8026127: Deflater/Inflater documentation incomplete/misleading

Reviewed-by: lancea

Author: jaikiran

src/java.base/share/classes/java/util/zip/Deflater.java

@@ -57,36 +57,7 @@
  * The following code fragment demonstrates a trivial compression
  * and decompression of a string using {@code Deflater} and
  * {@code Inflater}.
- *
- * <blockquote><pre>
- * try {
- *     // Encode a String into bytes
- *     String inputString = "blahblahblah";
- *     byte[] input = inputString.getBytes("UTF-8");
- *
- *     // Compress the bytes
- *     byte[] output = new byte[100];
- *     Deflater compresser = new Deflater();
- *     compresser.setInput(input);
- *     compresser.finish();
- *     int compressedDataLength = compresser.deflate(output);
- *     compresser.end();
- *
- *     // Decompress the bytes
- *     Inflater decompresser = new Inflater();
- *     decompresser.setInput(output, 0, compressedDataLength);
- *     byte[] result = new byte[100];
- *     int resultLength = decompresser.inflate(result);
- *     decompresser.end();
- *
- *     // Decode the bytes into a String
- *     String outputString = new String(result, 0, resultLength, "UTF-8");
- * } catch (java.io.UnsupportedEncodingException ex) {
- *     // handle
- * } catch (java.util.zip.DataFormatException ex) {
- *     // handle
- * }
- * </pre></blockquote>
+ * {@snippet id="compdecomp" lang="java" class="Snippets" region="DeflaterInflaterExample"}
  *
  * @apiNote
  * To release resources used by this {@code Deflater}, the {@link #end()} method

src/java.base/share/classes/java/util/zip/Inflater.java

@@ -56,35 +56,7 @@
  * The following code fragment demonstrates a trivial compression
  * and decompression of a string using {@code Deflater} and
  * {@code Inflater}.
- *
- * <blockquote><pre>
- * try {
- *     // Encode a String into bytes
- *     String inputString = "blahblahblah\u20AC\u20AC";
- *     byte[] input = inputString.getBytes("UTF-8");
- *
- *     // Compress the bytes
- *     byte[] output = new byte[100];
- *     Deflater compresser = new Deflater();
- *     compresser.setInput(input);
- *     compresser.finish();
- *     int compressedDataLength = compresser.deflate(output);
- *
- *     // Decompress the bytes
- *     Inflater decompresser = new Inflater();
- *     decompresser.setInput(output, 0, compressedDataLength);
- *     byte[] result = new byte[100];
- *     int resultLength = decompresser.inflate(result);
- *     decompresser.end();
- *
- *     // Decode the bytes into a String
- *     String outputString = new String(result, 0, resultLength, "UTF-8");
- * } catch (java.io.UnsupportedEncodingException ex) {
- *     // handle
- * } catch (java.util.zip.DataFormatException ex) {
- *     // handle
- * }
- * </pre></blockquote>
+ * {@snippet id="compdecomp" lang="java" class="Snippets" region="DeflaterInflaterExample"}
  *
  * @apiNote
  * To release resources used by this {@code Inflater}, the {@link #end()} method

src/java.base/share/classes/java/util/zip/snippet-files/Snippets.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.util.zip;
+
+import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
+
+class Snippets {
+
+    void deflaterInflaterExample() {
+        // @start region="DeflaterInflaterExample"
+
+        // Encode a String into bytes
+        String inputString = "blahblahblah\u20AC\u20AC";
+        byte[] input = inputString.getBytes(StandardCharsets.UTF_8);
+
+        // Compress the bytes
+        ByteArrayOutputStream compressedBaos = new ByteArrayOutputStream();
+        Deflater compressor = new Deflater();
+        try {
+            compressor.setInput(input);
+            // Let the compressor know that the complete input
+            // has been made available
+            compressor.finish();
+            // Keep compressing the input till the compressor
+            // is finished compressing
+            while (!compressor.finished()) {
+                // Use some reasonable size for the temporary buffer
+                // based on the data being compressed
+                byte[] tmpBuffer = new byte[100];
+                int numCompressed = compressor.deflate(tmpBuffer);
+                // Copy over the compressed bytes from the temporary
+                // buffer into the final byte array
+                compressedBaos.write(tmpBuffer, 0, numCompressed);
+            }
+        } finally {
+            // Release the resources held by the compressor
+            compressor.end();
+        }
+
+        // Decompress the bytes
+        Inflater decompressor = new Inflater();
+        ByteArrayOutputStream decompressedBaos = new ByteArrayOutputStream();
+        try {
+            byte[] compressed = compressedBaos.toByteArray();
+            decompressor.setInput(compressed, 0, compressed.length);
+            while (!decompressor.finished()) {
+                // Use some reasonable size for the temporary buffer,
+                // based on the data being decompressed; in this example,
+                // we use a small buffer size
+                byte[] tmpBuffer = new byte[100];
+                int numDecompressed = 0;
+                try {
+                    numDecompressed = decompressor.inflate(tmpBuffer);
+                } catch (DataFormatException dfe) {
+                    // Handle the exception suitably, in this example
+                    // we just rethrow it
+                    throw new RuntimeException(dfe);
+                }
+                // Copy over the decompressed bytes from the temporary
+                // buffer into the final byte array
+                decompressedBaos.write(tmpBuffer, 0, numDecompressed);
+            }
+        } finally {
+            // Release the resources held by the decompressor
+            decompressor.end();
+        }
+        // Decode the bytes into a String
+        String outputString = decompressedBaos.toString(StandardCharsets.UTF_8);
+
+        // @end
+    }
+
+}