,49 @@ public final class NPOIFSDocument implements POIFSViewable {
          _block_size = _filesystem.getBlockStoreBlockSize();
       }
 
+      // start from the beginning 
+      bis.reset();
+      
       // Store it
-      _stream.updateContents(contents);
+      OutputStream os = _stream.getOutputStream();
+      byte buf[] = new byte[1024];
+      int length = 0;
+      
+      for (int readBytes; (readBytes = bis.read(buf)) != -1; length += readBytes) {
+          os.write(buf, 0, readBytes);
+      }
 
       // And build the property for it
-      this._property = new DocumentProperty(name, contents.length);
+      this._property = new DocumentProperty(name, length);
       _property.setStartBlock(_stream.getStartBlock());     
    }
    
+   public NPOIFSDocument(String name, int size, NPOIFSFileSystem filesystem, POIFSWriterListener writer) 
+      throws IOException 
+   {
+       this._filesystem = filesystem;
+
+       if (size < POIFSConstants.BIG_BLOCK_MINIMUM_DOCUMENT_SIZE) {
+           _stream = new NPOIFSStream(filesystem.getMiniStore());
+           _block_size = _filesystem.getMiniStore().getBlockStoreBlockSize();
+       } else {
+           _stream = new NPOIFSStream(filesystem);
+           _block_size = _filesystem.getBlockStoreBlockSize();
+       }
+       
+       OutputStream innerOs = _stream.getOutputStream();
+       DocumentOutputStream os = new DocumentOutputStream(innerOs, size);
+       POIFSDocumentPath path = new POIFSDocumentPath(name.split("\\\\"));
+       String docName = path.getComponent(path.length()-1);
+       POIFSWriterEvent event = new POIFSWriterEvent(os, path, docName, size);
+       writer.processPOIFSWriterEvent(event);
+       innerOs.close();
+
+       // And build the property for it
+       this._property = new DocumentProperty(name, size);
+       _property.setStartBlock(_stream.getStartBlock());     
+   }
+   
    int getDocumentBlockSize() {
       return _block_size;
    }
diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
index 9c1a6b31d1..bf7d1f7457 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSFileSystem.java
@@ -117,12 +117,14 @@ public class NPOIFSFileSystem extends BlockStore
         // Mark us as having a single empty BAT at offset 0
         _header.setBATCount(1);
         _header.setBATArray(new int[] { 0 });
-        _bat_blocks.add(BATBlock.createEmptyBATBlock(bigBlockSize, false));
+        BATBlock bb = BATBlock.createEmptyBATBlock(bigBlockSize, false);
+        bb.setOurBlockIndex(0);
+        _bat_blocks.add(bb);
+
         setNextBlock(0, POIFSConstants.FAT_SECTOR_BLOCK);
-        
-        // Now associate the properties with the empty block
-        _property_table.setStartBlock(1);
         setNextBlock(1, POIFSConstants.END_OF_CHAIN);
+
+        _property_table.setStartBlock(POIFSConstants.END_OF_CHAIN);
     }
 
     /**
@@ -483,13 +485,11 @@ public class NPOIFSFileSystem extends BlockStore
      */
     @Override
     protected int getFreeBlock() throws IOException {
+        int numSectors = bigBlockSize.getBATEntriesPerBlock();
+
        // First up, do we have any spare ones?
        int offset = 0;
-       for(int i=0; i<_bat_blocks.size(); i++) {
-          int numSectors = bigBlockSize.getBATEntriesPerBlock();
-
-          // Check this one
-          BATBlock bat = _bat_blocks.get(i);
+       for (BATBlock bat : _bat_blocks) {
           if(bat.hasFreeSectors()) {
              // Claim one of them and return it
              for(int j=0; j<numSectors; j++) {
@@ -699,8 +699,13 @@ public class NPOIFSFileSystem extends BlockStore
      * Has our in-memory objects write their state
      *  to their backing blocks 
      */
-    private void syncWithDataSource() throws IOException
-    {
+    private void syncWithDataSource() throws IOException {
+        // Properties
+        NPOIFSStream propStream = new NPOIFSStream(this, _header.getPropertyStart());
+        _property_table.preWrite();
+        _property_table.write(propStream);
+        // _header.setPropertyStart has been updated on write ...
+        
        // HeaderBlock
        HeaderBlockWriter hbw = new HeaderBlockWriter(_header);
        hbw.writeBlock( getBlockAt(-1) );
@@ -713,11 +718,6 @@ public class NPOIFSFileSystem extends BlockStore
        
