/*******************************************************************************
* Copyright (c) 2000, 2006 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.core.internal.runtime;
import java.util.*;
import org.eclipse.core.runtime.IAdapterFactory;
import org.eclipse.core.runtime.IAdapterManager;
/**
* This class is the standard implementation of <code>IAdapterManager</code>. It provides
* fast lookup of property values with the following semantics:
* <ul>
* <li>At most one factory will be invoked per property lookup
* <li>If multiple installed factories provide the same adapter, only the first found in
* the search order will be invoked.
* <li>The search order from a class with the definition <br>
* <code>class X extends Y implements A, B</code><br> is as follows: <il>
* <li>the target's class: X
* <li>X's superclasses in order to <code>Object</code>
* <li>a breadth-first traversal of the target class's interfaces in the order returned by
* <code>getInterfaces</code> (in the example, A and its superinterfaces then B and its
* superinterfaces) </il>
* </ul>
*
* @see IAdapterFactory
* @see IAdapterManager
*/
public final class AdapterManager implements IAdapterManager {
/**
* Cache of adapters for a given adaptable class. Maps String -> Map
* (adaptable class name -> (adapter class name -> factory instance))
* Thread safety note: The outer map is synchronized using a synchronized
* map wrapper class. The inner map is not synchronized, but it is immutable
* so synchronization is not necessary.
*/
private Map adapterLookup;
/**
* Cache of classes for a given type name. Avoids too many loadClass calls.
* (factory -> (type name -> Class)).
* Thread safety note: Since this structure is a nested hash map, and both
* the inner and outer maps are mutable, access to this entire structure is
* controlled by the classLookupLock field. Note the field can still be
* nulled concurrently without holding the lock.
*/
private Map classLookup;
/**
* The lock object controlling access to the classLookup data structure.
*/
private final Object classLookupLock = new Object();
/**
* Cache of class lookup order (Class -> Class[]). This avoids having to compute often, and
* provides clients with quick lookup for instanceOf checks based on type name.
* Thread safety note: The map is synchronized using a synchronized
* map wrapper class. The arrays within the map are immutable.
*/
private Map classSearchOrderLookup;
/**
* Map of factories, keyed by <code>String</code>, fully qualified class name of
* the adaptable class that the factory provides adapters for. Value is a <code>List</code>
* of <code>IAdapterFactory</code>.
*/
private final HashMap factories;
private final ArrayList lazyFactoryProviders;
private static final AdapterManager singleton = new AdapterManager();
public static AdapterManager getDefault() {
return singleton;
}
/**
* Private constructor to block instance creation.
*/
private AdapterManager() {
factories = new HashMap(5);
lazyFactoryProviders = new ArrayList(1);
}
/**
* Given a type name, add all of the factories that respond to those types into
* the given table. Each entry will be keyed by the adapter class name (supplied in
* IAdapterFactory.getAdapterList).
*/
private void addFactoriesFor(String typeName, Map table) {
List factoryList = (List) getFactories().get(typeName);
if (factoryList == null)
return;
for (int i = 0, imax = factoryList.size(); i < imax; i++) {
IAdapterFactory factory = (IAdapterFactory) factoryList.get(i);
if (factory instanceof IAdapterFactoryExt) {
String[] adapters = ((IAdapterFactoryExt) factory).getAdapterNames();
for (int j = 0; j < adapters.length; j++) {
if (table.get(adapters[j]) == null)
table.put(adapters[j], factory);
}
} else {
Class[] adapters = factory.getAdapterList();
for (int j = 0; j < adapters.length; j++) {
String adapterName = adapters[j].getName();
if (table.get(adapterName) == null)
table.put(adapterName, factory);
}
}
}
}
private void cacheClassLookup(IAdapterFactory factory, Class clazz) {
synchronized (classLookupLock) {
//cache reference to lookup to protect against concurrent flush
Map lookup = classLookup;
if (lookup == null)
classLookup = lookup = new HashMap(4);
HashMap classes = (HashMap) lookup.get(factory);
if (classes == null) {
classes = new HashMap(4);
lookup.put(factory, classes);
}
classes.put(clazz.getName(), clazz);
}
}
private Class cachedClassForName(IAdapterFactory factory, String typeName) {
synchronized (classLookupLock) {
Class clazz = null;
//cache reference to lookup to protect against concurrent flush
Map lookup = classLookup;
if (lookup != null) {
HashMap classes = (HashMap) lookup.get(factory);
if (classes != null) {
clazz = (Class) classes.get(typeName);
}
}
return clazz;
}
}
/**
* Returns the class with the given fully qualified name, or null
* if that class does not exist or belongs to a plug-in that has not
* yet been loaded.
