org.milyn.javabean.context.BeanIdStore Maven / Gradle / Ivy
package org.milyn.javabean.context;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.milyn.assertion.AssertArgument;
import org.milyn.javabean.repository.BeanId;
/**
* Bean Id Store
*
* Represents a map of BeanId's. Every BeanId has it own unique index. The index
* is incremental. The index starts with zero.
*
* Once a BeanId is registered it can never be unregistered.
*
* This object is thread safe.
*
* @author [email protected]
*
*/
public class BeanIdStore {
private volatile HashMap beanIdMap = new HashMap();
/**
* registers a beanId name and returns the {@link BeanId} object.
* If the beanId name is already registered then belonging BeanId
* is returned.
*
* This method doesn't have a performance penalty anymore when then BeanId
* already exists.
*
* @return A new or existing BeanId.
*/
public BeanId register(String beanIdName) {
AssertArgument.isNotEmpty(beanIdName, "beanIdName");
BeanId beanId = beanIdMap.get(beanIdName);
if(beanId == null) {
synchronized(this) {
beanId = beanIdMap.get(beanIdName);
if(beanId == null) {
@SuppressWarnings("unchecked")
HashMap newBeanIdMap = (HashMap) beanIdMap.clone();
beanId = new BeanId(this, newBeanIdMap.size(), beanIdName);
newBeanIdMap.put(beanIdName, beanId);
beanIdMap = newBeanIdMap;
}
}
}
return beanId;
}
/**
* @return The BeanId or null if it is not registered;
*
*/
public BeanId getBeanId(String beanId) {
return beanIdMap.get(beanId);
}
/**
* @return if the bean Id name is already registered.
*
*/
public boolean containsBeanId(String beanId) {
return beanIdMap.containsKey(beanId);
}
/**
* Returns a copy of the internal bean id map
*
* @return An map where the key is the string based beanId and the value is the BeanId.
*
*/
public synchronized Map getBeanIdMap() {
return Collections.unmodifiableMap(beanIdMap);
}
/**
* @return the current index size.
*
*/
public int size() {
return beanIdMap.size();
}
}