Description
:octocat: For this assignment, you can view all materials from this repo DI-OOAD-22Fall-public.
And if you have any question about this assignment, you are welcomed to submit an issue here!
Background story
YeeTone is working hard on OOAD project of Code Management Platform topic.
In his group, he is responsible for the backend using Java language, but he is not quite clear about the principle of DI (dependency injection) on Spring framework. If you could write some code passing all testcases about DI, he will be easily understand your idea and do a satisfactory work in the final presentation!
Before starting this DI assignment:
Here are some suggestions from the document author:
Please be patient and read EVERY sentence in the document carefully
Please listen to Mrs.ZHU or Mr.YUAN’s explanation in class clearly
This DI assignment will be very interesting, and YeeTone hopes you could enjoy it
If you feel difficult about the assignment and need help, please watch this video
I. Classes
1. BeanFactory
This class is an interface, which is used to inject instance according to the property files.
Here is the definition:
Load all inject data from file , which is a standard Java Properties file.
void loadValueProperties(File file);
Load all value data from file , which is a standard Java Properties file.
<T> T createInstance(Class<T> clazz); Create an instance which type is T.
Notice:
2. We ensure that in the JUnit test cases, ALL abstract class or interface that are passed as clazz are declared in the inject property file.
2. Inject
This class is an annotation. Here is the definition:
Please read the following requirement from 2.1 to 2.2.
2.1 On Fields: ElementType.FIELD
If @Inject is marked on field, only the user defined classes that could be annotated by
@Inject annotation, which means, in <T> T createInstance(Class<T> clazz) method, we not only needs to create an instance for the current class, but also create instance for all fields that identified by @Inject .
2.2 On Constructor: ElementType.CONSTRUCTOR
1. If @Inject is marked on constructor, we ensure that ONLY ONE constructor in each class could be annotated by @Inject annotation, and ONLY use the constructor that identified by
@Inject to create an instance.
2. Other than that, we ensure that classes in test cases have ONLY ONE constructor identified by @Inject , or the test class only has the default constructor, which means in <T> T createInstance(Class<T> clazz) method, the constructor is either annotated by @Inject or the constructor is the default constructor.
For example,
When creating the object of class AB2 , you needs to invoke the ONLY constructor with parameters A and B. The constructor is annotated with @Inject , so you also need to create instances for the constructor parameters instead of null .
3. Value
This class is an annotation as well. Here is the definition:
Example 1 for i:
public class Example1 {
@Value(value = “homo+1145141919810+114514”, delimiter = “\+”) private int homo; // homo will be 114514 //homo is not a decimal number and 1145141919810 exceeds INTEGER.MAX_VALUE // + is a special character in regex expression, so we use \ to escape it.
@Value(value = “deadbeef deadc0de TrUe false”, delimiter = ” “) private boolean magic; // magic will be true //deadbeef and deadc0de are not boolean Strings, and TrUe is equal to boolean value true regardless of cases.
@Value(value = “never gonna give you up”) private String lyric; // lyric will be “never gonna give you up” //default delimiter is “,” so lyric is “never gonna give you up” directly
}
ii. For the array type, you should ONLY select those values fit the type requirements into the array;
Example 2 for ii:
public class Example2 {
@Value(value = “[10086,10010,10000,baadfood]”) private int[] mobiles; // mobiles wil be an array of length 3, whose values are 10086, 10010 and 10000. // baadfood is not a decimal number, so we ignore it.
@Value(value = “[FaLSe-0-1-Yes-No-tRuE]”, delimiter = “-“)
private boolean[] yesOrNo; // yesOrNo wil be an array of length 2, whose values are false and true.
// 0, 1, Yes, No are not boolean Strings, so they are omitted. // FaLSe and tRuE are equal to boolean values false and true regardless of cases.
@Value(value = “[never gonna give you up]”, delimiter = ” “) private String[] swindle; // swindle will be an array of length 5 // Its values are “never”, “gonna”, “give”, “you”, “up”
}
iii. For the generic type, you should ONLY select those values fit the type requirements into the container and consider the characteristic of the container type(i.e. Set should NOT contain duplicate values, and Map should NOT contain duplicate keys).
Example 3 for iii:
public class Example3 { @Value(value = “[2345,360,kingsoft,]”) private List<String> rogue3Software; // rogue3Software will be a list of size 3
// Its values are “2345”, “360”, “kingsoft”.
