phill84.org » java

寫了個超級簡單的 chatroom …

phill84 — Fri, 17 Apr 2009 11:03:48 +0000

兩個 class 加兩個 jsp …
功能極其有限 lol

source 在這裡

How to distinguish incoming trunks in asterisk-java

phill84 — Thu, 19 Mar 2009 10:28:52 +0000

Suppose you have asterisk 1.6 with freepbx and you are developing with the latest asterisk-java library. Somehow you wanna perform different tasks based on calls coming through different SIP trunks.

When there’s a new incoming call, asterisk-java will trigger a newChannelEvent, but there’s no information in this event that can be used for distinguish from which trunk this call is coming in.

By default the accountcode in this NewChannelEvent is null, which makes sense because the accountcode is used for billing, and no one, at least not many people, wants to record the charge of SIP trunk because that’s usually done by the SIP provider to which the trunk is registered to. But since the accountcode is null and useless here, maybe we can use it as an identifier to distinguish the incoming trunk, it may be not the smartest solution, but at least it’s a working one

The solution is pretty easy. Just open extensions_custom.conf and add
[ext-did-custom] exten => ,1,Set(CDR(accountcode)=)
et voilà!

If you try to make a call from outside now, in this NewChannelEvent the accountcode is still null, but there will be a NewAccountCodeEvent and you can see that the accountcode is set in this event, and from the same uniqueid you can tell that both the NewChannelEvent and NewAccountCodeEvent belong to the same call.

*note: Remeber that you should never manually edit extensions_additional.conf, the file is generated by freepbx and all the changes you have done will be overrided the next time you apply some changes in freepbx

quicksorting with stacks

phill84 — Tue, 10 Jun 2008 20:55:27 +0000

public void quicksort(int[] d, int lo, int hi){
	if(lo<hi){
		int pivotIndex=partition(d, lo, hi);
		quicksort(d,lo,pivotIndex-1);
		quicksort(d,pivotIndex+1,hi);
		}
	public int partition(int[] d,int lo, int hi){
		intStack smaller = new intStack();
		intStack larger = new intStack();
		int pivot = d[hi];
		for(int i=lo;i<hi;i++){
			if(d[i]<pivot)
				smaller.push(d[i]);
			else
				larger.push(d[i]);
		}
		int i=lo;
		while(!smaller.isEmpty()){
			d[i]=smaller.pop();
			i++;
		}
		d[i] = pivot;
		int pivotIndex = i;
		i++;
		while(!larger.isEmpty()){
			d[i] = larger.pop();
			i++;
		}
	return pivotIndex;
	}
}

One-way QuickSort implemented in Java

phill84 — Mon, 02 Jun 2008 07:21:08 +0000

The codes might be not optimized, and the first elements of all arrays are chosen as the pivots, which will cause a tremendous slow-down when the array is sorted already.

public static void swap(int[] ar, int a, int b){
	int tmp = ar[a];
	ar[a] = ar[b];
	ar[b] = tmp;
}
public static int partition(int[] a, int left, int right) {
	int pivot=a[left];
	int m=left;
	for(int i=left+1;i<=right;i++){
		if (a[i]<pivot){
			m++;
			swap(a, i, m);
		}	
	}
	swap(a, left, m);
	return m;
}
public static void quicksort(int[] a, int left, int right){
	if (left>=right)
	return;
	int pivotIndex = partition(a, left, right);
	quicksort(a, left, pivotIndex-1);
	quicksort(a, pivotIndex+1, right);
}