        // SBATs
        _mini_store.syncWithDataSource();
-       
-       // Properties
-       _property_table.write(
-             new NPOIFSStream(this, _header.getPropertyStart())
-       );
     }
     
     /**
diff --git a/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java b/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
index 5d8d1fa882..5d444b8cb9 100644
--- a/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
+++ b/src/java/org/apache/poi/poifs/filesystem/NPOIFSStream.java
@@ -20,6 +20,7 @@
 package org.apache.poi.poifs.filesystem;
 
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.util.Iterator;
 
@@ -47,6 +48,7 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
 {
 	private BlockStore blockStore;
 	private int startBlock;
+	private OutputStream outStream;
 	
 	/**
 	 * Constructor for an existing stream. It's up to you
@@ -92,7 +94,7 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
       }
       return new StreamBlockByteBufferIterator(startBlock);
    }
-   
+
    /**
     * Updates the contents of the stream to the new
     *  set of bytes.
@@ -100,62 +102,16 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
     *  need to update the size in the property yourself
     */
    public void updateContents(byte[] contents) throws IOException {
-      // How many blocks are we going to need?
-      int blockSize = blockStore.getBlockStoreBlockSize();
-      int blocks = (int)Math.ceil( ((double)contents.length) / blockSize );
-      
-      // Make sure we don't encounter a loop whilst overwriting
-      //  the existing blocks
-      ChainLoopDetector loopDetector = blockStore.getChainLoopDetector();
-      
-      // Start writing
-      int prevBlock = POIFSConstants.END_OF_CHAIN;
-      int nextBlock = startBlock;
-      for(int i=0; i<blocks; i++) {
-         int thisBlock = nextBlock;
-         
-         // Allocate a block if needed, otherwise figure
-         //  out what the next block will be
-         if(thisBlock == POIFSConstants.END_OF_CHAIN) {
-            thisBlock = blockStore.getFreeBlock();
-            loopDetector.claim(thisBlock);
-            
-            // We're on the end of the chain
-            nextBlock = POIFSConstants.END_OF_CHAIN;
-            
-            // Mark the previous block as carrying on to us if needed
-            if(prevBlock != POIFSConstants.END_OF_CHAIN) {
-               blockStore.setNextBlock(prevBlock, thisBlock);
-            }
-            blockStore.setNextBlock(thisBlock, POIFSConstants.END_OF_CHAIN);
-            
-            // If we've just written the first block on a 
-            //  new stream, save the start block offset
-            if(this.startBlock == POIFSConstants.END_OF_CHAIN) {
-               this.startBlock = thisBlock;
-            }
-         } else {
-            loopDetector.claim(thisBlock);
-            nextBlock = blockStore.getNextBlock(thisBlock);
-         }
-         
-         // Write it
-         ByteBuffer buffer = blockStore.createBlockIfNeeded(thisBlock);
-         int startAt = i*blockSize;
-         int endAt = Math.min(contents.length - startAt, blockSize);
-         buffer.put(contents, startAt, endAt); 
-         
-         // Update pointers
-         prevBlock = thisBlock;
-      }
-      int lastBlock = prevBlock;
-      
-      // If we're overwriting, free any remaining blocks
-      NPOIFSStream toFree = new NPOIFSStream(blockStore, nextBlock);
-      toFree.free(loopDetector);
-      
-      // Mark the end of the stream
-      blockStore.setNextBlock(lastBlock, POIFSConstants.END_OF_CHAIN);
+       OutputStream os = getOutputStream();
+       os.write(contents);
+       os.close();
+   }
+
+   public OutputStream getOutputStream() throws IOException {
+       if (outStream == null) {
+           outStream = new StreamBlockByteBuffer();
+       }
+       return outStream;
    }
    
