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Encoding issue, failing with Assertion Error

I have a class with a function as follows
`
private static Path compileNamedModuleTest() throws IOException {
Path base = Paths.get(".", "named");
Path src = base.resolve("src");
Path classes = base.resolve("classes");
ModuleInfoMaker maker = new ModuleInfoMaker(src);
maker.writeJavaFiles("test",
"module test {}",
"package test; public sealed interface Base permits test.a.ImplA1, test.a.ImplA2, test.b.ImplB, test.c.ImplC {}",
"package test.a; public final class ImplA1 implements test.Base {}",
"package test.a; public final class ImplA2 implements test.Base {}",
"package test.b; public final class ImplB implements test.Base {}",
"package test.c; public final class ImplC implements test.Base {}"
);
System.out.println("Default Charset: "
+ Charset.defaultCharset());
if (!CompilerUtils.compile(src, classes.resolve("test"), "--enable-preview", "-source", System.getProperty("java.specification.version"))) {
throw new AssertionError("Compilation didn't succeed!");
}
Files.delete(classes.resolve("test").resolve("test").resolve("c").resolve("ImplC.class"));
return classes;
}
`
and WriteJavaFiles function as
/**
* Create java source files of the given module
*/
public void writeJavaFiles(String module, String moduleInfoJava, String... contents)
throws IOException
{
Path msrc = dir.resolve(module);
new JavaSource(moduleInfoJava).write(msrc);
for (String c : contents) {
new JavaSource(c).write(msrc);
}
}
I am getting error as Error:
Java files created during execution have encoding issues due to which
compilation fails.
./named/src/test/test/a/ImplA1.java:1: error: illegal character: '\u009b'
/named/src/test/test/a/ImplA2.java:1: error: illegal character: '\u0080'
Which I believe is an encoding issue and need to add charset.defaultCharset() somewhere. But I am unsure where to put it?
JavaSource class
static class JavaSource {
final String source;
JavaSource(String source) {
this.source = source;
}
/**
* Writes the source code to a file in a specified directory.
* #param dir the directory
* #throws IOException if there is a problem writing the file
*/
public void write(Path dir) throws IOException {
Path file = dir.resolve(getJavaFileNameFromSource(source));
Files.createDirectories(file.getParent());
try (BufferedWriter out = Files.newBufferedWriter(file)) {
out.write(source.replace("\n", System.lineSeparator()));
}
}
I tried adding Charset as argument in WriteJavaFiles but did not help.

Handlebars if method returns null / empty string

I currently use handlebars in java (com.github.jknack.handlebars)
and have a handlebars helper method to get a link (with some logic behind)
{{ getLink data.node}}
which just render the url /subfolder/link.html
In my handlebars template I now only want to print the url (a-tag) when the helper method returns a non empty string (e.g. there is a link available)
I tried it with
{{#if getLink data.node }}
Link-Text
{{/if}}
but no link was rendered
What would be the correct syntax for my if?
Thanks
RCX
Edit:
getLink Helper Method in LinkHelper.class
public CharSequence getLink(JsonObject node, Options options) throws IOException {
String link = fetchLink(node);
if(link != null){
return link;
}
return "";
}
registered via
HandlebarsTemplateEngineImpl.getHandlebars().registerHelpers(new LinkHelper());

