WidgetCacheNamespace.java

/*
* Copyright 2010-2011 Research In Motion Limited.
*
* 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 blackberry.web.widget.caching;

import net.rim.device.api.script.Scriptable;
import net.rim.device.api.script.ScriptableFunction;

import blackberry.web.widget.bf.BrowserFieldScreen;
import java.lang.ref.WeakReference;

public class WidgetCacheNamespace extends Scriptable {

    public static final String NAME = "blackberry.widgetcache";

    public static final String LABEL_GET_CURRENT_SIZE = "getCurrentSize";
    public static final String LABEL_GET_CACHES_INFORMATION = "getCacheInformation";
    public static final String LABEL_CLEAR_ALL = "clearAll";
    public static final String LABEL_CLEAR_CACHE = "clearCache";
    public static final String LABEL_HAS_CACHE = "hasCache";

    private WeakReference _widgetScreenWeakReference;

    private GetCurrentSize _funcGetCurrentSize;
    private GetCachesInformation _funcGetCachesInformation;
    private ClearAll _funcClearAll;
    private ClearCache _funcClearCache;
    private HasCache _funcHasCache;

    public WidgetCacheNamespace( BrowserFieldScreen widgetScreen ) {
        _widgetScreenWeakReference = new WeakReference(widgetScreen);

        _funcGetCurrentSize = new GetCurrentSize();
        _funcGetCachesInformation = new GetCachesInformation();
        _funcClearAll = new ClearAll();
        _funcClearCache = new ClearCache();
        _funcHasCache = new HasCache();
    }

    /* @Override */public Scriptable getParent() {
        return null;
    }

    /* @Override */public Object getField( String name ) throws Exception {
        if( name.equals( LABEL_GET_CURRENT_SIZE ) ) {
            return _funcGetCurrentSize;
        }

        if( name.equals( LABEL_GET_CACHES_INFORMATION ) ) {
            return _funcGetCachesInformation;
        }

        if( name.equals( LABEL_CLEAR_ALL ) ) {
            return _funcClearAll;
        }

        if( name.equals( LABEL_CLEAR_CACHE ) ) {
            return _funcClearCache;
        }

        if( name.equals( LABEL_HAS_CACHE ) ) {
            return _funcHasCache;
        }

        return UNDEFINED;
    }

    /* @Override */public boolean putField( String name, Object value ) throws Exception {
        return false;
    }

    private BrowserFieldScreen getWidgetScreen() {
        Object o = _widgetScreenWeakReference.get();
        if (o instanceof BrowserFieldScreen) {
            return (BrowserFieldScreen) o;
        } else {
            return null;
        }
    }
    
    private class GetCurrentSize extends ScriptableFunction {
        /* @Override */public Object invoke( Object thiz, Object[] args ) throws Exception {
            if( args == null || args.length == 0 ) {
                CacheManager mgr = getWidgetScreen().getCacheManager();
                if( mgr != null ) {
                    int size = mgr.getTotalCacheSize();
                    return new Integer( size );
                } else {
                    return null;
                }
            }

            throw new IllegalArgumentException();
        }
    }

    private class GetCachesInformation extends ScriptableFunction {
        /* @Override */public Object invoke( Object thiz, Object[] args ) throws Exception {
            if( args == null || args.length == 0 ) {
                CacheManager mgr = getWidgetScreen().getCacheManager();
                if( mgr != null ) {
                    return mgr.getScriptableCacheItems();
                } else {
                    return null;
                }
            }

            throw new IllegalArgumentException();
        }
    }

    private class ClearAll extends ScriptableFunction {
        /* @Override */public Object invoke( Object thiz, Object[] args ) throws Exception {
            if( args == null || args.length == 0 ) {
                CacheManager mgr = getWidgetScreen().getCacheManager();
                if( mgr != null ) {
                    mgr.clearAll();
                    return UNDEFINED;
                } else {
                    return null;
                }
            }

            throw new IllegalArgumentException();
        }
    }

    private class ClearCache extends ScriptableFunction {
        /* @Override */public Object invoke( Object thiz, Object[] args ) throws Exception {
            if( args != null && args.length == 1 && args[ 0 ] != null ) {
                CacheManager mgr = getWidgetScreen().getCacheManager();
                if( mgr != null ) {
                    mgr.clearCache( args[ 0 ].toString() );
                    return UNDEFINED;
                } else {
                    return null;
                }
            }

            throw new IllegalArgumentException();
        }
    }

    private class HasCache extends ScriptableFunction {
        /* @Override */public Object invoke( Object thiz, Object[] args ) throws Exception {
            if( args != null && args.length == 1 && args[ 0 ] != null ) {
                CacheManager mgr = getWidgetScreen().getCacheManager();
                if( mgr != null ) {
                    return new Boolean( mgr.hasCache( args[ 0 ].toString() ) );
                } else {
                    return null;
                }
            }

            throw new IllegalArgumentException();
        }
    }
}