DAM Media Handlers

In this section, you will create a specific Text Handler that generates thumbnails with a watermark.

Proceed as follows:

1. In Eclipse, create the myBundle Maven project:

   1. In the Menu bar, click File, select New, then Other... .

   2. In the dialog, expand the Maven folder, select Maven Project and click Next.

   3. Check the Create a simple project box and the Use default Workspace locations box, then click Next.

   4. Define the Maven project:

      • Group Id: com.day.cq5.myhandler

      • Artifact Id: myBundle

      • Name: My CQ5 bundle

      • Description: This is my CQ5 bundle

   5. Click Finish.

2. Set the Java Compiler to version 1.5:

   1. Right-click the myBundle project, select Properties.

   2. Select Java Compiler and set following properties to 1.5:

      • Compiler compliance level

      • Generated .class files compatibility

      • Source compatibility

   3. Click OK.

   4. In the dialog window, click Yes.

3. Replace the code in the pom.xml file with the following code:

   <project xmlns="http://maven.apache.org/POM/4.0.0" 
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
       <!-- ====================================================================== -->
       <!-- P A R E N T  P R O J E C T  D E S C R I P T I O N                      -->
       <!-- ====================================================================== -->
       <parent>
           <groupId>com.day.cq.dam</groupId>
           <artifactId>dam</artifactId>
           <version>5.2.14</version>
           <relativePath>../parent</relativePath>
       </parent>
   
       <!-- ====================================================================== -->
       <!-- P R O J E C T  D E S C R I P T I O N                                   -->
       <!-- ====================================================================== -->
     <groupId>com.day.cq5.myhandler</groupId>
     <artifactId>myBundle</artifactId>
     <name>My CQ5 bundle</name>
     <version>0.0.1-SNAPSHOT</version>
     <description>This is my CQ5 bundle</description>
       <packaging>bundle</packaging>
   
       <!-- ====================================================================== -->
       <!-- B U I L D   D E F I N I T I O N                                        -->
       <!-- ====================================================================== -->
       <build>
           <plugins>
               <plugin>
                   <groupId>org.apache.felix</groupId>
                   <artifactId>maven-scr-plugin</artifactId>
               </plugin>
               <plugin>
                   <groupId>org.apache.sling</groupId>
                   <artifactId>maven-sling-plugin</artifactId>
                   <configuration>
                       <slingUrlSuffix>/libs/dam/install/</slingUrlSuffix>
                   </configuration>
               </plugin>
               <plugin>
                   <groupId>org.apache.felix</groupId>
                   <artifactId>maven-bundle-plugin</artifactId>
                   <extensions>true</extensions>
                   <configuration>
                       <instructions>
                           <Bundle-Category>cq5</Bundle-Category>
                           <Export-Package>
                               com.day.cq5.myhandler
                           </Export-Package>
                       </instructions>
                   </configuration>
               </plugin>
           </plugins>
       </build>
   
       <!-- ====================================================================== -->
       <!-- D E P E N D E N C I E S                                                -->
       <!-- ====================================================================== -->
       <dependencies>
           <dependency>
               <groupId>com.day.cq.dam</groupId>
               <artifactId>cq-dam-api</artifactId>
               <version>5.2.10</version>
               <scope>provided</scope>
           </dependency>
           <dependency>
               <groupId>com.day.cq.dam</groupId>
               <artifactId>cq-dam-core</artifactId>
               <version>5.2.10</version>
               <scope>provided</scope>
           </dependency>
           <dependency>
               <groupId>com.day.cq</groupId>
               <artifactId>cq-commons</artifactId>
           </dependency>
           <dependency>
               <groupId>javax.jcr</groupId>
               <artifactId>jcr</artifactId>
           </dependency>
           <dependency>
               <groupId>org.apache.felix</groupId>
               <artifactId>org.osgi.compendium</artifactId>
           </dependency>
           <dependency>
               <groupId>org.slf4j</groupId>
               <artifactId>slf4j-api</artifactId>
           </dependency>
           <dependency>
               <groupId>commons-lang</groupId>
               <artifactId>commons-lang</artifactId>
           </dependency>
           <dependency>
               <groupId>commons-collections</groupId>
               <artifactId>commons-collections</artifactId>
           </dependency>
           <dependency>
               <groupId>commons-io</groupId>
               <artifactId>commons-io</artifactId>
           </dependency>
           <dependency>
               <groupId>com.day.commons</groupId>
               <artifactId>day-commons-gfx</artifactId>
           </dependency>
           <dependency>
               <groupId>com.day.commons</groupId>
               <artifactId>day-commons-text</artifactId>
           </dependency>
           <dependency>
               <groupId>com.day.cq.workflow</groupId>
               <artifactId>cq-workflow-api</artifactId>
           </dependency>
           <dependency>
               <groupId>com.day.cq.wcm</groupId>
               <artifactId>cq-wcm-foundation</artifactId>
               <version>5.2.22</version>
           </dependency>
   
       </dependencies>
           
   

4. Create the package com.day.cq5.myhandler that will contain the Java classes under myBundle/src/main/java:

   1. Under myBundle, right-click src/main/java, select New, then Package.

   2. Name it com.day.cq5.myhandler and click Finish.

5. Create the Java class MyHandler:

   1. In Eclipse, under myBundle/src/main/java, right-click the com.day.cq5.myhandler package, select New, then Class.

   2. In the dialog window, name the Java Class MyHandler and click Finish. Eclipse creates and opens the file MyHandler.java.

