Caching Class path Resource Loader : Resource Loader « Velocity « Java

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Java » Velocity » Resource LoaderScreenshots 
Caching Class path Resource Loader


import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.collections.ExtendedProperties;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.runtime.resource.loader.ResourceLoader;

public class CachingClasspathResourceLoader extends ResourceLoader {
  private Map urlMap = new HashMap();

  public void init(ExtendedProperties configuration) {
  }

  public synchronized InputStream getResourceStream(String resourceName)
      throws ResourceNotFoundException {
    try {
      URL url = getURL(resourceName);

      if (url == null) {
        throw new ResourceNotFoundException("Can not find resource: "
            + resourceName);
      }
      return url.openStream();
    catch (IOException e) {
      throw new ResourceNotFoundException("Can not find resource: "
          + resourceName + " - Reason: " + e.getMessage());
    }
  }

  public long getLastModified(Resource res) {
    try {
      URL url = getURL(res.getName());
      long lm = url.openConnection().getLastModified();
      return lm;
    catch (Exception e) {
      rsvc.error(e);
      return 0;
    }
  }

  public boolean isSourceModified(Resource res) {
    long lastModified = getLastModified(res);
    return (lastModified != res.getLastModified());
  }

  private URL getURL(String rn) {
    if (urlMap.containsKey(rn)) {
      return (URLurlMap.get(rn);
    }

    ClassLoader cl = this.getClass().getClassLoader();
    URL url = cl.getResource(rn);

    if (url != null) {
      urlMap.put(rn, url);
    }

    return url;
  }
}
           
       
velocity-CachingClasspathResourceLoader.zip( 2,193 k)
Related examples in the same category
1.Resource Loader Demo
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