    // TODO Streaming write support
@@ -222,5 +178,87 @@ public class NPOIFSStream implements Iterable<ByteBuffer>
          throw new UnsupportedOperationException();
       }
    }
+   
+   protected class StreamBlockByteBuffer extends OutputStream {
+       byte oneByte[] = new byte[1];
+       ByteBuffer buffer;
+       // Make sure we don't encounter a loop whilst overwriting
+       // the existing blocks
+       ChainLoopDetector loopDetector;
+       int prevBlock, nextBlock;
+
+       protected StreamBlockByteBuffer() throws IOException {
+           loopDetector = blockStore.getChainLoopDetector();
+           prevBlock = POIFSConstants.END_OF_CHAIN;
+           nextBlock = startBlock;
+       }
+
+       protected void createBlockIfNeeded() throws IOException {
+           if (buffer != null && buffer.hasRemaining()) return;
+           
+           int thisBlock = nextBlock;
+           
+           // Allocate a block if needed, otherwise figure
+           //  out what the next block will be
+           if(thisBlock == POIFSConstants.END_OF_CHAIN) {
+              thisBlock = blockStore.getFreeBlock();
+              loopDetector.claim(thisBlock);
+              
+              // We're on the end of the chain
+              nextBlock = POIFSConstants.END_OF_CHAIN;
+              
+              // Mark the previous block as carrying on to us if needed
+              if(prevBlock != POIFSConstants.END_OF_CHAIN) {
+                 blockStore.setNextBlock(prevBlock, thisBlock);
+              }
+              blockStore.setNextBlock(thisBlock, POIFSConstants.END_OF_CHAIN);
+              
+              // If we've just written the first block on a 
+              //  new stream, save the start block offset
+              if(startBlock == POIFSConstants.END_OF_CHAIN) {
+                 startBlock = thisBlock;
+              }
+           } else {
+              loopDetector.claim(thisBlock);
+              nextBlock = blockStore.getNextBlock(thisBlock);
+           }
+
+           buffer = blockStore.createBlockIfNeeded(thisBlock);
+           
+           // Update pointers
+           prevBlock = thisBlock;
+       }
+       
+       public void write(int b) throws IOException {
+            oneByte[0] = (byte)(b & 0xFF);
+            write(oneByte);
+       }
+    
+        public void write(byte[] b, int off, int len) throws IOException {
+            if ((off < 0) || (off > b.length) || (len < 0) ||
+                    ((off + len) > b.length) || ((off + len) < 0)) {
+                throw new IndexOutOfBoundsException();
+            } else if (len == 0) {
+                return;
+            }
+
+            do {
+                createBlockIfNeeded();
+                int writeBytes = Math.min(buffer.remaining(), len);
+                buffer.put(b, off, writeBytes);
+                off += writeBytes;
+                len -= writeBytes;
+            } while (len > 0);
+        }
+    
+        public void close() throws IOException {
+            // If we're overwriting, free any remaining blocks
+            NPOIFSStream toFree = new NPOIFSStream(blockStore, nextBlock);
+            toFree.free(loopDetector);
+            
+            // Mark the end of the stream
+            blockStore.setNextBlock(prevBlock, POIFSConstants.END_OF_CHAIN);
+        }
+   }
 }
 
diff --git a/src/java/org/apache/poi/poifs/property/NPropertyTable.java b/src/java/org/apache/poi/poifs/property/NPropertyTable.java
index aed08a521b..eb2e51458a 100644
--- a/src/java/org/apache/poi/poifs/property/NPropertyTable.java
+++ b/src/java/org/apache/poi/poifs/property/NPropertyTable.java
@@ -17,8 +17,8 @@
 
 package org.apache.poi.poifs.property;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Iterator;
@@ -124,17 +124,34 @@ public final class NPropertyTable extends PropertyTableBase {
     }
  
     /**
+     * Prepare to be written
+     */
+    public void preWrite() {
+        List<Property> pList = new ArrayList<Property>();
+        // give each property its index
+        int i=0;
+        for (Property p : _properties) {
+            // only handle non-null properties 
+            if (p == null) continue;
+            p.setIndex(i++);
+            pList.add(p);
+        }
+
+        // prepare each property for writing
+        for (Property p : pList) p.preWrite();
+    }    
+    
+    /**
      * Writes the properties out into the given low-level stream
      */
     public void write(NPOIFSStream stream) throws IOException {
-       // TODO - Use a streaming write
-       ByteArrayOutputStream baos = new ByteArrayOutputStream();
+       OutputStream os = stream.getOutputStream();
        for(Property property : _properties) {
           if(property != null) {
-             property.writeData(baos);
+             property.writeData(os);
           }
        }
-       stream.updateContents(baos.toByteArray());
+       os.close();
        
