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Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
EntryUpdateState.java | 50% | 76.9% | 100% | 76.9% |
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/*
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* Copyright (c) 2002-2003 by OpenSymphony
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* All rights reserved.
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*/
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package com.opensymphony.oscache.base;
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/**
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* Holds the state of a Cache Entry that is in the process of being (re)generated.
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* This is not synchronized; the synchronization must be handled by the calling
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* classes.
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*
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* @author <a href="mailto:chris@swebtec.com">Chris Miller</a>
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* @author Author: $
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* @version Revision: $
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*/
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public class EntryUpdateState { |
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/**
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* The initial state when this object is first created
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*/
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public static final int NOT_YET_UPDATING = -1; |
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/**
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* Update in progress state
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*/
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public static final int UPDATE_IN_PROGRESS = 0; |
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/**
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* Update complete state
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*/
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public static final int UPDATE_COMPLETE = 1; |
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/**
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* Update cancelled state
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*/
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public static final int UPDATE_CANCELLED = 2; |
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/**
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* Current update state
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*/
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int state = NOT_YET_UPDATING;
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/**
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* This is the initial state when an instance this object is first created.
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* It indicates that a cache entry needs updating, but no thread has claimed
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* responsibility for updating it yet.
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*/
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public boolean isAwaitingUpdate() { |
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return state == NOT_YET_UPDATING;
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} |
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/**
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* The thread that was responsible for updating the cache entry (ie, the thread
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* that managed to grab the update lock) has decided to give up responsibility
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* for performing the update. OSCache will notify any other threads that are
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* waiting on the update so one of them can take over the responsibility.
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*/
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public boolean isCancelled() { |
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return state == UPDATE_CANCELLED;
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} |
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/**
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* The update of the cache entry has been completed.
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*/
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public boolean isComplete() { |
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return state == UPDATE_COMPLETE;
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} |
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/**
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* The cache entry is currently being generated by the thread that got hold of
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* the update lock.
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*/
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public boolean isUpdating() { |
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return state == UPDATE_IN_PROGRESS;
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} |
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/**
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* Updates the state to <code>UPDATE_CANCELLED</code>. This should <em>only<em>
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* be called by the thread that managed to get the update lock.
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*/
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public void cancelUpdate() { |
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if (state != UPDATE_IN_PROGRESS) {
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throw new IllegalStateException("Cannot cancel cache update - current state (" + state + ") is not UPDATE_IN_PROGRESS"); |
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} |
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state = UPDATE_CANCELLED; |
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} |
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/**
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* Updates the state to <code>UPDATE_COMPLETE</code>. This should <em>only</em>
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* be called by the thread that managed to get the update lock.
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*/
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public void completeUpdate() { |
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if (state != UPDATE_IN_PROGRESS) {
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throw new IllegalStateException("Cannot complete cache update - current state (" + state + ") is not UPDATE_IN_PROGRESS"); |
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} |
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state = UPDATE_COMPLETE; |
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} |
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/**
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* Attempt to change the state to <code>UPDATE_IN_PROGRESS</code>. Calls
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* to this method must be synchronized on the EntryUpdateState instance.
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*/
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public void startUpdate() { |
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if ((state != NOT_YET_UPDATING) && (state != UPDATE_CANCELLED)) {
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throw new IllegalStateException("Cannot begin cache update - current state (" + state + ") is not NOT_YET_UPDATING or UPDATE_CANCELLED"); |
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} |
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state = UPDATE_IN_PROGRESS; |
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} |
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} |
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