During the
boot process, file systems listed in
/etc/fstab are automatically mounted (unless they are listed with
the
noauto option).
device /mount-point fstype options dumpfreq passno
- device
-
A device name (which should exist), as explained in Section 18.2.
- mount-point
-
A directory (which should exist), on which to mount the file system.
- fstype
-
The file system type to pass to mount(8). The default
FreeBSD file system is ufs.
- options
-
Either rw for read-write file systems, or ro for read-only file systems, followed by any other options that
may be needed. A common option is noauto for file systems not
normally mounted during the boot sequence. Other options are listed in the mount(8) manual
page.
- dumpfreq
-
This is used by dump(8) to determine
which file systems require dumping. If the field is missing, a value of zero is
assumed.
- passno
-
This determines the order in which file systems should be checked. File systems that
should be skipped should have their passno set to zero. The root
file system (which needs to be checked before everything else) should have its passno set to one, and other file systems' passno should be set to values greater than one. If more than one
file systems have the same passno then fsck(8) will attempt
to check file systems in parallel if possible.
Consult the fstab(5) manual page
for more information on the format of the /etc/fstab file and
the options it contains.
The mount(8) command is
what is ultimately used to mount file systems.
In its most basic form, you use:
There are plenty of options, as mentioned in the mount(8) manual page,
but the most common are:
Mount Options
-a-
Mount all the file systems listed in /etc/fstab. Except
those marked as “noauto”, excluded by the -t
flag, or those that are already mounted.
-d-
Do everything except for the actual mount system call. This option is useful in
conjunction with the -v flag to determine what mount(8) is actually
trying to do.
-f-
Force the mount of an unclean file system (dangerous), or forces the revocation of
write access when downgrading a file system's mount status from read-write to
read-only.
-r-
Mount the file system read-only. This is identical to using the ro (rdonly for FreeBSD versions older
than 5.2) argument to the -o option.
-t fstype-
Mount the given file system as the given file system type, or mount only file systems
of the given type, if given the -a option.
“ufs” is the default file system type.
-u-
Update mount options on the file system.
-v-
Be verbose.
-w-
Mount the file system read-write.
The -o option takes a comma-separated list of the options,
including the following:
- noexec
-
Do not allow execution of binaries on this file system. This is also a useful security
option.
- nosuid
-
Do not interpret setuid or setgid flags on the file system. This is also a useful
security option.
delete everything except the config.ini under the folder /eclipse/configuration, and then start eclipse to load the new installed plugins.
If Java runs out of memory, the following error occurs:
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
This can have two reasons:
- Your Java application has a memory leak. There are tools like YourKit Java Profiler that help you to identify such leaks.
- Your Java application really needs a lot of memory (more than 128
MB by default!). In this case the Java heap size can be increased using
the following runtime parameters:
java -Xms<initial heap size> -Xmx<maximum heap size>
Defaults are:
java -Xms32m -Xmx128m
You can set this either in the Java Control Panel or on the command line, depending on the environment you run your application.
======Current Editor===============================================================
IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
// must from the UI Thread, else get the null.
IWorkbenchPage page = window.getActivePage();
IEditorPart editor = page.getActiveEditor();
======Current Property==========================================================
1. Common Way:
IViewReference[] viewRefs = Ub900Plugin.getPlugin().getWorkbench()
.getActiveWorkbenchWindow().getActivePage().getViewReferences();
for (int i = 0; i < viewRefs.length; i++) {
if (viewRefs[i].getId()
.equals("org.eclipse.ui.views.PropertySheet")) {
PropertySheet sheet = (PropertySheet) viewRefs[i]
.getPart(false);
((PropertySheetPage) sheet.getCurrentPage()).refresh();
}
}
2. EMF Property Sheet:
Editor.getPropertySheetPage();
The EMF ResourceSet is located in the EdtingDomain of Editor
The JAVA field (which is located in the Object in the heap) is default initialized as 0, false, and null.
A a = new A(); // equal
A a; // a is pointer/ref in the stack. (In stack the integer value take the random value)
a = new A(); // new A() is the Object in the heap. (In heap the integer value will be initialized as 0)
Composition: b's lifetime is up to its context (object of A).
