Set HelpFormatter print stream

Avoid System.setOut() hack

Author: garydgregory

src/main/java/org/apache/commons/cli/HelpFormatter.java

@@ -19,6 +19,7 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.PrintStream;
 import java.io.PrintWriter;
 import java.io.Serializable;
 import java.io.StringReader;
@@ -29,6 +30,7 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.Supplier;
 
 /**
@@ -78,9 +80,25 @@ public static final class Builder implements Supplier<HelpFormatter> {
          */
         private boolean showDeprecated;
 
+        /**
+         * The output PrintStream, defaults to {@link System#out}.
+         */
+        private PrintStream printStream = System.out;
+
         @Override
         public HelpFormatter get() {
-            return new HelpFormatter(showDeprecated);
+            return new HelpFormatter(showDeprecated, printStream);
+        }
+
+        /**
+         * Sets the output PrintStream, defaults to {@link System#out}.
+         *
+         * @param printStream the output PrintStream, not null.
+         * @return this.
+         */
+        public Builder setPrintStream(final PrintStream printStream) {
+            this.printStream = Objects.requireNonNull(printStream, "printStream");
+            return this;
         }
 
         /**
@@ -100,6 +118,7 @@ public Builder setShowDeprecated(final boolean showDeprecated) {
      * This class implements the {@code Comparator} interface for comparing Options.
      */
     private static final class OptionComparator implements Comparator<Option>, Serializable {
+
         /** The serial version UID. */
         private static final long serialVersionUID = 5305467873966684014L;
 
@@ -232,6 +251,11 @@ public static Builder builder() {
      */
     private final boolean showDeprecated;
 
+    /**
+     * Where to print help.
+     */
+    private final PrintStream printStream;
+
     /**
      * The separator displayed between the long option and its value.
      */
@@ -241,16 +265,18 @@ public static Builder builder() {
      * Constructs a new instance.
      */
     public HelpFormatter() {
-        this.showDeprecated = false;
+        this(false, System.out);
     }
 
     /**
      * Constructs a new instance.
+     * @param printStream TODO
      */
-    private HelpFormatter(final boolean showDeprecated) {
+    private HelpFormatter(final boolean showDeprecated, final PrintStream printStream) {
         // TODO All other instance HelpFormatter instance variables.
         // Make HelpFormatter immutable for 2.0
         this.showDeprecated = showDeprecated;
+        this.printStream = printStream;
     }
 
     /**
@@ -460,7 +486,7 @@ public int getWidth() {
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to  {@link System#out}  by default.
      *
      * @param width the number of characters to be displayed on each line
      * @param cmdLineSyntax the syntax for this application
@@ -474,7 +500,7 @@ public void printHelp(final int width, final String cmdLineSyntax, final String
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to {@link System#out} by default.
      *
      * @param width the number of characters to be displayed on each line
      * @param cmdLineSyntax the syntax for this application
@@ -485,7 +511,7 @@ public void printHelp(final int width, final String cmdLineSyntax, final String
      */
     public void printHelp(final int width, final String cmdLineSyntax, final String header, final Options options, final String footer,
         final boolean autoUsage) {
-        final PrintWriter pw = new PrintWriter(System.out);
+        final PrintWriter pw = new PrintWriter(printStream);
         printHelp(pw, width, cmdLineSyntax, header, options, getLeftPadding(), getDescPadding(), footer, autoUsage);
         pw.flush();
     }
@@ -545,7 +571,7 @@ public void printHelp(final PrintWriter pw, final int width, final String cmdLin
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to {@link System#out} by default.
      *
      * @param cmdLineSyntax the syntax for this application
      * @param options the Options instance
@@ -556,7 +582,7 @@ public void printHelp(final String cmdLineSyntax, final Options options) {
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to {@link System#out} by default.
      *
      * @param cmdLineSyntax the syntax for this application
      * @param options the Options instance
@@ -568,7 +594,7 @@ public void printHelp(final String cmdLineSyntax, final Options options, final b
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to {@link System#out} by default.
      *
      * @param cmdLineSyntax the syntax for this application
      * @param header the banner to display at the beginning of the help
@@ -581,7 +607,7 @@ public void printHelp(final String cmdLineSyntax, final String header, final Opt
 
     /**
      * Prints the help for {@code options} with the specified command line syntax. This method prints help information
-     * to System.out.
+     * to {@link System#out} by default.
      *
      * @param cmdLineSyntax the syntax for this application
      * @param header the banner to display at the beginning of the help

src/test/java/org/apache/commons/cli/HelpFormatterTest.java

@@ -20,7 +20,6 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.ByteArrayOutputStream;
 import java.io.PrintWriter;

src/test/java/org/apache/commons/cli/bug/BugsTest.java

@@ -231,30 +231,33 @@ public void test13425() throws Exception {
     @Test
     public void test13666() throws Exception {
         final Options options = new Options();
-        final Option dir = OptionBuilder.withDescription("dir").hasArg().create('d');
-        options.addOption(dir);
-
+        final Option dirOption = OptionBuilder.withDescription("dir").hasArg().create('d');
+        options.addOption(dirOption);
         final PrintStream oldSystemOut = System.out;
         try {
-            final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-            final PrintStream print = new PrintStream(bytes);
-
-            // capture this platform's eol symbol
-            print.println();
-            final String eol = bytes.toString();
-            bytes.reset();
-
-            System.setOut(new PrintStream(bytes));
-
+            final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            final String eol = System.lineSeparator();
+            System.setOut(new PrintStream(baos));
             final HelpFormatter formatter = new HelpFormatter();
             formatter.printHelp("dir", options);
-
-            assertEquals("usage: dir" + eol + " -d <arg>   dir" + eol, bytes.toString());
+            assertEquals("usage: dir" + eol + " -d <arg>   dir" + eol, baos.toString());
         } finally {
             System.setOut(oldSystemOut);
         }
     }
 
+    @Test
+    public void test13666_Builder() throws Exception {
+        final Options options = new Options();
+        final Option dirOption = OptionBuilder.withDescription("dir").hasArg().create('d');
+        options.addOption(dirOption);
+        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        final String eol = System.lineSeparator();
+        final HelpFormatter formatter = HelpFormatter.builder().setPrintStream(new PrintStream(baos)).get();
+        formatter.printHelp("dir", options);
+        assertEquals("usage: dir" + eol + " -d <arg>   dir" + eol, baos.toString());
+    }
+
     @Test
     public void test13935() throws Exception {
         final OptionGroup directions = new OptionGroup();