I have the following model classes:
package com.ab.model;
import java.util.List;
public class Request {
public Request(String requestType, Body body, List<String> emails) {
this.requestType = requestType;
this.body =body;
this.emails = emails;
}
private String requestType;
private Body body;
private List<String> emails;
public String getRequestType() {
return requestType;
}
public void setRequestType(String requestType) {
this.requestType = requestType;
}
public Body getBody() {
return body;
}
public void setBody(Body body) {
this.body = body;
}
public List<String> getEmails() {
return emails;
}
public void setEmails(List<String> emails) {
this.emails = emails;
}
}
class Body {
private String content;
private List<Header> headers;
public Body(String content, List<Header> headers) {
this.content = content;
this.headers = headers;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public List<Header> getHeaders() {
return headers;
}
public void setHeaders(List<Header> headers) {
this.headers = headers;
}
}
class Header {
private String headerName;
public Header (String headerName) {
this.headerName = headerName;
}
public String getHeaderName() {
return headerName;
}
public void setHeaderName(String headerName) {
this.headerName = headerName;
}
}
And the following instance of the Request class:
Request request = new Request(
"get",
new Body("abcdefg",
Arrays.asList(new Header("header_one"))),
Arrays.asList("a#a.com", "b#b.com"));
Do you know any library or algorithm that can serialize the request object into the following string?
requestType = "get"
body.content = "abcdefg"
body.headers[0].headerName = "header_one"
emails[0] = "a#a.com"
emails[1] = "b#b.com"
I know I can serialize it as json, xml, etc, but these don't fit my use case.
Basically I need a serialization like:
field.nestedField.reallyNestedField = "its primitive value"
As a next step, I am planning to read the generated string and generate arbitrary data for each field/nestedField then deserialize it back using PropertyUtils from Apache e.g.:
PropertyUtils.setProperty(requestObject, "requestType", "random type");
PropertyUtils.setProperty(requestObject, "body.content", "random content");
//...
Many thanks!
Andrei
What about overriding your toString() default methods to read and output your member variables as text. You can use super to refer to your SuperClass and it's members.
PS: You don't have default constructors in your classes! In case you have constructors with your argument list it is suggested to include your no-argument default constructor in your class! Especially in case you are implementing some logic related to serialisation / deserialisation!
You can iterate and recurse on the class/object properties using Commons PropertyUtils.
Depending on how complex your implementation is, you might need to do some type checking for primitive/wrapper/collection types (the below leverages Commons ClassUtils).
public static List<String> getPropertyDescriptorPaths(Class<?> clazz) {
return getPropertyDescriptorPaths("", clazz);
}
private static List<String> getPropertyDescriptorPaths(String prefix, Class<?> clazz) {
List<String> paths = new ArrayList<>();
PropertyDescriptor[] descriptors = PropertyUtils.getPropertyDescriptors(clazz);
for (PropertyDescriptor pd : descriptors) {
if (isSimpleType(pd.getPropertyType())) {
paths.add(prefix + pd.getName());
} else if (!pd.getName().equals("class")) {
paths.addAll(getPropertyDescriptorPaths(pd.getName() + ".", pd.getPropertyType()));
}
}
return paths;
}
private static boolean isSimpleType(Class<?> clazz) {
return ClassUtils.isPrimitiveOrWrapper(clazz) || clazz.equals(String.class) || isCollectionOrArray(clazz);
}
private static boolean isCollectionOrArray(Class<?> clazz) {
return isCollection(clazz) || clazz.isArray();
}
private static final List<Class<?>> COLLECTION_TYPES = Arrays.asList(new Class<?>[] { List.class, Map.class, Set.class });
private static boolean isCollection(Class<?> clazz) {
for (Class<?> eachClass : COLLECTION_TYPES) {
if (eachClass.isAssignableFrom(clazz)) {
return true;
}
}
return false;
}
The condition for comparing property name to class is because each object has a getClass() method, and we don't care about that.
Using this with your classes, we get the result:
System.out.println(getPropertyDescriptorPaths(Request.class));
// [emails, requestType, body.headers, body.content]
Related
I have below classes:
public class Result<T> {
public int code;
public Object meta;
public T data;
}
public class User {
public int id;
public String name;
}
public class Error {
public String field;
public String message;
}
I want to deserialize a JSON payload based on code field. If code >= 10, return Result<ArrayList<Error>>, otherwise return Result<User>
Currently, I map JSON to Result<Object> first, then check the code field. Based on that value I make second map to desired object.
