1 files changed, 250 insertions, 0 deletions
diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/gui/AbstractVelocityGuiFormBuilderImpl.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/gui/AbstractVelocityGuiFormBuilderImpl.java
new file mode 100644
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--- /dev/null
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/gui/AbstractVelocityGuiFormBuilderImpl.java
@@ -0,0 +1,250 @@
+/*
+ * Copyright 2017 Graz University of Technology EAAF-Core Components has been developed in a
+ * cooperation between EGIZ, A-SIT Plus, A-SIT, and Graz University of Technology.
+ *
+ * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by the European
+ * Commission - subsequent versions of the EUPL (the "Licence"); You may not use this work except in
+ * compliance with the Licence. You may obtain a copy of the Licence at:
+ * https://joinup.ec.europa.eu/news/understanding-eupl-v12
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the Licence
+ * is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the Licence for the specific language governing permissions and limitations under
+ * the Licence.
+ *
+ * This product combines work with different licenses. See the "NOTICE" text file for details on the
+ * various modules and licenses. The "NOTICE" text file is part of the distribution. Any derivative
+ * works that you distribute must include a readable copy of the "NOTICE" text file.
+*/
+
+package at.gv.egiz.eaaf.core.impl.gui;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.StringWriter;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import at.gv.egiz.eaaf.core.api.data.EAAFConstants;
+import at.gv.egiz.eaaf.core.api.gui.IGuiBuilderConfiguration;
+import at.gv.egiz.eaaf.core.api.gui.IVelocityGuiBuilderConfiguration;
+import at.gv.egiz.eaaf.core.api.gui.IVelocityGuiFormBuilder;
+import at.gv.egiz.eaaf.core.exceptions.GuiBuildException;
+import at.gv.egiz.eaaf.core.impl.gui.velocity.VelocityProvider;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.velocity.VelocityContext;
+import org.apache.velocity.app.VelocityEngine;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Abstract VeloCity based GUI builder implementation.
+ *
+ * @author tlenz
+ *
+ */
+public abstract class AbstractVelocityGuiFormBuilderImpl implements IVelocityGuiFormBuilder {
+  private static final Logger log =
+      LoggerFactory.getLogger(AbstractVelocityGuiFormBuilderImpl.class);
+  private static final String DEFAULT_CONTENT_TYPE = EAAFConstants.CONTENTTYPE_HTML_UTF8;
+
+  private VelocityEngine engine;
+
+  /**
+   * Velocity based GUI builder.
+   *
+   * @throws GuiBuildException In case of a error
+   */
+  public AbstractVelocityGuiFormBuilderImpl() throws GuiBuildException {
+    try {
+      engine = VelocityProvider.getClassPathVelocityEngine();
+
+    } catch (final Exception e) {
+      log.error("Initialization of Velocity-Engine to render GUI components FAILED.", e);
+      throw new GuiBuildException(
+          "Initialization of Velocity-Engine to render GUI components FAILED.", e);
+
+    }
+
+  }
+
+  @Override
+  public final void build(final HttpServletRequest httpReq, final HttpServletResponse httpResp,
+      final IGuiBuilderConfiguration config, final String loggerName) throws GuiBuildException {
+    if (config instanceof IVelocityGuiBuilderConfiguration) {
+      build(httpReq, httpResp, (IVelocityGuiBuilderConfiguration) config, loggerName);
+    } else {
+      throw new IllegalStateException(this.getClass().getName() + " needs a "
+          + IVelocityGuiBuilderConfiguration.class.getName());
+    }
+
+
+  }
+
+  @Override
+  public final void build(final HttpServletRequest httpReq, final HttpServletResponse httpResp,
+      final IGuiBuilderConfiguration config, final String contentType, final String loggerName)
+      throws GuiBuildException {
+    if (config instanceof IVelocityGuiBuilderConfiguration) {
+      build(httpReq, httpResp, (IVelocityGuiBuilderConfiguration) config, contentType, loggerName);
+    } else {
+      throw new IllegalStateException(this.getClass().getName() + " needs a "
+          + IVelocityGuiBuilderConfiguration.class.getName());
+    }
+
+  }
+
+  @Override
+  public void build(final HttpServletRequest httpReq, final HttpServletResponse httpResp,
+      final IVelocityGuiBuilderConfiguration config, final String loggerName)
+      throws GuiBuildException {
+    build(httpReq, httpResp, config, getInternalContentType(config), loggerName);
+
+  }
+
+  @Override
