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CAMEL-21208: Replace manual string-based code generation with FreeMarker templates #22200

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CAMEL-21208: Replace manual string-based code generation with FreeMarker templates #22200

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c8a5ccc
CAMEL-21208: Replace manual string-based code generation with FreeMar…
gnodet Mar 23, 2026
c52a7ca
CAMEL-21208: Fix review findings
gnodet Mar 23, 2026
2870d10
CAMEL-21208: Minor cleanup from review
gnodet Mar 27, 2026
7cddc10
CAMEL-21208: Add unit test for TemplateHelper
gnodet Mar 27, 2026
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7 changes: 7 additions & 0 deletions dsl/camel-jbang/camel-jbang-core/pom.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,13 @@
<artifactId>plexus-xml</artifactId>
</dependency>

<!-- template engine for code generation -->
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>${freemarker-version}</version>
</dependency>

<!-- test dependencies -->
<dependency>
<groupId>org.apache.camel</groupId>
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108 changes: 21 additions & 87 deletions ...jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/Export.java
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Expand Up @@ -17,24 +17,24 @@
package org.apache.camel.dsl.jbang.core.commands;

import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.apache.camel.dsl.jbang.core.common.CamelJBangConstants;
import org.apache.camel.dsl.jbang.core.common.PropertyResolver;
import org.apache.camel.dsl.jbang.core.common.RuntimeType;
import org.apache.camel.dsl.jbang.core.common.RuntimeUtil;
import org.apache.camel.dsl.jbang.core.common.SourceScheme;
import org.apache.camel.tooling.maven.MavenGav;
import org.apache.camel.dsl.jbang.core.common.TemplateHelper;
import org.apache.camel.util.CamelCaseOrderedProperties;
import org.apache.camel.util.FileUtil;
import org.apache.camel.util.IOHelper;
import picocli.CommandLine.Command;

import static org.apache.camel.dsl.jbang.core.common.CamelJBangConstants.CAMEL_SPRING_BOOT_VERSION;
Expand Down Expand Up @@ -300,72 +300,6 @@ protected String getVersion() {
return "1.0-SNAPSHOT";
}

public Comparator<MavenGav> mavenGavComparator() {
return new Comparator<MavenGav>() {
@Override
public int compare(MavenGav o1, MavenGav o2) {
int r1 = rankGroupId(o1);
int r2 = rankGroupId(o2);

if (r1 > r2) {
return -1;
} else if (r2 > r1) {
return 1;
} else {
return o1.toString().compareTo(o2.toString());
}
}

int rankGroupId(MavenGav o1) {
String g1 = o1.getGroupId();
if (g1 == null) {
return 0;
}

switch (g1) {
case "org.springframework.boot" -> {
return 30;
}
case "io.quarkus" -> {
return 30;
}
case "org.apache.camel.quarkus" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-quarkus-core".equals(a1)) {
return 21;
}
return 20;
}
case "org.apache.camel.springboot" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-spring-boot-starter".equals(a1)) {
return 21;
} else if ("camel-spring-boot-engine-starter".equals(a1)) {
return 22;
}
return 20;
}
case "org.apache.camel" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-main".equals(a1)) {
return 11;
}
return 10;
}
case "org.apache.camel.kamelets" -> {
return 5;
}
default -> {
return 0;
}
}
}
};
}

// Maven reproducible builds: https://maven.apache.org/guides/mini/guide-reproducible-builds.html
protected String getBuildMavenProjectDate() {
// 2024-09-23T10:00:00Z
Expand All @@ -378,33 +312,33 @@ protected void copyDockerFiles(String buildDir) throws Exception {
Path docker = Path.of(buildDir).resolve("src/main/docker");
Files.createDirectories(docker);
String[] ids = gav.split(":");
String templateName = "templates/Dockerfile" + javaVersion + ".tmpl";
InputStream is = ExportCamelMain.class.getClassLoader().getResourceAsStream(templateName);
if (is == null) {

Map<String, Object> model = new HashMap<>();
model.put("ArtifactId", ids[1]);
model.put("Version", ids[2]);
model.put("AppJar", ids[1] + "-" + ids[2] + ".jar");

