I have collection table in database which have fields:
published,name,descrption and collection_type.
And this collection_type can be three different String values :Collection,Trend,Occasion.
Showing whole elements with this working.
public List<Collection> list() {
QueryParams queryParams = new QueryParams();
queryParams.setWhere("published = true");
return list(queryParams);
}
But showing specific elements for example Occasions failed. How to fix the code to show the elements?
public List<Collection> occasions() {
QueryParams queryParams = new QueryParams();
final StringBuilder sb = new StringBuilder();
sb.append("published = true ");
sb.append("AND collection_type = '");
sb.append("CollectionType.OCCASION.getName()'");
queryParams.setWhere(sb.toString());
return list(queryParams);
}
public enum CollectionType {
COLLECTION("COLLECTION"), TREND("TREND"), OCCASION("OCCASION");
private String name;
private CollectionType(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
Suppose, the problem is, that you don't set a ENUM's name, but a "CollectionType.OCCASION.getName()'" string. Try to change your code to:
public List<Collection> occasions() {
QueryParams queryParams = new QueryParams();
final StringBuilder sb = new StringBuilder();
sb.append("published = true ");
sb.append("AND collection_type = '");
sb.append(CollectionType.OCCASION.getName());
sb.append("'");
queryParams.setWhere(sb.toString());
return list(queryParams);
}
Related
So I've got 4 subclasses which extend DessertItem Class with toString() methods:
//candy
public String toString() {
String line1 = String.format("%-25s$%",super.getName());
String line2Pt1 = String.format("%-16.2flbs%#-8.2/f.:%", candyWeight, pricePerPound);
String line2Pt2 = String.format("%-6f", calculateCost());
String line2Pt3 = String.format("[Tax: $%.-4f]", super.calculateTax());
String outputVar = String.format("%s\n\t%-45s%s%17s", line1, line2Pt1, line2Pt2, line2Pt3);
return outputVar;
}
//cookie
public String toString() {
String line1 = String.format("%-25s$%",super.getName());
String line2Pt1 = String.format("%-16.2flbs%#-8.2/f.:%", cookieQty, pricePerDozen);
String line2Pt2 = String.format("%-6f", calculateCost());
String line2Pt3 = String.format("[Tax: $%.-4f]", super.calculateTax());
String outputVar = String.format("%s\n\t%-45s%s%17s", line1, line2Pt1, line2Pt2, line2Pt3);
return outputVar;
}
//icecream
public String toString() {
String line1 = String.format("%-25s$%",super.getName());
String line2Pt1 = String.format("%-16.2dscoops%#-8.2/f.:%", scoopCount, pricePerScoop);
String line2Pt2 = String.format("%-6f", calculateCost());
String line2Pt3 = String.format("[Tax: $%.-4f]", super.calculateTax());
String outputVar = String.format("%s\n\t%-45s%s%17s", line1, line2Pt1, line2Pt2, line2Pt3);
return outputVar;
}
//Sundae class which extends IceCream class
public String toString() {
String line1 = String.format("%-25s$%",super.getName());
String line2Pt1 = String.format("%-16.2sTopping: %#-8.2/f.:%", toppingName, toppingPrice);
String line2Pt2 = String.format("%-6f", calculateCost());
String line2Pt3 = String.format("[Tax: $%.-4f]", super.calculateTax());
String outputVar = String.format("%s\n\t%-45s%s%17s", line1, line2Pt1, line2Pt2, line2Pt3);
return outputVar;
}
Also, I have got another class - Order, in which I would like to get toString() method values:
public String toString() {
String finalOutput = "";
finalOutput += "------------------------Receipt-------------------";
for() {
So, my question is How do I access the toString values from sublasses, and then how do I ittereate through them, so I can add the value into my finalOutput variable?
