Add ProxyWriter.setReference(Writer)

Like roxyOutputStream.setReference(OutputStream)

Author: garydgregory

pom.xml

@@ -132,7 +132,7 @@ file comparators, endian transformation classes, and much more.
     </commons.osgi.import>
     <commons.scmPubUrl>https://svn.apache.org/repos/infra/websites/production/commons/content/proper/commons-io/</commons.scmPubUrl>
     <commons.scmPubCheckoutDirectory>site-content</commons.scmPubCheckoutDirectory>
-    <commons.bytebuddy.version>1.18.4</commons.bytebuddy.version>
+    <commons.bytebuddy.version>1.18.7</commons.bytebuddy.version>
     <japicmp.skip>false</japicmp.skip>
     <commons.release.isDistModule>true</commons.release.isDistModule>
     <!-- JaCoCo: Don't make code coverage worse than: -->

src/changes/changes.xml

@@ -63,6 +63,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action type="fix" dev="ggregory" due-to="Martin Wiesner">Fix typos in Javadoc of FileUtils and related test classes #833.</action>
       <!-- ADD -->
       <action type="add" dev="ggregory" due-to="Gary Gregory, Piotr P. Karwasz">Add and use IOUtils.closeQuietlySuppress(Closeable, Throwable) #818.</action>
+      <action type="add" dev="ggregory" due-to="Gary Gregory">Add ProxyWriter.setReference(Writer).</action>
       <!-- UPDATE -->
       <action type="update" dev="ggregory"             due-to="Gary Gregory, Dependabot">Bump org.apache.commons:commons-parent from 91 to 97 #816.</action>
       <action type="update" dev="ggregory"             due-to="Gary Gregory, Dependabot">Bump commons-codec:commons-codec from 1.19.0 to 1.21.0 #812.</action>

src/main/java/org/apache/commons/io/output/ProxyWriter.java

@@ -181,6 +181,18 @@ protected void handleIOException(final IOException e) throws IOException {
         throw e;
     }
 
+    /**
+     * Sets the underlying writer.
+     *
+     * @param out the underlying output writer.
+     * @return {@code this} instance.
+     * @since 2.22.0
+     */
+    public ProxyWriter setReference(final Writer out) {
+        this.out = out;
+        return this;
+    }
+
     /**
      * Invokes the delegate's {@code write(char[])} method.
      *

src/test/java/org/apache/commons/io/output/ProxyWriterTest.java

@@ -17,20 +17,57 @@
 package org.apache.commons.io.output;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.io.IOException;
 import java.io.OutputStreamWriter;
+import java.io.StringWriter;
 import java.io.UnsupportedEncodingException;
 import java.io.Writer;
+import java.util.concurrent.atomic.AtomicBoolean;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /**
  * Test {@link ProxyWriter}.
  */
 class ProxyWriterTest {
 
+    private StringWriter target;
+
+    private ProxyWriter proxied;
+
+    private final AtomicBoolean hitArray = new AtomicBoolean();
+    private final AtomicBoolean hitArrayAt = new AtomicBoolean();
+    private final AtomicBoolean hitInt = new AtomicBoolean();
+
+    @BeforeEach
+    public void setUp() {
+        target = new StringWriter() {
+
+            @Override
+            public void write(final char[] ba) throws IOException {
+                hitArray.set(true);
+                super.write(ba);
+            }
+
+            @Override
+            public void write(final char[] b, final int off, final int len) {
+                hitArrayAt.set(true);
+                super.write(b, off, len);
+            }
+
+            @Override
+            public synchronized void write(final int ba) {
+                hitInt.set(true);
+                super.write(ba);
+            }
+        };
+        proxied = new ProxyWriter(target);
+    }
+
     @Test
     void testAppendChar() throws Exception {
         try (StringBuilderWriter writer = new StringBuilderWriter();
@@ -226,6 +263,16 @@ void testNullString() throws Exception {
         }
     }
 
+    @Test
+    void testSetReference() throws Exception {
+        assertFalse(hitArray.get());
+        proxied.setReference(new StringWriter());
+        proxied.write('y');
+        assertFalse(hitArray.get());
+        assertEquals(0, target.toString().length());
+        assertEquals("", target.toString());
+    }
+
     @Test
     void testWriteCharArray() throws Exception {
         try (StringBuilderWriter writer = new StringBuilderWriter();