/*
* File: MatrixUnionIterator.java
* Authors: Kevin R. Dixon
* Company: Sandia National Laboratories
* Project: Cognitive Framework Lite
*
* Copyright March 23, 2006, Sandia Corporation. Under the terms of Contract
* DE-AC04-94AL85000, there is a non-exclusive license for use of this work by
* or on behalf of the U.S. Government. Export of this program may require a
* license from the United States Government. See CopyrightHistory.txt for
* complete details.
*
*
*/
package gov.sandia.cognition.math.matrix;
import gov.sandia.cognition.annotation.CodeReview;
import gov.sandia.cognition.annotation.CodeReviewResponse;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Iterator that stops at all nonzero entries for EITHER underlying matrix
*
* @author Kevin R. Dixon
* @since 1.0
*/
@CodeReview(
reviewer="Jonathan McClain",
date="2006-05-16",
changesNeeded=false,
comments="A few comments, marked with triple slashes",
response=@CodeReviewResponse(
respondent="Kevin R. Dixon",
date="2006-05-18",
moreChangesNeeded=false,
comments="Fixes from J.T.'s code review"
)
)
public class MatrixUnionIterator
implements Iterator<TwoMatrixEntry>
{
/**
* Iterator from the first Matrix
*/
private Iterator<MatrixEntry> firstIterator;
/**
* Iterator from the second Matrix
*/
private Iterator<MatrixEntry> secondIterator;
/**
* TwoMatrixEntry that represents the entries in each Matrix
*/
private TwoMatrixEntry internalEntry;
/**
* Entry from the first Matrix
*/
private MatrixEntry firstInternalEntry;
/**
* Entry from the Second Matrix
*/
private MatrixEntry secondInternalEntry;
/**
* The comparator for iterating over matrix indices.
*/
private EntryIndexComparator<MatrixEntry> indexComparator = null;
/**
* Creates a new instance of MatrixUnionIterator
* @param firstIterator Iterator from the first Matrix
* @param secondIterator Iterator from the second Matrix
* @param internalEntry TwoMatrixEntry for this
* @param indexComparator The index comparator for the matrices.
*/
public MatrixUnionIterator(
Iterator<MatrixEntry> firstIterator,
Iterator<MatrixEntry> secondIterator,
TwoMatrixEntry internalEntry,
EntryIndexComparator<MatrixEntry> indexComparator)
{
this.setFirstIterator( firstIterator );
this.setSecondIterator( secondIterator );
this.setInternalEntry( internalEntry );
this.setFirstInternalEntry( null );
this.setSecondInternalEntry( null );
this.setIndexComparator(indexComparator);
}
/**
* getter for firstInterator
* @return Iterator from the first Matrix
*/
public Iterator<MatrixEntry> getFirstIterator()
{
return this.firstIterator;
}
/**
* setter for firstInterator
* @param firstIterator Iterator from the first Matrix
*/
public void setFirstIterator(
Iterator<MatrixEntry> firstIterator)
{
this.firstIterator = firstIterator;
}
/**
* getter for secondIterator
* @return Iterator from the second matrix
*/
public Iterator<MatrixEntry> getSecondIterator()
{
return this.secondIterator;
}
/**
* setter for secondIterator
* @param secondIterator Iterator from the second Matrix
*/
public void setSecondIterator(
Iterator<MatrixEntry> secondIterator)
{
this.secondIterator = secondIterator;
}
/**
* getter for firstInternalEntry
* @return MatrixEntry into the first Matrix
*/
public MatrixEntry getFirstInternalEntry()
{
return this.firstInternalEntry;
}
/**
* setter for firstInternalEntry
* @param firstInternalEntry MatrixEntry for the first Matrix
*/
public void setFirstInternalEntry(
MatrixEntry firstInternalEntry)
{
this.firstInternalEntry = firstInternalEntry;
}
/**
* getter for secondInternalEntry
* @return MatrixEntry from the second Matrix
*/
public MatrixEntry getSecondInternalEntry()
{
return this.secondInternalEntry;
}
/**
* setter for secondInternalEntry
* @param secondInternalEntry MatrixEntry from the second Matrix
*/
public void setSecondInternalEntry(
MatrixEntry secondInternalEntry)
{
this.secondInternalEntry = secondInternalEntry;
}
/**
* getter for internalEntry
* @return TwoMatrixEntry that represents the entries of both matrices
*/
public TwoMatrixEntry getInternalEntry()
{
return this.internalEntry;
}
/**
* setter for internalEntry
* @param internalEntry TwoMatrixEntry that contains the entries for both matrices
*/
public void setInternalEntry(
TwoMatrixEntry internalEntry)
{
this.internalEntry = internalEntry;
}
/**
* Gets the index comparator.
*
* @return The index comparator.
*/
public EntryIndexComparator<MatrixEntry> getIndexComparator()
{
return indexComparator;
}
/**
* Sets the index comparator.
