Java tutorial
/* * Copyright 2011 Amazon Technologies, Inc. * * 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://aws.amazon.com/apache2.0 * * This file 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 com.amazonaws.eclipse.explorer.s3.dnd; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.io.RandomAccessFile; import org.eclipse.core.resources.IFile; import org.eclipse.core.resources.IResource; import org.eclipse.core.runtime.CoreException; import org.eclipse.core.runtime.IProgressMonitor; import org.eclipse.core.runtime.IStatus; import org.eclipse.core.runtime.Status; import org.eclipse.core.runtime.jobs.Job; import org.eclipse.jface.util.LocalSelectionTransfer; import org.eclipse.jface.viewers.IStructuredSelection; import org.eclipse.jface.viewers.StructuredSelection; import org.eclipse.swt.SWT; import org.eclipse.swt.dnd.DropTargetEvent; import org.eclipse.swt.dnd.TransferData; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.FileDialog; import org.eclipse.ui.navigator.CommonDropAdapter; import org.eclipse.ui.navigator.CommonDropAdapterAssistant; import com.amazonaws.eclipse.core.AwsToolkitCore; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.model.S3Object; import com.amazonaws.services.s3.model.S3ObjectSummary; /** * Handles dropping an S3 key onto a supported resource in the project explorer. */ public class DownloadDropAssistant extends CommonDropAdapterAssistant { public DownloadDropAssistant() { } /** * All validation is left to the configuration in plugin.xml. Any match * between possibleChildren and possibleDropTargets will be considered * valid. */ @Override public IStatus validateDrop(Object target, int operation, TransferData transferType) { return validatePluginTransferDrop( (IStructuredSelection) LocalSelectionTransfer.getTransfer().getSelection(), target); } @Override public IStatus validatePluginTransferDrop(IStructuredSelection aDragSelection, Object aDropTarget) { if (aDropTarget instanceof IResource) return Status.OK_STATUS; else return Status.CANCEL_STATUS; } @Override public IStatus handlePluginTransferDrop(IStructuredSelection aDragSelection, Object aDropTarget) { return doDrop(aDropTarget, aDragSelection); } @Override public IStatus handleDrop(CommonDropAdapter aDropAdapter, final DropTargetEvent aDropTargetEvent, Object aTarget) { if (aDropTargetEvent.data instanceof StructuredSelection) { IStructuredSelection s3ObjectSelection = (StructuredSelection) aDropTargetEvent.data; return doDrop(aTarget, s3ObjectSelection); } return Status.OK_STATUS; } protected IStatus doDrop(Object aTarget, IStructuredSelection s3ObjectSelection) { if (!(aTarget instanceof IResource)) { return Status.CANCEL_STATUS; } // Drop targets can be folders, projects, or files. In the case of // files, we just want to identify the parent directory. IResource resource = (IResource) aTarget; if (resource instanceof IFile) { resource = resource.getParent(); } final IResource dropFolder = resource; final S3ObjectSummary s3object = (S3ObjectSummary) s3ObjectSelection.getFirstElement(); final File f = dropFolder.getLocation().toFile(); if (!f.exists()) return Status.CANCEL_STATUS; String fileName = getOutputFileName(s3object, f); if (fileName == null || fileName.length() == 0) { return Status.CANCEL_STATUS; } final File outputFile = new File(fileName); new DownloadObjectJob("Downloading " + s3object.getKey(), s3object, dropFolder, outputFile).schedule(); return Status.OK_STATUS; } /** * Opens a save-file dialog to prompt the user for a file name. */ private String getOutputFileName(final S3ObjectSummary s3object, final File f) { FileDialog dialog = new FileDialog(Display.getDefault().getActiveShell(), SWT.SAVE); dialog.setFilterPath(f.getAbsolutePath()); dialog.setFileName(s3object.getKey()); dialog.setOverwrite(true); String fileName = dialog.open(); return fileName; } /** * Async job to download an object from S3 */ private final class DownloadObjectJob extends Job { private final S3ObjectSummary s3object; private final IResource dropFolder; private final File outputFile; private DownloadObjectJob(String name, S3ObjectSummary s3object, IResource dropFolder, File outputFile) { super(name); this.s3object = s3object; this.dropFolder = dropFolder; this.outputFile = outputFile; } @Override protected IStatus run(final IProgressMonitor monitor) { FileOutputStream fos = null; try { AmazonS3 client = AwsToolkitCore.getClientFactory().getS3Client(); S3Object object = client.getObject(s3object.getBucketName(), s3object.getKey()); // This number is used for reporting only; the download // will appear to complete early if the file is bigger // than 2GB. long totalNumBytes = object.getObjectMetadata().getContentLength(); if (totalNumBytes > Integer.MAX_VALUE) totalNumBytes = Integer.MAX_VALUE; monitor.beginTask("Downloading", (int) totalNumBytes); // For a new file this is a no-op, but it truncates an // existing file for overwrite. RandomAccessFile raf = new RandomAccessFile(outputFile, "rw"); raf.setLength(0); raf.close(); fos = new FileOutputStream(outputFile); InputStream is = object.getObjectContent(); byte[] buffer = new byte[4096]; int bytesRead = 0; while ((bytesRead = is.read(buffer)) > 0) { fos.write(buffer, 0, bytesRead); monitor.worked(bytesRead); } } catch (Exception e) { return new Status(Status.ERROR, AwsToolkitCore.PLUGIN_ID, "Error downloading file from S3", e); } finally { if (fos != null) { try { fos.close(); } catch (Exception e) { AwsToolkitCore.getDefault().logException("Couldn't close file output stream", e); } } monitor.done(); } // Refresh the drop folder // TODO: this won't work if they chose another folder in the // file selection dialog. Display.getDefault().asyncExec(new Runnable() { public void run() { try { dropFolder.refreshLocal(1, monitor); } catch (CoreException e) { AwsToolkitCore.getDefault().logException("Couldn't refresh local files", e); } } }); return Status.OK_STATUS; } } }