Use a modified version of NullPrintStream in integration tests

The default version from Commons-IO does not avoid doing
utf-8 conversion and other work, so it is not well suited for
cases where lots of output happens.

Using an optimized version can bring down runtime of integration-tests
somewhat, especially for large files where XLS2CSV prints out lots of
data

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1899532 13f79535-47bb-0310-9956-ffa450edef68

poi-integration/src/test/java/org/apache/poi/stress/OptimizedNullPrintStream.java

@@ -0,0 +1,60 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+package org.apache.poi.stress;
+
+import java.io.IOException;
+
+import org.apache.commons.io.output.NullPrintStream;
+
+/**
+ * A slightly improved version of {@link org.apache.commons.io.output.NullPrintStream}
+ * which overrides some more methods to avoid doing string-conversion or
+ * utf-8 decoding when the actual printing is not done anyway
+ */
+@SuppressWarnings("NullableProblems")
+class OptimizedNullPrintStream extends NullPrintStream {
+
+    @Override
+    public void println(String x) {
+        // empty as NullPrintStream still performs UTF-8 conversion
+        // and other stuff which takes considerable time!
+    }
+
+    @Override
+    public void print(String s) {
+        // empty as NullPrintStream still performs UTF-8 conversion
+        // and other stuff which takes considerable time!
+    }
+
+    @Override
+    public void write(byte[] buf, int off, int len) {
+        // empty as NullPrintStream still performs UTF-8 conversion
+        // and other stuff which takes considerable time!
+    }
+
+    @Override
+    public void write(byte[] b) throws IOException {
+        // empty as NullPrintStream still performs UTF-8 conversion
+        // and other stuff which takes considerable time!
+    }
+
+    @Override
+    public void write(int b) {
+        // empty as NullPrintStream still performs UTF-8 conversion
+        // and other stuff which takes considerable time!
+    }
+}

poi-integration/src/test/java/org/apache/poi/stress/XSSFFileHandler.java

@@ -36,7 +36,6 @@ import java.util.Set;
 
 import javax.xml.transform.TransformerException;
 
-import org.apache.commons.io.output.NullPrintStream;
 import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
 import org.apache.poi.EncryptedDocumentException;
 import org.apache.poi.examples.ss.ExcelComparator;
@@ -190,7 +189,7 @@ public class XSSFFileHandler extends SpreadsheetHandler {
         PrintStream oldOut = System.out;
         String testFile = file.getParentFile().getName() + "/" + file.getName();
         try {
-            System.setOut(new NullPrintStream());
+            System.setOut(new OptimizedNullPrintStream());
             FromHowTo.main(new String[]{file.getAbsolutePath()});
             XLSX2CSV.main(new String[]{file.getAbsolutePath()});
             ExcelComparator.main(new String[]{file.getAbsolutePath(), file.getAbsolutePath()});