public class Line extends Object
| 构造器 | 说明 |
|---|---|
Line(Point startPoint,
Point endPoint) |
A constructor used to create a
Line instance with specified start and end points. |
| 限定符和类型 | 方法 | 说明 |
|---|---|---|
boolean |
equals(Object object) |
Indicates whether some other object is "equal to" this one.
|
double |
getDistance() |
Obtains the distance between the start point and end point of this line.
|
Point |
getEndPoint() |
Obtains the line's end point.
|
float |
getEndPointX() |
Obtains the x-coordinate of the line's end point.
|
float |
getEndPointY() |
Obtains the y-coordinate of the line's end point.
|
Point |
getStartPoint() |
Obtains the line's start point.
|
float |
getStartPointX() |
Obtains the x-coordinate of the line's start point.
|
float |
getStartPointY() |
Obtains the y-coordinate of the line's start point.
|
int |
hashCode() |
Returns a hash code value for the object.
|
boolean |
isEmpty() |
Checks whether the distance between the start point and end point of this line is zero.
|
boolean |
isVertical(Line line) |
Checks whether a specified line and this line are vertical.
|
void |
set(float startPointX,
float startPointY,
float endPointX,
float endPointY) |
Sets the coordinates for this line's start and end points.
|
void |
set(Line line) |
Sets attributes of this line.
|
void |
set(Point startPoint,
Point endPoint) |
Sets the start and end points for this line.
|
void |
setEmpty() |
Sets the coordinates of this line's start and end points to (0, 0).
|
void |
setEndPoint(Point point) |
Sets the end point for this line.
|
void |
setEndPointX(float x) |
Sets the x-coordinate for this line's end point.
|
void |
setEndPointY(float y) |
Sets the y-coordinate for this line's end point.
|
void |
setStartPoint(Point point) |
Sets the start point for this line.
|
void |
setStartPointX(float x) |
Sets the x-coordinate for this line's start point.
|
void |
setStartPointY(float y) |
Sets the y-coordinate for this line's start point.
|
String |
toString() |
Returns a string representation of the object.
|
void |
translate(float dx,
float dy) |
Translates this line by a specified distance.
|
void |
translate(Point point) |
Translates this line, whose offsets on the x- and y- axes are specified by a
Point instance. |
public boolean isEmpty()
true if the length of this line is zero; returns false otherwise.public void set(Line line)
line - Indicates the line attributes to set.public void set(float startPointX,
float startPointY,
float endPointX,
float endPointY)
startPointX - Indicates the x-coordinate of the line's start point to set.startPointY - Indicates the y-coordinate of the line's start point to set.endPointX - Indicates the x-coordinate of the line's end point to set.endPointY - Indicates the y-coordinate of the line's end point to set.public void set(Point startPoint, Point endPoint)
startPoint - Indicates the start point to set.endPoint - Indicates the end point to set.public void setStartPointX(float x)
x - Indicates the x-coordinate to set.public void setStartPointY(float y)
y - Indicates the y-coordinate to set.public void setEndPointX(float x)
x - Indicates the x-coordinate to set.public void setEndPointY(float y)
y - Indicates the y-coordinate to set.public void setEmpty()
public double getDistance()
public Point getStartPoint()
public Point getEndPoint()
public float getStartPointX()
public float getStartPointY()
public float getEndPointX()
public float getEndPointY()
public void setStartPoint(Point point)
point - Indicates the start point to set.public void setEndPoint(Point point)
point - Indicates the end point to set.public void translate(float dx,
float dy)
dx - Indicates the offset of this line on the x-axis.dy - Indicates the offset of this line on the y-axis.public void translate(Point point)
Point instance.point - Indicates the Point instance that specifies the offsets of this line on the x- and y- axes.public int hashCode()
ObjectHashMap.
The general contract of hashCode is:
hashCode method
must consistently return the same integer, provided no information
used in equals comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode method on each of
the two objects must produce the same integer result.
Object.equals(java.lang.Object)
method, then calling the hashCode method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
hashCode 在类中 ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public boolean equals(Object object)
Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
x and y, multiple invocations of
x.equals(y) consistently return true
or consistently return false, provided no
information used in equals comparisons on the
objects is modified.
x,
x.equals(null) should return false.
The equals method for class Object implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x and
y, this method returns true if and only
if x and y refer to the same object
(x == y has the value true).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
equals 在类中 Objectobject - the reference object with which to compare.true if this object is the same as the obj
argument; false otherwise.Object.hashCode(),
HashMappublic String toString()
ObjecttoString method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
public boolean isVertical(Line line)
line - Indicates the specified line.true if two lines are vertical; returns false otherwise.