/*
* The MIT License
*
* Copyright (c) 2011-2013, CloudBees, Inc., Stephen Connolly.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.cloudbees.plugins.credentials;
import edu.umd.cs.findbugs.annotations.CheckForNull;
import edu.umd.cs.findbugs.annotations.NonNull;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jvnet.tiger_types.Types;
/**
* Translates {@link Credentials} from one type into another. We only support point-to-point translation, not a chain.
* Translation is designed to help plugins migrate towards common credential interfaces once they have been
* standardized, so the intention is that a plugin that implemented an old credential type and has migrated to the
* new type would also provide a translator.
*
* @param <F> the class that the resolver resolves from.
* @param <T> the class that the resolver resolves to. Typically this class will have a {@code readResolve()} method
* that returns an instance of the class that the resolver resolves from.
* @see ResolveWith
* @since 1.6
*/
public abstract class CredentialsResolver<F extends Credentials, T extends Credentials> {
/**
* Our logger.
*
* @since 1.6
*/
@NonNull
private static final Logger LOGGER = Logger.getLogger(CredentialsResolver.class.getName());
/**
* The class we can resolve from.
*/
@NonNull
private final Class<F> fromClass;
/**
* The class we can resolve to.
*/
@NonNull
private final Class<T> toClass;
/**
* Constructor.
*
* @param fromClass the class to resolve from.
* @param toClass the class to resolve to.
*/
@SuppressWarnings("unused") // API entry point
protected CredentialsResolver(@NonNull Class<F> fromClass, @NonNull Class<T> toClass) {
fromClass.getClass(); // throw NPE if null
toClass.getClass(); // throw NPE if null
this.fromClass = fromClass;
this.toClass = toClass;
}
/**
* Infers the to type of the corresponding {@link Credentials} from the outer class.
* This version works when you follow the common convention, where a resolver
* is written as the static nested class of the resolved class.
*
* @param fromClass the class to resolve from.
*/
@SuppressWarnings("unused") // API entry point
protected CredentialsResolver(@NonNull Class<F> fromClass) {
fromClass.getClass(); // throw NPE if null
this.fromClass = fromClass;
@SuppressWarnings("unchecked")
final Class<T> toClass = (Class<T>) getClass().getEnclosingClass();
if (toClass == null) {
throw new AssertionError(getClass()
+ " doesn't have an outer class. Use the constructor that takes the Class object explicitly.");
}
this.toClass = toClass;
// detect an type error
Type bt = Types.getBaseClass(getClass(), Credentials.class);
if (bt instanceof ParameterizedType) {
ParameterizedType pt = (ParameterizedType) bt;
// this 't' is the closest approximation of T of Descriptor<T>.
Class<?> t = Types.erasure(pt.getActualTypeArguments()[0]);
if (!t.isAssignableFrom(fromClass)) {
throw new AssertionError("Outer class " + fromClass + " of " + getClass() + " is not assignable to " + t
+ ". Perhaps wrong outer class?");
}
}
}
/**
* Retrieves the {@link CredentialsResolver} for the specified type (if it exists)
*
* @param clazz the type.
* @param <C> the type.
* @return the {@link CredentialsResolver} to use or {@code null} if no resolver is required.
*/
@CheckForNull
public static <C extends Credentials> CredentialsResolver<Credentials, C> getResolver(@NonNull Class<C> clazz) {
final ResolveWith resolveWith = clazz.getAnnotation(ResolveWith.class);
if (resolveWith != null) {
// if the reflective instantiation proves a hot point, put a cache in front.
try {
@SuppressWarnings("unchecked")
final CredentialsResolver<Credentials, C> resolver = resolveWith.value().newInstance();
if (Credentials.class.isAssignableFrom(resolver.getFromClass())
&& clazz.isAssignableFrom(resolver.getToClass())) {
return resolver;
}
LOGGER.log(Level.SEVERE, "Resolver {0} for type {1} resolves to {2} which is not assignable to {1}",
new Object[]{resolver.getClass(), clazz, resolver.getToClass()});
} catch (InstantiationException e) {
LOGGER.log(Level.WARNING, "Could not instantiate resolver: " + resolveWith.value(), e);
return null;
} catch (IllegalAccessException e) {
LOGGER.log(Level.WARNING, "Could not instantiate resolver: " + resolveWith.value(), e);
return null;
}
}
return null;
}
/**
* Returns the class to resolve from.
*
* @return the class to resolve from.
*/
@NonNull
public Class<F> getFromClass() {
return fromClass;
}
/**
* Returns the class to resolve to.
*
* @return the class to resolve to.
*/
@NonNull
public Class<T> getToClass() {
return toClass;
}
/**
* Resolves the supplied credentials.
*
* @param original the original type of credential.
* @return the resolved credentials or the original if they already implement the required interface.
*/
@NonNull
public T resolve(@NonNull F original) {
original.getClass(); // throw NPE if null
if (toClass.isInstance(original)) {
return toClass.cast(original);
}
// if proven hot-spot, may want to consider adding a cache... but we shouldn't be looking up
// credentials all the time, only when providing user with a list of credentials or when looking up
// one for use.
return doResolve(original);
}
/**
* Resolves the supplied credentials.
*
* @param originals credentials of the original type.
* @return the resolved credentials.
*/
@NonNull
public final List<T> resolve(@CheckForNull Collection<? extends F> originals) {
List<T> result = new ArrayList<T>();
if (originals != null) {
for (F original : originals) {
if (original != null) {
result.add(resolve(original));
}
}
}
return result;
}
/**
* Resolves the supplied credentials.
*
* @param original the original type of credential.
* @return the resolved credentials.
*/
@NonNull
protected abstract T doResolve(@NonNull F original);
}