Android example source code file (NetworkStateTracker.java)

This example Android source code file (NetworkStateTracker.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, content, dbg, event_network_subtype_changed, event_state_changed, filewriter, gatewayaddr, handler, inetaddress, io, ioexception, message, net, network, networkinfo, networkstatetracker, os, string, tag, unable

The NetworkStateTracker.java Android example source code

/*
 * Copyright (C) 2008 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.net;

import java.io.FileWriter;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;

import android.os.Handler;
import android.os.Message;
import android.os.SystemProperties;
import android.content.Context;
import android.text.TextUtils;
import android.util.Log;


/**
 * Each subclass of this class keeps track of the state of connectivity
 * of a network interface. All state information for a network should
 * be kept in a Tracker class. This superclass manages the
 * network-type-independent aspects of network state.
 *
 * {@hide}
 */
public abstract class NetworkStateTracker extends Handler {

    protected NetworkInfo mNetworkInfo;
    protected Context mContext;
    protected Handler mTarget;
    protected String mInterfaceName;
    protected String[] mDnsPropNames;
    private boolean mPrivateDnsRouteSet;
    protected int mDefaultGatewayAddr;
    private boolean mDefaultRouteSet;
    private boolean mTeardownRequested;

    private static boolean DBG = true;
    private static final String TAG = "NetworkStateTracker";

    public static final int EVENT_STATE_CHANGED = 1;
    public static final int EVENT_SCAN_RESULTS_AVAILABLE = 2;
    /**
     * arg1: 1 to show, 0 to hide
     * arg2: ID of the notification
     * obj: Notification (if showing)
     */
    public static final int EVENT_NOTIFICATION_CHANGED = 3;
    public static final int EVENT_CONFIGURATION_CHANGED = 4;
    public static final int EVENT_ROAMING_CHANGED = 5;
    public static final int EVENT_NETWORK_SUBTYPE_CHANGED = 6;
    public static final int EVENT_RESTORE_DEFAULT_NETWORK = 7;

    public NetworkStateTracker(Context context,
            Handler target,
            int networkType,
            int subType,
            String typeName,
            String subtypeName) {
        super();
        mContext = context;
        mTarget = target;
        mTeardownRequested = false;

        this.mNetworkInfo = new NetworkInfo(networkType, subType, typeName, subtypeName);
    }

    public NetworkInfo getNetworkInfo() {
        return mNetworkInfo;
    }

    /**
     * Return the system properties name associated with the tcp buffer sizes
     * for this network.
     */
    public abstract String getTcpBufferSizesPropName();

    /**
     * Return the IP addresses of the DNS servers available for the mobile data
     * network interface.
     * @return a list of DNS addresses, with no holes.
     */
    public String[] getNameServers() {
        return getNameServerList(mDnsPropNames);
    }

    /**
     * Return the IP addresses of the DNS servers available for this
     * network interface.
     * @param propertyNames the names of the system properties whose values
     * give the IP addresses. Properties with no values are skipped.
     * @return an array of {@code String}s containing the IP addresses
     * of the DNS servers, in dot-notation. This may have fewer
     * non-null entries than the list of names passed in, since
     * some of the passed-in names may have empty values.
     */
    static protected String[] getNameServerList(String[] propertyNames) {
        String[] dnsAddresses = new String[propertyNames.length];
        int i, j;

        for (i = 0, j = 0; i < propertyNames.length; i++) {
            String value = SystemProperties.get(propertyNames[i]);
            // The GSM layer sometimes sets a bogus DNS server address of
            // 0.0.0.0
            if (!TextUtils.isEmpty(value) && !TextUtils.equals(value, "0.0.0.0")) {
                dnsAddresses[j++] = value;
            }
        }
        return dnsAddresses;
    }

    public void addPrivateDnsRoutes() {
        if (DBG) {
            Log.d(TAG, "addPrivateDnsRoutes for " + this +
                    "(" + mInterfaceName + ") - mPrivateDnsRouteSet = "+mPrivateDnsRouteSet);
        }
        if (mInterfaceName != null && !mPrivateDnsRouteSet) {
            for (String addrString : getNameServers()) {
                if (addrString != null) {
                    try {
                        InetAddress inetAddress = InetAddress.getByName(addrString);
                        if (DBG) Log.d(TAG, "  adding " + addrString);
                        if (NetworkUtils.addHostRoute(mInterfaceName, inetAddress, null)) {
                            mPrivateDnsRouteSet = true;
                        }
                    } catch (UnknownHostException e) {
                        if (DBG) Log.d(TAG, " DNS address " + addrString + " : Exception " + e);
                    }
                }
            }
        }
    }