        // Update the start position if needed
        if(getStartBlock() != stream.getStartBlock()) {
diff --git a/src/testcases/org/apache/poi/poifs/filesystem/TestNPOIFSFileSystem.java b/src/testcases/org/apache/poi/poifs/filesystem/TestNPOIFSFileSystem.java
index ba6d1c0c0d..3008fc5b92 100644
--- a/src/testcases/org/apache/poi/poifs/filesystem/TestNPOIFSFileSystem.java
+++ b/src/testcases/org/apache/poi/poifs/filesystem/TestNPOIFSFileSystem.java
@@ -17,13 +17,18 @@
 
 package org.apache.poi.poifs.filesystem;
 
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Iterator;
 
-import junit.framework.TestCase;
-
 import org.apache.poi.POIDataSamples;
 import org.apache.poi.hpsf.PropertySet;
 import org.apache.poi.hpsf.PropertySetFactory;
@@ -33,14 +38,17 @@ import org.apache.poi.poifs.property.NPropertyTable;
 import org.apache.poi.poifs.property.Property;
 import org.apache.poi.poifs.property.RootProperty;
 import org.apache.poi.poifs.storage.HeaderBlock;
+import org.apache.poi.util.IOUtils;
+import org.junit.Test;
 
 /**
  * Tests for the new NIO POIFSFileSystem implementation
  */
-public final class TestNPOIFSFileSystem extends TestCase {
+public final class TestNPOIFSFileSystem {
    private static final POIDataSamples _inst = POIDataSamples.getPOIFSInstance();
 
-   public void testBasicOpen() throws Exception {
+   @Test
+   public void basicOpen() throws Exception {
       NPOIFSFileSystem fsA, fsB;
       
       // With a simple 512 block file
@@ -58,7 +66,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
       }
    }
 
-   public void testPropertiesAndFatOnRead() throws Exception {
+   @Test
+   public void propertiesAndFatOnRead() throws Exception {
       NPOIFSFileSystem fsA, fsB;
       
       // With a simple 512 block file
@@ -196,7 +205,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Check that for a given block, we can correctly figure
     *  out what the next one is
     */
-   public void testNextBlock() throws Exception {
+   @Test
+   public void nextBlock() throws Exception {
       NPOIFSFileSystem fsA = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
       NPOIFSFileSystem fsB = new NPOIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
       for(NPOIFSFileSystem fs : new NPOIFSFileSystem[] {fsA,fsB}) {
@@ -253,7 +263,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
    /**
     * Check we get the right data back for each block
     */
-   public void testGetBlock() throws Exception {
+   @Test
+   public void getBlock() throws Exception {
       NPOIFSFileSystem fsA = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
       NPOIFSFileSystem fsB = new NPOIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
       for(NPOIFSFileSystem fs : new NPOIFSFileSystem[] {fsA,fsB}) {
@@ -322,7 +333,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Ask for free blocks where there are some already
     *  to be had from the FAT
     */
-   public void testGetFreeBlockWithSpare() throws Exception {
+   @Test
+   public void getFreeBlockWithSpare() throws Exception {
       NPOIFSFileSystem fs = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
       
       // Our first BAT block has spares
@@ -349,7 +361,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Ask for free blocks where no free ones exist, and so the
     *  file needs to be extended and another BAT/XBAT added
     */
-   public void testGetFreeBlockWithNoneSpare() throws Exception {
+   @Test
+   public void getFreeBlockWithNoneSpare() throws Exception {
       NPOIFSFileSystem fs = new NPOIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
       int free;
 
