Yarn

java.lang.Object
- Yarn

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Yarn>
```
public class Yarn
extends java.lang.Object
implements java.lang.Comparable<Yarn>, java.io.Serializable
```
A class representing a pseudoline. Each such pseudoline corresponds to a connected path of rhombs, all edges parallel to a given edge. Each Yarn begins and ends at a Terminus. The intersection of two Yarns is a Join.

See Also:
Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

static long serialVersionUID
For serialization.

Fields
Modifier and Type	Field and Description
`static long`	`serialVersionUID` For serialization.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`add(Join j)` Add a Join to the end of the list of Joins.
`void`	`add(Yarn y)` Add a Yarn to the end of the list of Yarns that this one crosses.
`void`	`add(Yarn y, Join j)` Add a Yarn at the end of the list of Yarns and a Join at the end of the list of Joins.
`void`	`addFirst(Join j)` Add a Join to the beginning of the list of Joins.
`void`	`addFirst(Yarn y)` Add a Yarn to the beginning of the list of Yarns that this one crosses.
`void`	`addLast(Join j)` Add a Join to the end of the list of Joins.
`void`	`addLast(Yarn y)` Add a Yarn to the end of the list of Yarns that this one crosses.
`boolean`	`ccwStart(Yarn other)` Move counterclockwise through the Termini, starting with the start of this.
`void`	`collapse(Join j)` Remove a Join from the list of Joins on this Yarn.
`int`	`compareTo(Yarn other)` Compare to another Yarn on the basis of the start and end indices of their Termini.
`boolean`	`consecutive(Yarn y1, Yarn y2)` Check to see if this hits two other Yarns in a row.
`static Yarn`	`createYarn(Terminus s, Terminus e)` Public static factory method.
`java.util.List<Yarn>`	`cross()`
`int`	`crossCount()`
`boolean`	`crosses(Yarn other)` Check if this crosses a particular Yarn.
`int`	`crossRatio(Yarn other)` Compute the sign of the cross ratio between this and another Yarn.
`java.lang.String`	`crossString()` A String listing all Yarns this crosses.
`Join`	`firstJoin()` Getter method.
`java.util.List<Yarn>`	`getCross()` Getter method.
`int`	`getEndAngle()` Getter method.
`int`	`getEndIndex()` Getter method.
`Yarn`	`getOpposite()` Getter method.
`int`	`getStartAngle()` Getter method.
`int`	`getStartIndex()` Getter method.
`boolean`	`hits(Yarn y1, Yarn y2)` Check to see if this hits two other Yarns in a row.
`java.lang.Iterable<Join>`	`joins()`
`Join`	`joinWith(Yarn other)` Assuming that this crosses a given Yarn, return the corresponding Join.
`Join`	`lastJoin()` Getter method.
`Yarn`	`nextYarn(Yarn y1, Yarn y2)` Assume that y1 and y2 intersect this consecutively.
`void`	`remove(Join j)` Remove a Join from the list of Joins between this Yarn and other Yarns.
`void`	`remove(Yarn y)` Remove a Yarn from the list of Yarns that cross this one.
`void`	`removeFirst()` Remove the first Yarn that this one crosses, along with the corresponding Join.
`void`	`removeLast()` Remove the last Yarn that this one crosses, along with the corresponding Join.
`void`	`setOpposite(Yarn y)` Set the Yarn opposite this one.
`boolean`	`shouldCross(Yarn other)` A method for use shortly after construction.
`static java.util.List<Hex>`	`surroundingTriples(Yarn y0, Yarn y1, Yarn y2)` Assume that y0, y1 and y2 intersect in a triple.
`void`	`swap(Yarn y1, Yarn y2)` Swap the positions of two Yarns that cross this one.
`boolean`	`symmetric()` Determine if this Yarn is its own opposite.
`void`	`symmetrize()` Call this method when the list of Yarns crossing this one has been partly filled, and likewise for its opposite.
`java.lang.String`	`toString()` A basic String describing this Yarn.
`boolean`	`valid()` Check for validity of crossings.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - serialVersionUID
```
public static final long serialVersionUID
```
    For serialization.
    
    See Also:
    Constant Field Values
- Method Detail
  - createYarn
```
public static Yarn createYarn(Terminus s,
              Terminus e)
```
    Public static factory method.
    
    Parameters:
    s - The start.
    e - The end.
  - firstJoin
```
public Join firstJoin()
```
    Getter method.
    
    Returns:
    The first intersection with another Yarn, determined by proximity to the starting Terminus. null if there are no Joins.
  - lastJoin
```
public Join lastJoin()
```
    Getter method.
    
    Returns:
    The last intersection with another Yarn, determined by proximity to the starting Terminus. null if there are no Joins.
  - add
```
public void add(Yarn y)
```
    Add a Yarn to the end of the list of Yarns that this one crosses.
    