String ftlName = "Dockerfile" + javaVersion + ".ftl";
String context;
try {
context = TemplateHelper.processTemplate(ftlName, model);
} catch (IOException e) {
// fallback to JDK 21 template
printer().printf("No Dockerfile template for Java %s, falling back to Java 21 template%n", javaVersion);
is = ExportCamelMain.class.getClassLoader().getResourceAsStream("templates/Dockerfile21.tmpl");
context = TemplateHelper.processTemplate("Dockerfile21.ftl", model);
}
String context = IOHelper.loadText(is);
IOHelper.close(is);

String appJar = ids[1] + "-" + ids[2] + ".jar";
context = context.replaceAll("\\{\\{ \\.ArtifactId }}", ids[1]);
context = context.replaceAll("\\{\\{ \\.Version }}", ids[2]);
context = context.replaceAll("\\{\\{ \\.AppJar }}", appJar);
Files.writeString(docker.resolve("Dockerfile"), context);
}

// Copy the readme.md into the same Maven project root directory.
protected void copyReadme(String buildDir, String appJar) throws Exception {
String[] ids = gav.split(":");
InputStream is = ExportCamelMain.class.getClassLoader().getResourceAsStream("templates/readme.md.tmpl");
String context = IOHelper.loadText(is);
IOHelper.close(is);
Map<String, Object> model = new HashMap<>();
model.put("ArtifactId", ids[1]);
model.put("Version", ids[2]);
model.put("AppRuntimeJar", appJar);

context = context.replaceAll("\\{\\{ \\.ArtifactId }}", ids[1]);
context = context.replaceAll("\\{\\{ \\.Version }}", ids[2]);
context = context.replaceAll("\\{\\{ \\.AppRuntimeJar }}", appJar);
String context = TemplateHelper.processTemplate("readme.md.ftl", model);
Files.writeString(Path.of(buildDir).resolve("readme.md"), context);
}
}
195 changes: 139 additions & 56 deletions ...-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/ExportBaseCommand.java
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Expand Up @@ -406,46 +406,144 @@ private static String humanReadableSize(long bytes) {
}
}

protected static String mavenRepositoriesAsPomXml(String repos) {
StringBuilder sb = new StringBuilder();
int i = 1;
sb.append(" <repositories>\n");
if (!repos.isEmpty()) {
/**
* Builds a list of repository data maps from a comma-separated repos string, for use with FreeMarker templates.
*/
protected static List<Map<String, Object>> buildRepositoryList(String repos) {
List<Map<String, Object>> result = new ArrayList<>();
if (repos != null && !repos.isEmpty()) {
int i = 1;
for (String repo : repos.split(",")) {
sb.append(" <repository>\n");
sb.append(" <id>custom").append(i++).append("</id>\n");
sb.append(" <url>").append(repo).append("</url>\n");
if (repo.contains("snapshots")) {
sb.append(" <releases>\n");
sb.append(" <enabled>false</enabled>\n");
sb.append(" </releases>\n");
sb.append(" <snapshots>\n");
sb.append(" <enabled>true</enabled>\n");
sb.append(" </snapshots>\n");
}
sb.append(" </repository>\n");
Map<String, Object> r = new HashMap<>();
r.put("id", "custom" + i++);
r.put("url", repo);
r.put("isSnapshot", repo.contains("snapshots"));
result.add(r);
}
}
sb.append(" </repositories>\n");
sb.append(" <pluginRepositories>\n");
if (!repos.isEmpty()) {
for (String repo : repos.split(",")) {
sb.append(" <pluginRepository>\n");
sb.append(" <id>custom").append(i++).append("</id>\n");
sb.append(" <url>").append(repo).append("</url>\n");
if (repo.contains("snapshots")) {
sb.append(" <releases>\n");
sb.append(" <enabled>false</enabled>\n");
sb.append(" </releases>\n");
sb.append(" <snapshots>\n");
sb.append(" <enabled>true</enabled>\n");
sb.append(" </snapshots>\n");
return result;
}

/**
* Builds a list of dependency data maps from the deps set, for use with FreeMarker templates.
*/
protected List<Map<String, Object>> buildDependencyList(Set<String> deps) {
List<MavenGav> gavs = new ArrayList<>();
for (String dep : deps) {
MavenGav gav = parseMavenGav(dep);
String gid = gav.getGroupId();
if ("org.apache.camel".equals(gid)) {
// uses BOM so version should not be included
gav.setVersion(null);
}
gavs.add(gav);
}

