/*
* Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package com.amazonaws.auth;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import com.amazonaws.internal.config.InternalConfig;
import com.amazonaws.internal.config.SignerConfig;
/** Signer factory. */
public final class SignerFactory {
private static final String QUERY_STRING_SIGNER = "QueryStringSignerType";
private static final String VERSION_THREE_SIGNER = "AWS3SignerType";
private static final String VERSION_FOUR_SIGNER = "AWS4SignerType";
private static final String NO_OP_SIGNER = "NoOpSignerType";
private static final Map<String, Class<? extends Signer>> SIGNERS
= new ConcurrentHashMap<String, Class<? extends Signer>>();
static {
// Register the standard signer types.
SIGNERS.put(QUERY_STRING_SIGNER, QueryStringSigner.class);
SIGNERS.put(VERSION_THREE_SIGNER, AWS3Signer.class);
SIGNERS.put(VERSION_FOUR_SIGNER, AWS4Signer.class);
SIGNERS.put(NO_OP_SIGNER, NoOpSigner.class);
}
/**
* Private so you're not tempted to instantiate me.
*/
private SignerFactory() {
}
/**
* Register an implementation class for the given signer type.
*
* @param signerType The name of the signer type to register.
* @param signerClass The class implementing the given signature protocol.
*/
public static void registerSigner(
final String signerType,
final Class<? extends Signer> signerClass) {
if (signerType == null) {
throw new IllegalArgumentException("signerType cannot be null");
}
if (signerClass == null) {
throw new IllegalArgumentException("signerClass cannot be null");
}
SIGNERS.put(signerType, signerClass);
}
/**
* Returns a non-null signer for the specified service and region according
* to the internal configuration which provides a basic default algorithm
* used for signer determination.
*
* @param serviceName
* The name of the service to talk to.
* @param regionName
* The name of the region to talk to; not necessarily the region
* used for signing.
*/
public static Signer getSigner(String serviceName, String regionName) {
return lookupAndCreateSigner(serviceName, regionName);
}
/**
* Returns an instance of the given signer type and configures it with the
* given service name (if applicable).
*
* @param signerType
* The type of signer to create.
* @param serviceName
* The name of the service to configure on the signer.
* @return a non-null signer.
*/
public static Signer getSignerByTypeAndService(String signerType,
final String serviceName) {
return createSigner(signerType, serviceName);
}
/**
* Internal implementation for looking up and creating a signer by service
* name and region.
*/
private static Signer lookupAndCreateSigner(String serviceName, String regionName) {
InternalConfig config = InternalConfig.Factory.getInternalConfig();
SignerConfig signerConfig =
config.getSignerConfig(serviceName, regionName);
String signerType = signerConfig.getSignerType();
return createSigner(signerType, serviceName);
}
/**
* Internal implementation to create a signer by type and service name,
* and configuring it with the service name if applicable.
*/
private static Signer createSigner(String signerType,
final String serviceName) {
Class<? extends Signer> signerClass = SIGNERS.get(signerType);
if (signerClass == null)
throw new IllegalArgumentException();
Signer signer;
try {
signer = signerClass.newInstance();
} catch (InstantiationException ex) {
throw new IllegalStateException(
"Cannot create an instance of " + signerClass.getName(),
ex);
} catch (IllegalAccessException ex) {
throw new IllegalStateException(
"Cannot create an instance of " + signerClass.getName(),
ex);
}
if (signer instanceof ServiceAwareSigner) {
((ServiceAwareSigner) signer).setServiceName(serviceName);
}
return signer;
}
}