本文整理汇总了Java中com.alibaba.dubbo.common.utils.Holder类的典型用法代码示例。如果您正苦于以下问题：Java Holder类的具体用法？Java Holder怎么用？Java Holder使用的例子？那么, 这里精选的类代码示例或许可以为您提供帮助。
Holder类属于com.alibaba.dubbo.common.utils包，在下文中一共展示了Holder类的7个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: getExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*
* @param name
* @return
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
if ("true".equals(name)) {
return getDefaultExtension();
}
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
instance = createExtension(name);
holder.set(instance);
}
}
}
return (T) instance;
}
示例2: getExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*
* @param name extension name
* @return extension
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
if ("true".equals(name)) {
return getDefaultExtension();
}
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
instance = createExtension(name);
holder.set(instance);
}
}
}
return (T) instance;
}
示例3: getExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*
* @param name
* @return
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
if ("true".equals(name)) {
return getDefaultExtension();
}
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
instance = createExtension(name);
holder.set(instance);
}
}
}
return (T) instance;
}
示例4: getLoadedExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回扩展点实例，如果没有指定的扩展点或是还没加载（即实例化）则返回<code>null</code>。注意：此方法不会触发扩展点的加载。
* <p />
* 一般应该调用{@link #getExtension(String)}方法获得扩展，这个方法会触发扩展点加载。
*
* @see #getExtension(String)
*/
@SuppressWarnings("unchecked")
public T getLoadedExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
return (T) holder.get();
}
示例5: getExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*根据名称获取当前扩展的指定实现
* @param name
* @return
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
//获取默认实现
if ("true".equals(name)) {
return getDefaultExtension();
}
//从缓存获取
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
//缓存不存在，创建实例
instance = createExtension(name);
//加入缓存
holder.set(instance);
}
}
}
return (T) instance;
}
示例6: getLoadedExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回扩展点实例，如果没有指定的扩展点或是还没加载（即实例化）则返回<code>null</code>。注意：此方法不会触发扩展点的加载。
* <p/>
* 一般应该调用{@link #getExtension(String)}方法获得扩展，这个方法会触发扩展点加载。
*
* @see #getExtension(String)
*/
@SuppressWarnings("unchecked")
public T getLoadedExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
return (T) holder.get();
}
示例7: getExtension
import com.alibaba.dubbo.common.utils.Holder; //导入依赖的package包/类
/**
* 返回指定名字的扩展。如果指定名字的扩展不存在，则抛异常 {@link IllegalStateException}.
*
* @param name
* @return
*/
@SuppressWarnings("unchecked")
public T getExtension(String name) {
if (name == null || name.length() == 0)
throw new IllegalArgumentException("Extension name == null");
if ("true".equals(name)) {
return getDefaultExtension();
}
//先从缓存中去取
Holder<Object> holder = cachedInstances.get(name);
if (holder == null) {
//如果缓存中没有的话在创建一个然后放进去，但是此时并没有实际内容，只有一个空的容器Holder
cachedInstances.putIfAbsent(name, new Holder<Object>());
holder = cachedInstances.get(name);
}
Object instance = holder.get();
if (instance == null) {
synchronized (holder) {
instance = holder.get();
if (instance == null) {
//根据名字创建特定的扩展
instance = createExtension(name);
holder.set(instance);
}
}
}
return (T) instance;
}