*/
private Class classForName(IAdapterFactory factory, String typeName) {
Class clazz = cachedClassForName(factory, typeName);
if (clazz == null) {
try {
if (factory instanceof IAdapterFactoryExt)
factory = ((IAdapterFactoryExt) factory).loadFactory(false);
if (factory != null) {
clazz = factory.getClass().getClassLoader().loadClass(typeName);
cacheClassLookup(factory, clazz);
}
} catch (ClassNotFoundException e) {
// class not yet loaded
}
}
return clazz;
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IAdapterManager#getAdapterTypes(java.lang.Class)
*/
public String[] computeAdapterTypes(Class adaptable) {
Set types = getFactories(adaptable).keySet();
return (String[]) types.toArray(new String[types.size()]);
}
/**
* Computes the adapters that the provided class can adapt to, along
* with the factory object that can perform that transformation. Returns
* a table of adapter class name to factory object.
* @param adaptable
*/
private Map getFactories(Class adaptable) {
//cache reference to lookup to protect against concurrent flush
Map lookup = adapterLookup;
if (lookup == null)
adapterLookup = lookup = Collections.synchronizedMap(new HashMap(30));
Map table = (Map) lookup.get(adaptable.getName());
if (table == null) {
// calculate adapters for the class
table = new HashMap(4);
Class[] classes = computeClassOrder(adaptable);
for (int i = 0; i < classes.length; i++)
addFactoriesFor(classes[i].getName(), table);
// cache the table
lookup.put(adaptable.getName(), table);
}
return table;
}
public Class[] computeClassOrder(Class adaptable) {
Class[] classes = null;
//cache reference to lookup to protect against concurrent flush
Map lookup = classSearchOrderLookup;
if (lookup == null)
classSearchOrderLookup = lookup = Collections.synchronizedMap(new HashMap());
else
classes = (Class[]) lookup.get(adaptable);
// compute class order only if it hasn't been cached before
if (classes == null) {
ArrayList classList = new ArrayList();
computeClassOrder(adaptable, classList);
classes = (Class[]) classList.toArray(new Class[classList.size()]);
lookup.put(adaptable, classes);
}
return classes;
}
/**
* Builds and returns a table of adapters for the given adaptable type.
* The table is keyed by adapter class name. The
* value is the <b>sole<b> factory that defines that adapter. Note that
* if multiple adapters technically define the same property, only the
* first found in the search order is considered.
*
* Note that it is important to maintain a consistent class and interface
* lookup order. See the class comment for more details.
*/
private void computeClassOrder(Class adaptable, Collection classes) {
Class clazz = adaptable;
Set seen = new HashSet(4);
while (clazz != null) {
classes.add(clazz);
computeInterfaceOrder(clazz.getInterfaces(), classes, seen);
clazz = clazz.getSuperclass();
}
}
private void computeInterfaceOrder(Class[] interfaces, Collection classes, Set seen) {
List newInterfaces = new ArrayList(interfaces.length);
for (int i = 0; i < interfaces.length; i++) {
Class interfac = interfaces[i];
if (seen.add(interfac)) {
//note we cannot recurse here without changing the resulting interface order
classes.add(interfac);
newInterfaces.add(interfac);
}
}
for (Iterator it = newInterfaces.iterator(); it.hasNext();)
computeInterfaceOrder(((Class) it.next()).getInterfaces(), classes, seen);
}
/**
* Flushes the cache of adapter search paths. This is generally required whenever an
* adapter is added or removed.
* <p>
* It is likely easier to just toss the whole cache rather than trying to be smart
* and remove only those entries affected.