==C++==
class A{
B b;
}
==java==
class A{
B b;
public A(){
b = new B();
}
}
Aggregation: b can live without its context (object of A).
============================================
==C++==
class B{
B* b;
}
==java==
class B{
B b;
public A(B b){
this.b = b;
}
}
The situation where an application simply wants to share data without the need
for a generated type-safe API. The reflective EMF API is sometimes all one
really needs.
EMF provides a dynamic implementation of the reflective API
(that is, the EObject interface) which, although slower than the one
provided by the generated classes, implements the exact same behavior. If you
don't need a type-safe API, then the only advantage of generating Java classes,
as opposed to simply using the dynamic implementation, is that they use less
memory and provide faster access to the data. The down-side is that the
generated classes have to be maintained as the model evolves, and they have to
be deployed along with the application. This is the normal trade-off between
dynamic and static implementations.
Dynamic:
================create dynamic models (types)=========================
EcoreFactory ecoreFactory = EcoreFactory.eINSTANCE;
EcorePackage ecorePackage = EcorePackage.eINSTANCE;
EClass employeeClass = ecoreFactory.createEClass();
employeeClass.setName("Employee");
EAttribute employeeName = ecoreFactory.createEAttribute();
employeeName.setName("name");
employeeName.setEType(ecorePackage.getEString());
employeeClass.getEAttributes().add(employeeName);
EAttribute employeeManager = ecoreFactory.createEAttribute();
employeeManager.setName("manager");
employeeManager.setEType(ecorePackage.getEBoolean());
employeeClass.getEAttributes().add(employeeManager);
EClass departmentClass = ecoreFactory.createEClass();
departmentClass.setName("Department");
EAttribute departmentName = ecoreFactory.createEAttribute();
departmentName.setName("name");
departmentName.setEType(ecorePackage.getEString());
departmentClass.getEAttributes().add(departmentName);
EAttribute departmentNumber = ecoreFactory.createEAttribute();
departmentNumber.setName("number");
departmentNumber.setEType(ecorePackage.getEInt());
departmentClass.getEAttributes().add(departmentNumber);
EReference departmentEmployees = ecoreFactory.createEReference();
departmentEmployees.setName("employees");
departmentEmployees.setEType(employeeClass);
departmentEmployees.setUpperBound(
EStructuralFeature.UNBOUNDED_MULTIPLICITY);
departmentEmployees.setContainment(true);
departmentClass.getEReferences().add(departmentEmployees);
EPackage companyPackage = ecoreFactory.createEPackage();
companyPackage.setName("company");
companyPackage.setNsPrefix("company");
companyPackage.setNsURI("http:///com.example.company.ecore");
companyPackage.getEClassifiers().add(employeeClass);
companyPackage.getEClassifiers().add(departmentClass);
=====================create objects==============================
EFactory companyFactory = companyPackage.getEFactoryInstance();
EObject employee1 = companyFactory.create(employeeClass);
employee1.eSet(employeeName, "John");
EObject employee2 = companyFactory.create(employeeClass);
employee2.eSet(employeeName, "Katherine");
employee2.eSet(employeeManager, Boolean.TRUE);
EObject department = companyFactory.create(departmentClass);
department.eSet(departmentName, "ABC");
department.eSet(departmentNumber, new Integer(123));
((List)department.eGet(departmentEmployees)).add(employee1);
((List)department.eGet(departmentEmployees)).add(employee2);
Purpose: use the Instances of the class java.lang.Class to represent classes and interfaces in a running Java application.
1. create Object:
A a = (A)Class.forName("A").newInstance(); //If A isn't a correct Class Name, it's a Runtime-Exception "ClassForName", comparing to the Compile-Exception from "new A()"
2. get Attributes/Methods information at Runtime:
Class c = Class.forName(args[0]);
Method m[] = c.getDeclaredMethods();
摘要: 在Eclipse中使用IAdaptable接口的方式有兩種
1：某個類希望提供新的接口，但又不希望將其暴露在API中，在這種情況下，IAdaptable接口中的方法getAdaptor()方法將由本類實現。（希望支持新的接口，而又不想把已經發布的API造成影響，這種機制很有用）
2：外界要求某個類提供新的服務，這種情況下不需要修改現有類的代碼，getAdaptor（）由一個工廠提供。（不使用d...
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