Lazy creation of output streams. Only create output streams when absolutely necessary.

git-svn-id: file:///humgen/gsa-scr1/gsa-engineering/svn_contents/trunk@824 348d0f76-0448-11de-a6fe-93d51630548a

java/src/org/broadinstitute/sting/gatk/OutputTracker.java

@@ -118,7 +118,7 @@ public class OutputTracker {
     /**
      * Remove pointers to alternate, local output streams.
      */
-    public void removeLocalStreams() {
+    public void cleanup() {
         localOut.remove();
         localErr.remove();
     }

java/src/org/broadinstitute/sting/gatk/executive/OutputMerger.java

@@ -1,10 +1,10 @@
 package org.broadinstitute.sting.gatk.executive;
 
 import org.broadinstitute.sting.utils.StingException;
+import org.broadinstitute.sting.utils.io.LazyFileOutputStream;
 
 import java.io.File;
 import java.io.IOException;
-import java.io.FileOutputStream;
 import java.io.OutputStream;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -32,41 +32,41 @@ import java.nio.channels.WritableByteChannel;
  * thread which is doing the writing. 
  */
 public class OutputMerger {
-    /**
-     * Create a unique identifier
-     */
-    private static int id = 0;
-
     /**
      * Is writing to these streams complete?
      */
     private boolean complete = false;
 
-    /**
-     * File objects that the output and error data went into.
-     */
-    private File outFile;
-    private File errFile;
-
     /**
      * The printstreams which should be written to.
      */
-    private FileOutputStream out = null;
-    private FileOutputStream err = null;
+    private LazyFileOutputStream out = null;
+    private LazyFileOutputStream err = null;
 
     public OutputMerger() {
-        try {
-            outFile = File.createTempFile("gatkout_" + id, null);
-            errFile = File.createTempFile("gatkerr_" + id, null);
-
-            out = new FileOutputStream( outFile );
-            err = new FileOutputStream( errFile );
-        }
-        catch( IOException ex ) {
-            throw new StingException("Unable to open temporary file for GATK output",ex);   
-        }
+        out = new LazyFileOutputStream( outStreamFactory );
+        err = new LazyFileOutputStream( errStreamFactory );
     }
 
+    /**
+     * Creates a generic output stream for temporary data.
+     */
+    private static class TempFileFactory implements LazyFileOutputStream.FileFactory {
+        private final String prefix;
+        public TempFileFactory( String prefix ) { this.prefix = prefix; }
+        public File create() throws IOException { return File.createTempFile(prefix,null); }
+    }
+
+    /**
+     * Creates a stream for temporary out (not err) data.
+     */
+    private static final TempFileFactory outStreamFactory = new TempFileFactory("gatkout_");
+
+    /**
+     * Creates a stream for temporary err data.
+     */
+    private static final TempFileFactory errStreamFactory = new TempFileFactory("gatkerr_");
+
     /**
      * Waits for any the given OutputMerger to be ready for merging.
      */
@@ -95,18 +95,19 @@ public class OutputMerger {
             throw new IllegalStateException("Tried to complete an output merge twice.");
 
         try {
-            out.flush();
-            err.flush();
-            out.close();
-            err.close();
+            if( out.isCreated() ) {
+                out.flush();
+                out.close();
+            }
+            if( err.isCreated() ) {
+                err.flush();
+                err.close();
+            }
         }
         catch( IOException ex ) {
             throw new StingException( "Unable to close sharding output files", ex );
         }
 
-        out = null;
-        err = null;
-
         this.complete = true;
 
         // Notify waiting listeners that this shard is complete and ready for merging.
@@ -119,8 +120,8 @@ public class OutputMerger {
                 throw new StingException("Tried to merge incomplete stream into output");
         }
 
-        transferContentsToTarget( outFile, globalOut );
-        transferContentsToTarget( errFile, globalErr );
+        if( out.isCreated() ) transferContentsToTarget( out.getBackingFile(), globalOut );
+        if( err.isCreated() ) transferContentsToTarget( err.getBackingFile(), globalErr );
     }
 
     /**

java/src/org/broadinstitute/sting/gatk/executive/ShardTraverser.java

@@ -53,7 +53,7 @@ public class ShardTraverser implements Callable {
         finally {
             dataProvider.close();
             output.complete();
-            outputTracker.removeLocalStreams();            
+            outputTracker.cleanup();            
         }
 
         return accumulator;

java/src/org/broadinstitute/sting/utils/io/LazyFileOutputStream.java

@@ -0,0 +1,115 @@
+package org.broadinstitute.sting.utils.io;
+
+import org.broadinstitute.sting.utils.StingException;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FileNotFoundException;
+/**
+ * User: hanna
+ * Date: May 26, 2009
+ * Time: 3:51:49 PM
+ * BROAD INSTITUTE SOFTWARE COPYRIGHT NOTICE AND AGREEMENT
+ * Software and documentation are copyright 2005 by the Broad Institute.
+ * All rights are reserved.
+ *
+ * Users acknowledge that this software is supplied without any warranty or support.
+ * The Broad Institute is not responsible for its use, misuse, or
+ * functionality.
+ */
+
+/**
+ * An output stream that only initializes itself the first time its used.
+ * Needs a callback that can create an output stream.
+ */
+public class LazyFileOutputStream extends OutputStream {
+    /**
+     * Generates output files on demand.
+     */
+    private final FileFactory factory;
+
+    private File targetFile = null;
+
+    /**
+     * The target for any writes performed by the output stream.
+     */
+    private FileOutputStream targetOutputStream = null;
+
+    /**
+     * Create a new LazyOutputStream, indicating how to create a new stream.
+     * @param factory Creator of the output stream, when necessary.
+     */
+    public LazyFileOutputStream( FileFactory factory ) {
+        this.factory = factory;
+    }
+
+    /**
+     * Indicates whether the LazyOutputStream had to get off its butt and create
+     * a new output stream.
+     * @return
+     */
+    public boolean isCreated() {
+        return targetOutputStream != null;
+    }
+
+    /**
+     * Public method to return the lazily created file.
+     * @return Stream created by the lazy loader.
+     * @throw StingException if no stream was created.
+     */
+    public File getBackingFile() {
+        if( targetFile == null )
+            throw new StingException("No lazy-loaded stream was created.");
+        return targetFile;
+    }
+
+    @Override
+    public void close() throws IOException {
+        getBackingOutputStream().close();
+    }
+
+    @Override
+    public void flush() throws IOException {
+        getBackingOutputStream().flush();
+    }
+
+    @Override
+    public void write(byte[] b) throws IOException {
+        getBackingOutputStream().write(b);
+    }
+
+    @Override
+    public void write(byte[] b, int off, int len) throws IOException {
+        getBackingOutputStream().write(b,off,len);
+    }
+
+    @Override
+    public void write(int b) throws IOException {
+        getBackingOutputStream().write(b);
+    }
+
+    /**
+     * Lazy loader for the output stream.
+     */
+    protected OutputStream getBackingOutputStream() {
+        if( targetOutputStream == null ) {
+            try {
+                targetFile = factory.create();
+                targetOutputStream = new FileOutputStream( targetFile );
+            }
+            catch( IOException ex ) {
+                throw new StingException("Unable to open new temp file", ex );
+            }
+        }
+        return targetOutputStream;
+    }        
+
+    /**
+     * Teaches the LazyOutputStream how to create a new outputstream when necessary.
+     */
+    public interface FileFactory {
+        public File create() throws IOException;
+    }
+}