+  public void build(final HttpServletRequest httpReq, final HttpServletResponse httpResp,
+      final IVelocityGuiBuilderConfiguration config, final String contentType,
+      final String loggerName) throws GuiBuildException {
+
+    InputStream is = null;
+    try {
+      final String viewName = config.getViewName();
+      is = getTemplateInputStream(config);
+
+      // build Velocity Context from input paramters
+      final VelocityContext context = buildContextFromViewParams(config.getViewParameters());
+
+      // evaluate template
+      final StringWriter writer = new StringWriter();
+      engine.evaluate(context, writer, loggerName, new BufferedReader(new InputStreamReader(is, "UTF-8")));
+
+      // write template to response
+      final byte[] content = writer.toString().getBytes("UTF-8");
+      httpResp.setStatus(HttpServletResponse.SC_OK);
+      httpResp.setContentLength(content.length);
+      httpResp.setContentType(contentType);
+      httpResp.getOutputStream().write(content);
+
+      if (log.isTraceEnabled()) {
+        log.trace("Write Content for viewName:" + viewName + ". Contentsize:"
+            + String.valueOf(content.length) + " BufferSize:" + httpResp.getBufferSize()
+            + " ContentType:" + contentType);
+        for (final String el : httpResp.getHeaderNames()) {
+          log.trace(" * Headername:" + el + " Value:" + httpResp.getHeader(el));
+        }
+
+      }
+
+    } catch (final IOException e) {
+      log.error("GUI form-builder has an internal error.", e);
+      throw new GuiBuildException("GUI form-builder has an internal error.", e);
+
+    } finally {
+      if (is != null) {
+        try {
+          is.close();
+
+        } catch (final IOException e) {
+          log.error("Can NOT close GUI-Template InputStream.", e);
+
+        }
+      }
+    }
+
+  }
+
+  /**
+   * Generate a new {@link VelocityContext} and populate it with MOA-ID GUI parameters.
+   *
+   * @param config GUI builder config
+   * @return Context of Velocity engine
+   */
+  @Override
+  public VelocityContext generateVelocityContextFromConfiguration(
+      final IVelocityGuiBuilderConfiguration config) {
+    return buildContextFromViewParams(config.getViewParameters());
+
+  }
+
+  /**
+   * Load the template from different resources.
+   *
+   * @param config GUI builder config
+   * @return An {@link InputStream} but never null. The {@link InputStream} had to be closed be the
+   *         invoking method
+   * @throws GuiBuildException In case of an error
+   */
+  @Override
+  public InputStream getTemplateInputStream(final IVelocityGuiBuilderConfiguration config)
+      throws GuiBuildException {
+    InputStream is = config.getTemplate(config.getViewName());
+    if (is == null) {
+      log.trace("Loading GUI template:" + config.getViewName() + " from default resources ... ");
+      is = getInternalTemplate(config);
+
+      if (is == null) {
+        log.warn("No GUI with viewName:" + config.getViewName() + " FOUND.");
+        throw new GuiBuildException("No GUI with viewName:" + config.getViewName() + " FOUND.");
+
+      }
+    }
+    return is;
+
+  }
+
+  /**
+   * Load an internal template from default resources.
+   *
+   * @param config GUI builder config
+   * @return Template that should be used
+   * @throws GuiBuildException in case of an error
+   */
+  protected abstract InputStream getInternalTemplate(IVelocityGuiBuilderConfiguration config)
+      throws GuiBuildException;
+
+
+  protected String getInternalClasspathTemplateDir(final IVelocityGuiBuilderConfiguration config,
+      final String defaultClassPathDir) {
+    String dir = config.getClasspathTemplateDir();
+    if (dir != null) {
+      if (!dir.endsWith("/")) {
+        dir += "/";
+      }
+
+      return dir;
+
+    } else {
+      return defaultClassPathDir;
+    }
+  }
+
+  private VelocityContext buildContextFromViewParams(final Map<String, Object> viewParams) {
+    final VelocityContext context = new VelocityContext();
+
+    if (viewParams != null) {
+      final Iterator<Entry<String, Object>> interator = viewParams.entrySet().iterator();
+      while (interator.hasNext()) {
+        final Entry<String, Object> el = interator.next();
+        context.put(el.getKey(), el.getValue());
+      }
+
+    }
+
+    return context;
+  }
+
+  private String getInternalContentType(final IGuiBuilderConfiguration config) {
+    if (StringUtils.isEmpty(config.getDefaultContentType())) {
+      return DEFAULT_CONTENT_TYPE;
+    } else {
+      return config.getDefaultContentType();
+    }
+
+  }
+
+}