Handlebars.java is not well documented and missing couple of unit tests (consider to contribute if this answer helped), for some reason calling nested JsonObject removed at this commit, you can still call nested String, but there is a trick with parentheses.
Full example:
import com.github.jknack.handlebars.Context;
import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Helper;
import com.github.jknack.handlebars.Template;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.Map;
public class HandlebarsJavaTest {
public static void main(String[] args) throws IOException {
Handlebars handlebars = new Handlebars();
Gson gson = new Gson();
handlebars.registerHelper("getLink", (Helper<Map<String, Object>>) (jsonObject, options) -> {
String link = fetchLink(jsonObject);
return link != null ? link : "";
});
String data = "{'data':{'node':'/bla.html', 'node2':'inside node2'}}";
// Pay attention to parentheses !!!
// {{#if (getLink data.node)}} throws ClassCastException, java.lang.String cannot be cast to java.util.Map
String rawTemplate = "{{#if (getLink data)}} Link-Text {{/if}}";
Type type = new TypeToken<Map<String, Object>>(){}.getType();
Map<String, Object> map = gson.fromJson(data, type);
Template template = handlebars.compileInline(rawTemplate);
Context context = Context.newBuilder(map).build();
System.out.println(template.apply(context));
}
private static String fetchLink(Map<String, Object> map) {
try {
return map.get("node").toString();
} catch (NullPointerException npe) {
return null;
}
}
}
Output:
Link-Text
If node is just a string ( same output )
public static void main(String[] args) throws IOException {
Handlebars handlebars = new Handlebars();
Gson gson = new Gson();
handlebars.registerHelper("getLink", (Helper<String>) (node, options) -> node != null ? node : "");
String data = "{'data':{'node':'/bla.html', 'node2':'inside node2'}}";
// Pay attention to parentheses !!!
String rawTemplate = "{{#if (getLink data.node)}} Link-Text {{/if}}";
Type type = new TypeToken<Map<String, Object>>(){}.getType();
Map<String, Object> map = gson.fromJson(data, type);
Template template = handlebars.compileInline(rawTemplate);
Context context = Context.newBuilder(map).build();
System.out.println(template.apply(context));
}
If you insist node is an object using this.[data] or this.[data.node] will not do the work, working example for the same output:
import com.github.jknack.handlebars.Context;
import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Helper;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
public class HandlebarsJavaTest {
public static void main(String[] args) throws Exception {
System.out.println(
new Handlebars()
.registerHelper("getLink", (Helper<JsonObject>) (json, options) -> {
try {
// logic here
return json.get("data").getAsJsonObject().get("node").getAsJsonObject().get("link").getAsString();
} catch (NullPointerException npe) {
return null;
}
})
// Pay attention to parentheses !!
.compileInline("{{#if (getLink this) }} Link-Text {{/if}}")
.apply(
Context
.newBuilder(
new Gson()
.fromJson(
"{ 'data': { 'node': { 'link': '/bla.html' }, 'node2': 'inside node2' } }",
JsonObject.class
)
).build()
)
);
}
}
If you have time, consider to contribute to this open source by adding proper documentation or at least unit tests {{#if (method param)}}.
According to the source code
package com.github.jknack.handlebars;
public class IfBlockTest extends AbstractTest {
#Test
public void falsy() throws IOException {
// empty string
shouldCompileTo("{{#if value}}true{{else}}false{{/if}}", $("value", ""), "false");
BTW, the #if built-in helper will return False for empty string, so if getLink will execute return ""; the if condition will not and the text will not be rendered, to assert this you can add {{else}} before the closing if {{/if}} and see that what is rendered.

