Object
- AbstractJoint<T>

Type Parameters:

T - the PhysicsBody type

All Implemented Interfaces:

DataContainer, Joint<T>, Shiftable, Ownable

Direct Known Subclasses:

AbstractPairedBodyJoint, AbstractSingleBodyJoint
```
public abstract class AbstractJoint<T extends PhysicsBody>
extends Object
implements Joint<T>, Shiftable, DataContainer, Ownable
```
Represents an abstract implementation of constrained motion between PhysicsBodys.

Since:

5.0.0

Version:

5.0.0

Author:

William Bittle

Field Summary

Fields
Modifier and Type	Field	Description
`protected List<T>`	`bodies`	An unmodifiable list of the bodies
`protected boolean`	`collisionAllowed`	Whether the pair of bodies joined together can collide with each other
`protected Object`	`owner`	The joint owner
`protected Object`	`userData`	The user data

Fields inherited from interface Joint
SPRING_MODE_FREQUENCY, SPRING_MODE_STIFFNESS

Constructor Summary

Constructors
Constructor Description

AbstractJoint(List<T> bodies)
Default constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`List<T>`	`getBodies()`	Returns an unmodifiable list of bodies involved in this joint.
`T`	`getBody(int index)`	Returns the body at the given index.
`int`	`getBodyCount()`	Returns the number of bodies involved in this joint.
`Iterator<T>`	`getBodyIterator()`	Returns an iterator for the bodies involved in this joint.
`protected static double`	`getConstraintImpulseMixing(double deltaTime, double stiffness, double damping)`	Returns the constraint impulse mixing parameter.
`protected static double`	`getErrorReductionParameter(double deltaTime, double stiffness, double damping)`	Returns the error reduction parameter.
`protected static double`	`getFrequency(double naturalFrequency)`	Returns the frequency given the natural frequency.
`protected static double`	`getNaturalFrequency(double frequency)`	Returns the natural frequency of the given frequency.
`protected static double`	`getNaturalFrequency(double stiffness, double mass)`	Returns the natural frequency given the spring stiffness and mass.
`Object`	`getOwner()`	Returns the owner for this body.
`protected static double`	`getSpringDampingCoefficient(double mass, double naturalFrequency, double dampingRatio)`	Returns the spring damping coefficient.
`protected static double`	`getSpringStiffness(double mass, double naturalFrequency)`	Returns the spring stiffness, k, from Hooke's Law.
`Object`	`getUserData()`	Gets the custom user data.
`boolean`	`isCollisionAllowed()`	Returns true if collision between the joined `PhysicsBody`s is allowed.
`boolean`	`isEnabled()`	Returns true if this `Joint` is enabled.
`boolean`	`isMember(CollisionBody<?> body)`	Returns true if the given body is a member of this joint.
`void`	`setCollisionAllowed(boolean flag)`	Sets whether collision is allowed between the joined `PhysicsBody`s.
`void`	`setOwner(Object owner)`	Sets the owner of this body.
`void`	`setUserData(Object userData)`	Sets the custom user data to the given data.
`String`	`toString()`

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

Methods inherited from interface Joint
getReactionForce, getReactionTorque, initializeConstraints, solvePositionConstraints, solveVelocityConstraints

Methods inherited from interface Shiftable
shift

- Field Detail
  - bodies
```
protected final List<T extends PhysicsBody> bodies
```
    An unmodifiable list of the bodies
  - collisionAllowed
```
protected boolean collisionAllowed
```
    Whether the pair of bodies joined together can collide with each other
  - userData
```
protected Object userData
```
    The user data
  - owner
```
protected Object owner
```
    The joint owner
- Constructor Detail
  - AbstractJoint
```
public AbstractJoint(List<T> bodies)
```
    Default constructor.
    