    Parameters:
    y - The Yarn we add.
  - addFirst
```
public void addFirst(Yarn y)
```
    Add a Yarn to the beginning of the list of Yarns that this one crosses.
    
    Parameters:
    y - The Yarn we add.
  - addLast
```
public void addLast(Yarn y)
```
    Add a Yarn to the end of the list of Yarns that this one crosses.
    
    Parameters:
    y - The Yarn we add.
  - add
```
public void add(Join j)
```
    Add a Join to the end of the list of Joins.
    
    Parameters:
    j - The Join we add.
  - addFirst
```
public void addFirst(Join j)
```
    Add a Join to the beginning of the list of Joins.
    
    Parameters:
    j - The Join we add.
  - addLast
```
public void addLast(Join j)
```
    Add a Join to the end of the list of Joins.
    
    Parameters:
    j - The Join we add.
  - add
```
public void add(Yarn y,
       Join j)
```
    Add a Yarn at the end of the list of Yarns and a Join at the end of the list of Joins.
    
    Parameters:
    y - The Yarn we add.
    j - The Join we add.
  - remove
```
public void remove(Yarn y)
```
    Remove a Yarn from the list of Yarns that cross this one.
    
    Parameters:
    y - The Yarn we remove.
  - remove
```
public void remove(Join j)
```
    Remove a Join from the list of Joins between this Yarn and other Yarns.
    
    Parameters:
    j - The Join we remove.
  - removeFirst
```
public void removeFirst()
```
    Remove the first Yarn that this one crosses, along with the corresponding Join.
  - removeLast
```
public void removeLast()
```
    Remove the last Yarn that this one crosses, along with the corresponding Join.
  - setOpposite
```
public void setOpposite(Yarn y)
```
    Set the Yarn opposite this one. The opposite Yarn is the image of this one under a 180-degree rotation.
    
    Parameters:
    y - The Yarn that we are declaring to be opposite this one.
  - symmetric
```
public boolean symmetric()
```
    Determine if this Yarn is its own opposite.
    
    Returns:
    true if this Yarn is invariant under a 180-degree rotation.
  - symmetrize
```
public void symmetrize()
```
    Call this method when the list of Yarns crossing this one has been partly filled, and likewise for its opposite. This method fills the list for this one the rest of the way, by adding the entries from the list of the crossings of the opposite Yarn to the end of the list for this Yarn, in reverse order.
  - collapse
```
public void collapse(Join j)
```
    Remove a Join from the list of Joins on this Yarn. Do this if we are eliminating a Join entirely, because it is being removed form the edge.
    
    Parameters:
    j - The Join that we remove.
  - getStartIndex
```
public int getStartIndex()
```
    Getter method.
    
    Returns:
    The index in the global list of Termini of the starting Terminus.
  - getEndIndex
```
public int getEndIndex()
```
    Getter method.
    
    Returns:
    The index in the global list of Termini of the ending Terminus.
  - getStartAngle
```
public int getStartAngle()
```
    Getter method.
    
    Returns:
    The angle of the starting Terminus.
  - getEndAngle
```
public int getEndAngle()
```
    Getter method.
    
    Returns:
    The angle of the ending Terminus.
  - getOpposite
```
public Yarn getOpposite()
```
    Getter method.
    
    Returns:
    The image of this Yarn under a 180-degree rotation. This image must be determined and set manually, and it is initialized to null. Also, if the set of all Yarns is not symmetric under such a rotation, then this method returns null.
  - compareTo
```
public int compareTo(Yarn other)
```
    Compare to another Yarn on the basis of the start and end indices of their Termini.
    
    Specified by:
    
    compareTo in interface java.lang.Comparable<Yarn>
    
    Parameters:
    other - The Yarn to which we compare this one.
    
    Returns:
    The difference between the minimum of the indices of the two Termini of this Yarn and the minimum of the indices of the two termini of other.
  - hits
```
public boolean hits(Yarn y1,
           Yarn y2)
```
    Check to see if this hits two other Yarns in a row.
    
    Parameters:
    y1 - The first Yarn for which we check for an intersection with this one.
    y2 - The second Yarn for which we check for an intersection with this one.
    
    Returns:
    true if this hits y1 followed immediately by y2.
  - swap
```
public void swap(Yarn y1,
        Yarn y2)
```
    Swap the positions of two Yarns that cross this one. This should only be done if this crosses the two Yarns one immediately after the other.
    
    Parameters:
    y1 - The first of the two Yarns we swap.
    y2 - The second of the two Yarns we swap.
    See Also:
    hits(Yarn, Yarn)
  - consecutive
```
public boolean consecutive(Yarn y1,
                  Yarn y2)
```
    Check to see if this hits two other Yarns in a row.
    
