/*
Line.java
Test if two line segments are intersecting or not
Line segment 1 is between endpoints (x1,y1) and (x2,y2)
Line segment 2 is between endpoints (u1,v1) and (u2,v2)
Usage: java Line x1 y1 x2 y2 u1 v1 u2 v2
> java Line
java Line 0 1 1 0 0 0 1 1
> java Line 0 1 1 0 0 0 1 1
t * 1.000000 = 0.000000 + u * 1.000000
t * -1.000000 = -1.000000 + u * 1.000000
---
t * 1.000000 = 0.000000 + u * 1.000000
t * -1.000000 = -1.000000 + u * 1.000000
---
t = nom(1.000000) / denom(2.000000) = 0.500000
u = nom(-1.000000) / denom(-2.000000) = 0.500000
true
*/
public class Line
{
// line1: 0 <= t <= 1
// x = ax1 + t * (ax2 - ax1)
// y = ay1 + t * (ay2 - ay1)
// line2: 0 <= u <= 1
// x = bx1 + u * (bx2 - bx1)
// y = by1 + u * (by2 - by1)
// returns true if two lines intersect; and false otherwise
public static boolean isTwoLinesIntersecting(
double ax1, double ay1, double ax2, double ay2,
double bx1, double by1, double bx2, double by2)
{
double nom, denom;
double ax21 = ax2 - ax1;
double bax1 = bx1 - ax1;
double bx21 = bx2 - bx1;
double ay21 = ay2 - ay1;
double bay1 = by1 - ay1;
double by21 = by2 - by1;
// t * (ax2 - ax1) = (bx1 - ax1) + u * (bx2 - bx1)
// t * (ay2 - ay1) = (by1 - ay1) + u * (by2 - by1)
System.out.printf(" t * %f = %f + u * %f\n", ax21, bax1, bx21);
System.out.printf(" t * %f = %f + u * %f\n", ay21, bay1, by21);
System.out.printf(" ---\n");
// ==>
// t * (ax2 - ax1) * (by2 - by1) = (bx1 - ax1) * (by2 - by1) + u * (bx2 - bx1) * (by2 - by1)
// t * (ay2 - ay1) * (bx2 - bx1) = (by1 - ay1) * (bx2 - bx1) + u * (by2 - by1) * (bx2 - bx1)
System.out.printf(" t * %f = %f + u * %f\n", ax21*by21, bax1*by21, bx21*by21);
System.out.printf(" t * %f = %f + u * %f\n", ay21*bx21, bay1*bx21, by21*bx21);
System.out.printf(" ---\n");
// ==>
// t = (bx1 - ax1) * (by2 - by1) - (by1 - ay1) * (bx2 - bx1)
// / [ (ax2 - ax1) * (by2 - by1) - (ay2 - ay1) * (bx2 - bx1)]
// u = (ax1 - bx1) * (ay2 - ay1) - (ay1 - by1) * (ax2 - ax1)
// / [ (bx2 - bx1) * (ay2 - ay1) - (by2 - by1) * (ax2 - ax1)]
nom = (bx1 - ax1) * (by2 - by1) - (by1 - ay1) * (bx2 - bx1);
denom = (ax2 - ax1) * (by2 - by1) - (ay2 - ay1) * (bx2 - bx1);
double t = nom / denom;
System.out.printf(" t = nom(%f) / denom(%f) = %f\n", nom, denom, t);
nom = (ax1 - bx1) * (ay2 - ay1) - (ay1 - by1) * (ax2 - ax1);
denom = (bx2 - bx1) * (ay2 - ay1) - (by2 - by1) * (ax2 - ax1);
double u = nom / denom;
System.out.printf(" u = nom(%f) / denom(%f) = %f\n", nom, denom, u);
if(t>=0 && t <=1 && u>=0 && u<=1) return true;
else return false;
}
public static void main(String[] args)
{
if(args.length != 8)
{
System.out.println("java line 0 1 1 0 0 0 1 1");
System.exit(0);
}
double ax1 = Double.parseDouble(args[0]);
double ay1 = Double.parseDouble(args[1]);
double ax2 = Double.parseDouble(args[2]);
double ay2 = Double.parseDouble(args[3]);
double bx1 = Double.parseDouble(args[4]);
double by1 = Double.parseDouble(args[5]);
double bx2 = Double.parseDouble(args[6]);
double by2 = Double.parseDouble(args[7]);
System.out.println(Line.isTwoLinesIntersecting(
