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feat: Parameters injection (#201)
* Parameters injection annotation * update doc on annotation usage and installation
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‎docs/content/utilities/parameters.mdx

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@@ -264,4 +264,106 @@ And then use it like this :
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S3Provider provider = new S3Provider(ParamManager.getCacheManager());
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provider.setTransformationManager(ParamManager.getTransformationManager()); // optional, needed for transformations
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String value = provider.withBucket("myBucket").get("myKey");
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```
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```
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## Annotation
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You can make use of the annotation ```@Param``` to inject a parameter value in a variable.
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```java
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@Param(key = "/my/parameter")
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private String value;
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```
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By default it will use ```SSMProvider``` to retrieve the value from AWS System Manager Parameter Store.
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You could specify a different provider as long as it extends ```BaseProvider``` and/or a ```Transformer```.
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For example:
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```java
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@Param(key = "/my/parameter/json", provider = SecretsProvider.class, transformer = JsonTransformer.class)
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private ObjectToDeserialize value;
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```
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In this case ```SecretsProvider``` will be used to retrieve a raw value that is then trasformed into the target Object by using ```JsonTransformer```.
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To show the convenience of the annotation compare the following two code snippets.
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```java:title=AppWithoutAnnotation.java
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public class AppWithoutAnnotation implements RequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
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// Get an instance of the SSM Provider
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SSMProvider ssmProvider = ParamManager.getSsmProvider();
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// Retrieve a single parameter
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ObjectToDeserialize value = ssmProvider
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.withTransformation(Transformer.json)
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.get("/my/parameter/json");
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}
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```
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And with the usage of ```@Param```
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```java:title=AppWithAnnotation.java
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public class AppWithAnnotation implements RequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
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@Param(key = "/my/parameter/json" transformer = JsonTransformer.class)
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ObjectToDeserialize value;
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}
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```
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### Install
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If you want to use the ```@Param``` annotation in your project add configuration to compile-time weave (CTW) the powertools-parameters aspects into your project.
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* [maven](https://maven.apache.org/):
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```xml
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<build>
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<plugins>
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...
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<plugin>
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<groupId>org.codehaus.mojo</groupId>
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<artifactId>aspectj-maven-plugin</artifactId>
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<version>1.11</version>
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<configuration>
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...
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<aspectLibraries>
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...
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<aspectLibrary>
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<groupId>software.amazon.lambda</groupId>
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<artifactId>powertools-parameters</artifactId>
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</aspectLibrary>
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</aspectLibraries>
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</configuration>
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<executions>
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<execution>
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<goals>
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<goal>compile</goal>
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</goals>
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</execution>
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</executions>
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</plugin>
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...
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</plugins>
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</build>
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```
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**Note:** If you are working with lambda function on runtime post java8, please refer [issue](https://github.com/awslabs/aws-lambda-powertools-java/issues/50) for workaround
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* [gradle](https://gradle.org):
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```groovy
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plugins{
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id 'java'
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id 'aspectj.AspectjGradlePlugin' version '0.0.6'
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}
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repositories {
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jcenter()
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}
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dependencies {
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...
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implementation 'software.amazon.lambda:powertools-parameters:1.0.1'
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aspectpath 'software.amazon.lambda:powertools-parameters:1.0.1'
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}
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```
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**Note:**
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Please add `aspectjVersion = '1.9.6'` to the `gradle.properties` file. The aspectj plugin works at the moment with gradle 5.x only if
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you are using `java 8` as runtime. Please refer to [open issue](https://github.com/awslabs/aws-lambda-powertools-java/issues/146) for more details.

‎powertools-parameters/pom.xml

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@@ -82,7 +82,6 @@
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<artifactId>aspectjrt</artifactId>
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<scope>compile</scope>
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</dependency>
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<!-- Test dependencies -->
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<dependency>
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<groupId>org.junit.jupiter</groupId>
@@ -99,6 +98,11 @@
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<artifactId>mockito-core</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.mockito</groupId>
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<artifactId>mockito-inline</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.apache.commons</groupId>
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<artifactId>commons-lang3</artifactId>
@@ -109,6 +113,11 @@
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<artifactId>assertj-core</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.aspectj</groupId>
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<artifactId>aspectjweaver</artifactId>
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<scope>test</scope>
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</dependency>
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</dependencies>
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</project>

‎powertools-parameters/src/main/java/software/amazon/lambda/powertools/parameters/BaseProvider.java

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@@ -104,7 +104,7 @@ public BaseProvider withMaxAge(int maxAge, ChronoUnit unit) {
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* @param transformerClass Class of the transformer to apply. For convenience, you can use {@link Transformer#json} or {@link Transformer#base64} shortcuts.
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* @return the provider itself in order to chain calls (eg. <pre>provider.withTransformation(json).get("key", MyObject.class)</pre>).
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*/
107-
protected BaseProvider withTransformation(Class<? extends Transformer> transformerClass) {
107+
public BaseProvider withTransformation(Class<? extends Transformer> transformerClass) {
108108
if (transformationManager == null) {
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throw new IllegalStateException("Trying to add transformation while no TransformationManager has been provided.");
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}