ObjectMapper mapper = new ObjectMapper();
Result<Object> tempResult = mapper.readValue(json, new TypeReference<Result<Object>>() {});
if (tempResult.code < 10) {
Result<User> result = mapper.readValue(json, new TypeReference<Result<User>>() {});
return result;
} else {
Result<ArrayList<Error>> result = mapper.readValue(json, new TypeReference<Result<ArrayList<Error>>>() {});
return result;
}
Is there an elegant way to do this without deserializing it 2 times?
You need to implement custom TypeIdResolver:
class UserTypeIdResolverBase extends TypeIdResolverBase {
#Override
public String idFromValue(Object value) {
throw new IllegalStateException("Not implemented!");
}
#Override
public String idFromValueAndType(Object value, Class<?> suggestedType) {
throw new IllegalStateException("Not implemented!");
}
#Override
public JsonTypeInfo.Id getMechanism() {
return JsonTypeInfo.Id.CUSTOM;
}
#Override
public JavaType typeFromId(DatabindContext context, String id) {
if (Integer.parseInt(id) < 10) {
return context.getTypeFactory().constructType(new TypeReference<Result<User>>() {});
}
return context.getTypeFactory().constructType(new TypeReference<Result<List<Error>>>() {});
}
}
and declare it for a Result class:
#JsonTypeInfo(property = "code", use = JsonTypeInfo.Id.CUSTOM, visible = true)
#JsonTypeIdResolver(UserTypeIdResolverBase.class)
class Result<T>
I have use case were I need to get requestBody based on selection of field.below is same code which I was able get the dynamic responseBody Based on selection ProtocolType.Is there is any way that swagger can read the RequestBody Dynamically.
Controller.Java
#ApiOperation(value = "Protocol Account", tags = {"ProtocolAccount"})
#RequestMapping(value = "/protocolAccount/{protocolName}",
method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
#ResponseBody public ProtocolAccount getProtocol(#PathVariable String protocolName)
{
return service.getProtocol(protocolName);
}
Service.Java
public ProtocolAccount getProtocol(String protocolName){
ProtocolAccount protocolAccount=new ProtocolAccount();
Object object=ProtocolType.fromMap(protocolName);
protocolAccount.setProtocol(object);
return protocolAccount;
}
POJOs
public class ProtocolAccount
{
String Id;
private Object protocolType
}
public class Protocol{
private String port;
}
public class FTPProtocol extends Protocol{
/*Some Fields*/
}
public class SFTPProtocol extends Protocol{
/*Some Fields*/
}
Enumeration
public enum ProtocolType
{
SFTP("SFTP"), FTPS("FTPS"), AS2("AS2"), FTP("FTP");
private final String value;
private static final EnumMap<ProtocolType,
Object>map = new EnumMap<ProtocolType, Object>(ProtocolType.class);
static{
map.put(ProtocolType.SFTP, new SFTPProtocol());
map.put(ProtocolType.FTP, new FTPProtocol());
map.put(ProtocolType.FTPS,new FTPSProtocol());
}
ProtocolType(String v){
value=v;
}
public static ProtocolType fromValue(String val){
return EnumSet.allOf(ProtocolType.class)
.stream().filter(e->e.value.equals(val))
.findFirst().orElseThrow(()->new IllegalArgumentException(val));
}
public String value(){
return value;
}
public static Object fromMap(String value)
{
return map.get(ProtocolType.fromValue(value));
}
}
I have defined JSON response which I want to deserialize into Java Objects. I managed to do it "manually" with the Tree Model but if possible I would like to use Data Binding instead. The problem is that I need some custom logic for some parts.
The JSON looks like this:
{
"resourcedescriptions": [
{
"path": "somePath",
"tag_pagetype": "default",
"tag_bookingcenter": [
"bc_ch",
"bc_de"
],
"resources": [
{
"path": "somePathDe.html",
"lang": "de",
"lastmodified": 1399020442914,
"mimetype": "text/html"
},
{
"path": "somePathEn.html",
"lang": "en",
"lastmodified": 1399907224208,
"mimetype": "text/html"
}
],
"lastmodified": 1399907224208
},
{
"path": "someOtherPath",
"tag_pagetype": "special",
"tag_bookingcenter": [
"bc_ch"
],
"resources": [
{
"path": "someOtherPathDe.html",
"lang": "de",
"lastmodified": 1399020442914,
"mimetype": "text/html"
},
{
"path": "someOtherPathEn.html",
"lang": "en",
"lastmodified": 1399907224208,
"mimetype": "text/html"
}
],
"lastmodified": 1399907224208
}
]
}
My Java Classes would be:
public class ResourceDescription {
private String path;
private LocalDateTime lastModified;
private String chartConfig;
private final List<Tag> tags = new ArrayList<Tag>();
private final List<Resource> resources = new ArrayList<Resource>();
}
public class Resource {
private String lang;
private String path;
private String mimeType;
private LocalDateTime lastModified;
}
public class Tag {
private String namespace;
private String name;
}
First question which I still don't fully understand even with reading many posts here. How do I deserialize this array of Resources from the JSON into my List of the ResourceDescription?
