Solved Using Metadata

Hello all, I'm making a grenade plugin and I need to use Metadata to set and read Metadata,
but setMetadata()'s second arguement has to be a MetadataValue, how would I save a String into a metadataValue and then extract it at later point?

example:

Code:

public void  ProjectileHitEvent(org.bukkit.event.entity.ProjectileHitEvent evt)
{
   evt.getEntity().setMetadata("ExplosiveType", "Anti-grav"); //Problem here
  String type = String.valueOf(evt.getEntity().getMetadata("ExplosiveType")
    getLogger.info(type);
}

Should return : "Anti-grav", but it doesn't.

 

You have to create a own MetadatValue class.


The class could look like this one that i used in my Plugin.
In this class you would have to use the value() method to get the value because i were to lazy to set up all the other methods correctly.

You can set a metadata with setMetadata("NAME", new MyMetadata(YOURPLUGIN, "VALUE"))

And get the metadata with value() and cast it to a String

Code:java

 
package me.leo.sorcery;
 
import org.bukkit.metadata.MetadataValue;
import org.bukkit.plugin.Plugin;
 
public class MyMetadata implements MetadataValue{
 
Object value;
Plugin p;
 
public MyMetadata(Plugin p, Object o) {
this.p = p;
this.value = o;
}
 
@Override
public boolean equals(Object obj) {
return value.equals(obj);
}
 
public void set(Object o) {
this.value = o;
}
 
@Override
public boolean asBoolean() {
throw new NullPointerException();
}
 
@Override
public byte asByte() {
throw new NullPointerException();
}
 
@Override
public double asDouble() {
throw new NullPointerException();
}
 
@Override
public float asFloat() {
throw new NullPointerException();
}
 
@Override
public int asInt() {
throw new NullPointerException();
}
 
@Override
public long asLong() {
throw new NullPointerException();
}
 
@Override
public short asShort() {
throw new NullPointerException();
}
 
@Override
public String asString() {
throw new NullPointerException();
}
 
@Override
public Plugin getOwningPlugin() {
return p;
}
 
@Override
public void invalidate() {
return;
 
}
 
@Override
public Object value() {
return value;
}
 
}

 

http://jd.bukkit.org/rb/doxygen/de/d59/interfaceorg_1_1bukkit_1_1metadata_1_1MetadataValue.html

Metadata is an object with a value and the value can be returned as almost all basic data types.
Create a new MetadataValue with the value you want This is an Object value so you'll cast it to a string.

I've never done this so sorry if I am somehow incorrect but I've just read through the API java docs and it makes sense to me.

 

caelum19
Metadata is useful when you want to share that data with other plugins... if you don't, it's faster to just use a HashMap.
You can use entity's ID (or entity's unique ID if you want to save the hashmap) as key and whatever value you want, then you just retrieve it.
It would be more complicated to retrieve a metadata value, here's how it's done: http://wiki.bukkit.org/Plugin_Tutorial#Metadata

 

CoderCloud

Tried that and it works, thank you very much.

AlexLeporiday

Oh right I understand now, thanks.


Digi

Ohh okay then, I'll use hashtags, but it's useful to know how to use Metadata anyway