‎powertools-parameters/src/main/java/software/amazon/lambda/powertools/parameters/Param.java

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@@ -0,0 +1,30 @@
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package software.amazon.lambda.powertools.parameters;
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import software.amazon.lambda.powertools.parameters.transform.Transformer;
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import java.lang.annotation.ElementType;
6+
import java.lang.annotation.Retention;
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import java.lang.annotation.RetentionPolicy;
8+
import java.lang.annotation.Target;
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/**
11+
* {@code Param} is used to signal that the annotated field should be
12+
* populated with a value retrieved from a parameter store through a {@link ParamProvider}.
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*
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* <p>By default {@code Param} use {@link SSMProvider} as parameter provider. This can be overridden specifying
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* the annotation variable {@code Param(provider = <Class-of-the-provider>)}.<br/>
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* The library provide a provider for AWS System Manager Parameters Store ({@link SSMProvider}) and a provider
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* for AWS Secrets Manager ({@link SecretsProvider}).
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* The user can implement a custom provider by extending the abstract class {@link BaseProvider}.</p>
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*
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* <p>If the parameter value requires transformation before being assigned to the annotated field
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* users can specify a {@link Transformer}
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* </p>
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*/
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@Retention(RetentionPolicy.RUNTIME)
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@Target(ElementType.FIELD)
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public @interface Param {
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String key();
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Class<? extends BaseProvider> provider() default SSMProvider.class;
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Class<? extends Transformer> transformer() default Transformer.class;
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}

‎powertools-parameters/src/main/java/software/amazon/lambda/powertools/parameters/ParamManager.java

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Original file line numberDiff line numberDiff line change
@@ -18,6 +18,10 @@
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import software.amazon.lambda.powertools.parameters.cache.CacheManager;
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import software.amazon.lambda.powertools.parameters.transform.TransformationManager;
2020

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import java.lang.reflect.Constructor;
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import java.lang.reflect.InvocationTargetException;
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import java.util.concurrent.ConcurrentHashMap;
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2125
/**
2226
* Utility class to retrieve instances of parameter providers.
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* Each instance is unique (singleton).
@@ -27,22 +31,28 @@ public final class ParamManager {
2731
private static final CacheManager cacheManager = new CacheManager();
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private static final TransformationManager transformationManager = new TransformationManager();
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30-
private static SecretsProvider secretsProvider;
31-
private static SSMProvider ssmProvider;
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private static ConcurrentHashMap<Class<? extends BaseProvider>, BaseProvider> providers = new ConcurrentHashMap<>();
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/**
37+
* Get a concrete implementation of {@link BaseProvider}.<br/>
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* You can specify {@link SecretsProvider} or {@link SSMProvider} or create your custom provider
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* by extending {@link BaseProvider} if you need to integrate with a different parameter store.
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* @return a {@link SecretsProvider}
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*/
42+
public static <T extends BaseProvider> T getProvider(Class<T> providerClass) {
43+
if (providerClass == null) {
44+
throw new IllegalStateException("providerClass cannot be null.");
45+
}
46+
return (T) providers.computeIfAbsent(providerClass, (k) -> createProvider(k));
47+
}
3248

3349
/**
3450
* Get a {@link SecretsProvider} with default {@link SecretsManagerClient}.<br/>
3551
* If you need to customize the region, or other part of the client, use {@link ParamManager#getSecretsProvider(SecretsManagerClient)} instead.
3652
* @return a {@link SecretsProvider}
3753
*/
3854
public static SecretsProvider getSecretsProvider() {
39-
if (secretsProvider == null) {
40-
secretsProvider = SecretsProvider.builder()
41-
.withCacheManager(cacheManager)
42-
.withTransformationManager(transformationManager)
43-
.build();
44-
}
45-
return secretsProvider;
55+
return getProvider(SecretsProvider.class);
4656
}
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/**
@@ -51,13 +61,7 @@ public static SecretsProvider getSecretsProvider() {
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* @return a {@link SSMProvider}
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*/
5363
public static SSMProvider getSsmProvider() {
54-
if (ssmProvider == null) {
55-
ssmProvider = SSMProvider.builder()
56-
.withCacheManager(cacheManager)
57-
.withTransformationManager(transformationManager)
58-
.build();
59-
}
60-
return ssmProvider;
64+
return getProvider(SSMProvider.class);
6165
}
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6367
/**
@@ -66,14 +70,11 @@ public static SSMProvider getSsmProvider() {
6670
* @return a {@link SecretsProvider}
6771
*/
6872
public static SecretsProvider getSecretsProvider(SecretsManagerClient client) {
69-
if (secretsProvider == null) {
70-
secretsProvider = SecretsProvider.builder()
71-
.withClient(client)
72-
.withCacheManager(cacheManager)
73-
.withTransformationManager(transformationManager)
74-
.build();
75-
}
76-
return secretsProvider;
73+
return (SecretsProvider) providers.computeIfAbsent(SecretsProvider.class, (k) -> SecretsProvider.builder()
74+
.withClient(client)
75+
.withCacheManager(cacheManager)
76+
.withTransformationManager(transformationManager)
77+
.build());
7778
}
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7980
/**
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8283
* @return a {@link SSMProvider}
8384
*/
8485
public static SSMProvider getSsmProvider(SsmClient client) {
85-
if (ssmProvider == null) {
86-
ssmProvider = SSMProvider.builder()
87-
.withClient(client)
88-
.withCacheManager(cacheManager)
89-
.withTransformationManager(transformationManager)
90-
.build();
91-
}
92-
return ssmProvider;
86+
return (SSMProvider) providers.computeIfAbsent(SSMProvider.class, (k) -> SSMProvider.builder()
87+
.withClient(client)
88+
.withCacheManager(cacheManager)
89+
.withTransformationManager(transformationManager)
90+
.build());
9391
}
9492