@Value(value = “{hatsune-miku-39-39-39c5bb}”, delimiter = “-“) private Set<Integer> mikuSet; // mikuSet will be a set of size 1, which only contains 39.
// hatsune, miku, 39c5bb are not decimal numbers, so they are not allowed to be injected into the set.
@Value(value = “{never-gonna:give-you-up,never-gonna:let-you-down}”, delimiter = “,”) private Map<String, String> swindle; //swindle will be a map with 1 entry // The entry’s key is “never-gonna” and value is “let-you-down”.
// The value “give-you-up” is replaced by “let-you-down”
@Value(value = “{tRUe:955,fALsE:icu,Yes:955,No:996}”, delimiter = “,”) private Map<Boolean, Integer> work; //work will be a map with 1 entry // The entry’s key is true and value is 955.
// icu is not an integer number, so its entry is ignored
// Yes and No are not boolean String, so their entries are ignored as well
}
iv. For the array types(i.e. boolean[] , int[] and String[] ) and the generic container types(i.e. List<?> , Set<?> and Map<?, ?> ), the values() will be the String with brackets after being replaced; And for the entries of Map<?, ?> , the key and values are connected via : so the delimiter() of Map type will NEVER be “:” , and the key or value of entries will NEVER contain “:” as well. You need to use delimiter() to split the entry elements.
To simplify the problem, we ensure that:
1. We will not contain the delimiter() String for the entry-key element in the testcases for Map<?,?> type injection.
2. You do not need to consider some special expression character in regex expression, such as
‘+’ , ‘*’ and ‘?’ . If it appears, we will use \ to escapeҁԎ҂, so you do not need to worry about the usage of String::split method.
Example 4 for iv:
This could be easily understood, so we omitted the example 5. vi. If no value fit the requirement, then there are some default values for all types except String :
Example 6 for vi:
3.1 On Fields: ElementType.FIELD
If @Value is marked on field, in <T> T createInstance(Class<T> clazz) method, we not only needs create an instance for current class, but also given those fields an specified value that identified by @Value . If the value() String appears in the value.properties , then first replace it as defined in the properties file; Otherwise, use itself as value() .
For example, consider the following code:
3.2 On Parameters: ElementType.PARAMETER
If @Value is marked on parameters in constructor, when execute the constructor, an specific value should be given to corresponding parameters. We ensure that, in our test cases, all parameters in the constructor that annotated by @Inject are either injected or annotated by
@Value . If the value() String appears in the value.properties , then first replace it as defined in the properties file; Otherwise, use itself as value() .
For example,
4. How to inject value?
If the value() String appears in the value.properties , then first replace it as defined in the properties file; Otherwise, use itself as value() . So that the inject value of the fields annotated by @Value are according to the mapping value in value.properties .
bili=bilibili-22-33-2233 or rick=[never,gonna,give,you,up] . You should read the
previous 6 explanations to inject values for it.
For example:
Some field code of a class:
properties file:
After injected:
Explanation:
bili and rick can be found in the properties file, so first replace the value() as defined in the
properties file.
For field bili , bilibili is not decimal number, so we ignore it; 22 is the first number meeting the requirement, so we select 22 as the result of bili variable.
For field rick , “never,gonna,give,you,up” is split by the default delimiter() and injects an array of values {“never”, “gonna”, “give”, “you”, “up”} into array rick.
For field hello , we cannot find “hello,world” in the properties file, so we use “hello,world” itself as value() . Variable hello is injected as String “hello” since “hello” is the first String meeting the requirement.
II. Properties
1. inject properties
In our test cases, we ensure that the left side will ONLY be Abstract Class, Class or Interface, while the right side is the implement class of the left side.
For example,
2. value properties
The left side are the key name of parameter value in @Value , while the right side are the specific value of the key that needs to be injected into parameter. If the value() String appears in the value.properties , then first replace it as defined in the properties file; Otherwise, use itself as value() .
For example,
III. Requirement
III. Requirement
You should create a public class named BeanFactoryImpl which implements the interface BeanFactory, and upload the file BeanFactoryImpl.java to Sakai.
There are localjudge JUnits and officialjudge JUnits for you. If you can pass all localjudge JUnits, then you will get at least points.
You will get a ZERO if one of the following happens:
File name does not meet the requirement
Compilation failure
