/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.os;
/** @hide */
public class Broadcaster
{
public Broadcaster()
{
}
/**
* Sign up for notifications about something.
*
* When this broadcaster pushes a message with senderWhat in the what field,
* target will be sent a copy of that message with targetWhat in the what field.
*/
public void request(int senderWhat, Handler target, int targetWhat)
{
synchronized (this) {
Registration r = null;
if (mReg == null) {
r = new Registration();
r.senderWhat = senderWhat;
r.targets = new Handler[1];
r.targetWhats = new int[1];
r.targets[0] = target;
r.targetWhats[0] = targetWhat;
mReg = r;
r.next = r;
r.prev = r;
} else {
// find its place in the map
Registration start = mReg;
r = start;
do {
if (r.senderWhat >= senderWhat) {
break;
}
r = r.next;
} while (r != start);
int n;
if (r.senderWhat != senderWhat) {
// we didn't find a senderWhat match, but r is right
// after where it goes
Registration reg = new Registration();
reg.senderWhat = senderWhat;
reg.targets = new Handler[1];
reg.targetWhats = new int[1];
reg.next = r;
reg.prev = r.prev;
r.prev.next = reg;
r.prev = reg;
if (r == mReg && r.senderWhat > reg.senderWhat) {
mReg = reg;
}
r = reg;
n = 0;
} else {
n = r.targets.length;
Handler[] oldTargets = r.targets;
int[] oldWhats = r.targetWhats;
// check for duplicates, and don't do it if we are dup.
for (int i=0; i<n; i++) {
if (oldTargets[i] == target && oldWhats[i] == targetWhat) {
return;
}
}
r.targets = new Handler[n+1];
System.arraycopy(oldTargets, 0, r.targets, 0, n);
r.targetWhats = new int[n+1];
System.arraycopy(oldWhats, 0, r.targetWhats, 0, n);
}
r.targets[n] = target;
r.targetWhats[n] = targetWhat;
}
}
}
/**
* Unregister for notifications for this senderWhat/target/targetWhat tuple.
*/
public void cancelRequest(int senderWhat, Handler target, int targetWhat)
{
synchronized (this) {
Registration start = mReg;
Registration r = start;
if (r == null) {
return;
}
do {
if (r.senderWhat >= senderWhat) {
break;
}
r = r.next;
} while (r != start);
if (r.senderWhat == senderWhat) {
Handler[] targets = r.targets;
int[] whats = r.targetWhats;
int oldLen = targets.length;
for (int i=0; i<oldLen; i++) {
if (targets[i] == target && whats[i] == targetWhat) {
r.targets = new Handler[oldLen-1];
r.targetWhats = new int[oldLen-1];
if (i > 0) {
System.arraycopy(targets, 0, r.targets, 0, i);
System.arraycopy(whats, 0, r.targetWhats, 0, i);
}
int remainingLen = oldLen-i-1;
if (remainingLen != 0) {
System.arraycopy(targets, i+1, r.targets, i,
remainingLen);
System.arraycopy(whats, i+1, r.targetWhats, i,
remainingLen);
}
break;
}
}
}
}
}
/**
* For debugging purposes, print the registrations to System.out
*/
public void dumpRegistrations()
{
synchronized (this) {
Registration start = mReg;
System.out.println("Broadcaster " + this + " {");
if (start != null) {
Registration r = start;
do {
System.out.println(" senderWhat=" + r.senderWhat);
int n = r.targets.length;
for (int i=0; i<n; i++) {
System.out.println(" [" + r.targetWhats[i]
+ "] " + r.targets[i]);
}
r = r.next;
} while (r != start);
}
System.out.println("}");
}
}
/**
* Send out msg. Anyone who has registered via the request() method will be
* sent the message.
*/
public void broadcast(Message msg)
{
synchronized (this) {
if (mReg == null) {
return;
}
int senderWhat = msg.what;
Registration start = mReg;
Registration r = start;
do {
if (r.senderWhat >= senderWhat) {
break;
}
r = r.next;
} while (r != start);
if (r.senderWhat == senderWhat) {
Handler[] targets = r.targets;
int[] whats = r.targetWhats;
int n = targets.length;
for (int i=0; i<n; i++) {
Handler target = targets[i];
Message m = Message.obtain();
m.copyFrom(msg);
m.what = whats[i];
target.sendMessage(m);
}
}
}
}
private class Registration
{
Registration next;
Registration prev;
int senderWhat;
Handler[] targets;
int[] targetWhats;
}
private Registration mReg;
}
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