*
* @param indexComparator The index comparator.
*/
protected void setIndexComparator(
EntryIndexComparator<MatrixEntry> indexComparator)
{
this.indexComparator = indexComparator;
}
/**
* Try to advance the first entry... if the iterator throws an
* exception, then there are no more elements in the matrix,
* so just null out the entry
*
* @return true if next was valid, false otherwise
*/
public boolean safeFirstNext()
{
boolean valid_next;
try
{
this.setFirstInternalEntry( this.getFirstIterator().next() );
valid_next = true;
}
catch (Exception e)
{
this.setFirstInternalEntry( null );
valid_next = false;
}
return valid_next;
}
/**
* Try to advance the second entry... if the iterator throws an
* exception, then there are no more elements in the vector,
* so just null out the entry
*
* @return true if next was valid, false otherwise
*/
public boolean safeSecondNext()
{
boolean valid_next;
try
{
this.setSecondInternalEntry( this.getSecondIterator().next() );
valid_next = true;
}
catch (Exception e)
{
this.setSecondInternalEntry( null );
valid_next = false;
}
return valid_next;
}
/**
* Internal routine for advancing the internal iterators
*/
protected void advanceInternalIterators()
{
boolean advance_first = false;
boolean advance_second = false;
EntryIndexComparator.Compare compare =
this.getIndexComparator().lowestIndex(
this.getFirstInternalEntry(), this.getSecondInternalEntry() );
if( compare == EntryIndexComparator.Compare.FIRST_LOWEST )
{
advance_first = true;
}
else if( compare == EntryIndexComparator.Compare.SECOND_LOWEST )
{
advance_second = true;
}
else if( compare == EntryIndexComparator.Compare.FIRST_ENTRY_NULL )
{
advance_second = true;
}
else if( compare == EntryIndexComparator.Compare.SECOND_ENTRY_NULL )
{
advance_first = true;
}
else if( compare == EntryIndexComparator.Compare.BOTH_ENTRIES_NULL )
{
advance_first = true;
advance_second = true;
}
else if( compare == EntryIndexComparator.Compare.ENTRIES_EQUAL )
{
advance_first = true;
advance_second = true;
}
else
{
throw new NoSuchElementException(
"Unknown Compare Enum: " + compare );
}
if( (advance_first == false) &&
(advance_second == false) )
{
throw new NoSuchElementException(
"Problem: Not advancing any iterators..." );
}
if( advance_first == true )
{
this.safeFirstNext();
}
if( advance_second == true )
{
this.safeSecondNext();
}
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
*/
public boolean hasNext()
{
return (this.getFirstIterator().hasNext() == true) ||
(this.getSecondIterator().hasNext() == true);
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
*/
public TwoMatrixEntry next()
{
if ( !this.hasNext() )
{
throw new NoSuchElementException( "No elements remaining." );
}
this.advanceInternalIterators();
EntryIndexComparator.Compare compare =
this.getIndexComparator().lowestIndex(
this.getFirstInternalEntry(), this.getSecondInternalEntry() );
if( compare == EntryIndexComparator.Compare.ENTRIES_EQUAL )
{
this.getInternalEntry().setRowIndex(
this.getFirstInternalEntry().getRowIndex() );
this.getInternalEntry().setColumnIndex(
this.getFirstInternalEntry().getColumnIndex() );
}
else if( compare == EntryIndexComparator.Compare.FIRST_LOWEST )
{
this.getInternalEntry().setRowIndex(
this.getFirstInternalEntry().getRowIndex() );
this.getInternalEntry().setColumnIndex(
this.getFirstInternalEntry().getColumnIndex() );
}
else if( compare == EntryIndexComparator.Compare.SECOND_LOWEST )
{
this.getInternalEntry().setRowIndex(
this.getSecondInternalEntry().getRowIndex() );
this.getInternalEntry().setColumnIndex(
this.getSecondInternalEntry().getColumnIndex() );
}
else if( compare == EntryIndexComparator.Compare.FIRST_ENTRY_NULL )
{
this.getInternalEntry().setRowIndex(
this.getSecondInternalEntry().getRowIndex() );
this.getInternalEntry().setColumnIndex(
this.getSecondInternalEntry().getColumnIndex() );
}
else if( compare == EntryIndexComparator.Compare.SECOND_ENTRY_NULL )
{
this.getInternalEntry().setRowIndex(
this.getFirstInternalEntry().getRowIndex() );
this.getInternalEntry().setColumnIndex(
this.getFirstInternalEntry().getColumnIndex() );
}
else
{
throw new NoSuchElementException( "No elements remaining." );
}
return this.getInternalEntry();
}
/**
* {@inheritDoc}
*
* @throws UnsupportedOperationException Always.
* @throws NoSuchElementException If there is no element to remove.
*/
public void remove()
throws UnsupportedOperationException, NoSuchElementException
{
throw new UnsupportedOperationException("Remove is not supported");
}
}