// sort artifacts
gavs.sort(mavenGavComparator());

List<Map<String, Object>> result = new ArrayList<>();
for (MavenGav gav : gavs) {
Map<String, Object> dep = new HashMap<>();
dep.put("groupId", gav.getGroupId());
dep.put("artifactId", gav.getArtifactId());
dep.put("version", gav.getVersion());
dep.put("scope", gav.getScope());
dep.put("isLib", "lib".equals(gav.getPackaging()));
dep.put("isKameletsUtils", "camel-kamelets-utils".equals(gav.getArtifactId()));
result.add(dep);
}
return result;
}

public Comparator<MavenGav> mavenGavComparator() {
return new Comparator<MavenGav>() {
@Override
public int compare(MavenGav o1, MavenGav o2) {
int r1 = rankGroupId(o1);
int r2 = rankGroupId(o2);

if (r1 > r2) {
return -1;
} else if (r2 > r1) {
return 1;
} else {
return o1.toString().compareTo(o2.toString());
}
sb.append(" </pluginRepository>\n");
}

int rankGroupId(MavenGav o1) {
String g1 = o1.getGroupId();
if (g1 == null) {
return 0;
}

switch (g1) {
case "org.springframework.boot" -> {
return 30;
}
case "io.quarkus" -> {
return 30;
}
case "org.apache.camel.quarkus" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-quarkus-core".equals(a1)) {
return 21;
}
return 20;
}
case "org.apache.camel.springboot" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-spring-boot-starter".equals(a1)) {
return 21;
} else if ("camel-spring-boot-engine-starter".equals(a1)) {
return 22;
}
return 20;
}
case "org.apache.camel" -> {
String a1 = o1.getArtifactId();
// main/core/engine first
if ("camel-main".equals(a1)) {
return 11;
}
return 10;
}
case "org.apache.camel.kamelets" -> {
return 5;
}
default -> {
return 0;
}
}
}
};
}

/**
* Formats build properties as XML property lines for inclusion in POM templates.
*/
protected String formatBuildProperties() {
Properties properties = mapBuildProperties();

if (!skipPlugins) {
Set<PluginExporter> exporters = PluginHelper.getActivePlugins(getMain(), repositories).values()
.stream()
.map(Plugin::getExporter)
.filter(Optional::isPresent)
.map(Optional::get)
.collect(Collectors.toSet());

for (PluginExporter exporter : exporters) {
exporter.getBuildProperties().forEach(properties::putIfAbsent);
}
}
sb.append(" </pluginRepositories>\n");
return sb.toString();

return properties.entrySet().stream()
.map(item -> String.format(" <%s>%s</%s>", item.getKey(), item.getValue(), item.getKey()))
.collect(Collectors.joining(System.lineSeparator()));
}

protected abstract Integer export() throws Exception;
Expand Down Expand Up @@ -487,30 +585,15 @@ protected void addDependencies(String... deps) {
dependencies.addAll(Arrays.asList(depsArray));
}

/**
* @deprecated Use {@link #formatBuildProperties()} instead for FreeMarker templates.
*/
@Deprecated
protected String replaceBuildProperties(String context) {
Properties properties = mapBuildProperties();

if (!skipPlugins) {
Set<PluginExporter> exporters = PluginHelper.getActivePlugins(getMain(), repositories).values()
.stream()
.map(Plugin::getExporter)
.filter(Optional::isPresent)
.map(Optional::get)
.collect(Collectors.toSet());

for (PluginExporter exporter : exporters) {
exporter.getBuildProperties().forEach(properties::putIfAbsent);
}
}

String mavenProperties = properties.entrySet().stream()
.map(item -> {
return String.format(" <%s>%s</%s>", item.getKey(), item.getValue(), item.getKey());
})
.collect(Collectors.joining(System.lineSeparator()));

String mavenProperties = formatBuildProperties();
if (!mavenProperties.isEmpty()) {
context = context.replaceFirst(Pattern.quote("{{ .BuildProperties }}"), Matcher.quoteReplacement(mavenProperties));
context = context.replaceFirst(Pattern.quote("{{ .BuildProperties }}"),
Matcher.quoteReplacement(mavenProperties));
} else {
context = context.replaceFirst(Pattern.quote("{{ .BuildProperties }}"), "");
}
Expand Down
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