Merge change I272af007 into eclair-mr2

import java.net.URISyntaxException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

/**

    private static class NameValueCache {

        private final String mVersionSystemProperty;

        private final HashMap<String, String> mValues = Maps.newHashMap();

        // the following needs synchronization because this structure is accessed from different

        // threads and they could be performing clear(), get(), put() at the same time.

        private final Map<String, String> mValues =

            	Collections.synchronizedMap(new HashMap<String, String>());

        private long mValuesVersion = 0;

        private final Uri mUri;

                mValues.clear();

                mValuesVersion = newValuesVersion;

            }

            if (!mValues.containsKey(name)) {

                String value = null;

            /*

             *  don't look for the key using containsKey() method because (key, object) mapping

             *  could be removed from mValues before get() is done like so:

             *

             *      say, mValues contains mapping for "foo"

             *      Thread# 1

             *          performs containsKey("foo")

             *          receives true

             *      Thread #2

             *          triggers mValues.clear()

             *      Thread#1

             *          since containsKey("foo") = true, performs get("foo")

             *          receives null

             *          thats incorrect!

             *

             *    to avoid the above, thread#1 should do get("foo") instead of containsKey("foo")

             *    since mValues is synchronized, get() will get a consistent value.

             *

             *    we don't want to make this method synchronized tho - because

             *    holding mutex is not desirable while a call could be made to database.

             */

            String value = mValues.get(name);

            if (value == null) {

                Cursor c = null;

                try {

                    c = cr.query(mUri, new String[] { Settings.NameValueTable.VALUE },

                } finally {

                    if (c != null) c.close();

                }

                return value;

            } else {

                return mValues.get(name);

            }

            return value;

        }

    }