Create an abstract class:
public abstract class ToMyString
{
public abstract String toString();
private static ArrayList<ToMyString> ivClasses = new ArrayList<>();
public ToMyString()
{
super();
}
protected void addClass( ToMyString aClass )
{
ivClasses.add( aClass );
}
protected String[] getToStrings()
{
String[] toStrings = new String[ivClasses.size()];
int index = 0;
for (ToMyString aClass : ivClasses)
toStrings[index++] = aClass.toString();
return toStrings;
}
}
Then for each of the classes you want the toString for:
public class SomeClass extends ToMyString
{
private SomeClass()
{
super();
addClass( this );
}
}
And finally to get the toString(), from ANY of the classes which extend ToMyString:
for (String aString : getToStrings())
process(aString);
I need to filter elements and then sort based on certain column. Post that I would need to find the unique entries based on combination of columns. Since it is file processing, pipe(|) is used as delimiter to denote the column value.
String s1= "12|Thor|Asgaurd|1000000|Avenger|Active"
String s2= "234|Iron man|New York|9999999|Avenger|Active"
String s3= "420|Loki|Asgaurd|||Inactive"
String s4= "12|Thor|Asgaurd Bank|1000000|Avenger HQ|Active"
Data first needs to be filtered based on the Active/Inactive status. Then it needs to be sorted based on 4th column. Lastly, the uniqueness needs to be maintained by combining column 1,2,3.
Expected Output =
"234|Iron man|New York|9999999|Avenger|Active"
"12|Thor|Asgaurd|1000000|Avenger|Active"
Creating a model class and parsing the string is the way to go, but if for some reaseon you don't want to do that you can do it this way:
import java.util.Comparator;
import java.util.stream.Collectors;
import java.util.stream.Stream;
List<String> result = Stream.of(s1, s2, s3, s4)
.filter(s -> s.split("\\|")[5].equals("Active"))
.sorted(Comparator.comparing(e -> e.split("\\|")[4]))
.collect(Collectors.toList());
First of all you should create an Object which represents your String data. Something like this:
public class MyObject {
private int id;
private String name;
private String location;
private Integer value;
private String category;
private String state;
public MyObject(String entry) {
String[] parts = entry.split("\\|");
if (parts.length != 6) {
throw new IllegalArgumentException("entry has not 6 parts");
}
id = Integer.parseInt(parts[0]);
name = parts[1];
location = parts[2];
try {
value = Integer.parseInt(parts[3]);
} catch (NumberFormatException ignored) {
}
category = parts[4];
state = parts[5];
}
// getters
#Override
public String toString() {
return String.join("|", String.valueOf(id), name, location, String.valueOf(value), category, state);
}
}
With this you can create a Stream of objects from your Strings and to the filter, sort and distinct operations afterwards:
Collection<MyObject> result = Stream.of(s1, s2, s3, s4)
.map(MyObject::new)
.filter(o -> "Active".equals(o.getState()))
.sorted(Comparator.comparing(MyObject::getValue).reversed())
.collect(Collectors.toMap(o -> Arrays.asList(o.getId(), o.getName()),
Function.identity(), (o1, o2) -> o1, LinkedHashMap::new))
.values();
result.forEach(System.out::println);
After the map operation you filter the values by state and sort them by column 4 (value in my case). At the end you collect all the values in a map for the distinct operation. Add all values you need distinction for to the Arrays.asList(). As values the map takes all the original values (Function.identity()). For duplicates we keep the first value ((o1, o2) -> o1) and we are using a LinkedHashMap to keep the order of the items. At the end wee use only the values of the map.
If you need a List instead of a Collection use new ArrayList(result).
The result will be this:
234|Iron man|New York|9999999|Avenger|Active
12|Thor|Asgaurd|1000000|Avenger|Active
It seems like you're unable to filter while everything is string only.
Try this,
create a new model class which can hold your columns.
Ex:
class MyData{
private String name;
private String city;
private String distance;
private String organization;
private String status;
//And create Getter Setter method for all above fields.
}
Now came to your main class where you can play with your code stuff.