ax1,ay1,ax2,ay2,bx1,by1,bx2,by2));
}
}
code for testing if two line segments are intersecting
dictionary appendix to MMSEG
appendix to the mmseg Chinese word segmentation tool
http://sites.google.com/site/sekewei/home/download/dictionary.zip
---
readme.txt
filelist:
getdic.c source to retrieve dictionary in use
getdic.exe binary to retrieve dictionary in use
gcc -o getdic -I../src getdic.c ../src/lexicon.c
mmsegmnt.c source to segment a chunk in simple mode
getchunk.c source to get a chunk for segmenting
mmseg.exe binary to segment words
gcc -o mmseg -I. mmseg.c search.c
segment.c b5char.c iofiles.c
lexicon.c message.c
..\dictionary\getchunk.c
..\dictionary\mmsegmnt.c
mmseg inp.txt out.txt ../lexicon/ complex verbose
usage: mmseg in out lexicon [complex|simple*] [verbose|standard|quiet*]
default options are simple and quiet
mklex1.c source to build dictionary tables CHR?.TXT
mklex1.exe binary to build dictionary tables CHR?.TXT
gcc -o mklex1 -I. ..\dictionary\mklex1.c
mklex1 TSAIWORD.TXT
mklex2.c source to build dictionary tables CHR?.LEX
mklex2.exe binary to build dictionary tables CHR?.LEX
gcc -o mklex2 -I. ..\dictionary\mklex2.c
mklex2 .
mklex3.c source to build dictionary tables CHR?.INX
mklex3.exe binary to build dictionary tables CHR?.INX
gcc -o mklex3 -I. ..\dictionary\mklex3.c
mklex3 .
mmsegwords_raw.txt retrieved dictionary in use (137546 items)
mmsegwords.txt revised dictionary (137555 items)
mmsegwords_sort.txt revised dictionary sorted (137555 items)
TSAIWORD.TXT separate sorted dictionary by Tsai (137425 items)
diff.txt difference between mmsegwords_sort.txt
and TSAIWORD.TXT
interface finder
/*
* @(#)InterfaceFinder.java v0.8, 2009/05/06-2020/2/8
*
* Search the class path for classes which implement a specific interface
*
* Usage: java -cp jar_file;class_folder;. InterfaceFinder interface_name_to_search
*/
import java.util.Enumeration;
import java.util.List;
import java.util.Vector;
import java.util.Stack;
import java.util.HashSet;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
/**
The interface finder is used to find all classes
implementing a specific interface.
The location in search includes all the subdirectories
in the class path. Typical usage is as follows.
List<Class> InterfaceFinder.getAvailableInterfaces("java.util.List");
* @since 0.8
* @version 0.8, 2009/05/06-2020/2/8
* @author Seke Wei
*/
public class InterfaceFinder
{
public static final String version="InterfaceFinder.java v0.8 2020/02/08";
/**
a file lister which uses the depth first strategy
to traverse all files under a given directory.
*/
public static class FileLister implements Enumeration
{
boolean hasMore;
Stack<File> fstack;
/**
constructor for file lister.
@param dir the root directory for search.
*/
public FileLister(File dir)
{
fstack = new Stack<>();
if(dir.isDirectory())
fstack.push(dir);
hasMore = true;
}
/**
check if there is still file available for listing.
@return true for elements available and false for otherwise.
