start implementation of guava based CacheManager

scm-webapp/src/main/java/sonia/scm/cache/CopyStrategy.java

@@ -0,0 +1,147 @@
+/**
+ * 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.cache;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import sonia.scm.io.DeepCopy;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.IOException;
+
+import java.util.Locale;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+public enum CopyStrategy
+{
+
+  NONE(false, false), READ(true, false), WRITE(false, true),
+    READWRITE(true, true);
+
+  /**
+   * Constructs ...
+   *
+   *
+   * @param copyOnRead
+   * @param copyOnWrite
+   */
+  private CopyStrategy(boolean copyOnRead, boolean copyOnWrite)
+  {
+    this.copyOnRead = copyOnRead;
+    this.copyOnWrite = copyOnWrite;
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param value
+   *
+   * @return
+   */
+  public static CopyStrategy fromString(String value)
+  {
+    return valueOf(value.toUpperCase(Locale.ENGLISH).replace("-", ""));
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param object
+   * @param <T>
+   *
+   * @return
+   */
+  public <T> T copyOnRead(T object)
+  {
+    return copyOnRead
+      ? deepCopy(object)
+      : object;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param object
+   * @param <T>
+   *
+   * @return
+   */
+  public <T> T copyOnWrite(T object)
+  {
+    return copyOnWrite
+      ? deepCopy(object)
+      : object;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param object
+   * @param <T>
+   *
+   * @return
+   */
+  private <T> T deepCopy(T object)
+  {
+    T copy = null;
+
+    try
+    {
+      copy = DeepCopy.copy(object);
+    }
+    catch (IOException ex)
+    {
+      throw new CacheException(
+        "could not create a copy of ".concat(object.toString()), ex);
+    }
+
+    return copy;
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  private boolean copyOnRead;
+
+  /** Field description */
+  private boolean copyOnWrite;
+}