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/*
* 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;
import com.google.android.collect.Maps;
import android.annotation.UnsupportedAppUsage;
import java.util.HashMap;
import java.util.concurrent.TimeoutException;
/**
* Controls and utilities for low-level {@code init} services.
*
* @hide
*/
public class SystemService {
private static HashMap<String, State> sStates = Maps.newHashMap();
/**
* State of a known {@code init} service.
*/
public enum State {
RUNNING("running"),
STOPPING("stopping"),
STOPPED("stopped"),
RESTARTING("restarting");
State(String state) {
sStates.put(state, this);
}
}
private static Object sPropertyLock = new Object();
static {
SystemProperties.addChangeCallback(new Runnable() {
@Override
public void run() {
synchronized (sPropertyLock) {
sPropertyLock.notifyAll();
}
}
});
}
/** Request that the init daemon start a named service. */
@UnsupportedAppUsage
public static void start(String name) {
SystemProperties.set("ctl.start", name);
}
/** Request that the init daemon stop a named service. */
@UnsupportedAppUsage
public static void stop(String name) {
SystemProperties.set("ctl.stop", name);
}
/** Request that the init daemon restart a named service. */
public static void restart(String name) {
SystemProperties.set("ctl.restart", name);
}
/**
* Return current state of given service.
*/
public static State getState(String service) {
final String rawState = SystemProperties.get("init.svc." + service);
final State state = sStates.get(rawState);
if (state != null) {
return state;
} else {
return State.STOPPED;
}
}
/**
* Check if given service is {@link State#STOPPED}.
*/
public static boolean isStopped(String service) {
return State.STOPPED.equals(getState(service));
}
/**
* Check if given service is {@link State#RUNNING}.
*/
public static boolean isRunning(String service) {
return State.RUNNING.equals(getState(service));
}
/**
* Wait until given service has entered specific state.
*/
public static void waitForState(String service, State state, long timeoutMillis)
throws TimeoutException {
final long endMillis = SystemClock.elapsedRealtime() + timeoutMillis;
while (true) {
synchronized (sPropertyLock) {
final State currentState = getState(service);
if (state.equals(currentState)) {
return;
}
if (SystemClock.elapsedRealtime() >= endMillis) {
throw new TimeoutException("Service " + service + " currently " + currentState
+ "; waited " + timeoutMillis + "ms for " + state);
}
try {
sPropertyLock.wait(timeoutMillis);
} catch (InterruptedException e) {
}
}
}
}
/**
* Wait until any of given services enters {@link State#STOPPED}.
*/
public static void waitForAnyStopped(String... services) {
while (true) {
synchronized (sPropertyLock) {
for (String service : services) {
if (State.STOPPED.equals(getState(service))) {
return;
}
}
try {
sPropertyLock.wait();
} catch (InterruptedException e) {
}
}
}
}
}
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