/* Command.java {{IS_NOTE Purpose: Description: History: Fri Aug 18 00:07:15 2006, Created by tomyeh }}IS_NOTE Copyright (C) 2006 Potix Corporation. All Rights Reserved. {{IS_RIGHT This program is distributed under GPL Version 2.0 in the hope that it will be useful, but WITHOUT ANY WARRANTY. }}IS_RIGHT */ package org.zkoss.zk.au; /** Represents a command of a request ({@link AuRequest}). * Each command is unique no matter {@link #getId} is the same or not. * All commands must be declared as static members of {@link AuRequest} * such that they will be initialized sequentially at begining. * Also, if a command will generate an event, it shall register the * event in its constructor. * * @author tomyeh */ abstract public class Command { private final String _id; private final int _flags; /** Whether to skip this command if previous commands ever caused errors. *In other words, it decides whether to skip this command when * {@link #process(AuRequest,boolean)} is called with errorEver = true; * This argument is used to control the behavior of * {@link #process(AuRequest,boolean)}. * * Part of the returned value of {@link #getFlags}. */ public static final int SKIP_IF_EVER_ERROR = 0x0001; /** Whether this command is ignorable. * In other words, it is ignored if there is any following command is * recieved. * * Part of the returned value of {@link #getFlags}. */ public static final int IGNORABLE = 0x0002; /** Whether this command belongs to the control group. * A new control-group command is dropped if there is already * another control-group command is in the queue. */ public static final int CTRL_GROUP = 0x0004; /** Whether to drop the existent command (in the queue) if it is the same * as the new arrival one. * By the same we mean both command's ID and target are the same. */ public static final int IGNORE_OLD_EQUIV = 0x0008; /** Whether to drop the existent command (in the queue) if it is the same * as the immediate following one. * By the same we mean both command's ID and target are the same. */ public static final int IGNORE_IMMEDIATE_OLD_EQUIV = 0x0010; /** * @param flags a combination of {@link #SKIP_IF_EVER_ERROR}, * {@link #IGNORABLE} and others */ protected Command(String id, int flags) { _id = id; _flags = flags; AuRequest.addCommand(this); } /** Returns the attributes of this command, a combination of * {@link #SKIP_IF_EVER_ERROR}, {@link #IGNORABLE} and others. */ public final int getFlags() { return _flags; } /** Returns ID of this command. */ public final String getId() { return _id; } public final String toString() { return _id; } public final boolean equals(Object o) { //prevent override return this == o; } /** Derived must override this method to process this command. */ abstract protected void process(AuRequest request); /** Called to process the specified request. * You don't override this method directly. * Rather, override {@link #process(AuRequest)}. * * @param everError whether any error ever occured before * processing this command. * Notice that multiple commands might be processed in one * execution. */ public final void process(AuRequest request, boolean everError) { if (!everError || !((_flags & SKIP_IF_EVER_ERROR) == 0)) process(request); } }
