| /* |
| * 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.os; |
| |
| import android.os.Bundle; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| |
| /** |
| * |
| * Defines a message containing a description and arbitrary data object that can be |
| * sent to a {@link Handler}. This object contains two extra int fields and an |
| * extra object field that allow you to not do allocations in many cases. |
| * |
| * <p class="note">While the constructor of Message is public, the best way to get |
| * one of these is to call {@link #obtain Message.obtain()} or one of the |
| * {@link Handler#obtainMessage Handler.obtainMessage()} methods, which will pull |
| * them from a pool of recycled objects.</p> |
| */ |
| public final class Message implements Parcelable { |
| /** |
| * User-defined message code so that the recipient can identify |
| * what this message is about. Each {@link Handler} has its own name-space |
| * for message codes, so you do not need to worry about yours conflicting |
| * with other handlers. |
| */ |
| public int what; |
| |
| // Use these fields instead of using the class's Bundle if you can. |
| /** arg1 and arg2 are lower-cost alternatives to using {@link #setData(Bundle) setData()} |
| if you only need to store a few integer values. */ |
| public int arg1; |
| |
| /** arg1 and arg2 are lower-cost alternatives to using {@link #setData(Bundle) setData()} |
| if you only need to store a few integer values.*/ |
| public int arg2; |
| |
| /** An arbitrary object to send to the recipient. This must be null when |
| * sending messages across processes. */ |
| public Object obj; |
| |
| /** Optional Messenger where replies to this message can be sent. |
| */ |
| public Messenger replyTo; |
| |
| /*package*/ long when; |
| |
| /*package*/ Bundle data; |
| |
| /*package*/ Handler target; |
| |
| /*package*/ Runnable callback; |
| |
| // sometimes we store linked lists of these things |
| /*package*/ Message next; |
| |
| private static Object mPoolSync = new Object(); |
| private static Message mPool; |
| private static int mPoolSize = 0; |
| |
| private static final int MAX_POOL_SIZE = 10; |
| |
| /** |
| * Return a new Message instance from the global pool. Allows us to |
| * avoid allocating new objects in many cases. |
| */ |
| public static Message obtain() { |
| synchronized (mPoolSync) { |
| if (mPool != null) { |
| Message m = mPool; |
| mPool = m.next; |
| m.next = null; |
| return m; |
| } |
| } |
| return new Message(); |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but copies the values of an existing |
| * message (including its target) into the new one. |
| * @param orig Original message to copy. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Message orig) { |
| Message m = obtain(); |
| m.what = orig.what; |
| m.arg1 = orig.arg1; |
| m.arg2 = orig.arg2; |
| m.obj = orig.obj; |
| m.replyTo = orig.replyTo; |
| if (orig.data != null) { |
| m.data = new Bundle(orig.data); |
| } |
| m.target = orig.target; |
| m.callback = orig.callback; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but sets the value for the <em>target</em> member on the Message returned. |
| * @param h Handler to assign to the returned Message object's <em>target</em> member. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h) { |
| Message m = obtain(); |
| m.target = h; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain(Handler)}, but assigns a callback Runnable on |
| * the Message that is returned. |
| * @param h Handler to assign to the returned Message object's <em>target</em> member. |
| * @param callback Runnable that will execute when the message is handled. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h, Runnable callback) { |
| Message m = obtain(); |
| m.target = h; |
| m.callback = callback; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but sets the values for both <em>target</em> and |
| * <em>what</em> members on the Message. |
| * @param h Value to assign to the <em>target</em> member. |
| * @param what Value to assign to the <em>what</em> member. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h, int what) { |
| Message m = obtain(); |
| m.target = h; |
| m.what = what; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but sets the values of the <em>target</em>, <em>what</em>, and <em>obj</em> |
| * members. |
| * @param h The <em>target</em> value to set. |
| * @param what The <em>what</em> value to set. |
| * @param obj The <em>object</em> method to set. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h, int what, Object obj) { |
| Message m = obtain(); |
| m.target = h; |
| m.what = what; |
| m.obj = obj; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but sets the values of the <em>target</em>, <em>what</em>, |
| * <em>arg1</em>, and <em>arg2</em> members. |
| * |
| * @param h The <em>target</em> value to set. |
| * @param what The <em>what</em> value to set. |
| * @param arg1 The <em>arg1</em> value to set. |
| * @param arg2 The <em>arg2</em> value to set. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h, int what, int arg1, int arg2) { |
| Message m = obtain(); |
| m.target = h; |
| m.what = what; |
| m.arg1 = arg1; |
| m.arg2 = arg2; |
| |
| return m; |
| } |
| |
| /** |
| * Same as {@link #obtain()}, but sets the values of the <em>target</em>, <em>what</em>, |