Java file encoding magic

Strange thing happened in Java Kingdom...
Long story short: I use Java API V3 to connect to QuickBooks and fetch the data form there (services for example).
Everything goes fine except the case when a service contains russian symbols (or probably non-latin symbols).
Here is Java code that does it (I know it's far from perfect)
package com.mde.test;
import static com.intuit.ipp.query.GenerateQuery.$;
import static com.intuit.ipp.query.GenerateQuery.select;
import java.util.LinkedList;
import java.util.List;
import com.intuit.ipp.core.Context;
import com.intuit.ipp.core.ServiceType;
import com.intuit.ipp.data.Item;
import com.intuit.ipp.exception.FMSException;
import com.intuit.ipp.query.GenerateQuery;
import com.intuit.ipp.security.OAuthAuthorizer;
import com.intuit.ipp.services.DataService;
import com.intuit.ipp.util.Config;
public class TestEncoding {
public static final String QBO_BASE_URL_SANDBOX = "https://sandbox-quickbooks.api.intuit.com/v3/company";
private static String consumerKey = "consumerkeycode";
private static String consumerSecret = "consumersecretcode";
private static String accessToken = "accesstokencode";
private static String accessTokenSecret = "accesstokensecretcode";
private static String appToken = "apptokencode";
private static String companyId = "companyidcode";
private static OAuthAuthorizer oauth = new OAuthAuthorizer(consumerKey, consumerSecret, accessToken, accessTokenSecret);
private static final int PAGING_STEP = 500;
public static void main(String[] args) throws FMSException {
List<Item> res = findAllServices(getDataService());
System.out.println(res.get(1).getName());
}
public static List<Item> findAllServices(DataService service) throws FMSException {
Item item = GenerateQuery.createQueryEntity(Item.class);
List<Item> res = new LinkedList<>();
for (int skip = 0; ; skip += PAGING_STEP) {
String query = select($(item)).skip(skip).take(PAGING_STEP).generate();
List<Item> items = (List<Item>)service.executeQuery(query).getEntities();
if (items.size() > 0)
res.addAll(items);
else
break;
}
System.out.println("All services fetched");
return res;
}
public static DataService getDataService() throws FMSException {
Context context = getContext();
if (context == null) {
System.out.println("Context is null, something wrong, dataService also will null.");
return null;
}
return getDataService(context);
}
private static Context getContext() {
try {
return new Context(oauth, appToken, ServiceType.QBO, companyId);
} catch (FMSException e) {
System.out.println("Context is not loaded");
return null;
}
}
protected static DataService getDataService(Context context) throws FMSException {
DataService service = new DataService(context);
Config.setProperty(Config.BASE_URL_QBO, QBO_BASE_URL_SANDBOX);
return new DataService(context);
}
}
This file is saved in UTF-8. And it prints something like
All services fetched
Сэрвыс, отнюдь
But! When I save this file in UTF-8 with BOM.... I get the correct data!
All services fetched
Сэрвыс, отнюдь
Does anybody can explain what is happening? :)
// I use Eclipse to run the code

You are fetching data from a system that doesn't share the same byte ordering as you, so when you save the file with BOM, it adds enough information in the file that future programs will read it in the remote system's byte ordering.
When you save it without BOM, it wrote the file in the remote system's byte ordering without any indication of the stored byte order, so when you read it you read it with the local system's (different) byte order. This jumbles up the bytes within the multi-byte characters, making the output appear as nonsense.