*/
public boolean hasMoreElements()
{
return hasMore;
}
/**
get the next available file.
directories are skipped.
@return the file.
*/
public File nextElement()
{
File next = null;
while(fstack.empty()==false)
{
next = (File) fstack.pop();
if(next.isFile())
break;
for(File f : next.listFiles())
fstack.push(f);
}
if(fstack.empty()) hasMore=false;
return next;
}
}
/**
get classes from a jar file which implements an interface.
@param jarFileName the jar filename.
@param iface the interface in search.
@return the set of classes in jar implementing the interface.
*/
public static List<Class> getClassesFromJARFile(String jarFileName, Class iface)
{
final List<Class> classes = new Vector<>();
JarInputStream jarFile = null;
String className = "";
try
{
jarFile = new JarInputStream(new FileInputStream(jarFileName));
JarEntry jarEntry;
while(true)
{
jarEntry = jarFile.getNextJarEntry();
if(jarEntry == null) break;
className = jarEntry.toString();
//System.err.println(className);
if(className.endsWith(".class") && className.indexOf("$") < 0 )
{
//extractClassFromJar(jar, packageName, classes, jarEntry)
className = className.replace('/','.');
className = className.substring(0, className.length() - ".class".length());
Class cl = Class.forName(className);
if(iface.isAssignableFrom(cl))
{
//System.err.println("\t"+className+" can be assigned to "+iface);
classes.add(cl);
}
}
}
jarFile.close();
}
catch (IOException ioe)
{
System.err.println("Unable to get Jar input stream from '"+jarFileName+"'"+ioe);
}
catch (ClassNotFoundException cnfe)
{
System.err.println("unable to find class named " + className.replace('/', '.') + "' within jar '" + jarFileName + "'"+cnfe);
}
return classes;
}
/**
get classes from a root directory which implements an interface.
@param dir the root directory.
@param iface the interface in search.
@return the set of classes in jar implementing the interface.
@throws IOException when there is a file open error.
*/
public static List<Class> getClassesFromDirectory(File dir, Class iface)
{
List<Class> classes = new Vector<>();
FileLister lister = new FileLister(dir);
while(lister.hasMoreElements())
{
File f = lister.nextElement();
String className = f.toString();
//System.err.println(className);
if(className.endsWith(".class") && className.indexOf("$") < 0 )
{
className = className.replace(File.separatorChar,'.');
className = className.substring(0, className.length() - ".class".length());
while(className.charAt(0)=='.') className = className.substring(1);
//System.err.println("\t"+className);
try
{
Class cl = Class.forName(className);
if(iface.isAssignableFrom(cl))
{
//System.err.println("\t"+className+" can be assigned to "+iface);
classes.add(cl);
}
}
catch(ClassNotFoundException cnfe)
{}
}
}
return classes;
}
/**
get classes from the class path which implements an interface.
@param iface the interface in search.
@return the set of classes in jar implementing the interface.
*/
public static List<Class> getAvailableClassesOfInterface(String iface)
{
List<Class> result = null;
try
{
Class iface_class = Class.forName(iface);
result = getAvailableClassesOfInterface(iface_class);
}
catch(ClassNotFoundException cnfe) {}
return result;
}
/**
get classes from the class path which implements an interface.
@param iface the interface in search.
@return the set of classes in jar implementing the interface.