    public void removePrivateDnsRoutes() {
        // TODO - we should do this explicitly but the NetUtils api doesnt
        // support this yet - must remove all.  No worse than before
        if (mInterfaceName != null && mPrivateDnsRouteSet) {
            if (DBG) {
                Log.d(TAG, "removePrivateDnsRoutes for " + mNetworkInfo.getTypeName() +
                        " (" + mInterfaceName + ")");
            }
            NetworkUtils.removeHostRoutes(mInterfaceName);
            mPrivateDnsRouteSet = false;
        }
    }

    public void addDefaultRoute() {
        if ((mInterfaceName != null) && (mDefaultGatewayAddr != 0) &&
                mDefaultRouteSet == false) {
            if (DBG) {
                Log.d(TAG, "addDefaultRoute for " + mNetworkInfo.getTypeName() +
                        " (" + mInterfaceName + "), GatewayAddr=" + mDefaultGatewayAddr);
            }
            InetAddress inetAddress = NetworkUtils.intToInetAddress(mDefaultGatewayAddr);
            if (inetAddress == null) {
                if (DBG) Log.d(TAG, " Unable to add default route. mDefaultGatewayAddr Error");
            } else {
                if (NetworkUtils.addDefaultRoute(mInterfaceName, inetAddress)) {
                    mDefaultRouteSet = true;
                } else {
                    if (DBG) Log.d(TAG, "  Unable to add default route.");
                }
            }
        }
    }

    public void removeDefaultRoute() {
        if (mInterfaceName != null && mDefaultRouteSet == true) {
            if (DBG) {
                Log.d(TAG, "removeDefaultRoute for " + mNetworkInfo.getTypeName() + " (" +
                        mInterfaceName + ")");
            }
            NetworkUtils.removeDefaultRoute(mInterfaceName);
            mDefaultRouteSet = false;
        }
    }

    /**
     * Reads the network specific TCP buffer sizes from SystemProperties
     * net.tcp.buffersize.[default|wifi|umts|edge|gprs] and set them for system
     * wide use
     */
   public void updateNetworkSettings() {
        String key = getTcpBufferSizesPropName();
        String bufferSizes = SystemProperties.get(key);

        if (bufferSizes.length() == 0) {
            Log.e(TAG, key + " not found in system properties. Using defaults");

            // Setting to default values so we won't be stuck to previous values
            key = "net.tcp.buffersize.default";
            bufferSizes = SystemProperties.get(key);
        }

        // Set values in kernel
        if (bufferSizes.length() != 0) {
            if (DBG) {
                Log.v(TAG, "Setting TCP values: [" + bufferSizes
                        + "] which comes from [" + key + "]");
            }
            setBufferSize(bufferSizes);
        }
    }

    /**
     * Release the wakelock, if any, that may be held while handling a
     * disconnect operation.
     */
    public void releaseWakeLock() {
    }

    /**
     * Writes TCP buffer sizes to /sys/kernel/ipv4/tcp_[r/w]mem_[min/def/max]
     * which maps to /proc/sys/net/ipv4/tcp_rmem and tcpwmem
     * 
     * @param bufferSizes in the format of "readMin, readInitial, readMax,
     *        writeMin, writeInitial, writeMax"
     */
    private void setBufferSize(String bufferSizes) {
        try {
            String[] values = bufferSizes.split(",");

            if (values.length == 6) {
              final String prefix = "/sys/kernel/ipv4/tcp_";
                stringToFile(prefix + "rmem_min", values[0]);
                stringToFile(prefix + "rmem_def", values[1]);
                stringToFile(prefix + "rmem_max", values[2]);
                stringToFile(prefix + "wmem_min", values[3]);
                stringToFile(prefix + "wmem_def", values[4]);
                stringToFile(prefix + "wmem_max", values[5]);
            } else {
                Log.e(TAG, "Invalid buffersize string: " + bufferSizes);
            }
        } catch (IOException e) {
            Log.e(TAG, "Can't set tcp buffer sizes:" + e);
        }
    }

    /**
     * Writes string to file. Basically same as "echo -n $string > $filename"
     * 
     * @param filename
     * @param string
     * @throws IOException
     */
    private void stringToFile(String filename, String string) throws IOException {
        FileWriter out = new FileWriter(filename);
        try {
            out.write(string);
        } finally {
            out.close();
        }
    }

    /**
     * Record the detailed state of a network, and if it is a
     * change from the previous state, send a notification to
     * any listeners.
     * @param state the new @{code DetailedState}
     */
    public void setDetailedState(NetworkInfo.DetailedState state) {
        setDetailedState(state, null, null);
    }