    Parameters:
    y1 - The first Yarn for which we check for an intersection with this one.
    y2 - The second Yarn for which we check for an intersection with this one.
    
    Returns:
    true if this hits y1 followed immediately by y2 or y2 followed immediately by y1.
  - crossCount
```
public int crossCount()
```
    Returns:
    The number of other Yarns this crosses.
  - crosses
```
public boolean crosses(Yarn other)
```
    Check if this crosses a particular Yarn.
    
    Parameters:
    other - The other Yarn that we are checking for a cross with this.
    
    Returns:
    true if other crosses this.
  - getCross
```
public java.util.List<Yarn> getCross()
```
    Getter method.
    
    Returns:
    A list of all the Yarns that cross this one.
  - shouldCross
```
public boolean shouldCross(Yarn other)
```
    A method for use shortly after construction. The list of other Yarns crossing this one has not been populated yet; this method determines if a given Yarn should be in that list. This is done by calculating a cross-ratio of the two Yarns; if it is negative, then they should cross.
    
    Parameters:
    other - A Yarn that we are checking to see if it should cross this.
    
    Returns:
    true if other should cross this.
  - crossRatio
```
public int crossRatio(Yarn other)
```
    Compute the sign of the cross ratio between this and another Yarn. This cross ratio is calculated by taking products of differences of the starting and ending indices of their Termini.
    
    Parameters:
    other - The Yarn for which we are computing the cross ratio with this.
    
    Returns:
    The sign of the cross ratio of this and other.
  - ccwStart
```
public boolean ccwStart(Yarn other)
```
    Move counterclockwise through the Termini, starting with the start of this. We will eventually hit the start or the end of other. If we hit the start first, return true; otherwise return false.
    
    Parameters:
    other - The Yarn for which we are comparing Termini positions with this.
    
    Returns:
    true if we hit the start of other before the end of other in a ccw traversal of Termini, starting with the start of this.
  - valid
```
public boolean valid()
```
    Check for validity of crossings. Iterate through all the Yarns crossing this one, and compute differences of angles of the Termini. If these differences are all less than Point.N() (mod 2N) then the crossings are valid; otherwise they're invalid.
    
    Returns:
    true if all crossings with this Yarn are valid.
  - joinWith
```
public Join joinWith(Yarn other)
```
    Assuming that this crosses a given Yarn, return the corresponding Join. If the given Yarn does not cross this one, return null.
    
    Parameters:
    other - The Yarn whose Join with this we are seeking.
    
    Returns:
    The Join between other and this.
  - nextYarn
```
public Yarn nextYarn(Yarn y1,
            Yarn y2)
```
    Assume that y1 and y2 intersect this consecutively. Then return the Yarn that comes after, on the side of y1. Return null if there is no such Yarn.
    
    Parameters:
    y1 - The first of two Yarns that intersect this consecutively.
    y2 - The second of two Yarns that intersect this consecutively.
    
    Returns:
    The Yarn, other than y2, that intersects this consecutively with y1. Return null if there is not such Yarn.
  - surroundingTriples
```
public static java.util.List<Hex> surroundingTriples(Yarn y0,
                                     Yarn y1,
                                     Yarn y2)
```
    Assume that y0, y1 and y2 intersect in a triple. Then return a list of all Triples that would be created or destroyed by flipping that Triple.
    
    Parameters:
    y0 - One of three Yarns.
    y1 - One of three Yarns.
    y2 - One of three Yarns.
    
    Returns:
    All Triples that would be created or destroyed by flipping the Triple on y0, y1, and y2.
  - toString
```
public java.lang.String toString()
```
    A basic String describing this Yarn.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    A String giving the indices of the start and end Termini.
  - crossString
```
public java.lang.String crossString()
```
    A String listing all Yarns this crosses.
    
    Returns:
    A String consisting of all the Yarns that cross this, separated by newlines.
  - cross
```
public java.util.List<Yarn> cross()
```
    Returns:
    A List of all the Yarns that cross this one.
  - joins
```
public java.lang.Iterable<Join> joins()
```
    Returns:
    An Iterable of all the Joins on this Yarn.

Class Yarn

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

serialVersionUID

Method Detail

createYarn

firstJoin

lastJoin

add

addFirst

addLast

add

addFirst

addLast

add

remove

remove

removeFirst

removeLast

setOpposite

symmetric

symmetrize

collapse

getStartIndex

getEndIndex

getStartAngle

getEndAngle

getOpposite

compareTo

hits

swap

consecutive

crossCount

crosses

getCross

shouldCross

crossRatio

ccwStart

valid

joinWith

nextYarn

surroundingTriples

toString

crossString

cross

joins