software.amazon.awssdk.codegen.poet.paginators.SyncResponseClassSpec Maven / Gradle / Ivy
/*
* Copyright 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 software.amazon.awssdk.codegen.poet.paginators;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.CodeBlock;
import com.squareup.javapoet.FieldSpec;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.ParameterizedTypeName;
import com.squareup.javapoet.TypeName;
import com.squareup.javapoet.TypeSpec;
import java.util.Collections;
import java.util.Iterator;
import java.util.Objects;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.lang.model.element.Modifier;
import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
import software.amazon.awssdk.codegen.model.intermediate.MemberModel;
import software.amazon.awssdk.codegen.model.service.PaginatorDefinition;
import software.amazon.awssdk.codegen.poet.ClassSpec;
import software.amazon.awssdk.codegen.poet.PoetUtils;
import software.amazon.awssdk.core.pagination.sync.PaginatedItemsIterable;
import software.amazon.awssdk.core.pagination.sync.PaginatedResponsesIterator;
import software.amazon.awssdk.core.pagination.sync.SdkIterable;
import software.amazon.awssdk.core.pagination.sync.SyncPageFetcher;
/**
* Java poet {@link ClassSpec} to generate the response class for sync paginated operations.
*/
public class SyncResponseClassSpec extends PaginatorsClassSpec {
protected static final String ITERATOR_METHOD = "iterator";
public SyncResponseClassSpec(IntermediateModel model, String c2jOperationName, PaginatorDefinition paginatorDefinition) {
super(model, c2jOperationName, paginatorDefinition);
}
@Override
public TypeSpec poetSpec() {
TypeSpec.Builder specBuilder = TypeSpec.classBuilder(className())
.addModifiers(Modifier.PUBLIC)
.addAnnotation(PoetUtils.generatedAnnotation())
.addSuperinterface(getSyncResponseInterface())
.addFields(fields().collect(Collectors.toList()))
.addMethod(constructor())
.addMethod(iteratorMethod())
.addMethods(getMethodSpecsForResultKeyList())
.addJavadoc(paginationDocs.getDocsForSyncResponseClass(
getClientInterfaceName()))
.addType(nextPageFetcherClass().build());
return specBuilder.build();
}
@Override
public ClassName className() {
return poetExtensions.getResponseClassForPaginatedSyncOperation(c2jOperationName);
}
/**
* Returns the interface that is implemented by the Paginated Sync Response class.
*/
private TypeName getSyncResponseInterface() {
return ParameterizedTypeName.get(ClassName.get(SdkIterable.class), responseType());
}
/**
* @return A Poet {@link ClassName} for the sync client interface
*/
protected ClassName getClientInterfaceName() {
return poetExtensions.getClientClass(model.getMetadata().getSyncInterface());
}
protected Stream fields() {
return Stream.of(syncClientInterfaceField(), requestClassField(), syncPageFetcherField());
}
protected FieldSpec syncClientInterfaceField() {
return FieldSpec.builder(getClientInterfaceName(), CLIENT_MEMBER, Modifier.PRIVATE, Modifier.FINAL).build();
}
private FieldSpec syncPageFetcherField() {
return FieldSpec.builder(SyncPageFetcher.class, NEXT_PAGE_FETCHER_MEMBER, Modifier.PRIVATE, Modifier.FINAL).build();
}
protected MethodSpec constructor() {
return MethodSpec.constructorBuilder()
.addModifiers(Modifier.PUBLIC)
.addParameter(getClientInterfaceName(), CLIENT_MEMBER)
.addParameter(requestType(), REQUEST_MEMBER)
.addStatement("this.$L = $L", CLIENT_MEMBER, CLIENT_MEMBER)
.addStatement("this.$L = $L", REQUEST_MEMBER, REQUEST_MEMBER)
.addStatement("this.$L = new $L()", NEXT_PAGE_FETCHER_MEMBER, nextPageFetcherClassName())
.build();
}
/**
* A {@link MethodSpec} for the overridden iterator() method which is inherited
* from the interface.
