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extracted StateBackedCreator interface

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This commit is contained in:
Michael Hunger
2011-03-25 11:22:20 +01:00
parent 8fa7aabdc0
commit b52de879de
2 changed files with 32 additions and 25 deletions
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46
spring-data-commons-core/src/main/java/org/springframework/data/persistence/AbstractConstructorEntityInstantiator.java
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@@ -17,24 +17,20 @@ import java.util.Map;
*/
public abstract class AbstractConstructorEntityInstantiator<BACKING_INTERFACE, STATE> implements EntityInstantiator<BACKING_INTERFACE, STATE> {
interface Instantiator<T, STATE> {
T create(STATE n, Class<T> c) throws Exception;
}
private final Logger log = LoggerFactory.getLogger(getClass());
private final Map<Class<? extends BACKING_INTERFACE>,Instantiator<? extends BACKING_INTERFACE,STATE>> cache = new HashMap<Class<? extends BACKING_INTERFACE>,Instantiator<? extends BACKING_INTERFACE,STATE>>();
private final Logger log = LoggerFactory.getLogger(getClass());
private final Map<Class<? extends BACKING_INTERFACE>,StateBackedCreator<? extends BACKING_INTERFACE,STATE>> cache = new HashMap<Class<? extends BACKING_INTERFACE>,StateBackedCreator<? extends BACKING_INTERFACE,STATE>>();
final public <T extends BACKING_INTERFACE> T createEntityFromState(STATE n, Class<T> c) {
try {
Instantiator<T, STATE> instantiator = (Instantiator<T, STATE>) cache.get(c);
if (instantiator!=null) return instantiator.create(n,c);
StateBackedCreator<T, STATE> creator = (StateBackedCreator<T, STATE>) cache.get(c);
if (creator !=null) return creator.create(n,c);
synchronized (cache) {
instantiator = (Instantiator<T, STATE>) cache.get(c);
if (instantiator!=null) return instantiator.create(n,c);
creator = (StateBackedCreator<T, STATE>) cache.get(c);
if (creator !=null) return creator.create(n,c);
Class<STATE> stateClass = (Class<STATE>) n.getClass();
instantiator=createInstantiator(c, stateClass);
cache.put(c,instantiator);
return instantiator.create(n,c);
creator =createInstantiator(c, stateClass);
cache.put(c, creator);
return creator.create(n,c);
}
} catch (IllegalArgumentException e) {
throw e;
@@ -46,20 +42,20 @@ public abstract class AbstractConstructorEntityInstantiator<BACKING_INTERFACE, S
}
public void setInstantiators(Map<Class<? extends BACKING_INTERFACE>,Instantiator<? extends BACKING_INTERFACE,STATE>> instantiators) {
public void setInstantiators(Map<Class<? extends BACKING_INTERFACE>,StateBackedCreator<? extends BACKING_INTERFACE,STATE>> instantiators) {
this.cache.putAll(instantiators);
}
protected <T extends BACKING_INTERFACE> Instantiator<T, STATE> createInstantiator(Class<T> type, final Class<STATE> stateType) {
Instantiator<T,STATE> instantiator=stateTakingConstructorInstantiator(type,stateType);
if (instantiator!=null) return instantiator;
instantiator = emptyConstructorStateSettingInstantiator(type,stateType);
if (instantiator!=null) return instantiator;
protected <T extends BACKING_INTERFACE> StateBackedCreator<T, STATE> createInstantiator(Class<T> type, final Class<STATE> stateType) {
StateBackedCreator<T,STATE> creator =stateTakingConstructorInstantiator(type,stateType);
if (creator !=null) return creator;
creator = emptyConstructorStateSettingInstantiator(type,stateType);
if (creator !=null) return creator;
return createFailingInstantiator(stateType);
}
private <T extends BACKING_INTERFACE> Instantiator<T, STATE> createFailingInstantiator(final Class<STATE> stateType) {
return new Instantiator<T, STATE>() {
private <T extends BACKING_INTERFACE> StateBackedCreator<T, STATE> createFailingInstantiator(final Class<STATE> stateType) {
return new StateBackedCreator<T, STATE>() {
public T create(STATE n, Class<T> c) throws Exception {
throw new IllegalArgumentException(getClass().getSimpleName() + ": entity " + c +
" must have either a constructor taking [" + stateType + "] or a no-arg constructor and state set method");
@@ -67,13 +63,13 @@ public abstract class AbstractConstructorEntityInstantiator<BACKING_INTERFACE, S
};
}
private <T extends BACKING_INTERFACE> Instantiator<T, STATE> emptyConstructorStateSettingInstantiator(Class<T> type, Class<STATE> stateType) {
private <T extends BACKING_INTERFACE> StateBackedCreator<T, STATE> emptyConstructorStateSettingInstantiator(Class<T> type, Class<STATE> stateType) {
final Constructor<T> constructor = getNoArgConstructor(type);
if (constructor == null) return null;
log.info("Using " + type + " no-arg constructor");
return new Instantiator<T, STATE>() {
return new StateBackedCreator<T, STATE>() {
public T create(STATE n, Class<T> c) throws Exception {
try {
StateProvider.setUnderlyingState(n);
@@ -93,13 +89,13 @@ public abstract class AbstractConstructorEntityInstantiator<BACKING_INTERFACE, S
return getDeclaredConstructor(type);
}
private <T extends BACKING_INTERFACE> Instantiator<T, STATE> stateTakingConstructorInstantiator(Class<T> type, Class<STATE> stateType) {
private <T extends BACKING_INTERFACE> StateBackedCreator<T, STATE> stateTakingConstructorInstantiator(Class<T> type, Class<STATE> stateType) {
Class<? extends STATE> stateInterface = (Class<? extends STATE>) stateType.getInterfaces()[0];
final Constructor<T> constructor = ClassUtils.getConstructorIfAvailable(type, stateInterface);
if (constructor == null) return null;
log.info("Using " + type + " constructor taking " + stateInterface);
return new Instantiator<T, STATE>() {
return new StateBackedCreator<T, STATE>() {
public T create(STATE n, Class<T> c) throws Exception {
return constructor.newInstance(n);
}

11
spring-data-commons-core/src/main/java/org/springframework/data/persistence/StateBackedCreator.java Normal file
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@@ -0,0 +1,11 @@
package org.springframework.data.persistence;
/**
* encapsulates the instantiator of state-backed classes and populating them with the provided state.
*
* Can be implemented and registered with the concrete AbstractConstructorEntityInstantiator to provide
* non reflection bases instantiaton for domain classes
*/
public interface StateBackedCreator<T, STATE> {
T create(STATE n, Class<T> c) throws Exception;
}