    Parameters:
    
    bodies - the list of bodies
    
    Throws:
    
    NullPointerException - when bodies is null or any element of bodies is null
    
    IllegalArgumentException - when bodies is empty
- Method Detail
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getFrequency
```
protected static final double getFrequency(double naturalFrequency)
```
    Returns the frequency given the natural frequency.
    Harmonic oscillator: f = (1 / 2π) * sqrt(k / m) Natural frequency: w = sqrt(k / m)
    Substituting w into the first equation and solving for w:
    f = (1 / 2π) * w f = w / 2π
    
    Parameters:
    
    naturalFrequency - the natural frequency
    
    Returns:
    
    double
  - getNaturalFrequency
```
protected static final double getNaturalFrequency(double frequency)
```
    Returns the natural frequency of the given frequency.
    The natural frequency can be determined by combining the following equations:
    Harmonic oscillator: f = 1 / (2π) * sqrt(k / m) Natural frequency: w = sqrt(k / m)
    Substituting w into the first equation and solving for w:
    f = 1 / (2π) * w w = f * 2π
    
    Parameters:
    
    frequency - the frequency
    
    Returns:
    
    double
    
    See Also:
    
    https://en.wikipedia.org/wiki/Hookes_law#Harmonic_oscillator
  - getNaturalFrequency
```
protected static final double getNaturalFrequency(double stiffness,
                                                  double mass)
```
    Returns the natural frequency given the spring stiffness and mass.
    Natural frequency: w = sqrt(k / m)
    
    Parameters:
    
    stiffness - the spring stiffness
    
    mass - the mass
    
    Returns:
    
    double
  - getSpringDampingCoefficient
```
protected static final double getSpringDampingCoefficient(double mass,
                                                          double naturalFrequency,
                                                          double dampingRatio)
```
    Returns the spring damping coefficient.
    The damping coefficient can be determined by the following equations:
    Damping Ratio: dr = actual damping (ad) / critical damping (cd) Critical Damping: cd = 2mw
    Where m is the mass and w is the natural frequency. Substituting cd into the first equation and solving for ad:
    dr = ad / 2mw ad = dr * 2mw
    
    Parameters:
    
    mass - the mass attached to the spring
    
    naturalFrequency - the natural frequency
    
    dampingRatio - the damping ratio
    
    Returns:
    
    double
    
    See Also:
    
    https://en.wikipedia.org/wiki/Damping_ratio
  - getSpringStiffness
```
protected static final double getSpringStiffness(double mass,
                                                 double naturalFrequency)
```
    Returns the spring stiffness, k, from Hooke's Law.
    The stiffness can be determined by the following equation and solving for k:
    Harmonic oscillator: f = 1 / (2π) * sqrt(k / m) f * 2π = sqrt(k / m) k / m = (f * 2π)² k = (f * 2π)² * m k = w² * m
    Where w is the natural frequency and m is the mass.
    
    Parameters:
    
    mass - the mass attached to the spring
    
    naturalFrequency - the natural frequency
    
    Returns:
    
    double
    
    See Also:
    
    https://en.wikipedia.org/wiki/Hookes_law#Harmonic_oscillator
  - getConstraintImpulseMixing
```
protected static final double getConstraintImpulseMixing(double deltaTime,
                                                         double stiffness,
                                                         double damping)
```
    Returns the constraint impulse mixing parameter.
    
    Parameters:
    
    deltaTime - the time step
    
    stiffness - the stiffness of the spring
    
    damping - the damping coefficient of the spring
    
    Returns:
    
    double
    
    See Also:
    
    http://www.ode.org/ode-latest-userguide.html#sec_3_8_2
  - getErrorReductionParameter
```
protected static final double getErrorReductionParameter(double deltaTime,
                                                         double stiffness,
                                                         double damping)
```
    Returns the error reduction parameter.
    
    Parameters:
    
    deltaTime - the time step
    
    stiffness - the stiffness of the spring
    
    damping - the damping coefficient of the spring
    
    Returns:
    
    double
    
    See Also:
    
    http://www.ode.org/ode-latest-userguide.html#sec_3_8_2
  - getBodies
```
public final List<T> getBodies()
```
    Description copied from interface: Joint
    
    Returns an unmodifiable list of bodies involved in this joint.
    