*/
public static List<Class> getAvailableClassesOfInterface(Class iface)
{
String cp = System.getProperty("java.class.path");
//System.out.println("java.class.path = " + cp);
List<Class> result = new Vector<>();
// semicolon (Windows) or colon (Unix) by System.getProperty("path.separator")
String separator = System.getProperty("path.separator");
for(String p : cp.split(separator))
{
File f = new File(p);
if(f.isDirectory())
result.addAll(getClassesFromDirectory(f, iface));
else if(f.isFile() && p.endsWith("jar"))
result.addAll(getClassesFromJARFile(p, iface));
}
HashSet<Class> set = new HashSet<>(result);
result.clear();
for(Class c : set)
{
//System.err.println(c);
result.add(c);
}
return result;
}
/**
InterfaceFinder.java
Search the class path for classes which implement a specific interface
Usage: java -cp jar_file;class_folder;. InterfaceFinder interface_name_to_search
Example:
> javac InterfaceFinder.java
> java -cp rt.jar;. InterfaceFinder java.util.List
class javax.management.relation.RoleUnresolvedList
class java.util.AbstractList
class java.util.SubList
class java.util.concurrent.CopyOnWriteArrayList
class javax.management.AttributeList
class java.util.AbstractSequentialList
class java.util.RandomAccessSubList
class java.util.ArrayList
class java.util.Vector
class java.util.Stack
class java.util.LinkedList
class javax.management.relation.RoleList
interface java.util.List
Note that since JDK 9 there is no rt.jar for testing
*/
public static void main(String args[])
{
String iface = "java.util.List";
if(args.length > 0)
iface = args[0];
List<Class> classes =
getAvailableClassesOfInterface(iface);
for(Class c : classes)
{
System.err.println(c);
}
}
}
computer speed of arithmetic operations
/**
根據speed.java四則運算時間測試結果,
整數乘/除餘運算時間約是整數加減運算時間的5/10倍以上
實數部份比較特別,乘和加減時間幾乎一樣,除法為加減法近200倍,求餘數為加減法近10倍以上.
C:\java>java speed ia is im id ip la ls lm ld lp fa fs fm fd fp da ds dm dd dp
The ia time is 438 ms, or 4.38000e-06 ms per ia
The is time is 422 ms, or 4.22000e-06 ms per is
The im time is 1906 ms, or 1.90600e-05 ms per im
The id time is 4938 ms, or 4.93800e-05 ms per id
The ip time is 5546 ms, or 5.54600e-05 ms per ip
The la time is 453 ms, or 4.53000e-06 ms per la
The ls time is 453 ms, or 4.53000e-06 ms per ls
The lm time is 2438 ms, or 2.43800e-05 ms per lm
The ld time is 7750 ms, or 7.75000e-05 ms per ld
The lp time is 7391 ms, or 7.39100e-05 ms per lp
The fa time is 328 ms, or 3.28000e-06 ms per fa
The fs time is 329 ms, or 3.29000e-06 ms per fs
The fm time is 328 ms, or 3.28000e-06 ms per fm
The fd time is 57422 ms, or 0.000574220 ms per fd
The fp time is 4860 ms, or 4.86000e-05 ms per fp
The da time is 328 ms, or 3.28000e-06 ms per da
The ds time is 328 ms, or 3.28000e-06 ms per ds
The dm time is 328 ms, or 3.28000e-06 ms per dm
The dd time is 66000 ms, or 0.000660000 ms per dd