Second and most complex question. The JSON properties prefixed with "tag_" need to be transformed into the Tag class, whereas the the property name represents the namespace and the value (single or array) represent the name. So if the pattern is "namespace:name", the first ResourceDescription would have the following tags:
tag_pagetype:default
tag_bookingcenter:bc_ch
tag_bookingcenter:bc_de
Third the "lastmodified" should be transformed into DateTime from Joda-Time.
Is this even possible with data binding or should I stick to the Tree Model?
How do I deserialize this array of Resources from the JSON into my
List of the ResourceDescription?
You have to create additional root class which contains resourcedescriptions property. For example:
class Root {
private List<ResourceDescription> resourcedescriptions;
public List<ResourceDescription> getResourcedescriptions() {
return resourcedescriptions;
}
public void setResourcedescriptions(List<ResourceDescription> resourcedescriptions) {
this.resourcedescriptions = resourcedescriptions;
}
#Override
public String toString() {
return String.valueOf(resourcedescriptions);
}
}
The JSON properties prefixed with "tag_" need to be transformed into
the Tag class, whereas the the property name represents the namespace
and the value (single or array) represent the name.
You can handle this case using #JsonAnySetter annotation. You have to add new method to ResourceDescription class which could look like this:
#JsonAnySetter
public void setAnyValues(String propertyName, Object value) {
if (propertyName.startsWith("tag_")) {
if (value instanceof String) {
tags.add(new Tag(propertyName, value.toString()));
} else if (value instanceof List) {
List<?> values = (List<?>) value;
for (Object v : values) {
tags.add(new Tag(propertyName, v.toString()));
}
}
// throw exception?
} else {
// handle another unknown properties
}
}
Third the "lastmodified" should be transformed into DateTime from
Joda-Time.
You can handle JodaTime types by adding jackson-datatype-joda library. When you add it you can register JodaModule module.
mapper.registerModule(new JodaModule());
Additional problem that your JSON contain properties written using lowercase, but your POJO properties are written using camel-case. You can change JSON or POJO or use #JsonProperty("property-name-from-JSON") annotation or implement your own naming strategy. For example:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy.PropertyNamingStrategyBase() {
#Override
public String translate(String propertyName) {
return propertyName.toLowerCase();
}
});
Full Java example how to you can deserialize your JSON:
import java.util.ArrayList;
import java.util.List;
import org.joda.time.LocalDateTime;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import com.fasterxml.jackson.datatype.joda.JodaModule;
public class JacksonProgram {
public static void main(String[] args) throws Exception {
String json = "{ ... }";
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JodaModule());
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy.PropertyNamingStrategyBase() {
#Override
public String translate(String propertyName) {
return propertyName.toLowerCase();
}
});
System.out.println(mapper.readValue(json, Root.class));
}
}
class Root {
private List<ResourceDescription> resourcedescriptions;
public List<ResourceDescription> getResourcedescriptions() {
return resourcedescriptions;
}
public void setResourcedescriptions(List<ResourceDescription> resourcedescriptions) {
this.resourcedescriptions = resourcedescriptions;
}
#Override
public String toString() {
return String.valueOf(resourcedescriptions);
}
}
class ResourceDescription {
private String path;
private LocalDateTime lastModified;
private String chartConfig;
private final List<Tag> tags = new ArrayList<Tag>();
private final List<Resource> resources = new ArrayList<Resource>();
#JsonAnySetter
public void setAnyValues(String propertyName, Object value) {
if (propertyName.startsWith("tag_")) {
if (value instanceof String) {
tags.add(new Tag(propertyName, value.toString()));
} else if (value instanceof List) {
List<?> values = (List<?>) value;
for (Object v : values) {
tags.add(new Tag(propertyName, v.toString()));
}
}
// throw exception?
