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 android.print; import android.annotation.NonNull; import android.annotation.Nullable; import java.util.Objects; /** * This class represents a print job from the perspective of an * application. It contains behavior methods for performing operations * on it as well as methods for querying its state. A snapshot of the * print job state is represented by the {@link PrintJobInfo} class. * The state of a print job may change over time. An application receives * instances of this class when creating a print job or querying for * its print jobs. */ public final class PrintJob { private final @NonNull PrintManager mPrintManager; private @NonNull PrintJobInfo mCachedInfo; PrintJob(@NonNull PrintJobInfo info, @NonNull PrintManager printManager) { mCachedInfo = info; mPrintManager = printManager; } /** * Gets the unique print job id. * * @return The id. */ public @Nullable PrintJobId getId() { return mCachedInfo.getId(); } /** * Gets the {@link PrintJobInfo} that describes this job. * <p> * <strong>Node:</strong>The returned info object is a snapshot of the * current print job state. Every call to this method returns a fresh * info object that reflects the current print job state. * </p> * * @return The print job info. */ public @NonNull PrintJobInfo getInfo() { if (isInImmutableState()) { return mCachedInfo; } PrintJobInfo info = mPrintManager.getPrintJobInfo(mCachedInfo.getId()); if (info != null) { mCachedInfo = info; } return mCachedInfo; } /** * Cancels this print job. You can request cancellation of a * queued, started, blocked, or failed print job. * * @see #isQueued() * @see #isStarted() * @see #isBlocked() * @see #isFailed() */ public void cancel() { final int state = getInfo().getState(); if (state == PrintJobInfo.STATE_QUEUED || state == PrintJobInfo.STATE_STARTED || state == PrintJobInfo.STATE_BLOCKED || state == PrintJobInfo.STATE_FAILED) { mPrintManager.cancelPrintJob(mCachedInfo.getId()); } } /** * Restarts this print job. You can request restart of a failed * print job. * * @see #isFailed() */ public void restart() { if (isFailed()) { mPrintManager.restartPrintJob(mCachedInfo.getId()); } } /** * Gets whether this print job is queued. Such a print job is * ready to be printed. You can request a cancellation via * {@link #cancel()}. * * @return Whether the print job is queued. * * @see #cancel() */ public boolean isQueued() { return getInfo().getState() == PrintJobInfo.STATE_QUEUED; } /** * Gets whether this print job is started. Such a print job is * being printed. You can request a cancellation via * {@link #cancel()}. * * @return Whether the print job is started. * * @see #cancel() */ public boolean isStarted() { return getInfo().getState() == PrintJobInfo.STATE_STARTED; } /** * Gets whether this print job is blocked. Such a print job is halted * due to an abnormal condition. You can request a cancellation via * {@link #cancel()}. * * @return Whether the print job is blocked. * * @see #cancel() */ public boolean isBlocked() { return getInfo().getState() == PrintJobInfo.STATE_BLOCKED; } /** * Gets whether this print job is completed. Such a print job * is successfully printed. You can neither cancel nor restart * such a print job. * * @return Whether the print job is completed. */ public boolean isCompleted() { return getInfo().getState() == PrintJobInfo.STATE_COMPLETED; } /** * Gets whether this print job is failed. Such a print job is * not successfully printed due to an error. You can request * a restart via {@link #restart()} or cancel via {@link #cancel()}. * * @return Whether the print job is failed. * * @see #restart() * @see #cancel() */ public boolean isFailed() { return getInfo().getState() == PrintJobInfo.STATE_FAILED; } /** * Gets whether this print job is cancelled. Such a print job was * cancelled as a result of a user request. This is a final state. * You cannot restart such a print job. * * @return Whether the print job is cancelled. */ public boolean isCancelled() { return getInfo().getState() == PrintJobInfo.STATE_CANCELED; } private boolean isInImmutableState() { final int state = mCachedInfo.getState(); return state == PrintJobInfo.STATE_COMPLETED || state == PrintJobInfo.STATE_CANCELED; } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } PrintJob other = (PrintJob) obj; return Objects.equals(mCachedInfo.getId(), other.mCachedInfo.getId()); } @Override public int hashCode() { PrintJobId printJobId = mCachedInfo.getId(); if (printJobId == null) { return 0; } else { return printJobId.hashCode(); } } }