Map<MyData> map = new HashMap<MyData>();
MyData myData = new MyData();
myData.setName("Thor");
myData.setCity("Asgaurd");
myData.setDistance("1000000");
myData.setOrganization("Avenger");
myData.setStatus("Active");
map.put(12, myData);
//Same thing for all other data (note: use the loop for data insertion in map)
Map<String, MyData> sorted = map.entrySet().stream().sorted(comparingByValue()).collect(toMap(e -> e.getKey(), e -> e.getValue().getName(), (e1, e2) -> e2,LinkedHashMap::new));
System.out.println("map after sorting by values: " + sorted);
You can solve your task this way:
Firstly, just create POJO(Plain Old Java Object) and override the toString() method.
class MarvelPerson {
private Integer id;
private String name;
private String origin;
private Integer point = null;
private String faction;
private String status;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getOrigin() {
return origin;
}
public void setOrigin(String origin) {
this.origin = origin;
}
public Integer getPoint() {
return point;
}
public void setPoint(Integer point) {
this.point = point;
}
public String getFaction() {
return faction;
}
public void setFaction(String faction) {
this.faction = faction;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
#Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(id);
builder.append("|");
builder.append(name);
builder.append("|");
builder.append(origin);
builder.append("|");
if(point != null) {
builder.append(point);
}
builder.append("|");
if(faction != null) {
builder.append(faction);
}
builder.append("|");
builder.append(status);
return builder.toString();
}
}
Then, you should write the parser from string to MarvelPerson. Side note: Carefully, my implementation is pretty basic, and I suppose it should be modified because I may not have foreseen some corner cases.
class PersonParser {
static MarvelPerson parse(String data) {
MarvelPerson person = new MarvelPerson();
String[] array = data.split("\\|", -1);
person.setId(Integer.parseInt(array[0]));
person.setName(array[1]);
person.setOrigin(array[2]);
if(!array[3].isEmpty()) {
person.setPoint(Integer.parseInt(array[3]));
}
if(!array[4].isEmpty()) {
person.setFaction(array[4]);
}
person.setStatus(array[5]);
return person;
}
}
And then your solution:
public class Test {
public static void main(String[] args) {
List<MarvelPerson> list = new ArrayList<>();
list.add(PersonParser.parse("12|Thor|Asgaurd|1000000|Avenger|Active"));
list.add(PersonParser.parse("234|Iron man|New York|9999999|Avenger|Active"));
list.add(PersonParser.parse("420|Loki|Asgaurd|||Inactive"));
list.add(PersonParser.parse("12|Thor|Asgaurd Bank|1000000|Avenger HQ|Actie"));
list.stream()
.filter(marvelPerson -> marvelPerson.getStatus().equals("Active"))
.sorted((o1, o2) -> o1.getPoint() <= o2.getPoint() ? 1 : -1)
.forEach(marvelPerson -> {
System.out.println(marvelPerson.toString());
});
}
}
The output to be printed:
234|Iron man|New York|9999999|Avenger|Active
12|Thor|Asgaurd|1000000|Avenger|Active
I have very big Stream of versioned documents ordered by document id and version.
E.g. Av1, Av2, Bv1, Cv1, Cv2
I have to convert this into another Stream whose records are aggregated by document id.
A[v1, v2], B[v1], C[v1, V2]
Can this be done without using Collectors.groupBy()? I don't want to use groupBy() because it will load all items in the stream into memory before grouping them. In theory, one need not load the whole stream in memory because it is ordered.