The dp time is 4953 ms, or 4.95300e-05 ms per dp
*/
public class speed
{
public static long operation(String op, long loop)
{
int i=500, i2=100, i1=50;
long l=5000,l2=1000, l1=500;
float f=1e3f, f2=1.01f, f1=2e3f;
double d=1e6, d2=1.01, d1=2e2;
long k;
//int loop=(int) 1e6;
long start = System.currentTimeMillis();
if(op.equals("ia")) for(k=1; k<=loop; k++) i=i+i2;
else if(op.equals("is")) for(k=1; k<=loop; k++) i=i-i2;
else if(op.equals("im")) for(k=1; k<=loop; k++) i=i*i2;
else if(op.equals("id")) for(k=1; k<=loop; k++) i=i/i2;
else if(op.equals("ip")) for(k=1; k<=loop; k++) i=i%i2;
else if(op.equals("la")) for(k=1; k<=loop; k++) l=l+l2;
else if(op.equals("ls")) for(k=1; k<=loop; k++) l=l-l2;
else if(op.equals("lm")) for(k=1; k<=loop; k++) l=l*l2;
else if(op.equals("ld")) for(k=1; k<=loop; k++) l=l/l2;
else if(op.equals("lp")) for(k=1; k<=loop; k++) l=l%l2;
else if(op.equals("fa")) for(k=1; k<=loop; k++) f=f+f2;
else if(op.equals("fs")) for(k=1; k<=loop; k++) f=f-f2;
else if(op.equals("fm")) for(k=1; k<=loop; k++) f=f*f2;
else if(op.equals("fd")) for(k=1; k<=loop; k++) f=f/f2;
else if(op.equals("fp")) for(k=1; k<=loop; k++) f=f%f2;
else if(op.equals("da")) for(k=1; k<=loop; k++) d=d+d2;
else if(op.equals("ds")) for(k=1; k<=loop; k++) d=d-d2;
else if(op.equals("dm")) for(k=1; k<=loop; k++) d=d*d2;
else if(op.equals("dd")) for(k=1; k<=loop; k++) d=d/d2;
else if(op.equals("dp")) for(k=1; k<=loop; k++) d=d%d2;
long end = System.currentTimeMillis();
long time = end - start;
return time;
}
public static void main(String args[])
{
if(args.length==0)
{
System.err.println("java speed [i|l|f|d][a|s|m|d|p]");
System.exit(0);
}
for(int a=0; a < args.length; a++)
{
String op = args[a];
long loop = (long) 1e8;
long time = operation(op,loop);
System.err.printf("The %s time is %d ms, or %g ms per %s\n",
op, time, (float) time / loop, op);
}
}
}
scanner.next and nextLine
一般用掃瞄器物件(Scanner)時,若依下法, 在讀數字後,再讀文字,會有讀不到文字情況,Scanner sc = new Scanner(System.in); int i = sc.nextInt(); // 讀數字,換行字元未讀走 String s = sc.nextLine(); // 讀換行前字串,會收到空字串這時,建議改用如下寫法,Scanner sc = new Scanner(System.in); int i = sc.nextInt(); // 讀數字,換行字元未讀走 String s = sc.nextLine(); // 故意用nextLine讀走下一換行前字串及換行字元 String s = sc.nextLine(); // 再用nextLine重新讀下一換行前字串及換行字元或Scanner sc = new Scanner(System.in); int i = sc.nextInt(); // 讀數字,換行字元未讀走 String s = sc.next(); // 讀下一個空格隔開前文字,這樣非空格文字仍可讀到如下測試範例 Test2.java 可自行試看看. ---- Test2.java -----------/* Test2.java >javac Test2.java >java Test2 input i=123 input s= input s2=456 i=123, s=, s2=456, end */ import java.util.*; public class Test2 { public static void main(String[] arg) { Scanner sc = new Scanner(System.in); System.err.printf("input i="); int i = sc.nextInt(); System.err.printf("input s="); String s = sc.nextLine(); // 前面有讀數字,後面文字會讀不到,只收到空字串 System.err.printf("\ninput s2="); String s2 = sc.nextLine(); System.err.printf("i=%d, s=%s, s2=%s, end\n",i,s, s2); } }
