changeset 9214:9102df72a659

8032020: Update try-with-resources demo Reviewed-by: darcy, alanb, smarks
author anazarov
date Fri, 31 Jan 2014 11:57:38 +0100
parents 3e5c16e99bc9
children 834ffbe66ddf
files src/share/sample/try-with-resources/index.html src/share/sample/try-with-resources/src/CustomAutoCloseableSample.java src/share/sample/try-with-resources/src/Unzip.java src/share/sample/try-with-resources/src/ZipCat.java
diffstat 4 files changed, 339 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/sample/try-with-resources/index.html	Fri Jan 31 11:57:38 2014 +0100
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+
+<html>
+<head>
+    <title>Try-with-Resources Feature Demo</title>
+</head>
+<body>
+<h2>Try-with-Resources Feature Demo</h2>
+
+<p>
+    This demo shows how to use the try-with-resources feature introduced in JDK7.
+</p>
+
+<ul>
+    <li><h3>Custom AutoCloseable.</h3>
+
+        <p>
+            Shows how to use a custom resource with the try-with-resources construct.
+            For more information, see the source file.
+        </p>
+        Source: <a href="src/CustomAutoCloseableSample.java">src/CustomAutoCloseableSample.java</a>
+
+    <li><h3>Unzip</h3>
+
+        <p>
+            Extracts archived files. For more information, see the source file.
+        </p>
+        Source: <a href="src/Unzip.java">src/Unzip.java</a>
+    <li><h3>ZipCat</h3>
+
+        <p>Prints data about a specified file from an archive. For more information, see the source file.</p>
+        Source: <a href="src/ZipCat.java">src/ZipCat.java</a>
+
+</ul>
+</body>
+</html>
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/sample/try-with-resources/src/CustomAutoCloseableSample.java	Fri Jan 31 11:57:38 2014 +0100
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This source code is provided to illustrate the usage of a given feature
+ * or technique and has been deliberately simplified. Additional steps
+ * required for a production-quality application, such as security checks,
+ * input validation, and proper error handling, might not be present in
+ * this sample code.
+ */
+
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+/**
+ * This sample demonstrates the ability to create custom resource that
+ * implements the {@code AutoCloseable} interface. This resource can be used in
+ * the try-with-resources construct.
+ */
+public class CustomAutoCloseableSample {
+
+    /**
+     * The main method for the CustomAutoCloseableSample program.
+     *
+     * @param args is not used.
+     */
+    public static void main(String[] args) {
+        /*
+         * TeeStream will be closed automatically after the try block.
+         */
+        try (TeeStream teeStream = new TeeStream(System.out, Paths.get("out.txt"));
+             PrintStream out = new PrintStream(teeStream)) {
+            out.print("Hello, world");
+        } catch (Exception e) {
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    /**
+     * Passes the output through to the specified output stream while copying it into a file.
+     * The TeeStream functionality is similar to the Unix tee utility.
+     * TeeStream implements AutoCloseable interface. See OutputStream for details.
+     */
+    public static class TeeStream extends OutputStream {
+
+        private final OutputStream fileStream;
+        private final OutputStream outputStream;
+
+        /**
+         * Creates a TeeStream.
+         *
+         * @param outputStream an output stream.
+         * @param outputFile   an path to file.
+         * @throws IOException If an I/O error occurs.
+         */
+        public TeeStream(OutputStream outputStream, Path outputFile) throws IOException {
+            this.fileStream = new BufferedOutputStream(Files.newOutputStream(outputFile));
+            this.outputStream = outputStream;
+        }
+
+        /**
+         * Writes the specified byte to the specified output stream
+         * and copies it to the file.
+         *
+         * @param b the byte to be written.
+         * @throws IOException If an I/O error occurs.
+         */
+        @Override
+        public void write(int b) throws IOException {
+            fileStream.write(b);
+            outputStream.write(b);
+        }
+
+        /**
+         * Flushes this output stream and forces any buffered output bytes
+         * to be written out.
+         * The <code>flush</code> method of <code>TeeStream</code> flushes
+         * the specified output stream and the file output stream.
+         *
+         * @throws IOException if an I/O error occurs.
+         */
+        @Override
+        public void flush() throws IOException {
+            outputStream.flush();
+            fileStream.flush();
+        }
+
+        /**
+         * Closes underlying streams and resources.
+         * The external output stream won't be closed.
+         * This method is the member of AutoCloseable interface and
+         * it will be invoked automatically after the try-with-resources block.
+         *
+         * @throws IOException If an I/O error occurs.
+         */
+        @Override
+        public void close() throws IOException {
+            try (OutputStream file = fileStream) {
+                flush();
+            }
+        }
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/sample/try-with-resources/src/Unzip.java	Fri Jan 31 11:57:38 2014 +0100
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This source code is provided to illustrate the usage of a given feature
+ * or technique and has been deliberately simplified. Additional steps
+ * required for a production-quality application, such as security checks,
+ * input validation, and proper error handling, might not be present in
+ * this sample code.
+ */
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.*;
+
+import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
+
+/**
+ * Extract (unzip) a file to the current directory.
+ */
+public class Unzip {
+
+    /**
+     * The main method for the Unzip program. Run the program with an empty
+     * argument list to see possible arguments.
+     *
+     * @param args the argument list for {@code Unzip}.
+     */
+    public static void main(String[] args) {
+        if (args.length != 1) {
+            System.out.println("Usage: Unzip zipfile");
+        }
+        final Path destDir = Paths.get(".");
+        /*
+         * Create AutoCloseable FileSystem. It will be closed automatically
+         * after the try block.
+         */
+        try (FileSystem zipFileSystem = FileSystems.newFileSystem(Paths.get(args[0]), null)) {
+
+            Path top = zipFileSystem.getPath("/");
+            Files.walk(top).skip(1).forEach(file -> {
+                Path target = destDir.resolve(top.relativize(file).toString());
+                System.out.println("Extracting " + target);
+                try {
+                    Files.copy(file, target, REPLACE_EXISTING);
+                } catch (IOException e) {
+                    throw new UncheckedIOException(e);
+                }
+            });
+        } catch (UncheckedIOException | IOException e) {
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/sample/try-with-resources/src/ZipCat.java	Fri Jan 31 11:57:38 2014 +0100
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This source code is provided to illustrate the usage of a given feature
+ * or technique and has been deliberately simplified. Additional steps
+ * required for a production-quality application, such as security checks,
+ * input validation, and proper error handling, might not be present in
+ * this sample code.
+ */
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+/**
+ * Prints data of the specified file to standard output from a zip archive.
+ */
+public class ZipCat {
+
+    /**
+     * The main method for the ZipCat program. Run the program with an empty
+     * argument list to see possible arguments.
+     *
+     * @param args the argument list for ZipCat
+     */
+    public static void main(String[] args) {
+        if (args.length != 2) {
+            System.out.println("Usage: ZipCat zipfile fileToPrint");
+        }
+        /*
+         * Creates AutoCloseable FileSystem and BufferedReader.
+         * They will be closed automatically after the try block.
+         * If reader initialization fails, then zipFileSystem will be closed
+         * automatically.
+         */
+        try (FileSystem zipFileSystem
+                = FileSystems.newFileSystem(Paths.get(args[0]),null);
+                InputStream input
+                = Files.newInputStream(zipFileSystem.getPath(args[1]))) {
+                    byte[] buffer = new byte[1024];
+                    int len;
+                    while ((len = input.read(buffer)) != -1) {
+                        System.out.write(buffer, 0, len);
+                    }
+
+        } catch (IOException e) {
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+}