Here's a solution I came up with:
Stream<Document> stream = Stream.of(
new Document("A", "v1"),
new Document("A", "v2"),
new Document("B", "v1"),
new Document("C", "v1"),
new Document("C", "v2")
);
Iterator<Document> iterator = stream.iterator();
Stream<GroupedDocument> result = Stream.generate(new Supplier<GroupedDocument>() {
Document lastDoc = null;
#Override
public GroupedDocument get() {
try {
Document doc = Optional.ofNullable(lastDoc).orElseGet(iterator::next);
String id = doc.getId();
GroupedDocument gd = new GroupedDocument(doc.getId());
gd.getVersions().add(doc.getVersion());
if (!iterator.hasNext()) {
return null;
}
while (iterator.hasNext() && (doc = iterator.next()).getId().equals(id)) {
gd.getVersions().add(doc.getVersion());
}
lastDoc = doc;
return gd;
} catch (NoSuchElementException ex) {
return null;
}
}
});
Here are the Document and GroupedDocument classes:
class Document {
private String id;
private String version;
public Document(String id, String version) {
this.id = id;
this.version = version;
}
public String getId() {
return id;
}
public String getVersion() {
return version;
}
}
class GroupedDocument {
private String id;
private List<String> versions;
public GroupedDocument(String id) {
this.id = id;
versions = new ArrayList<>();
}
public String getId() {
return id;
}
public List<String> getVersions() {
return versions;
}
#Override
public String toString() {
return "GroupedDocument{" +
"id='" + id + '\'' +
", versions=" + versions +
'}';
}
}
Note that the resulting stream is an infinite stream. After all the groups there will be an infinite number of nulls. You can take all the elements that are not null by using takeWhile in Java 9, or see this post.
You can use groupRuns in the StreamEx library for this:
class Document {
public String id;
public int version;
public Document(String id, int version) {
this.id = id;
this.version = version;
}
public String toString() {
return "Document{"+id+version+ "}";
}
}
public class MyClass {
private static List<Document> docs = asList(
new Document("A", 1),
new Document("A", 2),
new Document("B", 1),
new Document("C", 1),
new Document("C", 2)
);
public static void main(String args[]) {
StreamEx<List<Document>> groups = StreamEx.of(docs).groupRuns((l, r) -> l.id.equals(r.id));
for (List<Document> grp: groups.collect(toList())) {
out.println(grp);
}
}
}
which outputs:
[Document{A1}, Document{A2}]
[Document{B1}]
[Document{C1}, Document{C2}]
I can't verify this doesn't consume the entire stream, but I cannot imagine why it would need to given what groupRuns is meant to do.
Would a Map<String, Stream<String>> help you with what you need ?
A - v1, v2
B - v1
C - v1, v2
String[] docs = { "Av1", "Av2", "Bv1", "Cv1", "Cv2"};
Map<String, Stream<String>> map = Stream.<String>of(docs).
map(s ->s.substring(0, 1)).distinct(). //leave only A B C
collect(Collectors.toMap( s1 -> s1, //A B C as keys
s1 ->Stream.<String>of(docs). //value is filtered stream of docs
filter(s2 -> s1.substring(0, 1).
equals(s2.substring(0, 1)) ).
map(s3 -> s3.substring(1, s3.length())) //trim A B C
));
I have List of stories. Using unique property(id) I want to collect keyword and targeting as list of values. Can I do this with MultiMap? Or is there other library for this?
[{
id = 1,
title = Onboarding,
keyword = new joinee,
targeting = finance
}, {
id = 1,
title = Onboarding,
keyword = training,
targeting = HR
}]
The Desired output must like this :
{
id = 1,
title = Onboarding,
keyword = [new joinee,training], //may be keywords - plural
targeting = [HR,finance]
}
Sample my tried Code as follows:
package prac;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class JavaPrac {
public static void main(String[] args) {
Multimap<Integer, Map> multiMap = ArrayListMultimap.create();
List<Map> stories=new ArrayList();
Map story1=new HashMap();
story1.put("id", 1);
story1.put("title", "Onboarding");
story1.put("keyword","new joinee");
story1.put("targeting","finance");
Map story2=new HashMap();
story2.put("id", 1);
story2.put("title", "Onboarding");
story2.put("keyword","training");
story2.put("targeting","HR");
stories.add(story1);
stories.add(story2);
System.out.println(stories);
stories.forEach((story) -> {
multiMap.put((Integer) story.get("id"), story);
});
}
}
A multimap can only store multiple values per key but what you want is to combine those multiple values so that you get one element that has the same id and title as well as a collection of keywords and targeting information. Thus it would probably be best to either have something like MultiStory or already have Story contain those collections.
