added FastByteArrayInputStream, FastByteArrayOutputStream and DeepCopy

scm-core/src/main/java/sonia/scm/io/DeepCopy.java

@@ -0,0 +1,95 @@
+/**
+ * Copyright (c) 2010, Sebastian Sdorra All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. 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. 3. Neither the name of SCM-Manager;
+ * 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 REGENTS 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.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.io;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+/**
+ * Utility for making deep copies (vs. clone()'s shallow copies) of
+ * objects. Objects are first serialized and then deserialized. Error
+ * checking is fairly minimal in this implementation. If an object is
+ * encountered that cannot be serialized (or that references an object
+ * that cannot be serialized) an error is printed to System.err and
+ * null is returned. Depending on your specific application, it might
+ * make more sense to have copy(...) re-throw the exception.
+ *
+ * @author Sebastian Sdorra
+ * @since 1.29
+ * @see http://javatechniques.com/blog/faster-deep-copies-of-java-objects
+ */
+public final class DeepCopy
+{
+
+  /**
+   * Returns a copy of the object, or null if the object cannot
+   * be serialized.
+   *
+   * @param orig
+   * @param <T>
+   *
+   * @return
+   *
+   * @throws IOException
+   */
+  public static <T> T copy(T orig) throws IOException
+  {
+    T obj = null;
+
+    try
+    {
+
+      // Write the object out to a byte array
+      FastByteArrayOutputStream fbos = new FastByteArrayOutputStream();
+      ObjectOutputStream out = new ObjectOutputStream(fbos);
+
+      out.writeObject(orig);
+      out.flush();
+      out.close();
+
+      // Retrieve an input stream from the byte array and read
+      // a copy of the object back in.
+      ObjectInputStream in = new ObjectInputStream(fbos.getInputStream());
+
+      obj = (T) in.readObject();
+    }
+    catch (Exception ex)
+    {
+      throw new IOException("could not copy object", ex);
+    }
+
+    return obj;
+  }
+}

scm-core/src/main/java/sonia/scm/io/FastByteArrayInputStream.java

@@ -0,0 +1,161 @@
+/**
+ * Copyright (c) 2010, Sebastian Sdorra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. 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. 3. Neither the name of SCM-Manager;
+ * 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 REGENTS 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.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.io;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.InputStream;
+
+/**
+ * ByteArrayInputStream implementation that does not synchronize methods.
+ *
+ * @author Sebastian Sdorra
+ * @since 1.29
+ * @see http://javatechniques.com/blog/faster-deep-copies-of-java-objects
+ */
+public final class FastByteArrayInputStream extends InputStream
+{
+
+  /**
+   * Constructs ...
+   *
+   *
+   * @param buf
+   * @param count
+   */
+  public FastByteArrayInputStream(byte[] buf, int count)
+  {
+    this.buf = buf;
+    this.count = count;
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public final int available()
+  {
+    return count - pos;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public final int read()
+  {
+    return (pos < count)
+      ? (buf[pos++] & 0xff)
+      : -1;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param b
+   * @param off
+   * @param len
+   *
+   * @return
+   */
+  @Override
+  public final int read(byte[] b, int off, int len)
+  {
+    if (pos >= count)
+    {
+      return -1;
+    }
+
+    if ((pos + len) > count)
+    {
+      len = (count - pos);
+    }
+
+    System.arraycopy(buf, pos, b, off, len);
+    pos += len;
+
+    return len;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param n
+   *
+   * @return
+   */
+  @Override
+  public final long skip(long n)
+  {
+    if ((pos + n) > count)
+    {
+      n = count - pos;
+    }
+
+    if (n < 0)
+    {
+      return 0;
+    }
+
+    pos += n;
+
+    return n;
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /**
+   * Our byte buffer
+   */
+  private byte[] buf = null;
+
+  /**
+   * Number of bytes that we can read from the buffer
+   */
+  private int count = 0;
+
+  /**
+   * Number of bytes that have been read from the buffer
+   */
+  private int pos = 0;
+}

scm-core/src/main/java/sonia/scm/io/FastByteArrayOutputStream.java

@@ -0,0 +1,187 @@
+/**
+ * Copyright (c) 2010, Sebastian Sdorra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. 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. 3. Neither the name of SCM-Manager;
+ * 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 REGENTS 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.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.io;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * ByteArrayOutputStream implementation that doesn't synchronize methods
+ * and doesn't copy the data on toByteArray().
+ *
+ * @author Sebastian Sdorra
+ * @since 1.29
+ * @see http://javatechniques.com/blog/faster-deep-copies-of-java-objects
+ */
+public final class FastByteArrayOutputStream extends OutputStream
+{
+
+  /**
+   * Constructs a stream with buffer capacity size 5K
+   */
+  public FastByteArrayOutputStream()
+  {
+    this(5 * 1024);
+  }
+
+  /**
+   * Constructs a stream with the given initial size
+   *
+   * @param initSize
+   */
+  public FastByteArrayOutputStream(int initSize)
+  {
+    this.size = 0;
+    this.buf = new byte[initSize];
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param b
+   */
+  @Override
+  public final void write(byte b[])
+  {
+    verifyBufferSize(size + b.length);
+    System.arraycopy(b, 0, buf, size, b.length);
+    size += b.length;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param b
+   * @param off
+   * @param len
+   */
+  @Override
+  public final void write(byte b[], int off, int len)
+  {
+    verifyBufferSize(size + len);
+    System.arraycopy(b, off, buf, size, len);
+    size += len;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param b
+   */
+  @Override
+  public final void write(int b)
+  {
+    verifyBufferSize(size + 1);
+    buf[size++] = (byte) b;
+  }
+
+  /**
+   * Method description
+   *
+   */
+  public void reset()
+  {
+    size = 0;
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Returns the byte array containing the written data. Note that this
+   * array will almost always be larger than the amount of data actually
+   * written.
+   *
+   * @return
+   */
+  public byte[] getByteArray()
+  {
+    return buf;
+  }
+
+  /**
+   * Returns a ByteArrayInputStream for reading back the written data
+   *
+   * @return
+   */
+  public InputStream getInputStream()
+  {
+    return new FastByteArrayInputStream(buf, size);
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public int getSize()
+  {
+    return size;
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Ensures that we have a large enough buffer for the given size.
+   *
+   * @param sz
+   */
+  private void verifyBufferSize(int sz)
+  {
+    if (sz > buf.length)
+    {
+      byte[] old = buf;
+
+      buf = new byte[Math.max(sz, 2 * buf.length)];
+      System.arraycopy(old, 0, buf, 0, old.length);
+      old = null;
+    }
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /**
+   * Buffer and size
+   */
+  private byte[] buf = null;
+
+  /** Field description */
+  private int size = 0;
+}