Android example source code file (CursorToBulkCursorAdaptor.java)

This example Android source code file (CursorToBulkCursorAdaptor.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

abstractwindowedcursor, android, bundle, contentobserverproxy, contentprovider, crossprocesscursor, cursortobulkcursoradaptor, cursorwindow, database, denial, icontentobserver, illegalstateexception, os, override, permission, remoteexception, string, util, utilities, utils

The CursorToBulkCursorAdaptor.java Android example source code

/*
 * 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.database;

import android.database.sqlite.SQLiteMisuseException;
import android.os.Binder;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Config;
import android.util.Log;

import java.util.Map;


/**
 * Wraps a BulkCursor around an existing Cursor making it remotable.
 *
 * {@hide}
 */
public final class CursorToBulkCursorAdaptor extends BulkCursorNative 
        implements IBinder.DeathRecipient {
    private static final String TAG = "Cursor";
    private final CrossProcessCursor mCursor;
    private CursorWindow mWindow;
    private final String mProviderName;
    private final boolean mReadOnly;
    private ContentObserverProxy mObserver;

    private static final class ContentObserverProxy extends ContentObserver 
            {
        protected IContentObserver mRemote;

        public ContentObserverProxy(IContentObserver remoteObserver, DeathRecipient recipient) {
            super(null);
            mRemote = remoteObserver;
            try {
                remoteObserver.asBinder().linkToDeath(recipient, 0);
            } catch (RemoteException e) {
                // Do nothing, the far side is dead
            }
        }
        
        public boolean unlinkToDeath(DeathRecipient recipient) {
            return mRemote.asBinder().unlinkToDeath(recipient, 0);
        }

        @Override
        public boolean deliverSelfNotifications() {
            // The far side handles the self notifications.
            return false;
        }

        @Override
        public void onChange(boolean selfChange) {
            try {
                mRemote.onChange(selfChange);
            } catch (RemoteException ex) {
                // Do nothing, the far side is dead
            }
        }
    }

    public CursorToBulkCursorAdaptor(Cursor cursor, IContentObserver observer, String providerName,
            boolean allowWrite, CursorWindow window) {
        try {
            mCursor = (CrossProcessCursor) cursor;
            if (mCursor instanceof AbstractWindowedCursor) {
                AbstractWindowedCursor windowedCursor = (AbstractWindowedCursor) cursor;
                if (windowedCursor.hasWindow()) {
                    if (Log.isLoggable(TAG, Log.VERBOSE) || Config.LOGV) {
                        Log.v(TAG, "Cross process cursor has a local window before setWindow in "
                                + providerName, new RuntimeException());
                    }
                }
                windowedCursor.setWindow(window);
            } else {
                mWindow = window;
                mCursor.fillWindow(0, window);
            }
        } catch (ClassCastException e) {
            // TODO Implement this case.
            throw new UnsupportedOperationException(
                    "Only CrossProcessCursor cursors are supported across process for now", e);
        }
        mProviderName = providerName;
        mReadOnly = !allowWrite;

        createAndRegisterObserverProxy(observer);
    }
    
    public void binderDied() {
        mCursor.close();
        if (mWindow != null) {
            mWindow.close();
        }
    }
    
    public CursorWindow getWindow(int startPos) {
        mCursor.moveToPosition(startPos);
        
        if (mWindow != null) {
            if (startPos < mWindow.getStartPosition() ||
                    startPos >= (mWindow.getStartPosition() + mWindow.getNumRows())) {
                mCursor.fillWindow(startPos, mWindow);
            }            
            return mWindow;
        } else {
            return ((AbstractWindowedCursor)mCursor).getWindow();
        }
    }

    public void onMove(int position) {
        mCursor.onMove(mCursor.getPosition(), position);
    }

    public int count() {
        return mCursor.getCount();
    }

    public String[] getColumnNames() {
        return mCursor.getColumnNames();
    }

    public void deactivate() {
        maybeUnregisterObserverProxy();
        mCursor.deactivate();
    }

    public void close() {
        maybeUnregisterObserverProxy();
        mCursor.close();
    }

    public int requery(IContentObserver observer, CursorWindow window) {
        if (mWindow == null) {
            ((AbstractWindowedCursor)mCursor).setWindow(window);
        }
        try {
            if (!mCursor.requery()) {
                return -1;
            }
        } catch (IllegalStateException e) {
            IllegalStateException leakProgram = new IllegalStateException(
                    mProviderName + " Requery misuse db, mCursor isClosed:" +
                    mCursor.isClosed(), e);
            throw leakProgram;
        }
        
        if (mWindow != null) {
            mCursor.fillWindow(0, window);
            mWindow = window;
        }
        maybeUnregisterObserverProxy();
        createAndRegisterObserverProxy(observer);
        return mCursor.getCount();
    }

    public boolean getWantsAllOnMoveCalls() {
        return mCursor.getWantsAllOnMoveCalls();
    }

    /**
     * Create a ContentObserver from the observer and register it as an observer on the
     * underlying cursor.
     * @param observer the IContentObserver that wants to monitor the cursor
     * @throws IllegalStateException if an observer is already registered
     */
    private void createAndRegisterObserverProxy(IContentObserver observer) {
        if (mObserver != null) {
            throw new IllegalStateException("an observer is already registered");
        }
        mObserver = new ContentObserverProxy(observer, this);
        mCursor.registerContentObserver(mObserver);
    }

    /** Unregister the observer if it is already registered. */
    private void maybeUnregisterObserverProxy() {
        if (mObserver != null) {
            mCursor.unregisterContentObserver(mObserver);
            mObserver.unlinkToDeath(this);
            mObserver = null;
        }
    }

    public boolean updateRows(Map<? extends Long, ? extends Map values) {
        if (mReadOnly) {
            Log.w("ContentProvider", "Permission Denial: modifying "
                    + mProviderName
                    + " from pid=" + Binder.getCallingPid()
                    + ", uid=" + Binder.getCallingUid());
            return false;
        }
        return mCursor.commitUpdates(values);
    }

    public boolean deleteRow(int position) {
        if (mReadOnly) {
            Log.w("ContentProvider", "Permission Denial: modifying "
                    + mProviderName
                    + " from pid=" + Binder.getCallingPid()
                    + ", uid=" + Binder.getCallingUid());
            return false;
        }
        if (mCursor.moveToPosition(position) == false) {
            return false;
        }
        return mCursor.deleteRow();
    }

    public Bundle getExtras() {
        return mCursor.getExtras();
    }

    public Bundle respond(Bundle extras) {
        return mCursor.respond(extras);
    }
}