summary of time complexity for common data structures
常見資料結構之平均時間複雜度
=======================
運算之平均時間複雜度 新增 刪除 查詢
--限特定位置增刪查詢之線性容器--
陣列堆疊(尾入尾出) O(1) O(1) O(1)
鏈結堆疊(頭入頭出) O(1) O(1) O(1)
陣列佇列(環狀尾入頭出) O(1) O(1) O(1)
鏈結佇列(尾入頭出) O(1) O(1) O(1)
陣列雙邊佇列(環狀頭尾出入) O(1) O(1) O(1)
鏈結雙邊佇列(雙向頭尾出入) O(1) O(1) O(1)
--線性容器--
無序陣列清單 O(1) O(n) O(n)
無序鏈結清單 O(1) O(n) O(n)
有序陣列清單 O(n) O(n) O(log(n))
有序鏈結清單 O(n) O(n) O(n)
雜湊表 O(1) O(1) O(1)
--非線性容器--
二分搜索樹 O(log(n)) O(log(n)) O(log(n))
跳躍鏈結清單 O(log(n)) O(log(n)) O(log(n))
堆積(限頭才能刪除,查詢) O(log(n)) O(log(n)) O(1)
參考:
1.carrano-pie-05-data abstraction & problem solving with java
2.weiss-pie-04-data structures & problem solving using java
3.budd-awl-00-classic data structures in java
java container (jdk1.5)
java容器(since jdk1.5版) Version 0.2b, 2006/10/26
==================
各容器介面摘要(功能定義):
Collection 收藏: 放個別物件, 可重複放,無位置概念,無排序
Queue 佇列: 放個別物件, 可重複放,頭位置概念,部份排序
List 清單: 放個別物件, 可重複放,任意位置 ,無排序
Set 集合: 放個別物件,不可重複放,無位置概念,無排序
SortedSet 有序集合: 放個別物件,不可重複放,有頭尾概念,有排序
Map 映射: 放成對物件,不可重複放,無位置概念,無排序
SortedMap 有序映射: 放成對物件,不可重複放,有頭尾概念,有排序
各容器類別摘要(實作各介面的實體類別):
Collection: Vector,Stack,ArrayList,ArrayBlockingQueue,
LinkedList,PriorityQueue,HashSet,TreeSet
Queue: ArrayBlockingQueue,LinkedList,PriorityQueue
List: Vector,Stack,ArrayList,LinkedList
Set: HashSet,TreeSet
SortedSet: TreeSet
Map: HashMap,TreeMap,HashTable,Properties
SortedMap: TreeMap
--
Vector 向量,Stack 堆疊,ArrayList 陣列清單,LinkedList 鏈結清單,
ArrayBlockingQueue 陣列等候佇列,PriorityQueue 順位佇列,
HashSet 雜湊集合,TreeSet 樹狀集合,
HashMap 雜湊映射,TreeMap 樹狀映射,
HashTable 雜湊表,Properties 屬性表
容器演算法:
Collections.binarySearch/min/max/indexOfSublist/lastIndexOfSublist,
fill/copy/swap/shuffle/sort/reverse/rotate,
list/nCopies/enumeration/reverseOrder,
singleton/singletonList/singletonMap,
synchronizedCollection/synchronizedSet/synchronizedList,
synchronizedMap/synchronizedSortedSet/synchronizedSortedMap,
unmodifiableCollection/unmodifiableSet/unmodifiableList,
unmodifiableMap/unmodifiableSortedSet/unmodifiableSortedMap,
Arrays.asList/binarySearch/equals/fill/sort,
容器一般性功能須求:
新增容器,刪除容器,查詢容器元素個數,列舉容器元素,
新增元素,刪除元素,修改元素,查詢元素,擷取元素
各容器類別提供的方法:
Vector >AbstractList >AbstractCollection, 存取有同步,有元素概念,容量無限
*add/addElement/insertElementAt/addAll,
*remove/removeElement/removeElementAt,
clear/removeAllElements/removeAll/retainAll/removeRange,
*get/set/firstElement/lastElement/elementAt/setElementAt,
*indexOf/lastIndexOf,
subList/toArray/copyInto,
isEmpty/contains/containsAll/equals/hasCode,
*size/setSize/trimToSize/capacity/ensureCapacity,
toString/clone,
--
iterator/listIterartor
Stack >Vector >AbstractList >AbstractCollection, 存取有同步
*empty/push/peek/pop/search,
--
add/addElement/insertElementAt/addAll,
remove/removeElement/removeElementAt,
clear/removeAllElements/removeAll/retainAll/removeRange,