   3. In MyHandler.java replace the existing code with the following:

      package com.day.cq5.myhandler;
      
      import java.awt.Color;
      import java.awt.Rectangle;
      import java.awt.image.BufferedImage;
      import java.io.IOException;
      import java.io.InputStream;
      import java.io.InputStreamReader;
      
      import javax.jcr.Node;
      import javax.jcr.RepositoryException;
      import javax.jcr.Session;
      
      import org.apache.commons.io.IOUtils;
      import org.slf4j.Logger;
      import org.slf4j.LoggerFactory;
      
      import com.day.cq.dam.api.metadata.ExtractedMetadata;
      import com.day.cq.dam.core.AbstractAssetHandler;
      import com.day.image.Font;
      import com.day.image.Layer;
      import com.day.cq.wcm.foundation.ImageHelper;
      
      /**
       * The <code>MyHandler</code> can extract text files
       *
       * @scr.component inherit="true" immediate="true" metatype="false"
       * @scr.service
       */
      
       public class MyHandler extends AbstractAssetHandler {
      
           /**
            * Logger instance for this class.
            */
           private static final Logger log = LoggerFactory.getLogger(MyHandler.class);
           
           /**
            * Music icon margin
            */
           private static final int MARGIN = 10;
      
           /**
            * @see com.day.cq.dam.api.handler.AssetHandler#getMimeTypes()
            */
           public String[] getMimeTypes() {
               return new String[] {"text/plain"};
           }
      
           public ExtractedMetadata extractMetadata(Node asset) {
               ExtractedMetadata extractedMetadata = new ExtractedMetadata();
               InputStream data = getInputStream(asset);
               try {
                   // read text data
                   InputStreamReader reader = new InputStreamReader(data);
                   char[] buffer = new char[4096];
                   String text = "";
      
                   while (reader.read(buffer) != -1) {
                       text += new String(buffer);
                   }
                   reader.close();
                   long wordCount = this.wordCount(text);
      
                   extractedMetadata.setProperty("text", text);
                   extractedMetadata.setMetaDataProperty("Word Count",wordCount);
      
                   setMimetype(extractedMetadata, asset);
      
               } catch (Throwable t) {
                   log.error("handling error: " + t.toString(), t);
               } finally {
                   IOUtils.closeQuietly(data);
               }
               return extractedMetadata;
           }
      
           // ----------------------< helpers >----------------------------------------
           protected BufferedImage getThumbnailImage(Node node) {
               ExtractedMetadata metadata = extractMetadata(node);
               final String text = (String) metadata.getProperty("text");
               // create text layer
               final Layer layer = new Layer(500, 600, Color.WHITE);
               layer.setPaint(Color.black);
               Font font = new Font("Arial", 12);
               String displayText = this.getDisplayText(text, 600, 12);
               if(displayText!=null && displayText.length() > 0) {
                   // commons-gfx Font class would throw IllegalArgumentException on empty or null text
                   layer.drawText(10, 10, 500, 600, displayText, font, Font.ALIGN_LEFT, 0, 0);
               }
               // create watermark and merge with text layer
               Layer watermarkLayer;
         try {
                final Session session = node.getSession();
          watermarkLayer = ImageHelper.createLayer(session, "/var/dam/geometrixx/icons/certificate.png");
                watermarkLayer.setX(MARGIN);
                watermarkLayer.setY(MARGIN);
                layer.merge(watermarkLayer);
         } catch (RepositoryException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
         }
      
               layer.crop(new Rectangle(510, 600));
               return layer.getImage();
           }
      
           // ---------------< private >-----------------------------------------------
           /**
            * This method cuts lines if the text file is too long..
            *
            * @param text
            *            text to check
            * @param height
            *            text box height (px)
            * @param fontheight
            *            font height (px)
            * @return the text which will fit into the box
            */
           private String getDisplayText(String text, int height, int fontheight) {
               String trimmedText = text.trim();
               int numOfLines = height / fontheight;
               String lines[] = trimmedText.split("\n");
               if (lines.length <= numOfLines) {
                   return trimmedText;
               } else {
                   String cuttetText = "";
                   for (int i = 0; i < numOfLines; i++) {
                       cuttetText += lines[i] + "\n";
                   }
                   return cuttetText;
               }
           }
      
           /**
            * This method counts the number of words in a string
            *
            * @param text the String whose words would like to be counted
            * @return the number of words in the string
            */
           private long wordCount(String text) {
               // We need to keep track of the last character, if we have two white spaces in a row we dont want to double count
               // The starting of the document is always a whitespace
               boolean prevWhiteSpace = true;
               boolean currentWhiteSpace = true;
               char c;
               long numwords = 0;
               int j = text.length();
               int i = 0;
               while (i < j) {
                   c = text.charAt(i++);
                   if (c == 0) {
                       break;
                   }
                   currentWhiteSpace = Character.isWhitespace(c);
                   if (currentWhiteSpace && !prevWhiteSpace) {
                       numwords++;
                   }
                   prevWhiteSpace = currentWhiteSpace;
      
               }
               // If we do not end with a white space then we need to add one extra word
               if (!currentWhiteSpace) {
                   numwords++;
               }
               return numwords;
           }
       }

   4. Save the changes.

6. Compile the Java class and create the bundle:

   1. Right-click the myBundle project, select Run As, then Maven Install.

   2. The bundle myBundle-0.0.1-SNAPSHOT.jar (containing the compiled class) is created under myBundle/target.

7. In CRX Explorer, create a new node under /apps/myApp. Name = install, Type = nt:folder.

8. Copy the bundle myBundle-0.0.1-SNAPSHOT.jar and store it under /apps/myApp/install (for example with WebDAV).

   The new text handler is now active in CQ5.

9. In your browser, open the Apache Felix Web Management Console. Select the Components tab and disable the default text handler com.day.cq.dam.core.impl.handler.TextHandler.

From now on, whenever you upload a txt file into CQ5 under the /var/dam/documents folder, the file is copied into /content/dam/documents, its metadata are extracted and two thumbnails with a watermark are generated.