* </p>
*/
public synchronized void flushLookup() {
adapterLookup = null;
classLookup = null;
classSearchOrderLookup = null;
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IAdapterManager#getAdapter(java.lang.Object, java.lang.Class)
*/
public Object getAdapter(Object adaptable, Class adapterType) {
IAdapterFactory factory = (IAdapterFactory) getFactories(adaptable.getClass()).get(adapterType.getName());
Object result = null;
if (factory != null)
result = factory.getAdapter(adaptable, adapterType);
if (result == null && adapterType.isInstance(adaptable))
return adaptable;
return result;
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IAdapterManager#getAdapter(java.lang.Object, java.lang.Class)
*/
public Object getAdapter(Object adaptable, String adapterType) {
return getAdapter(adaptable, adapterType, false);
}
/**
* Returns an adapter of the given type for the provided adapter.
* @param adaptable the object to adapt
* @param adapterType the type to adapt the object to
* @param force <code>true</code> if the plug-in providing the
* factory should be activated if necessary. <code>false</code>
* if no plugin activations are desired.
*/
private Object getAdapter(Object adaptable, String adapterType, boolean force) {
IAdapterFactory factory = (IAdapterFactory) getFactories(adaptable.getClass()).get(adapterType);
if (force && factory instanceof IAdapterFactoryExt)
factory = ((IAdapterFactoryExt) factory).loadFactory(true);
Object result = null;
if (factory != null) {
Class clazz = classForName(factory, adapterType);
if (clazz != null)
result = factory.getAdapter(adaptable, clazz);
}
if (result == null && adaptable.getClass().getName().equals(adapterType))
return adaptable;
return result;
}
public boolean hasAdapter(Object adaptable, String adapterTypeName) {
return getFactories(adaptable.getClass()).get(adapterTypeName) != null;
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IAdapterManager#queryAdapter(java.lang.Object, java.lang.String)
*/
public int queryAdapter(Object adaptable, String adapterTypeName) {
IAdapterFactory factory = (IAdapterFactory) getFactories(adaptable.getClass()).get(adapterTypeName);
if (factory == null)
return NONE;
if (factory instanceof IAdapterFactoryExt) {
factory = ((IAdapterFactoryExt) factory).loadFactory(false); // don't force loading
if (factory == null)
return NOT_LOADED;
}
return LOADED;
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IAdapterManager#loadAdapter(java.lang.Object, java.lang.String)
*/
public Object loadAdapter(Object adaptable, String adapterTypeName) {
return getAdapter(adaptable, adapterTypeName, true);
}
/*
* @see IAdapterManager#registerAdapters
*/
public synchronized void registerAdapters(IAdapterFactory factory, Class adaptable) {
registerFactory(factory, adaptable.getName());
flushLookup();
}
/*
* @see IAdapterManager#registerAdapters
*/
public void registerFactory(IAdapterFactory factory, String adaptableType) {
List list = (List) factories.get(adaptableType);
if (list == null) {
list = new ArrayList(5);
factories.put(adaptableType, list);
}
list.add(factory);
}
/*
* @see IAdapterManager#unregisterAdapters
*/
public synchronized void unregisterAdapters(IAdapterFactory factory) {
for (Iterator it = factories.values().iterator(); it.hasNext();)
((List) it.next()).remove(factory);
flushLookup();
}
/*
* @see IAdapterManager#unregisterAdapters
*/
public synchronized void unregisterAdapters(IAdapterFactory factory, Class adaptable) {
List factoryList = (List) factories.get(adaptable.getName());
if (factoryList == null)
return;
factoryList.remove(factory);
flushLookup();
}
/*
* Shuts down the adapter manager by removing all factories
* and removing the registry change listener. Should only be
* invoked during platform shutdown.
*/
public synchronized void unregisterAllAdapters() {
factories.clear();
flushLookup();
}
public void registerLazyFactoryProvider(IAdapterManagerProvider factoryProvider) {
synchronized (lazyFactoryProviders) {
lazyFactoryProviders.add(factoryProvider);
}
}
public boolean unregisterLazyFactoryProvider(IAdapterManagerProvider factoryProvider) {
synchronized (lazyFactoryProviders) {
return lazyFactoryProviders.remove(factoryProvider);
}
}
public HashMap getFactories() {
// avoid the synchronize if we don't have to call it
if (lazyFactoryProviders.size() == 0)
return factories;
synchronized (lazyFactoryProviders) {
while (lazyFactoryProviders.size() > 0) {
IAdapterManagerProvider provider = (IAdapterManagerProvider) lazyFactoryProviders.remove(0);
if (provider.addFactories(this))
flushLookup();
}
}
return factories;
}
}