Java bounds что это

Bounded Type Parameters

There may be times when you want to restrict the types that can be used as type arguments in a parameterized type. For example, a method that operates on numbers might only want to accept instances of Number or its subclasses. This is what bounded type parameters are for.

To declare a bounded type parameter, list the type parameter’s name, followed by the extends keyword, followed by its upper bound, which in this example is Number . Note that, in this context, extends is used in a general sense to mean either «extends» (as in classes) or «implements» (as in interfaces).

public class Box  < private T t; public void set(T t) < this.t = t; >public T get() < return t; >public extends Number> void inspect(U u) < System.out.println("T: " + t.getClass().getName()); System.out.println("U: " + u.getClass().getName()); >public static void main(String[] args) < BoxintegerBox = new Box(); integerBox.set(new Integer(10)); integerBox.inspect("some text"); // error: this is still String! > >

By modifying our generic method to include this bounded type parameter, compilation will now fail, since our invocation of inspect still includes a String :

Box.java:21: inspect(U) in Box cannot be applied to (java.lang.String) integerBox.inspect("10"); ^ 1 error

In addition to limiting the types you can use to instantiate a generic type, bounded type parameters allow you to invoke methods defined in the bounds:

public class NaturalNumber  < private T n; public NaturalNumber(T n) < this.n = n; >public boolean isEven() < return n.intValue() % 2 == 0; > // . >

The isEven method invokes the intValue method defined in the Integer class through n.

Multiple Bounds

The preceding example illustrates the use of a type parameter with a single bound, but a type parameter can have multiple bounds:

A type variable with multiple bounds is a subtype of all the types listed in the bound. If one of the bounds is a class, it must be specified first. For example:

Class A < /* . */ >interface B < /* . */ >interface C < /* . */ >class D  < /* . */ >

If bound A is not specified first, you get a compile-time error:

class D  < /* . */ >// compile-time error

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Java bounds что это

All Implemented Interfaces: java.lang.Cloneable Direct Known Subclasses: BoundingBox, BoundingPolytope, BoundingSphere public abstract class Bounds extends java.lang.Object implements java.lang.Cloneable

The abstract base class for bounds objects. Bounds objects define a convex, closed volume that is used for various intersection and culling operations.

Constructor Summary

Bounds () Constructs a new Bounds object.

Method Summary
abstract java.lang.Object	clone () Makes a copy of a bounds object.
abstract Bounds	closestIntersection (Bounds[] boundsObjects) Finds closest bounding object that intersects this bounding object.
abstract void	combine (Bounds boundsObject) Combines this bounding object with a bounding object so that the resulting bounding object encloses the original bounding object and the given bounds object.
abstract void	combine (Bounds[] boundsObjects) Combines this bounding object with an array of bounding objects so that the resulting bounding object encloses the original bounding object and the given array of bounds object.
abstract void	combine (Point3d point) Combines this bounding object with a point.
abstract void	combine (Point3d[] points) Combines this bounding object with an array of points.
abstract boolean	equals (java.lang.Object bounds) Indicates whether the specified bounds object is equal to this Bounds object.
abstract int	hashCode () Returns a hash code for this Bounds object based on the data values in this object.
abstract boolean	intersect (Bounds boundsObject) Test for intersection with another bounds object.
abstract boolean	intersect (Bounds[] boundsObjects) Test for intersection with another bounds object.
abstract boolean	intersect (Point3d point) Test for intersection with a point.
abstract boolean	intersect (Point3d origin, Vector3d direction) Test for intersection with a ray.
abstract boolean	isEmpty () Tests whether the bounds is empty.
abstract void	set (Bounds boundsObject) Sets the value of this Bounds object.
abstract void	transform (Bounds bounds, Transform3D trans) Modifies the bounding object so that it bounds the volume generated by transforming the given bounding object.
abstract void	transform (Transform3D trans) Transforms this bounding object by the given matrix.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Bounds

clone

public abstract java.lang.Object clone()

Overrides: clone in class java.lang.Object

equals

public abstract boolean equals(java.lang.Object bounds)

Indicates whether the specified bounds object is equal to this Bounds object. They are equal if both the specified bounds object and this Bounds are instances of the same Bounds subclass and all of the data members of bounds are equal to the corresponding data members in this Bounds.

Overrides: equals in class java.lang.Object Parameters: bounds — the object with which the comparison is made. Returns: true if this Bounds object is equal to bounds ; otherwise false Since: Java 3D 1.2

hashCode

public abstract int hashCode()

Returns a hash code for this Bounds object based on the data values in this object. Two different Bounds objects of the same type with identical data values (i.e., Bounds.equals returns true) will return the same hash code. Two Bounds objects with different data members may return the same hash code value, although this is not likely.

Overrides: hashCode in class java.lang.Object Returns: a hash code for this Bounds object. Since: Java 3D 1.2

intersect

public abstract boolean intersect(Point3d origin, Vector3d direction)

Parameters: origin — the starting point of the ray direction — the direction of the ray Returns: true or false indicating if an intersection occured

intersect

Parameters: point — a point defining a position in 3-space Returns: true or false indicating if an intersection occured

intersect

Parameters: boundsObject — another bounds object Returns: true or false indicating if an intersection occurred

intersect

Parameters: boundsObjects — an array of bounding objects Returns: true or false indicating if an intersection occured

closestIntersection

public abstract Bounds closestIntersection(Bounds[] boundsObjects)

Parameters: boundsObjects — an array of bounds objects Returns: closest bounding object

combine

Combines this bounding object with a bounding object so that the resulting bounding object encloses the original bounding object and the given bounds object.

Parameters: boundsObject — another bounds object

combine

Combines this bounding object with an array of bounding objects so that the resulting bounding object encloses the original bounding object and the given array of bounds object.

Parameters: boundsObjects — an array of bounds objects

combine

Parameters: point — a 3d point in space

combine

Parameters: points — an array of 3d points in space

transform

Parameters: trans — the transformation matrix

transform

Modifies the bounding object so that it bounds the volume generated by transforming the given bounding object.

Parameters: bounds — the bounding object to be transformed trans — the transformation matrix

isEmpty

public abstract boolean isEmpty()

Tests whether the bounds is empty. A bounds is empty if it is null (either by construction or as the result of a null intersection) or if its volume is negative. A bounds with a volume of zero is not empty.

Returns: true if the bounds is empty; otherwise, it returns false

set

Parameters: boundsObject — another bounds object.

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Java bounds что это

The base class for objects that are used to describe the bounds of a node or other scene graph object. One interesting characteristic of a Bounds object is that it may have a negative width, height, or depth. A negative value for any of these indicates that the Bounds are «empty».

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Bounds (double minX, double minY, double minZ, double width, double height, double depth)

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Bounds

protected Bounds(double minX, double minY, double minZ, double width, double height, double depth)

Method Detail

getMinX

public final double getMinX()

getMinY

public final double getMinY()

getMinZ

public final double getMinZ()

getWidth

public final double getWidth()

getHeight

public final double getHeight()

getDepth

public final double getDepth()

getMaxX

public final double getMaxX()

getMaxY

public final double getMaxY()

getMaxZ

public final double getMaxZ()

isEmpty

public abstract boolean isEmpty()

contains

contains

contains

public abstract boolean contains(double x, double y)

contains

public abstract boolean contains(double x, double y, double z)

contains

contains

public abstract boolean contains(double x, double y, double w, double h)

contains

public abstract boolean contains(double x, double y, double z, double w, double h, double d)

intersects

intersects

public abstract boolean intersects(double x, double y, double w, double h)

intersects

public abstract boolean intersects(double x, double y, double z, double w, double h, double d)

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