package cz.cuni.amis.utils;
   
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileNotFoundException;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.OutputStream;
  
  public class GenericLoader<T> {
  	
  	/**
  	 * Loads the object of type T from input stream.
  	 * @param in
  	 * @return null (failure) || loaded object
  	 */
  	public T loadObject(InputStream in) {
  		try {
  			return (T) ((new ObjectInputStream(in)).readObject());
  		} catch (IOException e) {
  			return null;
  		} catch (ClassNotFoundException e) {
  			return null;
  		}
  	}
  	
  	/**
  	 * Loads the object of type T from file 'file'.
  	 * @param file
  	 * @return null (failure) || loaded object
  	 */
  	public T loadObject(File file) {
  		try {
  			return loadObject(new FileInputStream(file));
  		} catch (FileNotFoundException e) {
  			return null;
  		}
  	}
  	
  	/**
  	 * Loads the object of type T from the file at path 'pathAndFileName'.
  	 * @param pathAndFileName
  	 * @return null (failure) || loaded object
  	 */
  	public T loadObject(String pathAndFileName) {
  		return loadObject(new File(pathAndFileName));
  	}
  	
  	/**
  	 * Writes object to the output stream, returns success
  	 * @param object
  	 * @param out
  	 * @return success
  	 */
  	public boolean saveObject(T object, ObjectOutputStream out) {
  		try {
  			out.writeObject(object);
  		} catch (IOException e) {
  			return false;
  		}
  		return true;
  	}
  	
  	/**
  	 * Writes object to the output stream, returns success.
  	 * @param object
  	 * @param out
  	 * @return success
  	 */
  	public boolean saveObject(T object, OutputStream out) {
  		try {
  			return saveObject(object, new ObjectOutputStream(out));
  		} catch (IOException e) {
  			return false;
  		}
  	}
  	
  	/**
  	 * Writes object to the file;
  	 * @param object
  	 * @param file
  	 * @return success
  	 */
  	public boolean saveObject(T object, File file) {
  		try {
  			return saveObject(object, new FileOutputStream(file));
  		} catch (IOException e) {
  			return false;
  		}
  	}
  	
  	/**
  	 * Writes object to the file at 'pathAndFileName';
  	 * @param object
  	 * @param pathAndFileName
  	 * @return success
 	 */
 	public boolean saveObject(T object, String pathAndFileName) {
 		return saveObject(object, new File(pathAndFileName));
 	}
 
 }