} else {
// handle another unknown properties
}
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
public LocalDateTime getLastModified() {
return lastModified;
}
public void setLastModified(LocalDateTime lastModified) {
this.lastModified = lastModified;
}
public String getChartConfig() {
return chartConfig;
}
public void setChartConfig(String chartConfig) {
this.chartConfig = chartConfig;
}
public List<Tag> getTags() {
return tags;
}
public List<Resource> getResources() {
return resources;
}
#Override
public String toString() {
return "ResourceDescription [path=" + path + ", lastModified=" + lastModified
+ ", chartConfig=" + chartConfig + ", tags=" + tags + ", resources=" + resources
+ "]";
}
}
class Resource {
private String lang;
private String path;
private String mimeType;
private LocalDateTime lastModified;
public String getLang() {
return lang;
}
public void setLang(String lang) {
this.lang = lang;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
public String getMimeType() {
return mimeType;
}
public void setMimeType(String mimeType) {
this.mimeType = mimeType;
}
public LocalDateTime getLastModified() {
return lastModified;
}
public void setLastModified(LocalDateTime lastModified) {
this.lastModified = lastModified;
}
#Override
public String toString() {
return "Resource [lang=" + lang + ", path=" + path + ", mimeType=" + mimeType
+ ", lastModified=" + lastModified + "]";
}
}
class Tag {
private String namespace;
private String name;
public Tag() {
}
public Tag(String namespace, String name) {
this.namespace = namespace;
this.name = name;
}
public String getNamespace() {
return namespace;
}
public void setNamespace(String namespace) {
this.namespace = namespace;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#Override
public String toString() {
return "Tag [namespace=" + namespace + ", name=" + name + "]";
}
}
Above program prints:
[ResourceDescription [path=somePath, lastModified=2014-05-12T17:07:04.208, chartConfig=null, tags=[Tag [namespace=tag_pagetype, name=default], Tag [namespace=tag_bookingcenter, name=bc_ch], Tag [namespace=tag_bookingcenter, name=bc_de]], resources=[Resource [lang=de, path=somePathDe.html, mimeType=text/html, lastModified=2014-05-02T10:47:22.914], Resource [lang=en, path=somePathEn.html, mimeType=text/html, lastModified=2014-05-12T17:07:04.208]]], ResourceDescription [path=someOtherPath, lastModified=2014-05-12T17:07:04.208, chartConfig=null, tags=[Tag [namespace=tag_pagetype, name=special], Tag [namespace=tag_bookingcenter, name=bc_ch]], resources=[Resource [lang=de, path=someOtherPathDe.html, mimeType=text/html, lastModified=2014-05-02T10:47:22.914], Resource [lang=en, path=someOtherPathEn.html, mimeType=text/html, lastModified=2014-05-12T17:07:04.208]]]]
You will need to create a custom deserializer for ResourceDescription in order to accomplish what you need to do. The syntax for specifying a custom deserializer for ResourceDescription will look like this:
#JsonDeserialize(using=ResourceDescriptionDeserializer.class)
public class ResourceDescription { ... }
This deserializer will have to iterate through each of the keys for each resource description to see if it begins with "tag_", strip off the prefix and use the remaining for the namespace and populate the name/value for the Tag before adding it to the array of the ResourceDescription being created.
For all other attributes/types I think you can just defer to the default deserialization and set those attributes on their respective fields.
Then, to deserialize the list of ResourceDescriptions you can specify a TypeReference to avoid writing a custom deserializer for ResourceDescriptions. The code will look something like this:
Map<String, List<ResourceDescription>> resultMap =
objectMapper.readValue(JSON, new TypeReference<Map<String, List<ResourceDescription>>>() {});
List<ResourceDescription> descriptions = resultMap.get("resourcedescriptions");
Here's an article that doesn't quite pair with what you're doing but I think will help with the general idea:
Using Jackson to deserialize array nested within array in JSON object
I'm running into a few issues similar to what others have had in the past with Json parsing in Java. This is the first time I try something like this so any help/tips is extremely useful.
I'm trying to parse in data from this site: https://api.bitcoinaverage.com/exchanges/USD
I have tried numerous ways with both Json and Gson. And have tried looking for help here but to no avail.
