How to use org.openrdf.query.algebra

 // Solve for time
float time = (float)(intersectionDistance / lineLength);

// If time is outside the boundaries, return null. This algorithm can 
// return a negative time which indicates the previous intersection. 
if (time > 1.0f || time < 0.0f) {
  return null;
}

// Solve the intersection and normal
float ix = time * dx + start.x;
float iy = time * dy + start.y;
float nx = (float)((ix - cornerX) * inverseRadius);
float ny = (float)((iy - cornerY) * inverseRadius);

return new Intersection( ix, iy, time, nx, ny );

  @Override
  public ArbitraryLengthPath clone() {
    ArbitraryLengthPath clone = (ArbitraryLengthPath)super.clone();
    clone.setSubjectVar(getSubjectVar().clone());
    clone.setPathExpression(getPathExpression().clone());
    clone.setObjectVar(getObjectVar().clone());

    if (getContextVar() != null) {
      clone.setContextVar(getContextVar().clone());
    }

    return clone;
  }
}

  @Override
  public BinaryTupleOperator clone() {
    BinaryTupleOperator clone = (BinaryTupleOperator)super.clone();
    clone.setLeftArg(getLeftArg().clone());
    clone.setRightArg(getRightArg().clone());
    return clone;
  }
}

  @Override
  public void meet(final Filter filter) {
    //First visit children, then condition (reverse of default):
    filter.getArg().visit(this);
    filter.getCondition().visit(this);
  }
}

  @Override
  public UnaryTupleOperator clone() {
    UnaryTupleOperator clone = (UnaryTupleOperator)super.clone();
    clone.setArg(getArg().clone());
    return clone;
  }
}

  @Override
  public Filter clone() {
    Filter clone = (Filter)super.clone();
    clone.setCondition(getCondition().clone());
    return clone;
  }
}

  @Override
  public LeftJoin clone() {
    LeftJoin clone = (LeftJoin)super.clone();
    if (hasCondition()) {
      clone.setCondition(getCondition().clone());
    }
    return clone;
  }
}

  @Override
  public ExtensionElem clone() {
    ExtensionElem clone = (ExtensionElem)super.clone();
    clone.setExpr(getExpr().clone());
    return clone;
  }
}

@Override
public Projection clone() {
  Projection clone = (Projection)super.clone();
  clone.setProjectionElemList(getProjectionElemList().clone());
  return clone;
}

  @Override
  public BinaryValueOperator clone() {
    BinaryValueOperator clone = (BinaryValueOperator)super.clone();
    clone.setLeftArg(getLeftArg().clone());
    clone.setRightArg(getRightArg().clone());
    return clone;
  }
}

  @Override
  public OrderElem clone() {
    OrderElem clone = (OrderElem)super.clone();
    clone.setExpr(getExpr().clone());
    return clone;
  }
}

  @Override
  public ZeroLengthPath clone() {
    ZeroLengthPath clone = (ZeroLengthPath)super.clone();
    clone.setSubjectVar(getSubjectVar().clone());
    clone.setObjectVar(getObjectVar().clone());

    if (getContextVar() != null) {
      clone.setContextVar(getContextVar().clone());
    }

    return clone;
  }
}

@Override
public boolean equals(Object other) {
  if (other instanceof Projection && super.equals(other)) {
    Projection o = (Projection)other;
    return projElemList.equals(o.getProjectionElemList());
  }
  return false;
}

@Override
public boolean equals(Object other) {
  if (other instanceof Compare && super.equals(other)) {
    Compare o = (Compare)other;
    return operator.equals(o.getOperator());
  }
  return false;
}

  @Override
  public Bound clone() {
    Bound clone = (Bound)super.clone();
    clone.setArg(getArg().clone());
    return clone;
  }
}

  @Override
  public GroupElem clone() {
    GroupElem clone = (GroupElem)super.clone();
    clone.setOperator(getOperator().clone());
    return clone;
  }
}

@Override
public If clone() {
  If clone = (If)super.clone();
  clone.setCondition(condition.clone());
  if (result != null) {
    clone.setResult(result.clone());
  }
  if (alternative != null) {
    clone.setAlternative(alternative.clone());
  }
  return clone;
}

  @Override
  public CompareSubQueryValueOperator clone() {
    CompareSubQueryValueOperator clone = (CompareSubQueryValueOperator)super.clone();
    clone.setArg(getArg().clone());
    return clone;
  }
}

@Override
public boolean equals(Object other) {
  if (other instanceof CompareAny && super.equals(other)) {
    CompareAny o = (CompareAny)other;
    return operator.equals(o.getOperator());
  }
  return false;
}

@Override
public boolean equals(Object other) {
  if (other instanceof CompareAll && super.equals(other)) {
    CompareAll o = (CompareAll)other;
    return operator.equals(o.getOperator());
  }
  return false;
}