[Backport 9.0] add Java language examples (#4580)

Makefile

@@ -74,6 +74,10 @@ generate-language-examples:
 	@node docs/examples/generate-language-examples.js
 	@npm run format:fix-examples --prefix compiler
 
+generate-language-examples-with-java:
+	@node docs/examples/generate-language-examples.js java
+	@npm run format:fix-examples --prefix compiler
+
 lint-docs: ## Lint the OpenAPI documents after overlays
 	@npx @redocly/cli lint "output/openapi/elasticsearch-*.json" --config "docs/linters/redocly.yaml" --format stylish --max-problems 500
 

docs/examples/generate-language-examples.js

@@ -21,6 +21,8 @@ const fs = require('fs');
 const path = require('path');
 const { parseDocument: yamlParseDocument } = require('yaml');
 const { convertRequests, loadSchema } = require('@elastic/request-converter');
+const {parseRequest} = require("@elastic/request-converter/dist/parse");
+const {JavaCaller} = require("java-caller");
 
 const LANGUAGES = ['Python', 'JavaScript', 'Ruby', 'PHP', 'curl'];
 
@@ -44,6 +46,50 @@ async function generateLanguages(example) {
     });
   }
   data.alternatives = alternatives.concat(data.alternatives.filter(pair => !LANGUAGES.includes(pair.language)));
+
+  // specific java example generator
+  if (process.argv[2] === "java") {
+    const partialRequest = await parseRequest(request);
+    const java = new JavaCaller({
+      minimumJavaVersion: 21,
+      jar: "path/to/converter/jar/java-es-request-converter-1.0-SNAPSHOT.jar",
+    });
+
+    let correctParams = getCodeGenParamNames(partialRequest.params, partialRequest.request);
+    let body = partialRequest.body;
+    if (!body) {
+      body = {}
+    }
+
+    let javaReqs = [];
+    const javaParsedRequest = {
+      api: partialRequest.api,
+      params: correctParams,
+      query: partialRequest.query,
+      body: body,
+    };
+    javaReqs.push(javaParsedRequest)
+
+    let args = [];
+    args.push(JSON.stringify(javaReqs));
+
+    const {status, stdout, stderr} = await java.run(args);
+    if (status) {
+      console.log(stderr);
+      console.log(JSON.stringify(javaReqs));
+    }
+    else {
+      const alternative_java = [];
+      alternative_java.push({
+        language: "Java",
+        code: stdout,
+      });
+      // replace old java examples
+      data.alternatives = data.alternatives.filter(pair => pair.language !== "Java");
+      data.alternatives = data.alternatives.concat(alternative_java);
+    }
+  }
+
   doc.delete('alternatives');
   doc.add(doc.createPair('alternatives', data.alternatives));
   await fs.promises.writeFile(example, doc.toString({lineWidth: 132}));
@@ -61,6 +107,23 @@ async function* walkExamples(dir) {
   }
 }
 
+function getCodeGenParamNames(
+    params,
+    request,
+){
+  for (const [key, value] of Object.entries(params)) {
+    if (request?.path) {
+      for (const prop of request.path) {
+        if (prop.name === key && prop.codegenName !== undefined) {
+          delete params[key];
+          params[prop.codegenName] = value;
+        }
+      }
+    }
+  }
+  return params;
+}
+
 async function main() {
   let count = 0;
   let errors = 0;

docs/examples/package.json

@@ -6,6 +6,7 @@
     "@elastic/request-converter": "^9.1.1",
     "@redocly/cli": "^1.34.3",
     "@stoplight/spectral-cli": "^6.14.2",
-    "yaml": "^2.8.0"
+    "yaml": "^2.8.0",
+    "java-caller": "^4.1.1"
   }
 }