9593
public static CacheManager getCacheManager() {
@@ -99,4 +97,17 @@ public static CacheManager getCacheManager() {
9997
public static TransformationManager getTransformationManager() {
10098
return transformationManager;
10199
}
100+
101+
private static <T extends BaseProvider> T createProvider(Class<T> providerClass) {
102+
try {
103+
Constructor<T> constructor = providerClass.getDeclaredConstructor(CacheManager.class);
104+
T provider = constructor.newInstance(cacheManager);
105+
provider.setTransformationManager(transformationManager);
106+
return provider;
107+
} catch (NoSuchMethodException | IllegalAccessException | InstantiationException | InvocationTargetException e) {
108+
throw new RuntimeException("Unexpected error occurred. Please raise issue at " +
109+
"https://github.com/awslabs/aws-lambda-powertools-java/issues", e);
110+
}
111+
}
112+
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}

‎powertools-parameters/src/main/java/software/amazon/lambda/powertools/parameters/internal/LambdaParametersAspect.java

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package software.amazon.lambda.powertools.parameters.internal;
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import org.aspectj.lang.ProceedingJoinPoint;
4+
import org.aspectj.lang.annotation.Around;
5+
import org.aspectj.lang.annotation.Aspect;
6+
import org.aspectj.lang.annotation.Pointcut;
7+
import org.aspectj.lang.reflect.FieldSignature;
8+
import software.amazon.lambda.powertools.parameters.*;
9+
10+
@Aspect
11+
public class LambdaParametersAspect {
12+
13+
@Pointcut("get(* *) && @annotation(paramAnnotation)")
14+
public void getParam(Param paramAnnotation) {
15+
}
16+
17+
@Around("getParam(paramAnnotation)")
18+
public Object injectParam(final ProceedingJoinPoint joinPoint, final Param paramAnnotation) {
19+
if(null == paramAnnotation.provider()) {
20+
throw new IllegalArgumentException("provider for Param annotation cannot be null!");
21+
}
22+
BaseProvider provider = ParamManager.getProvider(paramAnnotation.provider());
23+
24+
if(paramAnnotation.transformer().isInterface()) {
25+
// No transformation
26+
return provider.get(paramAnnotation.key());
27+
} else {
28+
FieldSignature s = (FieldSignature) joinPoint.getSignature();
29+
if(String.class.isAssignableFrom(s.getFieldType())) {
30+
// Basic transformation
31+
return provider
32+
.withTransformation(paramAnnotation.transformer())
33+
.get(paramAnnotation.key());
34+
} else {
35+
// Complex transformation
36+
return provider
37+
.withTransformation(paramAnnotation.transformer())
38+
.get(paramAnnotation.key(), s.getFieldType());
39+
}
40+
}
41+
}
42+
43+
}

‎powertools-parameters/src/test/java/software/amazon/lambda/powertools/parameters/ParamManagerIntegrationTest.java

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2828
import java.util.ArrayList;
2929
import java.util.List;
3030
import java.util.Map;
31+
import java.util.concurrent.ConcurrentHashMap;
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3233
import static org.apache.commons.lang3.reflect.FieldUtils.writeStaticField;
3334
import static org.assertj.core.api.Assertions.assertThat;
@@ -57,8 +58,7 @@ public class ParamManagerIntegrationTest {
5758
public void setup() throws IllegalAccessException {
5859
openMocks(this);
5960

60-
writeStaticField(ParamManager.class, "ssmProvider", null, true);
61-
writeStaticField(ParamManager.class, "secretsProvider", null, true);
61+
writeStaticField(ParamManager.class, "providers", new ConcurrentHashMap<>(), true);
6262
}
6363

6464
@Test

‎powertools-parameters/src/test/java/software/amazon/lambda/powertools/parameters/internal/AnotherObject.java

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package software.amazon.lambda.powertools.parameters.internal;
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public class AnotherObject {
4+
5+
public AnotherObject() {}
6+
7+
private String another;
8+
private int object;
9+
10+
public String getAnother() {
11+
return another;
12+
}
13+
14+
public void setAnother(String another) {
15+
this.another = another;
16+
}
17+
18+
public int getObject() {
19+
return object;
20+
}
21+
22+
public void setObject(int object) {
23+
this.object = object;
24+
}
25+
}

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