Commit partial work

p3/src/relop/FileScan.java

@@ -9,7 +9,6 @@ import heap.HeapScan;
  * version takes schema into consideration and generates real tuples.
  */
 public class FileScan extends Iterator {
-	
 	private HeapFile file = null; // needed for restart(), getFile();
 	private HeapScan scan = null;
 	private RID rid = null;
@@ -70,7 +69,7 @@ public class FileScan extends Iterator {
 
   /**
    * Gets the next tuple in the iteration.
-   * 
+   *
    * @throws IllegalStateException if no more tuples
    */
   public Tuple getNext() {
@@ -83,7 +82,7 @@ public class FileScan extends Iterator {
   public RID getLastRID() {
 	  return rid;
   }
-  
+
   // getter; added so HashJoin doesn't have to copy the file;
   public HeapFile getFile(){
 	  return file;

p3/src/relop/KeyScan.java

@@ -9,12 +9,22 @@ import index.HashScan;
  * Wrapper for hash scan, an index access method.
  */
 public class KeyScan extends Iterator {
-	
+	private HeapFile file = null; // needed for restart(), getFile();
+	private HashScan scan = null;
+	private HashIndex index = null;
+	private SearchKey key = null;
+	private boolean isOpen;
+
   /**
    * Constructs an index scan, given the hash index and schema.
    */
   public KeyScan(Schema aSchema, HashIndex aIndex, SearchKey aKey, HeapFile aFile) {
-	  throw new UnsupportedOperationException("Not implemented");
+	this.schema = aSchema;
+	this.index = aIndex;
+	this.key = aKey;
+	this.file = aFile;
+	this.scan = this.index.openScan(this.key);
+	this.isOpen = true;
   }
 
   /**
@@ -22,44 +32,51 @@ public class KeyScan extends Iterator {
    * child iterators, and increases the indent depth along the way.
    */
   public void explain(int depth) {
-	  throw new UnsupportedOperationException("Not implemented");
+	throw new UnsupportedOperationException("Not implemented");
   }
 
   /**
    * Restarts the iterator, i.e. as if it were just constructed.
    */
   public void restart() {
-	  throw new UnsupportedOperationException("Not implemented");
+      this.isOpen = false; // In case of errors maybe?
+      this.close();
+      this.scan = this.index.openScan(this.key);
+      this.isOpen = true;
   }
 
   /**
    * Returns true if the iterator is open; false otherwise.
    */
   public boolean isOpen() {
-	  throw new UnsupportedOperationException("Not implemented");
+      return this.isOpen;
   }
 
   /**
    * Closes the iterator, releasing any resources (i.e. pinned pages).
    */
   public void close() {
-	  throw new UnsupportedOperationException("Not implemented");
+      if (this.isOpen()) {
+	  this.scan.close();
+	  this.scan = null;
+	  this.isOpen = false;
+      }
   }
 
   /**
    * Returns true if there are more tuples, false otherwise.
    */
   public boolean hasNext() {
-	  throw new UnsupportedOperationException("Not implemented");
+	throw new UnsupportedOperationException("Not implemented");
   }
 
   /**
    * Gets the next tuple in the iteration.
-   * 
+   *
    * @throws IllegalStateException if no more tuples
    */
   public Tuple getNext() {
-	  throw new UnsupportedOperationException("Not implemented");
+	throw new UnsupportedOperationException("Not implemented");
   }
 
 } // public class KeyScan extends Iterator