Blackberry - save / load application settings

Question

I know two ways to save / load application settings:

• use persistentstore
• use the file system (store as SDCard is optional)

I would like to know what are your practical skills for working with application settings?

Using PersistentStore to save / load application settings

Persistent storage provides facilities for saving objects when the device is rebooted. A permanent object consists of a key-value pair. When a persistent object is tied to persistent storage, this value of the object is stored in flash memory through a deep copy. Then the value can be obtained at a later point in time using the key.

An example of a helper class for saving and retrieving settings:

class PSOptions {
    private PersistentObject mStore;
    private LongHashtableCollection mSettings;
    private long KEY_URL = 0;
    private long KEY_ENCRYPT = 1;
    private long KEY_REFRESH_PERIOD = 2;

    public PSOptions() {
        // "AppSettings" = 0x71f1f00b95850cfeL
        mStore = PersistentStore.getPersistentObject(0x71f1f00b95850cfeL);
    }

    public String getUrl() {
        Object result = get(KEY_URL);
        return (null != result) ? (String) result : null;
    }

    public void setUrl(String url) {
        set(KEY_URL, url);
    }

    public boolean getEncrypt() {
        Object result = get(KEY_ENCRYPT);
        return (null != result) ? ((Boolean) result).booleanValue() : false;
    }

    public void setEncrypt(boolean encrypt) {
        set(KEY_ENCRYPT, new Boolean(encrypt));
    }

    public int getRefreshPeriod() {
        Object result = get(KEY_REFRESH_PERIOD);
        return (null != result) ? ((Integer) result).intValue() : -1;
    }

    public void setRefreshRate(int refreshRate) {
        set(KEY_REFRESH_PERIOD, new Integer(refreshRate));
    }

    private void set(long key, Object value) {
        synchronized (mStore) {
            mSettings = (LongHashtableCollection) mStore.getContents();
            if (null == mSettings) {
                mSettings = new LongHashtableCollection();
            }
            mSettings.put(key, value);
            mStore.setContents(mSettings);
            mStore.commit();
        }
    }

    private Object get(long key) {
        synchronized (mStore) {
            mSettings = (LongHashtableCollection) mStore.getContents();
            if (null != mSettings && mSettings.size() != 0) {
                return mSettings.get(key);
            } else {
                return null;
            }
        }
    }
}

http://img182.imageshack.us/img182/6348/appsettings.png

:

class Scr extends MainScreen implements FieldChangeListener {
    PSOptions mOptions = new PSOptions();

    BasicEditField mUrl = new BasicEditField("Url:",
            "http://stackoverflow.com/");
    CheckboxField mEncrypt = new CheckboxField("Enable encrypt", false);
    GaugeField mRefresh = new GaugeField("Refresh period", 1, 60 * 10, 10,
            GaugeField.EDITABLE|FOCUSABLE);
    ButtonField mLoad = new ButtonField("Load settings",
            ButtonField.CONSUME_CLICK);
    ButtonField mSave = new ButtonField("Save settings",
            ButtonField.CONSUME_CLICK);

    public Scr() {
        add(mUrl);
        mUrl.setChangeListener(this);
        add(mEncrypt);
        mEncrypt.setChangeListener(this);
        add(mRefresh);
        mRefresh.setChangeListener(this);
        HorizontalFieldManager hfm = new HorizontalFieldManager(USE_ALL_WIDTH);
        add(hfm);
        hfm.add(mLoad);
        mLoad.setChangeListener(this);
        hfm.add(mSave);
        mSave.setChangeListener(this);
        loadSettings();
    }

    public void fieldChanged(Field field, int context) {
        if (field == mLoad) {
            loadSettings();
        } else if (field == mSave) {
            saveSettings();
        }
    }

    private void saveSettings() {
        mOptions.setUrl(mUrl.getText());
        mOptions.setEncrypt(mEncrypt.getChecked());
        mOptions.setRefreshRate(mRefresh.getValue());
    }

    private void loadSettings() {
        mUrl.setText(mOptions.getUrl());
        mEncrypt.setChecked(mOptions.getEncrypt());
        mRefresh.setValue(mOptions.getRefreshPeriod());
    }
}

Answer 1

: RMS .

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Answer 2

PersistentStore, , .

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