Philip P. Moltmann | 9dcb86a | 2016-03-14 14:31:12 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.printservice.recommendation; |
| 18 | |
| 19 | import android.annotation.IntRange; |
| 20 | import android.annotation.NonNull; |
| 21 | import android.annotation.StringRes; |
| 22 | import com.android.internal.util.Preconditions; |
| 23 | |
| 24 | /** |
| 25 | * Wrapper for a {@link PrintServicePlugin}, isolating issues with the plugin as good as possible |
| 26 | * from the {@link RecommendationServiceImpl service}. |
| 27 | */ |
| 28 | class RemotePrintServicePlugin implements PrintServicePlugin.PrinterDiscoveryCallback { |
| 29 | /** Lock for this object */ |
| 30 | private final Object mLock = new Object(); |
| 31 | |
| 32 | /** The name of the print service. */ |
| 33 | public final @StringRes int name; |
| 34 | |
| 35 | /** If the print service if for more than a single vendor */ |
| 36 | public final boolean recommendsMultiVendorService; |
| 37 | |
| 38 | /** The package name of the full print service */ |
| 39 | public final @NonNull CharSequence packageName; |
| 40 | |
| 41 | /** Wrapped plugin */ |
| 42 | private final @NonNull PrintServicePlugin mPlugin; |
| 43 | |
| 44 | /** The number of printers discovered by the plugin */ |
| 45 | private @IntRange(from = 0) int mNumPrinters; |
| 46 | |
| 47 | /** If the plugin is started by not yet stopped */ |
| 48 | private boolean isRunning; |
| 49 | |
| 50 | /** Listener for changes to {@link #mNumPrinters}. */ |
| 51 | private @NonNull OnChangedListener mListener; |
| 52 | |
| 53 | /** |
| 54 | * Create a new remote for a {@link PrintServicePlugin plugin}. |
| 55 | * |
| 56 | * @param plugin The plugin to be wrapped |
| 57 | * @param listener The listener to be notified about changes in this plugin |
| 58 | * @param recommendsMultiVendorService If the plugin detects printers of more than a single |
| 59 | * vendor |
| 60 | * |
| 61 | * @throws PluginException If the plugin has issues while caching basic stub properties |
| 62 | */ |
| 63 | public RemotePrintServicePlugin(@NonNull PrintServicePlugin plugin, |
| 64 | @NonNull OnChangedListener listener, boolean recommendsMultiVendorService) |
| 65 | throws PluginException { |
| 66 | mListener = listener; |
| 67 | mPlugin = plugin; |
| 68 | this.recommendsMultiVendorService = recommendsMultiVendorService; |
| 69 | |
| 70 | // We handle any throwable to isolate our self from bugs in the plugin code. |
| 71 | // Cache simple properties to avoid having to deal with exceptions later in the code. |
| 72 | try { |
| 73 | name = Preconditions.checkArgumentPositive(mPlugin.getName(), "name"); |
| 74 | packageName = Preconditions.checkStringNotEmpty(mPlugin.getPackageName(), |
| 75 | "packageName"); |
| 76 | } catch (Throwable e) { |
| 77 | throw new PluginException(mPlugin, "Cannot cache simple properties ", e); |
| 78 | } |
| 79 | |
| 80 | isRunning = false; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Start the plugin. From now on there might be callbacks to the registered listener. |
| 85 | */ |
| 86 | public void start() |
| 87 | throws PluginException { |
| 88 | // We handle any throwable to isolate our self from bugs in the stub code |
| 89 | try { |
| 90 | synchronized (mLock) { |
| 91 | isRunning = true; |
| 92 | mPlugin.start(this); |
| 93 | } |
| 94 | } catch (Throwable e) { |
| 95 | throw new PluginException(mPlugin, "Cannot start", e); |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * Stop the plugin. From this call on there will not be any more callbacks. |
| 101 | */ |
| 102 | public void stop() throws PluginException { |
| 103 | // We handle any throwable to isolate our self from bugs in the stub code |
| 104 | try { |
| 105 | synchronized (mLock) { |
| 106 | mPlugin.stop(); |
| 107 | isRunning = false; |
| 108 | } |
| 109 | } catch (Throwable e) { |
| 110 | throw new PluginException(mPlugin, "Cannot stop", e); |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * Get the current number of printers reported by the stub. |
| 116 | * |
| 117 | * @return The number of printers reported by the stub. |
| 118 | */ |
| 119 | public @IntRange(from = 0) int getNumPrinters() { |
| 120 | return mNumPrinters; |
| 121 | } |
| 122 | |
| 123 | @Override |
| 124 | public void onChanged(@IntRange(from = 0) int numDiscoveredPrinters) { |
| 125 | synchronized (mLock) { |
| 126 | Preconditions.checkState(isRunning); |
| 127 | |
| 128 | mNumPrinters = Preconditions.checkArgumentNonnegative(numDiscoveredPrinters, |
| 129 | "numDiscoveredPrinters"); |
| 130 | |
| 131 | if (mNumPrinters > 0) { |
| 132 | mListener.onChanged(); |
| 133 | } |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * Listener to listen for changes to {@link #getNumPrinters} |
| 139 | */ |
| 140 | public interface OnChangedListener { |
| 141 | void onChanged(); |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Exception thrown if the stub has any issues. |
| 146 | */ |
| 147 | public class PluginException extends Exception { |
| 148 | private PluginException(PrintServicePlugin plugin, String message, Throwable e) { |
| 149 | super(plugin + ": " + message, e); |
| 150 | } |
| 151 | } |
| 152 | } |