ehcache memcache 区别_ehcache缓存原理_ehcache使用(12)

说明

1、首先要判断initialConfiguration这个参数是不是为空，判断的情况下肯定是为就直接调用了parseConfiguration这个方法，这个方法调用classpath默认路径来查找配置文件内容，初始化完configuration以后调用doInit方法。

2、doInit方法主要用来初始化最大的本地堆大小，初始化最大的本地持久化磁盘设置大小，集群模式，事务设置等等。

12.3 Cache类解析

cache的类继承结构如下所示：

说明：

Ehcache接口是整个缓存的核心接口，该接口提供的方法可以直接操作缓存，比如put,get等方法。由于方法太多我们只单拿出来put和get方法做一个深入分析。

先看put方法源码：

 private void putInternal(Element element, boolean doNotNotifyCacheReplicators, boolean useCacheWriter) {
        putObserver.begin();
        if (useCacheWriter) {
            initialiseCacheWriterManager(true);
        }

        checkStatus();

        if (disabled) {
            putObserver.end(PutOutcome.IGNORED);
            return;
        }

        if (element == null) {
            if (doNotNotifyCacheReplicators) {

                LOG.debug("Element from replicated put is null. This happens because the element is a SoftReference" +
                        " and it has been collected. Increase heap memory on the JVM or set -Xms to be the same as " +
                        "-Xmx to avoid this problem.");

            }
            putObserver.end(PutOutcome.IGNORED);
            return;
        }


        if (element.getObjectKey() == null) {
            putObserver.end(PutOutcome.IGNORED);
            return;
        }

        element.resetAccessStatistics();

        applyDefaultsToElementWithoutLifespanSet(element);

        backOffIfDiskSpoolFull();
        element.updateUpdateStatistics();
        boolean elementExists = false;
        if (useCacheWriter) {
            boolean notifyListeners = true;
            try {
                elementExists = !compoundStore.putWithWriter(element, cacheWriterManager);
            } catch (StoreUpdateException e) {
                elementExists = e.isUpdate();
                notifyListeners = configuration.getCacheWriterConfiguration().getNotifyListenersOnException();
                RuntimeException cause = e.getCause();
                if (cause instanceof CacheWriterManagerException) {
                    throw ((CacheWriterManagerException)cause).getCause();
                }
                throw cause;
            } finally {
                if (notifyListeners) {
                    notifyPutInternalListeners(element, doNotNotifyCacheReplicators, elementExists);
                }
            }
        } else {
            elementExists = !compoundStore.put(element);
            notifyPutInternalListeners(element, doNotNotifyCacheReplicators, elementExists);
        }
        putObserver.end(elementExists ? PutOutcome.UPDATED : PutOutcome.ADDED);

    }

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