*/
protected MethodSpec iteratorMethod() {
return MethodSpec.methodBuilder(ITERATOR_METHOD)
.addAnnotation(Override.class)
.addModifiers(Modifier.PUBLIC)
.returns(ParameterizedTypeName.get(ClassName.get(Iterator.class), responseType()))
.addStatement("return $1T.builder().$2L($3L).build()", PaginatedResponsesIterator.class,
NEXT_PAGE_FETCHER_MEMBER, nextPageFetcherArgument())
.build();
}
protected String nextPageFetcherArgument() {
return NEXT_PAGE_FETCHER_MEMBER;
}
/**
* Returns iterable of {@link MethodSpec} to generate helper methods for all members
* in {@link PaginatorDefinition#getResultKey()}. All the generated methods return an SdkIterable.
*
* The helper methods to iterate on paginated member will be generated only
* if {@link PaginatorDefinition#getResultKey()} is not null and a non-empty list.
*/
private Iterable getMethodSpecsForResultKeyList() {
if (paginatorDefinition.getResultKey() != null) {
return paginatorDefinition.getResultKey().stream()
.map(this::getMethodsSpecForSingleResultKey)
.filter(Objects::nonNull)
.collect(Collectors.toList());
}
return Collections.emptyList();
}
/*
* Generate a method spec for single element in {@link PaginatorDefinition#getResultKey()} list.
*
* If the element is "Folders" and its type is "List", generated code looks like:
*
* public SdkIterable folders() {
* Function> getIterator = response -> {
* if (response != null && response.folders() != null) {
* return response.folders().iterator();
* }
* return Collections.emptyIterator();
* };
*
* return PaginatedItemsIterable.builder().pagesIterable(this).itemIteratorFunction(getIterator).build();
* }
*/
private MethodSpec getMethodsSpecForSingleResultKey(String resultKey) {
MemberModel resultKeyModel = memberModelForResponseMember(resultKey);
// TODO: Support other types besides List or Map
if (!(resultKeyModel.isList() || resultKeyModel.isMap())) {
return null;
}
TypeName resultKeyType = getTypeForResultKey(resultKey);
return MethodSpec.methodBuilder(resultKeyModel.getFluentGetterMethodName())
.addModifiers(Modifier.PUBLIC, Modifier.FINAL)
.returns(ParameterizedTypeName.get(ClassName.get(SdkIterable.class), resultKeyType))
.addCode("$T getIterator = ",
ParameterizedTypeName.get(ClassName.get(Function.class),
responseType(),
ParameterizedTypeName.get(ClassName.get(Iterator.class),
resultKeyType)))
.addCode(getIteratorLambdaBlock(resultKey, resultKeyModel))
.addCode("\n")
.addStatement("return $T.<$T, $T>builder().pagesIterable(this).itemIteratorFunction(getIterator).build"
+ "()",
PaginatedItemsIterable.class, responseType(), resultKeyType)
.addJavadoc(CodeBlock.builder()
.add("Returns an iterable to iterate through the paginated {@link $T#$L()} member."
+ " The returned iterable is used to iterate through the results across all "
+ "response pages and not a single page.\n",
responseType(), resultKeyModel.getFluentGetterMethodName())
.add("\n")
.add("This method is useful if you are interested in iterating over the paginated "
+ "member in the response pages instead of the top level pages. "
+ "Similar to iteration over pages, this method internally makes service "
+ "calls to get the next list of results until the iteration stops or "
+ "there are no more results.")
.build())
.build();
}
/**
* Generates a inner class that implements {@link SyncPageFetcher}. An instance of this class
* is passed to {@link PaginatedResponsesIterator} to be used while iterating through pages.
*/
protected TypeSpec.Builder nextPageFetcherClass() {
return TypeSpec.classBuilder(nextPageFetcherClassName())
.addModifiers(Modifier.PRIVATE)
.addSuperinterface(ParameterizedTypeName.get(ClassName.get(SyncPageFetcher.class), responseType()))
.addMethod(MethodSpec.methodBuilder(HAS_NEXT_PAGE_METHOD)
.addModifiers(Modifier.PUBLIC)
.addAnnotation(Override.class)
.addParameter(responseType(), PREVIOUS_PAGE_METHOD_ARGUMENT)
.returns(boolean.class)
.addStatement(hasNextPageMethodBody())
.build())
.addMethod(MethodSpec.methodBuilder(NEXT_PAGE_METHOD)
.addModifiers(Modifier.PUBLIC)
.addAnnotation(Override.class)
.addParameter(responseType(), PREVIOUS_PAGE_METHOD_ARGUMENT)
.returns(responseType())
.addCode(nextPageMethodBody())
.build());
}
}
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