Here are the classes that are set up (these were auto generated):
Info.java:
public class Info{
private String display_URL;
private String display_name;
private Rates[] rates;
private String source;
private Number volume_btc;
private Number volume_percent;
public String getDisplay_URL(){
return this.display_URL;
}
public void setDisplay_URL(String display_URL){
this.display_URL = display_URL;
}
public String getDisplay_name(){
return this.display_name;
}
public void setDisplay_name(String display_name){
this.display_name = display_name;
}
public Rates[] getRates(){
return this.rates;
}
public void setRates(Rates[] rates){
this.rates = rates;
}
public String getSource(){
return this.source;
}
public void setSource(String source){
this.source = source;
}
public Number getVolume_btc(){
return this.volume_btc;
}
public void setVolume_btc(Number volume_btc){
this.volume_btc = volume_btc;
}
public Number getVolume_percent(){
return this.volume_percent;
}
public void setVolume_percent(Number volume_percent){
this.volume_percent = volume_percent;
}
}
Rates.java:
public class Rates {
private Number ask;
private Number bid;
private Number last;
public Number getAsk(){
return this.ask;
}
public void setAsk(Number ask){
this.ask = ask;
}
public Number getBid(){
return this.bid;
}
public void setBid(Number bid){
this.bid = bid;
}
public Number getLast(){
return this.last;
}
public void setLast(Number last){
this.last = last;
}
}
MainClass.java:
public class MainClass {
public static void main(String[] args) throws Exception {
Gson gson = new Gson();
String json = readUrl("https://api.bitcoinaverage.com/exchanges/USD");
Info page = gson.fromJson(json, Info.class);
System.out.println(page.getDisplay_name());
}
private static String readUrl(String urlString) throws Exception {
BufferedReader reader = null;
try {
URL url = new URL(urlString);
reader = new BufferedReader(new InputStreamReader(url.openStream()));
StringBuffer buffer = new StringBuffer();
int read;
char[] chars = new char[1024];
while ((read = reader.read(chars)) != -1)
buffer.append(chars, 0, read);
return buffer.toString();
} finally {
if (reader != null)
reader.close();
}
}
}
When I try to call a getter, a null is returned.
How do I go about parsing the data properly, and then being able to call an attribute from which ever object I want? For example, if I want an attribute from "anx_hk" or "bitfinex".
This is the first time me posting something here so I hope I'm following the proper guidelines.
I also plan on passing this over to Android once I get the fell for parsing Json better. Thanks for the help! It'll greatly be appreciated.
I'll be honest with you, that's a pretty lame API response. Here it is
{
"anx_hk": {
"display_URL": "https://anxbtc.com/",
"display_name": "ANXBTC",
"rates": {
"ask": 454.26,
"bid": 444.46,
"last": 443.78
},
"source": "bitcoincharts",
"volume_btc": 11.73,
"volume_percent": 0.02
},
...,
"timestamp": "Fri, 04 Apr 2014 04:30:26 -0000",
...
}
There's no JSON array here, so you can get rid of all your array types. This response is a JSON object, which contains a bunch of JSON objects (which share a format) and a JSON name value pair where the name is timestamp.
The common JSON objects have two fields of type double (that's what type your field should be, not Number)
"volume_btc": 11.73,
"volume_percent": 0.02
, three fields of type String
"display_URL": "https://anxbtc.com/",
"display_name": "ANXBTC",
"source": "bitcoincharts",
and one that is a JSON object that contains three more doubles
"rates": {
"ask": 454.26,
"bid": 444.46,
"last": 443.78
}
The actual issue here is that, I'm assuming, the JSON objects in the root JSON object have names that may change or new ones may be added. This is not a good fit for a POJO. Instead you'd want to use a Map<String, Info>, but Gson can't map to that by default. It is not well suited for such deserialization. You'd have to provide your own TypeAdapter.
Instead, I'm going to suggest you use Jackson.