get/set/firstElement/lastElement/elementAt/setElementAt,
indexOf/lastIndexOf,
subList/toArray/copyInto,
isEmpty/equals/contains/containsAll/hasCode,
size/setSize/trimToSize/capacity/ensureCapacity,
toString/clone,
--
iterator/listIterartor
ArrayList >AbstractList >AbstractCollection, 存取無同步,容量無限
*add/addAll,
*remove/removeRange/clear,
*get/set,
*indexOf/lastIndexOf,
*isEmpty/contains,
size/trimToSize/ensureCapacity,
clone/toArray,
--
iterator/listIterartor/equals/hasCode,
--
containsAll/removeAll/retainAll/toString
ArrayBlockingQueue >AbstractQueue >AbstractCollection 存取有同步,容量有限制
clear/contains/drainTo/iterator/
offer/peek/poll/put/remove/take
remainingCapacity/size/
toArray/toString
--
add/addAll/element/remove
--
containsAll/isEmpty/removeAll/retainAll
PriorityQueue >AbstractQueue >AbstractCollection 存取無同步,容量無限
add/clear/offer/peek/poll/remove
comparator/iterator/size
--
addAll/element/remove
--
contains/containsAll/isEmpty/removeAll/retainAll
toArray/toString
LinkedList >AbstractSequentialList >AbstractList
>AbstractCollection, 存取無同步,有頭尾概念,容量無限
*add/addAll/addFirst/addLast,
*remove/removeFirst/removeLast/clear,
*get/set/getFirst/getLast,
*contains/indexOf/lastIndexOf,
size/listIterator/clone/toArray,
--
iterator
--
equals/hashCode/removeRange/subList
containsAll/isEmpty/removeAll/retainAll/toString
HashSet >AbstractSet >AbstractCollection, 存取無同步,無順序概念
*add/remove/clear,
*contains/isEmpty/size,
*iterator/clone,
--
equals/hashCode/removeAll
--
addAll/containsAll/retainAll/toArray/toString
TreeSet >AbstractSet >AbstractCollection, 存取無同步,有順序概念
*add/addAll/remove/clear,
*contains/isEmpty/size,
*iterator/clone/comparator,
*first/last,
*headSet/tailSet/subSet,
--
equals/hashCode/removeAll
--
containsAll/retainAll/toArray/toString
HashMap >AbstractMap, 存取無同步,存放成對物件,無順序概念
*get/put/putAll/remove/clear,
*isEmpty/containsKey/containsValue,
values/keySet/entrySet,
size/clone
--
equals/hashCode/toString
TreeMap >AbstractMap, 存取無同步,存放成對物件,有順序概念
*get/put/putAll/remove/clear,
*containsKey/containsValue,
*headMap,tailMap,subMap,
values/keySet/entrySet,
firstKey/lastKey,
size/clone/comparator,
--
equals/hashCode/isEmpty/toString
HashTable >Dictionaries, 存取有同步,存放成對鍵值組
*get/put/putAll/remove/clear,
*isEmpty/containsKey/containsValue/contains,
keys/elements/values/keySet/entrySet,
size/clone/equals/hasCode/rehash/toString
--
get/put/remove,
elements/keys,
size/isEmpty,
Properties >HashTable >Dictionaries, 存取有同步,存放屬性鍵值組
*getProperty/setProperty,
*load/store/list,
*propertyNames,
--
*get/put/putAll/remove/clear,
*isEmpty/containsKey/containsValue/contains,
keys/elements/values/keySet/entrySet,
size/clone/equals/hasCode/rehash/toString
各容器介面提供的方法:
Collection
add/allAll/remove/removeAll/retainAll/clear,
isEmpty/contains/containsAll/equals/hasCode/size,
iterator/toArray,
Queue >Collection 多了頭位置概念
offer/
poll/remove/