@@ -479,7 +492,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Test that we can correctly get the list of directory
     *  entries, and the details on the files in them
     */
-   public void testListEntries() throws Exception {
+   @Test
+   public void listEntries() throws Exception {
       NPOIFSFileSystem fsA = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
       NPOIFSFileSystem fsB = new NPOIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
       NPOIFSFileSystem fsC = new NPOIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
@@ -519,7 +533,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Tests that we can get the correct contents for
     *  a document in the filesystem 
     */
-   public void testGetDocumentEntry() throws Exception {
+   @Test
+   public void getDocumentEntry() throws Exception {
       NPOIFSFileSystem fsA = new NPOIFSFileSystem(_inst.getFile("BlockSize512.zvi"));
       NPOIFSFileSystem fsB = new NPOIFSFileSystem(_inst.openResourceAsStream("BlockSize512.zvi"));
       NPOIFSFileSystem fsC = new NPOIFSFileSystem(_inst.getFile("BlockSize4096.zvi"));
@@ -552,7 +567,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Read a file, write it and read it again.
     * Then, alter+add some streams, write and read
     */
-   public void testReadWriteRead() throws Exception {
+   @Test
+   public void readWriteRead() throws Exception {
       // TODO
       // TODO
    }
@@ -561,7 +577,8 @@ public final class TestNPOIFSFileSystem extends TestCase {
     * Create a new file, write it and read it again
     * Then, add some streams, write and read
     */
-   public void testCreateWriteRead() throws Exception {
+   @Test
+   public void createWriteRead() throws Exception {
       NPOIFSFileSystem fs = new NPOIFSFileSystem();
       
       // Initially has a BAT but not SBAT
@@ -577,10 +594,11 @@ public final class TestNPOIFSFileSystem extends TestCase {
       fs.writeFilesystem(baos);
       fs = new NPOIFSFileSystem(new ByteArrayInputStream(baos.toByteArray()));
       
-      // Check it's still like that
+      // Property table entries have been added to the blocks 
       assertEquals(POIFSConstants.FAT_SECTOR_BLOCK, fs.getNextBlock(0));
       assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(1));
-      assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(2));
+      assertEquals(POIFSConstants.END_OF_CHAIN, fs.getNextBlock(2));
+      assertEquals(POIFSConstants.UNUSED_BLOCK, fs.getNextBlock(3));
       assertEquals(POIFSConstants.END_OF_CHAIN, fs.getRoot().getProperty().getStartBlock());
 
       // Now add a normal stream and a mini stream
@@ -588,6 +606,54 @@ public final class TestNPOIFSFileSystem extends TestCase {
       
       // TODO The rest of the test
    }
+
+   @Test
+   public void writPOIFSWriterListener() throws Exception {
+       File testFile = POIDataSamples.getSpreadSheetInstance().getFile("Simple.xls");
+       NPOIFSFileSystem src = new NPOIFSFileSystem(testFile);
+       byte wbDataExp[] = IOUtils.toByteArray(src.createDocumentInputStream("Workbook"));
+       
+       NPOIFSFileSystem nfs = new NPOIFSFileSystem();
+       copy(src.getRoot(), nfs.getRoot());
+       src.close();
+
+       ByteArrayOutputStream bos = new ByteArrayOutputStream();
+       nfs.writeFilesystem(bos);
+       nfs.close();
+       
+       POIFSFileSystem pfs = new POIFSFileSystem(new ByteArrayInputStream(bos.toByteArray()));
+       byte wbDataAct[] = IOUtils.toByteArray(pfs.createDocumentInputStream("Workbook"));
+       
+       assertThat(wbDataExp, equalTo(wbDataAct));
+   }
+
+   private static void copy(final DirectoryNode src, final DirectoryNode dest) throws IOException {
+       Iterator<Entry> srcIter = src.getEntries();
+       while(srcIter.hasNext()) {
+           Entry entry = srcIter.next();
+           if (entry.isDirectoryEntry()) {
+               DirectoryNode srcDir = (DirectoryNode)entry;
+               DirectoryNode destDir = (DirectoryNode)dest.createDirectory(srcDir.getName());
+               destDir.setStorageClsid(src.getStorageClsid());
+               copy(srcDir, destDir);
+           } else {
+               final DocumentNode srcDoc = (DocumentNode)entry;
+               // dest.createDocument(srcDoc.getName(), src.createDocumentInputStream(srcDoc));
+               dest.createDocument(srcDoc.getName(), srcDoc.getSize(), new POIFSWriterListener() {
+                   public void processPOIFSWriterEvent(POIFSWriterEvent event) {
+                       try {
+                           DocumentInputStream dis = src.createDocumentInputStream(srcDoc);
+                           IOUtils.copy(dis, event.getStream());
+                       } catch (IOException e) {
+                           throw new RuntimeException(e);
+                       }
+                   }
+               });
+           }
+       }
+       
+   }
+   
    
    // TODO Directory/Document write tests
 }