    /**
     * Record the detailed state of a network, and if it is a
     * change from the previous state, send a notification to
     * any listeners.
     * @param state the new @{code DetailedState}
     * @param reason a {@code String} indicating a reason for the state change,
     * if one was supplied. May be {@code null}.
     * @param extraInfo optional {@code String} providing extra information about the state change
     */
    public void setDetailedState(NetworkInfo.DetailedState state, String reason, String extraInfo) {
        if (DBG) Log.d(TAG, "setDetailed state, old ="+mNetworkInfo.getDetailedState()+" and new state="+state);
        if (state != mNetworkInfo.getDetailedState()) {
            boolean wasConnecting = (mNetworkInfo.getState() == NetworkInfo.State.CONNECTING);
            String lastReason = mNetworkInfo.getReason();
            /*
             * If a reason was supplied when the CONNECTING state was entered, and no
             * reason was supplied for entering the CONNECTED state, then retain the
             * reason that was supplied when going to CONNECTING.
             */
            if (wasConnecting && state == NetworkInfo.DetailedState.CONNECTED && reason == null
                    && lastReason != null)
                reason = lastReason;
            mNetworkInfo.setDetailedState(state, reason, extraInfo);
            Message msg = mTarget.obtainMessage(EVENT_STATE_CHANGED, mNetworkInfo);
            msg.sendToTarget();
        }
    }

    protected void setDetailedStateInternal(NetworkInfo.DetailedState state) {
        mNetworkInfo.setDetailedState(state, null, null);
    }

    public void setTeardownRequested(boolean isRequested) {
        mTeardownRequested = isRequested;
    }

    public boolean isTeardownRequested() {
        return mTeardownRequested;
    }
    
    /**
     * Send a  notification that the results of a scan for network access
     * points has completed, and results are available.
     */
    protected void sendScanResultsAvailable() {
        Message msg = mTarget.obtainMessage(EVENT_SCAN_RESULTS_AVAILABLE, mNetworkInfo);
        msg.sendToTarget();
    }

    /**
     * Record the roaming status of the device, and if it is a change from the previous
     * status, send a notification to any listeners.
     * @param isRoaming {@code true} if the device is now roaming, {@code false}
     * if it is no longer roaming.
     */
    protected void setRoamingStatus(boolean isRoaming) {
        if (isRoaming != mNetworkInfo.isRoaming()) {
            mNetworkInfo.setRoaming(isRoaming);
            Message msg = mTarget.obtainMessage(EVENT_ROAMING_CHANGED, mNetworkInfo);
            msg.sendToTarget();
        }
    }

    protected void setSubtype(int subtype, String subtypeName) {
        if (mNetworkInfo.isConnected()) {
            int oldSubtype = mNetworkInfo.getSubtype();
            if (subtype != oldSubtype) {
                mNetworkInfo.setSubtype(subtype, subtypeName);
                Message msg = mTarget.obtainMessage(
                        EVENT_NETWORK_SUBTYPE_CHANGED, oldSubtype, 0, mNetworkInfo);
                msg.sendToTarget();
            }
        }
    }

    public abstract void startMonitoring();

    /**
     * Disable connectivity to a network
     * @return {@code true} if a teardown occurred, {@code false} if the
     * teardown did not occur.
     */
    public abstract boolean teardown();

    /**
     * Reenable connectivity to a network after a {@link #teardown()}.
     */
    public abstract boolean reconnect();

    /**
     * Turn the wireless radio off for a network.
     * @param turnOn {@code true} to turn the radio on, {@code false}
     */
    public abstract boolean setRadio(boolean turnOn);

    /**
     * Returns an indication of whether this network is available for
     * connections. A value of {@code false} means that some quasi-permanent
     * condition prevents connectivity to this network.
     */
    public abstract boolean isAvailable();

    /**
     * Tells the underlying networking system that the caller wants to
     * begin using the named feature. The interpretation of {@code feature}
     * is completely up to each networking implementation.
     * @param feature the name of the feature to be used
     * @param callingPid the process ID of the process that is issuing this request
     * @param callingUid the user ID of the process that is issuing this request
     * @return an integer value representing the outcome of the request.
     * The interpretation of this value is specific to each networking
     * implementation+feature combination, except that the value {@code -1}
     * always indicates failure.
     */
    public abstract int startUsingNetworkFeature(String feature, int callingPid, int callingUid);

    /**
     * Tells the underlying networking system that the caller is finished
     * using the named feature. The interpretation of {@code feature}
     * is completely up to each networking implementation.
     * @param feature the name of the feature that is no longer needed.
     * @param callingPid the process ID of the process that is issuing this request
     * @param callingUid the user ID of the process that is issuing this request
     * @return an integer value representing the outcome of the request.
     * The interpretation of this value is specific to each networking
     * implementation+feature combination, except that the value {@code -1}
     * always indicates failure.
     */
    public abstract int stopUsingNetworkFeature(String feature, int callingPid, int callingUid);

    /**
     * Ensure that a network route exists to deliver traffic to the specified
     * host via this network interface.
     * @param hostAddress the IP address of the host to which the route is desired
     * @return {@code true} on success, {@code false} on failure
     */
    public boolean requestRouteToHost(InetAddress hostAddress) {
        return false;
    }

    /**
     * Interprets scan results. This will be called at a safe time for
     * processing, and from a safe thread.
     */
    public void interpretScanResultsAvailable() {
    }

}