booktitle.java

图书馆检索系统

package library;

import java.sql.*;

/**
* A class representing a book title
*
* @author dms
* @version 1.0
*/
public class BookTitle extends LibraryObject {
     
	private String callNumber;
	private String name;
	private String authors;
	private String isbn;
	private String edition;
	private String publisher;
	private int year;
	
	/**
	* class BookTitle constructor
	*
	*/
	public BookTitle(){} 
	
	/**
	* Class constructor which runs a 
	* specified sql statement to populate
	* the BookTitle object.  Use inherited
	* method <code>getNext</code> to
	* iterate through the resulting 
	* BookTitle objects
	* @param sql	SQL statement
	* @throws SQLException 
	*/
	public BookTitle(String sql) throws SQLException {
		
		ensureconnection();	
	  	mr = db.runQuery(sql);
	}

	/**
	* Sets the object to a specific title based on call number.
	*
	* @param cn String containing call number
	* @return true if success, false if otherwise
	*/
	public boolean getBookTitle(String cn) {
	
		ensureconnection();
		
		String sSQL = "";
		sSQL = "SELECT * FROM BookTitle WHERE CallNumber = '" + cn + "'";
				
		try {
			ResultSet r = db.runQuery(sSQL);
		  	r.next();
		  	setVariables(r);
		  	return true;
		}
		catch (SQLException e) {
		  	System.err.println(e.toString()); 
		  	return false;
		}
	}
  
	protected void setVariables(ResultSet r) throws SQLException {
   
   		callNumber = r.getString("CallNumber");
   		name = r.getString("name");
   		authors = r.getString("author");
   		edition = r.getString("edition");
   		isbn = r.getString("isbn");
   		year = r.getInt("year");
   		publisher = r.getString("publisher");

  	}
  	
  	/**
  	* Retrives the holds for this book title
  	* 
  	* @return Hold object, ready to be iterated using
  	* inherited getNext routine
  	* @throws SQLException
  	*/
  	public Hold getHolds() throws SQLException {
  		
  		String sql = "SELECT * FROM Hold WHERE CallNumber = '" + this.getCallNumber() + "'";
  		return new Hold(sql);	
  	}

  	/**
  	* Determines the number of holds this title has.
  	* 
  	* @return int containing number of holds for this title
  	*/
  	public int getHoldCount() {
  		
  		ensureconnection();
		
		String sql = "SELECT Count(*) as counted FROM Hold WHERE CallNumber = '" + this.getCallNumber() + "'";
				
		try {
			ResultSet r = db.runQuery(sql);
		  	r.next();
		  	return r.getInt("counted");
		}
		catch (SQLException e) {
		  	System.err.println(e.toString()); 
		  	return 0;
		}	
  		
  	}

	/**
	* Retrieves the books for this title
	*
	* @return Book object, ready to be iterated using
	* inherited method <code>getNext</code>
	* @throws SQLException
	*/
	public Book getBooks() throws SQLException {
		
  		String sql = "SELECT * FROM Book WHERE CallNumber = '" + this.getCallNumber() + "'";
  		return new Book(sql);	
		
	}

  	/**
  	* Determines the number of copies (books) this title has.
  	* 
  	* @return int containing number of books for this title
  	*/
  	public int getBookCount() {
  		
  		ensureconnection();
		
		String sql = "SELECT Count(*) as counted FROM Book WHERE CallNumber = '" + this.getCallNumber() + "'";
				
		try {
			ResultSet r = db.runQuery(sql);
		  	r.next();
		  	return r.getInt("counted");
		}
		catch (SQLException e) {
		  	System.err.println(e.toString()); 
		  	return 0;
		}	
  		
  	}

  	/**
  	* Determines the number of available copies (books) this title has.
  	* 
  	* @return int containing number of available books for this title
  	*/
  	public int getAvailableBookCount() {
  		
  		ensureconnection();
		
		String sql = "SELECT Count(*) as counted FROM Book WHERE (DueDate IS NULL) AND CallNumber = '" + this.getCallNumber() + "'";
				
		try {
			ResultSet r = db.runQuery(sql);
		  	r.next();
		  	return r.getInt("counted");
		}
		catch (SQLException e) {
		  	System.err.println(e.toString()); 
		  	return 0;
		}	
  		
  	}

	/**
	* Accessor for Call Number
	* @return String
	*/
	public String getCallNumber() {return callNumber;}

	/**
	* Accessor for Name
	* @return String
	*/
    public String getName() {return name;}

	/**
	* Accessor for isbn
	* @return String
	*/
    public String getISBN() {return isbn;}

	/**
	* Accessor for Edition
	* @return String
	*/
    public String getEdition() {return edition;}

	/**
	* Accessor for year of publication
	* @return int
	*/
    public int getYear() {return year;}
	
	/**
	* Accessor for authors
	* @return String
	*
	*/
	public String getAuthors() {return authors;}
	
	/**
	* Accessor for publisher
	* @return String
	*/
    public String getPublisher() {return publisher;}

	/**
	* Method used to determine if book title
	* is currently held.
	*
	* @return boolean true if held, false if not held
	* @throws SQLException
	*/
	public boolean isBookTitleHeld() throws SQLException {
		
		Hold hold = this.getHolds();

		if (hold.getNext())
			return true;
		else
			return false;	
		
	}

	/**
	* Returns a lightweight version of this object, which
	* only contains the necessary information to display
	* as a search result.
	*
	* @return A SearchResult object representing this title
	*/
	public SearchResult getSearchResult() {
		
		SearchResult sr = new SearchResult(getName(), getAuthors(), getCallNumber(), getEdition(), getYear());	
		return sr;
	}
}