mardi 1 avril 2014

Java reflection - how to list a class's methods (except inherited)?


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I have the following two Java classes (Command and Player). I would like to be able to list from the Command class all the public methods from the Player class, without having to hard-code them. I tried several ways, including an interface, or the command pattern, but I am not fluent in Java and I did not manage to make them work.


It seems to me that using Java's reflection API would be easier. However, when I use it to print the public methods from the Player class, I get extraneous methods, which I assume were inherited from the Object class.


Is there a way to only include those methods I defined myself (i.e. those starting with "public method: public void Player.")?


Thank you,


LC


Here is the output I get:



public method: public void Player.search(Command)
public method: public Room Player.getCurrentRoom()
public method: public void Player.engage()
public method: public void Player.trade(Command)
public method: public void Player.goRoom(Command)
public method: public void Player.takeItem(Command)
public method: public void Player.dropItem(Command)
public method: public void Player.lock(Command)
public method: public void Player.unlock(Command)
public method: public final void java.lang.Object.wait(long,int) throws java.lang.InterruptedException
public method: public final native void java.lang.Object.wait(long) throws java.lang.InterruptedException
public method: public final void java.lang.Object.wait() throws java.lang.InterruptedException
public method: public boolean java.lang.Object.equals(java.lang.Object)
public method: public java.lang.String java.lang.Object.toString()
public method: public native int java.lang.Object.hashCode()
public method: public final native java.lang.Class java.lang.Object.getClass()
public method: public final native void java.lang.Object.notify()
public method: public final native void java.lang.Object.notifyAll()


Here is the Command class:



import java.lang.reflect.Method;

public class Command
{

// a constant array that holds all valid command words
private static String[] validCommands;

private String commandWord;
private String secondWord;

public Command(String firstWord, String secondWord)
{
commandWord = firstWord;
this.secondWord = secondWord;
}

[...] //some code omitted

public boolean process(Player player)
{

Class pClass = player.getClass();
Method[] methods = pClass.getMethods();
for (int i = 0; i < methods.length; i++) {
System.out.println("public method: " + methods[i]);
}

boolean wantToQuit = false;

if(commandWord == null) {
System.out.println("I don't know what you mean...");
return false;
}

if (commandWord.equals("help")) {
printHelp();
}
else if (commandWord.equals("go")) {
player.goRoom(this);
}
else if (commandWord.equals("quit")) {
wantToQuit = quit();
}
else if (commandWord.equals("take")) {
player.takeItem(this);
}
else if (commandWord.equals("drop")) {
player.dropItem(this);
}
else if (commandWord.equals("search")) {
player.search(this);
}
else if (commandWord.equals("engage")) {
player.engage();
}
else if (commandWord.equals("trade")) {
player.trade(this);
}
else if (commandWord.equals("lock")) {
player.lock(this);
}
else if (commandWord.equals("unlock")) {
player.unlock(this);
}
else {
System.out.println("Invalid command. Type 'help' if you forgot the list of available commands.");
}
// else command not recognised.
return wantToQuit;
}
}


Here is the outline of the Player class:



public class Player
{
private String name;
private Room currentRoom;
private ArrayList<Item> items;

Player (String name, Room startingRoom)
{
this.name = name;
items = new ArrayList<Item>();
this.currentRoom = startingRoom;
printWelcome();
}

public void engage()
{
[...]
}

public void trade(Command command)
{
[...] }

public void goRoom(Command command)
{
[...] }

public void search(Command command)
{
[...] }

public void takeItem(Command command)
{
[...] }

public void dropItem(Command command)
{
[...] }

public void lock(Command command)
{
[...] }

public void unlock(Command command)
{
[...]
}

}


asked 45 secs ago






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