NoSuchMetodError Exception when Access Custom Library

I have a problem regarding java.lang.NoSuchMethodError. This program is about Compiler API (JSR 199). When I create a prototype for this it run work, but when I try to make it to become library it throw NoSuchMethodError Exception.
Here is the First Prototype:
public class DynaCompTest {
public static void main(String[] args) {
String fullName = "HelloWorld";
StringBuilder sourceCode = new StringBuilder();
sourceCode.append("public class HelloWorld {\n")
.append("\tpublic static void main(String[] args) {\n")
.append("\t\tSystem.out.println(\"Hello World\")\n")
.append("\t}\n")
.append("}");
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
JavaFileManager fileManager = new ClassFileManager(compiler.getStandardFileManager(null, null, null));
DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>();
List<JavaFileObject> jFiles = new ArrayList<>();
jFiles.add(new CharSequenceJavaFileObject(fullName, sourceCode));
compiler.getTask(null, fileManager, diagnostics, null, null, jFiles).call();
for (Diagnostic diagnostic : diagnostics.getDiagnostics()) {
System.out.format("Error on line %d in %s\n", diagnostic.getLineNumber(), diagnostic);
}
}
}
public class CharSequenceJavaFileObject extends SimpleJavaFileObject {
private CharSequence content;
public CharSequenceJavaFileObject(String className, CharSequence content) {
super(URI.create("string:///" + className.replace('.', '/') + Kind.SOURCE.extension), Kind.SOURCE);
this.content = content;
}
#Override
public CharSequence getCharContent(boolean ignoreEncodingErrors) {
return content;
}
}
public class ClassFileManager extends ForwardingJavaFileManager {
private JavaClassObject jClassObject;
public ClassFileManager(StandardJavaFileManager standardManager) {
super(standardManager);
}
#Override
public ClassLoader getClassLoader(Location location) {
return new SecureClassLoader() {
#Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
byte[] b = jClassObject.getBytes();
return super.defineClass(name, jClassObject.getBytes(), 0, b.length);
}
};
}
#Override
public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {
jClassObject = new JavaClassObject(className, kind);
return jClassObject;
}
}
public class JavaClassObject extends SimpleJavaFileObject {
protected final ByteArrayOutputStream bos = new ByteArrayOutputStream();
public JavaClassObject(String name, Kind kind) {
super(URI.create("string:///" + name.replace('.', '/') + kind.extension), kind);
}
public byte[] getBytes() {
return bos.toByteArray();
}
#Override
public OutputStream openOutputStream() {
return bos;
}
}
I changed the DynaCompTest become DynamicCompiler for the library:
public class DynamicCompiler {
private JavaCompiler compiler;
private JavaFileManager fileManager;
private List<JavaFileObject> jFiles;
private DiagnosticCollector<JavaFileObject> diagnostics;
public DiagnosticCollector<JavaFileObject> getDiagnostics() {
return diagnostics;
}
public DynamicCompiler(String className, StringBuilder sourceCode) {
compiler = ToolProvider.getSystemJavaCompiler();
fileManager = new ClassFileManager(compiler.getStandardFileManager(null, null, null));
diagnostics = new DiagnosticCollector<>();
jFiles = new ArrayList<>();
jFiles.add(new CharSequenceJavaFileObject(className, sourceCode));
}
public boolean doCompilation() {
return compiler.getTask(null, fileManager, diagnostics, null, null, jFiles).call();
}
}
And I created Second Prototype to test the library:
public class Compiler {
private static StringBuilder sourceCode = new StringBuilder();
public static void main(String[] args) {
boolean status;
sourceCode.append("public class HelloWorld {\n")
.append("\tpublic static void main(String[] args) {\n")
.append("\t\tSystem.out.println(\"Hello World\");\n")
.append("\t}\n")
.append("}");
DynamicCompiler compiler = new DynamicCompiler("HelloWorld", sourceCode);
status = compiler.doCompilation();
StringBuilder messages = new StringBuilder();
if (!status) {
for (Diagnostic diagnostic : compiler.getDiagnostics().getDiagnostics()) {
messages.append("Error on line ")
.append(diagnostic.getLineNumber())
.append(" in ")
.append(diagnostic)
.append("\n");
}
} else {
messages.append("BUILD SUCCESSFUL ");
}
System.out.println(messages.toString());
}
}
When I test with code above it run well and print BUILD SUCCESSFUL but when I tried to make it error for example I deleted the semicolon ; like the first prototype, it throw the NoSuchMethodError Exception when access the compiler.getDiagnostics().getDiagnostics() inside the looping.
The question is, why in the First Prototype it run well when try to make an error but when I tried with my own library it become Exception?
Edit
Here is the stacktrace:
/HelloWorld.java:3: error: ';' expected
System.out.println("Hello World")
^
1 error
Exception in thread "main" java.lang.NoSuchMethodError: org.ert.lib.DynamicCompiler.getDiagnostics()Ljavax/tools/DiagnosticCollector;
at org.ert.exp.Compiler.main(Compiler.java:28)
Java Result: 1
It should be like this:
Error on line 3 in /HelloWorld.java:3: error: ';' expected
System.out.println("Hello World")
^
When trying to debug it, it shown an error:
public DiagnosticCollector<JavaFileObject> getDiagnostics() {
return diagnostics; // Set Breakpoint here
}
Here is the error message:
Not able to submit breakpoint LineBreakpoint DynamicCompiler.java : 25, reason: No executable location available at line 25 in class org.ert.lib.DynamicCompiler.
Invalid LineBreakpoint DynamicCompiler.java : 25
Update
Got the problem, this problem will occur if we add the whole project instead build the jar of the library. So when I build the library jar it works. But anyone can explain why this thing happen when I try add the whole project instead the jar file?
Note
I'm using:
JDK 1.7 from Oracle
Netbeans 7.1.1

