Tuple.java

package simpledb;

import com.sun.org.apache.bcel.internal.classfile.Field;

/**
 * Tuple maintains information about the contents of a tuple.
 * Tuples have a specified schema specified by a TupleDesc object and contain
 * Field objects with the data for each field.
 */
public class Tuple {

	/**
	 * The tuple descriptor associated with this Tuple.
	 */
	protected TupleDesc tupledesc;
	
	/**
	 * The RecordId of this Tuple.
	 */
    protected RecordId recID;
    
    /**
     * The Fields of this Tuple.
     */
    protected Field fields[];
    
    /**
     * Create a new tuple with the specified schema (type).
     *
     * @param td the schema of this tuple. It must be a valid TupleDesc
     * instance with at least one field.
     */
    public Tuple(TupleDesc td) {
        if(td.numFields() > 0){
            tupledesc = td;
            fields = new Field[td.numFields()];
        }
    }

    /**
     * @return The TupleDesc representing the schema of this tuple.
     */
    public TupleDesc getTupleDesc() {
        return tupledesc;
    }

    /**
     * @return The RecordID representing the location of this tuple on
     *   disk. May be null.
     */
    public RecordId getRecordId() {
        return recID;
    }

    /**
     * Set the RecordID information for this tuple.
     * @param rid the new RecordID for this tuple.
     */
    public void setRecordId(RecordId rid) {
        recID = rid;
    }

    /**
     * Change the value of the ith field of this tuple.
     *
     * @param i index of the field to change. It must be a valid index.
     * @param f new value for the field.
     */
    public void setField(int i, Field f) {
        if(i >= 0 && i < fields.length)
            fields[i] = f;
    }

    /**
     * @return the value of the ith field, or null if it has not been set.
     *
     * @param i field index to return. Must be a valid index.
     */
    public Field getField(int i) {
        if(i >= 0 && i < fields.length)
            return fields[i];
        return null;
    }

    /**
     * Returns a string representing this Tuple.
     * Note that to pass the system tests, the format needs to be as
     * follows:
     * "fields[0]|fields[1]|...|fields[M-1]", where M is the number of fields.
     */
    public String toString() {
        // some code goes here
    	System.out.print(fields[0]);
    	for(int i=1; i< fields.length; i++){
    		System.out.print("|"+fields[i]);
    	}
        throw new UnsupportedOperationException("Implement this");
    }
}