Android example source code file (ContentProviderNative.java)

This example Android source code file (ContentProviderNative.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, assetfiledescriptor, bulkcursortocursoradaptor, bundle, content, contentproviderresult, contentvalues, cursorwindow, database, ibinder, ibulkcursor, icontentobserver, icontentprovider, net, network, os, parcel, remoteexception, string, uri

The ContentProviderNative.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.content;

import android.content.res.AssetFileDescriptor;
import android.database.BulkCursorNative;
import android.database.BulkCursorToCursorAdaptor;
import android.database.Cursor;
import android.database.CursorWindow;
import android.database.DatabaseUtils;
import android.database.IBulkCursor;
import android.database.IContentObserver;
import android.net.Uri;
import android.os.Binder;
import android.os.Bundle;
import android.os.RemoteException;
import android.os.IBinder;
import android.os.Parcel;
import android.os.ParcelFileDescriptor;
import android.os.Parcelable;

import java.io.FileNotFoundException;
import java.util.ArrayList;

/**
 * {@hide}
 */
abstract public class ContentProviderNative extends Binder implements IContentProvider {
    private static final String TAG = "ContentProvider";

    public ContentProviderNative()
    {
        attachInterface(this, descriptor);
    }

    /**
     * Cast a Binder object into a content resolver interface, generating
     * a proxy if needed.
     */
    static public IContentProvider asInterface(IBinder obj)
    {
        if (obj == null) {
            return null;
        }
        IContentProvider in =
            (IContentProvider)obj.queryLocalInterface(descriptor);
        if (in != null) {
            return in;
        }

        return new ContentProviderProxy(obj);
    }

    @Override
    public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
            throws RemoteException {
        try {
            switch (code) {
                case QUERY_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);

                    Uri url = Uri.CREATOR.createFromParcel(data);

                    // String[] projection
                    int num = data.readInt();
                    String[] projection = null;
                    if (num > 0) {
                        projection = new String[num];
                        for (int i = 0; i < num; i++) {
                            projection[i] = data.readString();
                        }
                    }

                    // String selection, String[] selectionArgs...
                    String selection = data.readString();
                    num = data.readInt();
                    String[] selectionArgs = null;
                    if (num > 0) {
                        selectionArgs = new String[num];
                        for (int i = 0; i < num; i++) {
                            selectionArgs[i] = data.readString();
                        }
                    }

                    String sortOrder = data.readString();
                    IContentObserver observer = IContentObserver.Stub.
                        asInterface(data.readStrongBinder());
                    CursorWindow window = CursorWindow.CREATOR.createFromParcel(data);

                    // Flag for whether caller wants the number of
                    // rows in the cursor and the position of the
                    // "_id" column index (or -1 if non-existent)
                    // Only to be returned if binder != null.
                    boolean wantsCursorMetadata = data.readInt() != 0;

                    IBulkCursor bulkCursor = bulkQuery(url, projection, selection,
                            selectionArgs, sortOrder, observer, window);
                    reply.writeNoException();
                    if (bulkCursor != null) {
                        reply.writeStrongBinder(bulkCursor.asBinder());

                        if (wantsCursorMetadata) {
                            reply.writeInt(bulkCursor.count());
                            reply.writeInt(BulkCursorToCursorAdaptor.findRowIdColumnIndex(
                                bulkCursor.getColumnNames()));
                        }
                    } else {
                        reply.writeStrongBinder(null);
                    }

                    return true;
                }

                case GET_TYPE_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    String type = getType(url);
                    reply.writeNoException();
                    reply.writeString(type);

                    return true;
                }

                case INSERT_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    ContentValues values = ContentValues.CREATOR.createFromParcel(data);

                    Uri out = insert(url, values);
                    reply.writeNoException();
                    Uri.writeToParcel(reply, out);
                    return true;
                }

                case BULK_INSERT_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    ContentValues[] values = data.createTypedArray(ContentValues.CREATOR);

                    int count = bulkInsert(url, values);
                    reply.writeNoException();
                    reply.writeInt(count);
                    return true;
                }

                case APPLY_BATCH_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    final int numOperations = data.readInt();
                    final ArrayList<ContentProviderOperation> operations =
                            new ArrayList<ContentProviderOperation>(numOperations);
                    for (int i = 0; i < numOperations; i++) {
                        operations.add(i, ContentProviderOperation.CREATOR.createFromParcel(data));
                    }
                    final ContentProviderResult[] results = applyBatch(operations);
                    reply.writeNoException();
                    reply.writeTypedArray(results, 0);
                    return true;
                }

