MessageDisplayUtils.java

package org.springframework.roo.support.util;

import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.commons.io.IOUtils;
import org.springframework.roo.support.logging.HandlerUtils;

/**
 * Retrieves text files from the classloader and displays them on-screen.
 * <p>
 * Respects normal Roo conventions such as all resources should appear under the
 * same package as the bundle itself etc.
 * 
 * @author Ben Alex
 * @since 1.1.1
 */
public abstract class MessageDisplayUtils {

  private static Logger LOGGER = HandlerUtils.getLogger(MessageDisplayUtils.class);

  /**
   * Same as {@link #displayFile(String, Class, boolean)} except it passes
   * false as the final argument.
   * 
   * @param fileName the simple filename (required)
   * @param owner the class which owns the file (required)
   */
  public static void displayFile(final String fileName, final Class<?> owner) {
    displayFile(fileName, owner, false);
  }

  /**
   * Displays the requested file via the LOGGER API.
   * <p>
   * Each file must available from the classloader of the "owner". It must
   * also be in the same package as the class of the "owner". So if the owner
   * is com.foo.Bar, and the file is called "hello.txt", the file must appear
   * in the same bundle as com.foo.Bar and be available from the resource path
   * "/com/foo/Hello.txt".
   * 
   * @param fileName the simple filename (required)
   * @param owner the class which owns the file (required)
   * @param important if true, it will display with a higher importance color
   *            where possible
   */
  public static void displayFile(final String fileName, final Class<?> owner,
      final boolean important) {
    final Level level = important ? Level.SEVERE : Level.FINE;
    final String owningPackage = owner.getPackage().getName().replace('.', '/');
    final String fullResourceName = "/" + owningPackage + "/" + fileName;
    final InputStream inputStream = owner.getClassLoader().getResourceAsStream(fullResourceName);
    if (inputStream == null) {
      throw new IllegalStateException("Could not locate '" + fileName + "'");
    }
    try {
      final String message = IOUtils.toString(inputStream);
      LOGGER.log(level, message);
    } catch (final Exception e) {
      throw new IllegalStateException(e);
    } finally {
      IOUtils.closeQuietly(inputStream);
    }
  }
}