yegor256#254 - TempInputStream + couple of puzzles

src/main/java/org/takes/rq/CapInputStream.java

@@ -34,6 +34,10 @@
  * @author Yegor Bugayenko (yegor@teamed.io)
  * @version $Id$
  * @since 0.16
+ * @todo #254:30min CapInputStream should delegate all standard InputStream
+ *  calls to it's origin. It's very important in context of closing stream -
+ *  right code should close the stream but default InputStream implementation
+ *  just throws IOException
  */
 final class CapInputStream extends InputStream {
 

src/main/java/org/takes/rq/RqMultipart.java

@@ -230,40 +230,40 @@ private ConcurrentMap<String, List<Request>> buildRequests(
          * @param boundary Boundary
          * @return Request
          * @throws IOException If fails
+         * @todo #254:30min in order to delete temporary files InputStream
+         *  instance on Request.body should be closed. In context of multipart
+         *  requests that means that body of all parts should be closed once
+         *  they are not needed anymore.
          */
         private Request make(final byte[] boundary) throws IOException {
             final File file = File.createTempFile(
                 RqMultipart.class.getName(), ".tmp"
             );
+            final FileChannel channel = new RandomAccessFile(
+                file, "rw"
+            ).getChannel();
             try {
-                final FileChannel channel = new RandomAccessFile(
-                    file, "rw"
-                ).getChannel();
-                try {
-                    channel.write(
-                        ByteBuffer.wrap(
-                            this.head().iterator().next().getBytes()
-                        )
-                    );
-                    // @checkstyle MultipleStringLiteralsCheck (1 line)
-                    channel.write(ByteBuffer.wrap("\r\n".getBytes()));
-                    this.copy(channel, boundary);
-                } finally {
-                    channel.close();
-                }
-                final InputStream input = new FileInputStream(file);
-                try {
-                    return new RqWithHeader(
-                        new RqLive(new FileInputStream(file)),
-                        "Content-Length",
-                        String.valueOf(file.length())
-                    );
-                } finally {
-                    input.close();
-                }
+                channel.write(
+                    ByteBuffer.wrap(
+                        this.head().iterator().next().getBytes()
+                    )
+                );
+                // @checkstyle MultipleStringLiteralsCheck (1 line)
+                channel.write(ByteBuffer.wrap("\r\n".getBytes()));
+                this.copy(channel, boundary);
             } finally {
-                file.delete();
+                channel.close();
             }
+            return new RqWithHeader(
+                new RqLive(
+                    new TempInputStream(
+                        new FileInputStream(file),
+                        file
+                    )
+                ),
+                "Content-Length",
+                String.valueOf(file.length())
+            );
         }
         /**
          * Copy until boundary reached.

src/main/java/org/takes/rq/TempInputStream.java

@@ -0,0 +1,100 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.takes.rq;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Input stream using a temporary cache file.
+ *
+ * <p>All implementations of this interface must be immutable and thread-safe.
+ *
+ * @author Andrey Eliseev (aeg.exper0@gmail.com)
+ * @version $Id$
+ * @since 0.31
+ */
+final class TempInputStream extends InputStream {
+
+    /**
+     * Original stream.
+     */
+    private final transient InputStream origin;
+
+    /**
+     * Temporary file used as a cache.
+     */
+    private final transient File file;
+
+    /**
+     * Ctor.
+     * @param stream Original stream
+     * @param temp Temporary file used as a cache.
+     */
+    TempInputStream(final InputStream stream, final File temp) {
+        super();
+        this.origin = stream;
+        this.file = temp;
+    }
+
+    /**
+     * Closes the Input stream, deleting the now useless temporary file.
+     * @throws IOException if some problem occurs.
+     */
+    @Override
+    public void close() throws IOException {
+        super.close();
+        this.origin.close();
+        if (!this.file.delete()) {
+            throw new IOException("unable to delete file");
+        }
+    }
+
+    @Override
+    public int read() throws IOException {
+        return this.origin.read();
+    }
+
+    @Override
+    public int read(final byte[] buf) throws IOException {
+        return this.origin.read(buf);
+    }
+
+    @Override
+    public int read(final byte[] buf, final int off,
+        final int len) throws IOException {
+        return this.origin.read(buf, off, len);
+    }
+
+    @Override
+    public long skip(final long num) throws IOException {
+        return this.origin.skip(num);
+    }
+
+    @Override
+    public int available() throws IOException {
+        return this.origin.available();
+    }
+}

src/test/java/org/takes/rq/TempInputStreamTest.java

@@ -0,0 +1,64 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.takes.rq;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link TempInputStream}.
+ * @author Andrey Eliseev (aeg.exper@gmail.com)
+ * @version $Id$
+ * @since 0.31
+ */
+public final class TempInputStreamTest {
+
+    /**
+     * TempInputStream can delete the underlying temporary file.
+     * @throws IOException if some problem occurs.
+     */
+    @Test
+    public void deletesTempFile() throws IOException {
+        final File file = File.createTempFile("tempfile", ".tmp");
+        final BufferedWriter out = new BufferedWriter(new FileWriter(file));
+        out.write("Temp file deletion test");
+        out.close();
+        final InputStream body = new TempInputStream(
+            new FileInputStream(file), file
+        );
+        body.close();
+        MatcherAssert.assertThat(
+            "File exists after stream closure",
+            file.exists(),
+            Matchers.is(false)
+        );
+    }
+}