                case DELETE_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    String selection = data.readString();
                    String[] selectionArgs = data.readStringArray();

                    int count = delete(url, selection, selectionArgs);

                    reply.writeNoException();
                    reply.writeInt(count);
                    return true;
                }

                case UPDATE_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    ContentValues values = ContentValues.CREATOR.createFromParcel(data);
                    String selection = data.readString();
                    String[] selectionArgs = data.readStringArray();

                    int count = update(url, values, selection, selectionArgs);

                    reply.writeNoException();
                    reply.writeInt(count);
                    return true;
                }

                case OPEN_FILE_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    String mode = data.readString();

                    ParcelFileDescriptor fd;
                    fd = openFile(url, mode);
                    reply.writeNoException();
                    if (fd != null) {
                        reply.writeInt(1);
                        fd.writeToParcel(reply,
                                Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
                    } else {
                        reply.writeInt(0);
                    }
                    return true;
                }

                case OPEN_ASSET_FILE_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);
                    Uri url = Uri.CREATOR.createFromParcel(data);
                    String mode = data.readString();

                    AssetFileDescriptor fd;
                    fd = openAssetFile(url, mode);
                    reply.writeNoException();
                    if (fd != null) {
                        reply.writeInt(1);
                        fd.writeToParcel(reply,
                                Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
                    } else {
                        reply.writeInt(0);
                    }
                    return true;
                }

                case CALL_TRANSACTION:
                {
                    data.enforceInterface(IContentProvider.descriptor);

                    String method = data.readString();
                    String stringArg = data.readString();
                    Bundle args = data.readBundle();

                    Bundle responseBundle = call(method, stringArg, args);

                    reply.writeNoException();
                    reply.writeBundle(responseBundle);
                    return true;
                }
            }
        } catch (Exception e) {
            DatabaseUtils.writeExceptionToParcel(reply, e);
            return true;
        }

        return super.onTransact(code, data, reply, flags);
    }

    public IBinder asBinder()
    {
        return this;
    }
}


final class ContentProviderProxy implements IContentProvider
{
    public ContentProviderProxy(IBinder remote)
    {
        mRemote = remote;
    }

    public IBinder asBinder()
    {
        return mRemote;
    }

    // Like bulkQuery() but sets up provided 'adaptor' if not null.
    private IBulkCursor bulkQueryInternal(
        Uri url, String[] projection,
        String selection, String[] selectionArgs, String sortOrder,
        IContentObserver observer, CursorWindow window,
        BulkCursorToCursorAdaptor adaptor) throws RemoteException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        int length = 0;
        if (projection != null) {
            length = projection.length;
        }
        data.writeInt(length);
        for (int i = 0; i < length; i++) {
            data.writeString(projection[i]);
        }
        data.writeString(selection);
        if (selectionArgs != null) {
            length = selectionArgs.length;
        } else {
            length = 0;
        }
        data.writeInt(length);
        for (int i = 0; i < length; i++) {
            data.writeString(selectionArgs[i]);
        }
        data.writeString(sortOrder);
        data.writeStrongBinder(observer.asBinder());
        window.writeToParcel(data, 0);

        // Flag for whether or not we want the number of rows in the
        // cursor and the position of the "_id" column index (or -1 if
        // non-existent).  Only to be returned if binder != null.
        final boolean wantsCursorMetadata = (adaptor != null);
        data.writeInt(wantsCursorMetadata ? 1 : 0);

        mRemote.transact(IContentProvider.QUERY_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);

        IBulkCursor bulkCursor = null;
        IBinder bulkCursorBinder = reply.readStrongBinder();
        if (bulkCursorBinder != null) {
            bulkCursor = BulkCursorNative.asInterface(bulkCursorBinder);

            if (wantsCursorMetadata) {
                int rowCount = reply.readInt();
                int idColumnPosition = reply.readInt();
                if (bulkCursor != null) {
                    adaptor.set(bulkCursor, rowCount, idColumnPosition);
                }
            }
        }

        data.recycle();
        reply.recycle();

