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/*
* Copyright (c) 2008 Israfil Consulting Services Corporation
* Copyright (c) 2008 Christian Edward Gruber
* All Rights Reserved
*
* This software is licensed under the Berkeley Standard Distribution license,
* (BSD license), as defined below:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of Israfil Consulting Services nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* $Id: Copyright.java 618 2008-04-14 14:03:03Z christianedwardgruber $
*/
package net.israfil.foundation.container;
import java.util.HashMap;
import java.util.Map;
import net.israfil.foundation.container.adapters.IndependentAutoWiringAdapter;
import net.israfil.foundation.container.error.ComponentAlreadyRegisteredError;
import net.israfil.foundation.container.error.CouldNotCreateComponentError;
import net.israfil.foundation.container.error.UnsatisfiedDependencyError;
import net.israfil.foundation.container.util.CyclicalReferenceDetectionUtil;
import net.israfil.foundation.container.util.NonDuplicateStack;
/**
* A default implementation of AutoWiringAdaptableContainer, a Container
* that uses an AutoWiringAdapter to ensure that components can be
* created appropriately with their dependencies satisfied automatically.
*
* This adapter is intended for constructor injection, but relies on the
* adapter to perform such. No reflection is used by this class itself.
*
*/
public class DefaultContainer extends AbstractContainer implements AutoWiringAdaptableContainer {
private Map<Object,Object> registry = new HashMap<Object,Object>();
private final boolean failEarly;
private boolean starting = false;
private final Object CREATION_MUTEX = new Object();
/**
* A default constructor that will throw errors regarding circular
* dependencies at registration time, throw missing dependency errors
* at wire-up (getComponent()) time, and has no parent.
*
* @param failEarly A boolean to indicate that this container should detect missing or circular dependencies at start() time.
*/
public DefaultContainer() {
super();
this.failEarly = false;
}
/**
* Construct this container such that it detects missing dependencies
* upon invocation of start(). Otherwise, it will fail at wire time,
* rather than at registration time. Circular references will give errors
* at registration time.
*
* @param failEarly A boolean to indicate that this container should detect missing or circular dependencies at start() time.
*/
public DefaultContainer(boolean failEarly) {
super();
this.failEarly = failEarly;
}
/**
* This method constructs a DefaultAutoWiringAdaptableContainer that
* has a parent container for backup resolution. The parent container
* can be of any type of Container.
*
* @param parent The parent container (optional)
*/
public DefaultContainer(Container parent) {
super(parent);
this.failEarly = false;
}
/**
* Construct this container such that it detects missing dependencies
* upon invocation of start(). Otherwise, it will fail at wire time,
* rather than at registration time. Circular references will give errors
* at registration time. This method also provides for a parent container.
* The parent container can be of any type of Container.
*
* @param failEarly A boolean to indicate that this container should detect missing or circular dependencies at start() time.
* @param parent The parent Container (optional)
*/
public DefaultContainer(Container parent, boolean failEarly) {
super(parent);
this.failEarly = failEarly;
}
public synchronized void start() {
if (isRunning() ||
starting) return;
if (getParent() != null && !getParent().isRunning()) throw new RuntimeException("Parent container is not started.");
this.starting = true;
if (failEarly) {
for (Object key : registry.keySet()) {
// force get each component, forcing all wiring.
Object ignore = getComponent(key);
if (false) ignore.hashCode(); // cover warning - compiler should remove
}
}
super.start();
starting = false;
}
public void registerType(Object key, Class<?> componentType) {
registerType(key,componentType, 0);
}
protected void registerType(Object key, Class<?> componentType, long timeout) {
registerType(key,new IndependentAutoWiringAdapter(componentType), timeout);
}
public void registerType(Object key, AutoWiringAdapter componentAdapter) {
registerType(key,componentAdapter,0);
}
/**
* Registers a component for later instantiation and (optionally) startup.
*
* @param key the key by which this component will be identified in the system
* @param componentAdapter an AutoWiringAdapter for creating this component and listing its dependencies
* @param timeout an (optional) timeout applied to any startup lifecycle
*/
protected void registerType(Object key, AutoWiringAdapter componentAdapter, long timeout) {
if (this.isRunning()) throw new RuntimeException("Cannot register when container is started.");
// FIXME: Figure out whether to support parent registry checking. Probably can't do it.
if (registry.containsKey(key)) throw new ComponentAlreadyRegisteredError("Component already registered for " + key);
detectCircularDependencies(key,componentAdapter);
registry.put(key, componentAdapter);
}
private void detectCircularDependencies(Object key,AutoWiringAdapter componentAdapter) {
NonDuplicateStack nds = new NonDuplicateStack();
nds.push(key);
CyclicalReferenceDetectionUtil.detectCircularDependencies(this.registry, nds, componentAdapter);
}
/**
* This method wires the object up with its dependencies, providing said
* dependencies to the object's adapter. It also starts the object if its
* startable
* @param originalKey
* @param adapter
* @return
*/
private Object wireObject(Object originalKey, AutoWiringAdapter adapter) {
Object[] dependencies = adapter.dependencies();
Object[] parameters = new Object[dependencies.length];
for (int depn = 0; depn < dependencies.length; depn++ ) {
Object key = adapter.dependencies()[depn];
parameters[depn] = getComponent(key);
if (parameters[depn] == null) throw new UnsatisfiedDependencyError("Could not materialize dependency for key " + key);
}
try {
Object o = adapter.create(parameters);
if (o == null) throw new InstantiationException("Could not create a non-null object. Adapter " + adapter.getClass().getName() + " returned null.");
else {
try {
Startable s = ((Startable)o);
if (!s.isRunning()) s.start();
} catch (ClassCastException e) {}
return o;
}
} catch (IllegalAccessException e) {
throw new CouldNotCreateComponentError("Could not create component " + originalKey + " of type " + adapter.getType(),e);
} catch (InstantiationException e) {
throw new CouldNotCreateComponentError("Could not create component " + originalKey + " of type " + adapter.getType(),e);
} catch (Throwable e) {
throw new CouldNotCreateComponentError("Could not create component " + originalKey + " of type " + adapter.getType(),e);
}
}
public Object getComponent(Object key) {
Object component = super.getStoredComponent(key);
if (component == null && registry.containsKey(key)) {
synchronized (CREATION_MUTEX) {
if (component == null) { // in case following thread gets in just after storage.
component = wireObject(key,(AutoWiringAdapter)registry.get(key));
store(key, component);
}
}
}
return component;
}
}
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