added util class for templates

scm-core/src/main/java/sonia/scm/template/Templates.java

@@ -0,0 +1,121 @@
+/**
+ * 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.template;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import com.google.common.io.Closeables;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.Writer;
+
+/**
+ * Util class for the template framework of scm-manager.
+ *
+ * @author Sebastian Sdorra
+ * @since 1.22
+ */
+public class Templates
+{
+
+  /**
+   * the logger for Templates
+   */
+  private static final Logger logger = LoggerFactory.getLogger(Templates.class);
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Renders the given template file with the {@link TemplateEngine} which is
+   * associated to extension of the file. If there is no {@link TemplateEngine}
+   * for the extension of the file, then the default {@link TemplateEngine}
+   * ({@link TemplateEngineFactory#getDefaultEngine()}) is used.
+   *
+   *
+   * @param factory template engine factory
+   * @param template file with template content
+   * @param ouput writer for the template output
+   * @param env environment for the template
+   *
+   * @throws IOException
+   */
+  public static void renderFileTemplate(TemplateEngineFactory factory,
+    File template, Writer ouput, Object env)
+    throws IOException
+  {
+    TemplateEngine engine = factory.getEngineByExtension(template.getPath());
+
+    if (engine == null)
+    {
+      if (logger.isWarnEnabled())
+      {
+        logger.warn(
+          "could not find template engine for path {}, use default engine",
+          template.getPath());
+      }
+
+      engine = factory.getDefaultEngine();
+    }
+
+    FileReader reader = null;
+
+    try
+    {
+      reader = new FileReader(template);
+
+      Template tpl = engine.getTemplate(template.getAbsolutePath(), reader);
+
+      if (tpl != null)
+      {
+        tpl.execute(ouput, env);
+      }
+      else
+      {
+
+        // this should never happen
+        throw new IOException("engine get template returned null");
+      }
+    }
+    finally
+    {
+      Closeables.closeQuietly(reader);
+    }
+
+  }
+}