If we put that all together, we get something like
class ApiResponse {
private Map<String, Info> page = new HashMap<>();
private Date timestamp;
public Map<String, Info> getPage() {
return page;
}
#JsonAnySetter
public void setPage(String name, Info value) {
page.put(name, value);
}
public Date getTimestamp() {
return timestamp;
}
public void setTimestamp(Date timestamp) {
this.timestamp = timestamp;
}
}
class Info {
private String display_URL;
private String display_name;
private Rates rates;
private String source;
private Double volume_btc;
private Double volume_percent;
public String getDisplay_URL() {
return this.display_URL;
}
public void setDisplay_URL(String display_URL) {
this.display_URL = display_URL;
}
public String getDisplay_name() {
return this.display_name;
}
public void setDisplay_name(String display_name) {
this.display_name = display_name;
}
public Rates getRates() {
return this.rates;
}
public void setRates(Rates rates) {
this.rates = rates;
}
public String getSource() {
return this.source;
}
public void setSource(String source) {
this.source = source;
}
public Double getVolume_btc() {
return this.volume_btc;
}
public void setVolume_btc(Double volume_btc) {
this.volume_btc = volume_btc;
}
public Double getVolume_percent() {
return this.volume_percent;
}
public void setVolume_percent(Double volume_percent) {
this.volume_percent = volume_percent;
}
}
class Rates {
private Double ask;
private Double bid;
private Double last;
public Number getAsk() {
return this.ask;
}
public void setAsk(Double ask) {
this.ask = ask;
}
public Double getBid() {
return this.bid;
}
public void setBid(Double bid) {
this.bid = bid;
}
public Double getLast() {
return this.last;
}
public void setLast(Double last) {
this.last = last;
}
}
With deserialization code such as
String json = readUrl("https://api.bitcoinaverage.com/exchanges/USD");
ObjectMapper mapper = new ObjectMapper();
ApiResponse response = mapper.readValue(json, ApiResponse.class);
System.out.println(response);
With appropriate toString() methods (mine were auto-generated with Eclipse), you would get something like
ApiResponse [pages={bitkonan=Info [display_URL=https://bitkonan.com/, display_name=BitKonan, rates=Rates [ask=475.0, bid=438.01, last=437.0], source=api, volume_btc=7.24, volume_percent=0.01], vaultofsatoshi=Info [display_URL=https://vaultofsatoshi.com, display_name=Vault of Satoshi, rates=Rates [ask=460.0, bid=460.0, last=460.0], source=api, volume_btc=11.46, volume_percent=0.02], bitstamp=Info [display_URL=https://bitstamp.net/, display_name=Bitstamp, rates=Rates [ask=439.16, bid=436.34, last=436.34], source=api, volume_btc=22186.29, volume_percent=35.19], ...}, timestamp=Fri Apr 04 01:02:43 EDT 2014]
as output.
The api response contains many objects, but seems that you are trying to read them as a single Info object.
You may try to read the response as a Map<String, Info>, and iterate the entries.
Map<String, Info> hashMap = gson.fromJson(body, HashMap.class);
for (Map.Entry entry : hashMap.entrySet()) {
// your code
}
How do I convert all TaskStatusConstant interface items into one List<String> automatically?
public interface TaskStatusConstant {
final static String NEW = "New";
final static String ACCEPTED = "Accepted";
final static String REJECTED = "Rejected";
final static String REASSIGNED = "Reassigned";
final static String COMPLETED = "Completed";
}
Those information should be represented in an enumeration.
public enum TaskStatusConstant {
NEW,
ACCEPTED,
REJECTED,
REASSIGNED,
COMPLETED
}
To iterate over an enum in Java use this:
for (TaskStatusConstant task: TaskStatusConstant.values()) {
// do what you want
}
You can use reflection, for example:
List<String> constants = new ArrayList<String>();
Field[] fields = TaskStatusConstant.class.getFields();
for (Field field : fields) {
if (field.getType().equals(String.class)) {
constants.add(field.getName());
}
}
for (String constant : constants) {
System.out.println(constant);
}
public enum TaskStatusConstant2 {
NEW("New"), ACCEPTED("Accepted"), REJECTED("Rejected"), REASSIGNED("Reassigned"), COMPLETED("Completed");
private String value;
private TaskStatusConstant2(String value) {
this.value = value;
}
public String getStatus() {
return value;
}
}
Just tried this one... Not sure this will work for my other codes :)
Using enum (recommended, has many benefits)
public enum TaskStatusConstant {
NEW("New"),
ACCEPTED("Accepted"),
REJECTED("Rejected"),
REASSIGNED("Reassigned"),
COMPLETED("Completed");
private final String toString;
private TaskStatusConstant(String toString) {
this.toString = toString;
}
#Override
public String toString() {
return toString;
}
public static List<String> valuesAsString() {
List<String> list = new ArrayList<String>();
for(TaskStatusConstant c : values()) {
list.add(c.toString());
}
return list;
}
}
Using reflection (not recommended, it's a hassle, sometimes necessary)
public static List<String> valuesAsString()
throws IllegalAccessException {
List<String> list = new ArrayList<String>();
for(Field f : TaskStatusConstant.class.getDeclaredFields()) {
if(f.getType() == String.class) {
f.setAccessible(true);
list.add((String)f.get(null));
}
}
return list;
}