        return bulkCursor;
    }

    public IBulkCursor bulkQuery(Uri url, String[] projection,
            String selection, String[] selectionArgs, String sortOrder, IContentObserver observer,
            CursorWindow window) throws RemoteException {
        return bulkQueryInternal(
            url, projection, selection, selectionArgs, sortOrder,
            observer, window,
            null /* BulkCursorToCursorAdaptor */);
    }

    public Cursor query(Uri url, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) throws RemoteException {
        //TODO make a pool of windows so we can reuse memory dealers
        CursorWindow window = new CursorWindow(false /* window will be used remotely */);
        BulkCursorToCursorAdaptor adaptor = new BulkCursorToCursorAdaptor();
        IBulkCursor bulkCursor = bulkQueryInternal(
            url, projection, selection, selectionArgs, sortOrder,
            adaptor.getObserver(), window,
            adaptor);
        if (bulkCursor == null) {
            return null;
        }
        return adaptor;
    }

    public String getType(Uri url) throws RemoteException
    {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);

        mRemote.transact(IContentProvider.GET_TYPE_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        String out = reply.readString();

        data.recycle();
        reply.recycle();

        return out;
    }

    public Uri insert(Uri url, ContentValues values) throws RemoteException
    {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        values.writeToParcel(data, 0);

        mRemote.transact(IContentProvider.INSERT_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        Uri out = Uri.CREATOR.createFromParcel(reply);

        data.recycle();
        reply.recycle();

        return out;
    }

    public int bulkInsert(Uri url, ContentValues[] values) throws RemoteException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        data.writeTypedArray(values, 0);

        mRemote.transact(IContentProvider.BULK_INSERT_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        int count = reply.readInt();

        data.recycle();
        reply.recycle();

        return count;
    }

    public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)
            throws RemoteException, OperationApplicationException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);
        data.writeInt(operations.size());
        for (ContentProviderOperation operation : operations) {
            operation.writeToParcel(data, 0);
        }
        mRemote.transact(IContentProvider.APPLY_BATCH_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionWithOperationApplicationExceptionFromParcel(reply);
        final ContentProviderResult[] results =
                reply.createTypedArray(ContentProviderResult.CREATOR);

        data.recycle();
        reply.recycle();

        return results;
    }

    public int delete(Uri url, String selection, String[] selectionArgs)
            throws RemoteException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        data.writeString(selection);
        data.writeStringArray(selectionArgs);

        mRemote.transact(IContentProvider.DELETE_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        int count = reply.readInt();

        data.recycle();
        reply.recycle();

        return count;
    }

    public int update(Uri url, ContentValues values, String selection,
            String[] selectionArgs) throws RemoteException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        values.writeToParcel(data, 0);
        data.writeString(selection);
        data.writeStringArray(selectionArgs);

        mRemote.transact(IContentProvider.UPDATE_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        int count = reply.readInt();

        data.recycle();
        reply.recycle();

        return count;
    }

    public ParcelFileDescriptor openFile(Uri url, String mode)
            throws RemoteException, FileNotFoundException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        data.writeString(mode);

        mRemote.transact(IContentProvider.OPEN_FILE_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionWithFileNotFoundExceptionFromParcel(reply);
        int has = reply.readInt();
        ParcelFileDescriptor fd = has != 0 ? reply.readFileDescriptor() : null;

        data.recycle();
        reply.recycle();

        return fd;
    }

    public AssetFileDescriptor openAssetFile(Uri url, String mode)
            throws RemoteException, FileNotFoundException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        url.writeToParcel(data, 0);
        data.writeString(mode);

        mRemote.transact(IContentProvider.OPEN_ASSET_FILE_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionWithFileNotFoundExceptionFromParcel(reply);
        int has = reply.readInt();
        AssetFileDescriptor fd = has != 0
                ? AssetFileDescriptor.CREATOR.createFromParcel(reply) : null;

        data.recycle();
        reply.recycle();

        return fd;
    }

    public Bundle call(String method, String request, Bundle args)
            throws RemoteException {
        Parcel data = Parcel.obtain();
        Parcel reply = Parcel.obtain();

        data.writeInterfaceToken(IContentProvider.descriptor);

        data.writeString(method);
        data.writeString(request);
        data.writeBundle(args);

        mRemote.transact(IContentProvider.CALL_TRANSACTION, data, reply, 0);

        DatabaseUtils.readExceptionFromParcel(reply);
        Bundle bundle = reply.readBundle();

        data.recycle();
        reply.recycle();

        return bundle;
    }

    private IBinder mRemote;
}