It seems that you have similar class exists in two different libraries(jars).
e.g.
com.test.Example.class in a.jar
com.test.Example.class in b.jar
Now class loader will load the first first Example.class and it seems that you need class which is there in b.jar. Then it will not throw exception such as NoMethodFound but throw an Exception that NoSuchMethodFound because class still exists in memory but can not find required method.
Such problems can be resolved by changing library order. You need to make required library's order higher. You can do this from the eclipse
Project Setting -> Java Build Path -> Order and Export.
Hope this is helpful.

After I tried with Eclipse Indigo, I found that it works when add the Project or add the jar file. While in Netbeans 7.1.1 will get an error if add the Project, but works if add the jar file.
Maybe it one of the bugs of Netbeans...
Thank you for your attention...

Simple K-Means doesnt handle iris.arff

I have this class below, i build it considering the examples given on the wiki and in a thesis, why can't SympleKMeans handle data? The class can print the Datasource dados, so its nothing wrong with processing file, the error is on the build.
package slcct;
import weka.clusterers.ClusterEvaluation;
import weka.clusterers.SimpleKMeans;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.converters.ConverterUtils.DataSource;
public class Cluster {
public String path;
public Instances dados;
public String[] options = new String[2];
public Cluster(String caminho, int nclusters, int seed ){
this.path = caminho;
this.options[0] = String.valueOf(nclusters);
this.options[1] = String.valueOf(seed);
}
public void ledados() throws Exception{
DataSource source = new DataSource(path);
dados = source.getDataSet();
System.out.println(dados)
if(dados.classIndex()==-1){
dados.setClassIndex(dados.numAttributes()-1);
}
}
public void imprimedados(){
for(int i=0; i<dados.numInstances();i++)
{
Instance actual = dados.instance(i);
System.out.println((i+1) + " : "+ actual);
}
}
public void clustering() throws Exception{
SimpleKMeans cluster = new SimpleKMeans();
cluster.setOptions(options);
cluster.setDisplayStdDevs(true);
cluster.getMaxIterations();
cluster.buildClusterer(dados);
Instances ClusterCenter = cluster.getClusterCentroids();
Instances SDev = cluster.getClusterStandardDevs();
int[] ClusterSize = cluster.getClusterSizes();
ClusterEvaluation eval = new ClusterEvaluation();
eval.setClusterer(cluster);
eval.evaluateClusterer(dados);
for(int i=0;i<ClusterCenter.numInstances();i++){
System.out.println("Cluster#"+( i +1)+ ": "+ClusterSize[i]+" dados .");
System.out.println("Centróide:"+ ClusterCenter.instance(i));
System.out.println("STDDEV:" + SDev.instance(i));
System.out.println("Cluster Evaluation:"+eval.clusterResultsToString());
}
}
}
The error:
weka.core.WekaException: weka.clusterers.SimpleKMeans: Cannot handle any class attribute!
at weka.core.Capabilities.test(Capabilities.java:1097)
at weka.core.Capabilities.test(Capabilities.java:1018)
at weka.core.Capabilities.testWithFail(Capabilities.java:1297)
at weka.clusterers.SimpleKMeans.buildClusterer(SimpleKMeans.java:228)
at slcct.Cluster.clustering(Cluster.java:53)//Here.
at slcct.Clustering.jButton1ActionPerformed(Clustering.java:104)

I believe you need not set the class index, as you are doing clustering and not classification. Try following this guide for programmatic Java clustering.

In your "ledados()" function just remove the code block given below. It will work. Because you have no defined class in your data.
if(dados.classIndex()==-1){
dados.setClassIndex(dados.numAttributes()-1);
}
Your new function:
public void ledados() throws Exception{
DataSource source = new DataSource(path);
dados = source.getDataSet();
System.out.println(dados) }

You would not need a class attribute in the data while doing k clustering