peek/element/
--
add/allAll/remove/removeAll/retainAll/clear,
isEmpty/contains/containsAll/equals/hasCode/size,
iterator/toArray,
List >Collection 多了任意位置概念
add/allAll/remove,
get/set,
indexOf/lastIndexOf,
listIterator/subList,
--
add/allAll/remove/removeAll/retainAll/clear,
isEmpty/contains/containsAll/equals/hasCode/size,
iterator/toArray,
Set >Collection 多了不重複存放概念
add/allAll/remove/removeAll/retainAll/clear,
isEmpty/contains/containsAll/equals/hasCode/size,
iterator/toArray,
SortedSet >Set >Collection 多了順序概念
first/last,
headSet/tailSet/subSet,
comparator,
--
add/allAll/remove/removeAll/retainAll/clear,
isEmpty/contains/containsAll/equals/hasCode/size,
iterator/toArray,
Map
get/put/putAll/remove/clear,
isEmpty/containsKey/containsValue,
values/keySet/entrySet,
size/equals/hasCode,
SortedMap >Map
firstKey/lastKey,
headMap/tailMap/subMap,
comparator,
--
get/put/putAll/remove/clear,
isEmpty/containsKey/containsValue,
values/keySet/entrySet,
size/equals/hasCode,
迭代列舉介面提供的方法:
Enumeration 列舉介面,不能刪除列舉物件,只能往後列舉
hasMoreElements/nextElement,
Iterator 迭代介面,可刪除列舉物件,只能往後列舉
hasNext/next/remove,
ListIterator 清單迭代介面,可往前後列舉,及增刪改物件
add/set/remove,
hasNext/hasPrevious,
next/previous,
nextIndex,previousIndex,
可比較及比較器介面提供的方法:
java.lang.Comparable 可比較介面
compareTo
java.util.Comparator 比較器介面
compare/equals
method and call stack
程式呼叫方法(method)步驟:
1.進入方法前,先壓入返回位址(return address)到堆疊(call stack)
2.進入方法後,利用堆疊配置區域變數(local variable)空間
3.依序拷貝引數列(argument list)數值到參數列(parameter list)變數
4.開始執行方法內指令,直到遇到return指令或方法結束大括號}
5.離開方法前,釋放堆疊的區域變數空間
6.從堆疊彈出返回位址,從返回位址繼續執行指令
1.進入方法前,先壓入返回位址(return address)到堆疊(call stack)
2.進入方法後,利用堆疊配置區域變數(local variable)空間
3.依序拷貝引數列(argument list)數值到參數列(parameter list)變數
4.開始執行方法內指令,直到遇到return指令或方法結束大括號}
5.離開方法前,釋放堆疊的區域變數空間
6.從堆疊彈出返回位址,從返回位址繼續執行指令
methods for creating a self-contained .jar with data file
Given Main.java, data1.dat, data2.dat,
methods for creating a self-contained .jar with data file
0.use getResourceAsStream to get jar data at package root
InputStream is = Main.class.getResourceAsStream("/"+dataName);
1.add to all *.java source
package my.package;
2.compile with package start location
java -d . *.java
3.vi manifest.txt
#Class-Path: my.package
Main-Class: my.package.Main
4.produce jar file with data files
jar cvfm mypackage.jar manifest.txt my data1.dat data2.dat
5.run by
java -jar mypackage.jar
java -cp mypackage.jar my.package.Main
lowly and highly motivated
Keep lowly motivated to see how subtly things can go by themselves;
Keep highly motivated to see how far you can go by yourself.
常無欲以觀其妙;
常有欲以觀其徼.
參考:
1.http://www.shunto.org.hk/DaoDeiJinS/DaoDeiJin003.htm
「徼」有邊界、巡守之意:
Keep highly motivated to see how far you can go by yourself.
常無欲以觀其妙;
常有欲以觀其徼.
參考:
1.http://www.shunto.org.hk/DaoDeiJinS/DaoDeiJin003.htm
「徼」有邊界、巡守之意:
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