| * <em>arg1</em>, <em>arg2</em>, and <em>obj</em> members. |
| * |
| * @param h The <em>target</em> value to set. |
| * @param what The <em>what</em> value to set. |
| * @param arg1 The <em>arg1</em> value to set. |
| * @param arg2 The <em>arg2</em> value to set. |
| * @param obj The <em>obj</em> value to set. |
| * @return A Message object from the global pool. |
| */ |
| public static Message obtain(Handler h, int what, |
| int arg1, int arg2, Object obj) { |
| Message m = obtain(); |
| m.target = h; |
| m.what = what; |
| m.arg1 = arg1; |
| m.arg2 = arg2; |
| m.obj = obj; |
| |
| return m; |
| } |
| |
| /** |
| * Return a Message instance to the global pool. You MUST NOT touch |
| * the Message after calling this function -- it has effectively been |
| * freed. |
| */ |
| public void recycle() { |
| synchronized (mPoolSync) { |
| if (mPoolSize < MAX_POOL_SIZE) { |
| clearForRecycle(); |
| |
| next = mPool; |
| mPool = this; |
| } |
| } |
| } |
| |
| /** |
| * Make this message like o. Performs a shallow copy of the data field. |
| * Does not copy the linked list fields, nor the timestamp or |
| * target/callback of the original message. |
| */ |
| public void copyFrom(Message o) { |
| this.what = o.what; |
| this.arg1 = o.arg1; |
| this.arg2 = o.arg2; |
| this.obj = o.obj; |
| this.replyTo = o.replyTo; |
| |
| if (o.data != null) { |
| this.data = (Bundle) o.data.clone(); |
| } else { |
| this.data = null; |
| } |
| } |
| |
| /** |
| * Return the targeted delivery time of this message, in milliseconds. |
| */ |
| public long getWhen() { |
| return when; |
| } |
| |
| public void setTarget(Handler target) { |
| this.target = target; |
| } |
| |
| /** |
| * Retrieve the a {@link android.os.Handler Handler} implementation that |
| * will receive this message. The object must implement |
| * {@link android.os.Handler#handleMessage(android.os.Message) |
| * Handler.handleMessage()}. Each Handler has its own name-space for |
| * message codes, so you do not need to |
| * worry about yours conflicting with other handlers. |
| */ |
| public Handler getTarget() { |
| return target; |
| } |
| |
| /** |
| * Retrieve callback object that will execute when this message is handled. |
| * This object must implement Runnable. This is called by |
| * the <em>target</em> {@link Handler} that is receiving this Message to |
| * dispatch it. If |
| * not set, the message will be dispatched to the receiving Handler's |
| * {@link Handler#handleMessage(Message Handler.handleMessage())}. */ |
| public Runnable getCallback() { |
| return callback; |
| } |
| |
| /** |
| * Obtains a Bundle of arbitrary data associated with this |
| * event, lazily creating it if necessary. Set this value by calling {@link #setData(Bundle)}. |
| */ |
| public Bundle getData() { |
| if (data == null) { |
| data = new Bundle(); |
| } |
| |
| return data; |
| } |
| |
| /** |
| * Like getData(), but does not lazily create the Bundle. A null |
| * is returned if the Bundle does not already exist. |
| */ |
| public Bundle peekData() { |
| return data; |
| } |
| |
| /** Sets a Bundle of arbitrary data values. Use arg1 and arg1 members |
| * as a lower cost way to send a few simple integer values, if you can. */ |
| public void setData(Bundle data) { |
| this.data = data; |
| } |
| |
| /** |
| * Sends this Message to the Handler specified by {@link #getTarget}. |
| * Throws a null pointer exception if this field has not been set. |
| */ |
| public void sendToTarget() { |
| target.sendMessage(this); |
| } |
| |
| /*package*/ void clearForRecycle() { |
| what = 0; |
| arg1 = 0; |
| arg2 = 0; |
| obj = null; |
| replyTo = null; |
| when = 0; |
| target = null; |
| callback = null; |
| data = null; |
| } |
| |
| /** Constructor (but the preferred way to get a Message is to call {@link #obtain() Message.obtain()}). |
| */ |
| public Message() { |
| } |
| |
| public String toString() { |
| StringBuilder b = new StringBuilder(); |
| |
| b.append("{ what="); |
| b.append(what); |
| |
| b.append(" when="); |
| b.append(when); |
| |
| if (arg1 != 0) { |
| b.append(" arg1="); |
| b.append(arg1); |
| } |
| |
| if (arg2 != 0) { |
| b.append(" arg2="); |
| b.append(arg2); |
| } |
| |
| if (obj != null) { |
| b.append(" obj="); |
| b.append(obj); |
| } |
| |
| b.append(" }"); |
| |
| return b.toString(); |
| } |
| |
| public static final Parcelable.Creator<Message> CREATOR |
| = new Parcelable.Creator<Message>() { |
| public Message createFromParcel(Parcel source) { |
| Message msg = Message.obtain(); |
| msg.readFromParcel(source); |
| return msg; |
| } |
| |
| public Message[] newArray(int size) { |
| return new Message[size]; |
| } |
| }; |
| |
| public int describeContents() { |
| return 0; |
| } |
| |
| public void writeToParcel(Parcel dest, int flags) { |
| if (obj != null || callback != null) { |
| throw new RuntimeException( |
| "Can't marshal objects across processes."); |
| } |
| dest.writeInt(what); |
| dest.writeInt(arg1); |
| dest.writeInt(arg2); |
| dest.writeLong(when); |
| dest.writeBundle(data); |
| Messenger.writeMessengerOrNullToParcel(replyTo, dest); |
| } |
| |
| private final void readFromParcel(Parcel source) { |
| what = source.readInt(); |
| arg1 = source.readInt(); |
| arg2 = source.readInt(); |
| when = source.readLong(); |
| data = source.readBundle(); |
| replyTo = Messenger.readMessengerOrNullFromParcel(source); |
| } |
| } |
| |