integrate Spring ModelAndView into EAAF GUI framework

1 files changed, 242 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
index 00000000..65e13b5a
--- /dev/null
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/gui/AbstractVelocityGUIFormBuilderImpl.java
@@ -0,0 +1,242 @@
+/*******************************************************************************
+ * 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 org.apache.commons.lang3.StringUtils;
+import org.apache.velocity.VelocityContext;
+import org.apache.velocity.app.VelocityEngine;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+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;
+
+/**
+ * @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;
+		
+	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(HttpServletRequest httpReq, HttpServletResponse httpResp, IGUIBuilderConfiguration config,
+			String loggerName) throws GUIBuildException {
+		if (config instanceof IVelocityGUIBuilderConfiguration)
+			build(httpReq, httpResp, config, loggerName);
+		else
+			throw new IllegalStateException(this.getClass().getName() + " needs a " + IVelocityGUIBuilderConfiguration.class.getName());
+		
+		
+	}
+
+	@Override
+	public final void build(HttpServletRequest httpReq, HttpServletResponse httpResp, IGUIBuilderConfiguration config,
+			String contentType, String loggerName) throws GUIBuildException {
+		if (config instanceof IVelocityGUIBuilderConfiguration)
+			build(httpReq, httpResp, config, loggerName);
+		else
+			throw new IllegalStateException(this.getClass().getName() + " needs a " + IVelocityGUIBuilderConfiguration.class.getName());
+		
+	}
+	
+	@Override
+	public void build(HttpServletRequest httpReq, HttpServletResponse httpResp, IVelocityGUIBuilderConfiguration config, String loggerName) throws GUIBuildException {
+		build(httpReq, httpResp, config, getInternalContentType(config), loggerName);
+		
+	}
+	
+	@Override
+	public void build(HttpServletRequest httpReq, HttpServletResponse httpResp, IVelocityGUIBuilderConfiguration config, 
+			String contentType, 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)));
+							
+			//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
+	 * @return
+	 */
+	@Override
+	public VelocityContext generateVelocityContextFromConfiguration(IVelocityGUIBuilderConfiguration config) {
+		return buildContextFromViewParams(config.getViewParameters());
+		
+	}
+	
+	/**
+	 * Load the template from different resources
+	 * 
+	 * @param config
+	 * @return An {@link InputStream} but never null. The {@link InputStream} had to be closed be the invoking method
+	 * @throws GUIBuildException
+	 */
+	@Override
+	public InputStream getTemplateInputStream(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
+	 * @return
+	 * @throws GUIBuildException
+	 */
+	abstract protected InputStream getInternalTemplate(IVelocityGUIBuilderConfiguration config) throws GUIBuildException;
+
+	
+	/**
+	 * @return
+	 */ 
+	protected String getInternalClasspathTemplateDir(IVelocityGUIBuilderConfiguration config, String defaultClassPathDir) {
+		String dir = config.getClasspathTemplateDir();
+		if (dir != null) {
+			if (!dir.endsWith("/"))
+				dir += "/";
+			
+			return dir;			
+			
+		} else
+			return defaultClassPathDir;
+	}
+	
+	/**
+	 * @param viewParams
+	 * @return
+	 */
+	private VelocityContext buildContextFromViewParams(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(IGUIBuilderConfiguration config) {
+		if (StringUtils.isEmpty(config.getDefaultContentType()))
+			return DEFAULT_CONTENT_TYPE;
+		
+		else
+			return config.getDefaultContentType();
+		
+	}
+
+}