Java tutorial
/* * Copyright (C) 2013 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 cn.edu.wyu.documentviewer.model; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.net.ProtocolException; import org.apache.commons.io.IOUtils; import android.content.ContentProviderClient; import android.content.ContentResolver; import android.database.Cursor; import android.net.Uri; import android.os.Parcel; import android.os.Parcelable; import android.provider.DocumentsContract; import android.provider.DocumentsContract.Document; import android.provider.DocumentsProvider; import cn.edu.wyu.documentviewer.DocumentsApplication; import cn.edu.wyu.documentviewer.RootCursorWrapper; /** * Representation of a {@link Document}. */ public class DocumentInfo implements Durable, Parcelable { private static final int VERSION_INIT = 1; private static final int VERSION_SPLIT_URI = 2; public String authority; public String documentId; public String mimeType; public String displayName; public long lastModified; public int flags; public String summary; public long size; public int icon; /** Derived fields that aren't persisted */ public Uri derivedUri; public DocumentInfo() { reset(); } @Override public void reset() { authority = null; documentId = null; mimeType = null; displayName = null; lastModified = -1; flags = 0; summary = null; size = -1; icon = 0; derivedUri = null; } @Override public void read(DataInputStream in) throws IOException { final int version = in.readInt(); switch (version) { case VERSION_INIT: throw new ProtocolException("Ignored upgrade"); case VERSION_SPLIT_URI: authority = DurableUtils.readNullableString(in); documentId = DurableUtils.readNullableString(in); mimeType = DurableUtils.readNullableString(in); displayName = DurableUtils.readNullableString(in); lastModified = in.readLong(); flags = in.readInt(); summary = DurableUtils.readNullableString(in); size = in.readLong(); icon = in.readInt(); deriveFields(); break; default: throw new ProtocolException("Unknown version " + version); } } @Override public void write(DataOutputStream out) throws IOException { out.writeInt(VERSION_SPLIT_URI); DurableUtils.writeNullableString(out, authority); DurableUtils.writeNullableString(out, documentId); DurableUtils.writeNullableString(out, mimeType); DurableUtils.writeNullableString(out, displayName); out.writeLong(lastModified); out.writeInt(flags); DurableUtils.writeNullableString(out, summary); out.writeLong(size); out.writeInt(icon); } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { DurableUtils.writeToParcel(dest, this); } public static final Creator<DocumentInfo> CREATOR = new Creator<DocumentInfo>() { @Override public DocumentInfo createFromParcel(Parcel in) { final DocumentInfo doc = new DocumentInfo(); DurableUtils.readFromParcel(in, doc); return doc; } @Override public DocumentInfo[] newArray(int size) { return new DocumentInfo[size]; } }; public static DocumentInfo fromDirectoryCursor(Cursor cursor) { final String authority = getCursorString(cursor, RootCursorWrapper.COLUMN_AUTHORITY); return fromCursor(cursor, authority); } public static DocumentInfo fromCursor(Cursor cursor, String authority) { final DocumentInfo info = new DocumentInfo(); info.updateFromCursor(cursor, authority); return info; } public void updateFromCursor(Cursor cursor, String authority) { this.authority = authority; this.documentId = getCursorString(cursor, Document.COLUMN_DOCUMENT_ID); this.mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE); this.documentId = getCursorString(cursor, Document.COLUMN_DOCUMENT_ID); this.mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE); this.displayName = getCursorString(cursor, Document.COLUMN_DISPLAY_NAME); this.lastModified = getCursorLong(cursor, Document.COLUMN_LAST_MODIFIED); this.flags = getCursorInt(cursor, Document.COLUMN_FLAGS); this.summary = getCursorString(cursor, Document.COLUMN_SUMMARY); this.size = getCursorLong(cursor, Document.COLUMN_SIZE); this.icon = getCursorInt(cursor, Document.COLUMN_ICON); this.deriveFields(); } public static DocumentInfo fromUri(ContentResolver resolver, Uri uri) throws FileNotFoundException { final DocumentInfo info = new DocumentInfo(); info.updateFromUri(resolver, uri); return info; } /** * Update a possibly stale restored document against a live * {@link DocumentsProvider}. */ public void updateSelf(ContentResolver resolver) throws FileNotFoundException { updateFromUri(resolver, derivedUri); } public void updateFromUri(ContentResolver resolver, Uri uri) throws FileNotFoundException { ContentProviderClient client = null; Cursor cursor = null; try { client = DocumentsApplication.acquireUnstableProviderOrThrow(resolver, uri.getAuthority()); cursor = client.query(uri, null, null, null, null); if (!cursor.moveToFirst()) { throw new FileNotFoundException("Missing details for " + uri); } updateFromCursor(cursor, uri.getAuthority()); } catch (Throwable t) { throw asFileNotFoundException(t); } finally { IOUtils.closeQuietly(cursor); ContentProviderClient.releaseQuietly(client); } } private void deriveFields() { derivedUri = DocumentsContract.buildDocumentUri(authority, documentId); } @Override public String toString() { return "Document{docId=" + documentId + ", name=" + displayName + "}"; } public boolean isCreateSupported() { return (flags & Document.FLAG_DIR_SUPPORTS_CREATE) != 0; } public boolean isThumbnailSupported() { return (flags & Document.FLAG_SUPPORTS_THUMBNAIL) != 0; } public boolean isDirectory() { return Document.MIME_TYPE_DIR.equals(mimeType); } public boolean isGridPreferred() { return (flags & Document.FLAG_DIR_PREFERS_GRID) != 0; } public boolean isDeleteSupported() { return (flags & Document.FLAG_SUPPORTS_DELETE) != 0; } public boolean isGridTitlesHidden() { return (flags & Document.FLAG_DIR_HIDE_GRID_TITLES) != 0; } public static String getCursorString(Cursor cursor, String columnName) { final int index = cursor.getColumnIndex(columnName); return (index != -1) ? cursor.getString(index) : null; } /** * Missing or null values are returned as -1. */ public static long getCursorLong(Cursor cursor, String columnName) { final int index = cursor.getColumnIndex(columnName); if (index == -1) return -1; final String value = cursor.getString(index); if (value == null) return -1; try { return Long.parseLong(value); } catch (NumberFormatException e) { return -1; } } /** * Missing or null values are returned as 0. */ public static int getCursorInt(Cursor cursor, String columnName) { final int index = cursor.getColumnIndex(columnName); return (index != -1) ? cursor.getInt(index) : 0; } public static FileNotFoundException asFileNotFoundException(Throwable t) throws FileNotFoundException { if (t instanceof FileNotFoundException) { throw (FileNotFoundException) t; } final FileNotFoundException fnfe = new FileNotFoundException(t.getMessage()); fnfe.initCause(t); throw fnfe; } public static int compareToIgnoreCaseNullable(String lhs, String rhs) { if (lhs == null) return -1; if (rhs == null) return 1; return lhs.compareToIgnoreCase(rhs); } }