    Specified by:
    
    getBodies in interface Joint<T extends PhysicsBody>
    
    Returns:
    
    List<T>
  - getBodyCount
```
public int getBodyCount()
```
    Description copied from interface: Joint
    
    Returns the number of bodies involved in this joint.
    
    Specified by:
    
    getBodyCount in interface Joint<T extends PhysicsBody>
    
    Returns:
    
    int
  - getBody
```
public T getBody(int index)
```
    Description copied from interface: Joint
    
    Returns the body at the given index.
    
    Specified by:
    
    getBody in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    index - the index
    
    Returns:
    
    T
  - getBodyIterator
```
public final Iterator<T> getBodyIterator()
```
    Description copied from interface: Joint
    
    Returns an iterator for the bodies involved in this joint.
    NOTE: The iterator is read-only and will throw if methods like remove are used.
    
    Specified by:
    
    getBodyIterator in interface Joint<T extends PhysicsBody>
    
    Returns:
    
    Iterator<T>
  - isEnabled
```
public boolean isEnabled()
```
    Description copied from interface: Joint
    
    Returns true if this Joint is enabled.
    A joint is only enabled if all joined PhysicsBodys are enabled.
    
    Specified by:
    
    isEnabled in interface Joint<T extends PhysicsBody>
    
    Returns:
    
    boolean
  - isMember
```
public boolean isMember(CollisionBody<?> body)
```
    Description copied from interface: Joint
    
    Returns true if the given body is a member of this joint.
    
    Specified by:
    
    isMember in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    body - the body
    
    Returns:
    
    boolean
  - isCollisionAllowed
```
public boolean isCollisionAllowed()
```
    Description copied from interface: Joint
    
    Returns true if collision between the joined PhysicsBodys is allowed.
    
    Specified by:
    
    isCollisionAllowed in interface Joint<T extends PhysicsBody>
    
    Returns:
    
    boolean
  - setCollisionAllowed
```
public void setCollisionAllowed(boolean flag)
```
    Description copied from interface: Joint
    
    Sets whether collision is allowed between the joined PhysicsBodys.
    
    Specified by:
    
    setCollisionAllowed in interface Joint<T extends PhysicsBody>
    
    Parameters:
    
    flag - true if collisions are allowed
  - getUserData
```
public Object getUserData()
```
    Description copied from interface: DataContainer
    
    Gets the custom user data.
    
    Specified by:
    
    getUserData in interface DataContainer
    
    Returns:
    
    Object will return null if not set
  - setUserData
```
public void setUserData(Object userData)
```
    Description copied from interface: DataContainer
    
    Sets the custom user data to the given data.
    
    Specified by:
    
    setUserData in interface DataContainer
    
    Parameters:
    
    userData - the user data
  - getOwner
```
public Object getOwner()
```
    Description copied from interface: Ownable
    
    Returns the owner for this body.
    
    Specified by:
    
    getOwner in interface Ownable
    
    Returns:
    
    Object
  - setOwner
```
public void setOwner(Object owner)
```
    Description copied from interface: Ownable
    
    Sets the owner of this body.
    
    Specified by:
    
    setOwner in interface Ownable
    
    Parameters:
    
    owner - the owner

Class AbstractJoint<T extends PhysicsBody>

Field Summary

Fields inherited from interface Joint

Constructor Summary

Method Summary

Methods inherited from class Object

Methods inherited from interface Joint

Methods inherited from interface Shiftable

Field Detail

bodies

collisionAllowed

userData

owner

Constructor Detail

AbstractJoint

Method Detail

toString

getFrequency

getNaturalFrequency

getNaturalFrequency

getSpringDampingCoefficient

getSpringStiffness

getConstraintImpulseMixing

getErrorReductionParameter

getBodies

getBodyCount

getBody

getBodyIterator

isEnabled

isMember

isCollisionAllowed

setCollisionAllowed

getUserData

setUserData

getOwner

setOwner