I'd suggest using proper objects instead of just maps but with maps and Java 8 lambdas you could use compute() etc. to build maps that contain collections and combine maps that don't.
Here's an example of how you'd do it with maps. Note that this is very bad style and an example using proper pojos will follow:
Disclaimer: example based on the OP's code, not recommended (read text above)
//Problem 1: we don't know the type of the values, i.e. we could put anything for "id" etc.
Map<String, Object> story1=new HashMap<>();
story1.put("id", 1);
story1.put("title", "Onboarding");
story1.put("keyword","new joinee");
story1.put("targeting","finance");
Map<String, Object> story2=new HashMap<>();
story2.put("id", 1);
story2.put("title", "Onboarding");
story2.put("keyword","training");
story2.put("targeting","HR");
List<Map<String, Object>> stories=new ArrayList<>();
stories.add(story1);
stories.add(story2);
Map<Integer, Map<String, Object>> combined = new HashMap<>();
stories.forEach((story) -> {
//Problem 2: because we don't know the type of the values we need a lot of nasty casts
Map<String, Object> combinedStory = combined.computeIfAbsent( (Integer)story.get( "id" ), k -> new HashMap<String, Object>() );
combinedStory.put("id", story.get( "id" ) );
combinedStory.put("title", story.get( "title" ) );
//Problem 3: the combined map would look a lot like your "story" maps but would contain different types
((List<String>)combinedStory.computeIfAbsent( "keyword", v -> new List<String>() )).add( (String)story.get("keyword") );
((List<String>)combinedStory.computeIfAbsent( "targeting", v -> new List<String>() )).add( (String)story.get("targeting") );
});
Using POJOs
Here's a greatly simplified example of how you'd do it with proper Java objects (POJOs). Note that those are meant to resemble your code as much as possible and there are a lot of other issues but addressing those would be way too much here and better designed code would be a lot larger and probably harder to understand - after all it's just meant to show you a difference.
First let's define our classes (for simplicity I made the fields public, you'd normally not do that):
class Story {
public final int id;
public String title;
public String keyword;
public String targeting;
public Story(int storyId) {
id = storyId ;
}
}
class MultiStory {
public final int id;
public String title;
public Set<String> keywords = new HashSet<>();
public Set<String> targetingInfo = new HashSet<>();
public MultiStory( int storyId ) {
id = storyId ;
}
}
Then let's reiterate the code above:
Story story1=new Story( 1 );
story1.title = "Onboarding";
story1.keyword = "new joinee";
story1.targeting = "finance";
Story story2=new Story( 1 );
story2.title = "Onboarding";
story2.keyword = "training";
story2.targeting = "HR";
List<Story> stories=new ArrayList<>();
stories.add(story1);
stories.add(story2);
Map<Integer, MultiStory> combined = new HashMap<>();
stories.forEach((story) -> {
MultiStory multiStory = combined.computeIfAbsent( story.id, v -> new MultiStory( story.id ) );
multiStory.title = story.title;
multiStory.keywords.add( story.keyword );
multiStory.targetingInfo.add( story.targeting );
});
As you can see, there are no casts needed and it's clear what fields are available (though not necessarily filled) which makes it easier to reason about the code and spot errors (the compiler can help a lot here which it couldn't to in the example that uses maps).
Here is a solution using classes to represent the story and tags:
public static void main(String[] args) {
TagsCollector app = new TagsCollector();
app.go();
}
private void go() {
List<Story> stories = createStories();
System.out.println(stories);
Map<Long, Tags> tagsById = collectTags(stories);
tagsById.forEach((aLong, tags) -> System.out.println(tags));
}
private List<Story> createStories() {
return Arrays.asList(
new Story(1, "Onboarding", "new joinee", "finance"),
new Story(1, "Onboarding", "training", "HR")
);
}
private Map<Long, Tags> collectTags(List<Story> stories) {
Map<Long, Tags> tagsById = new HashMap<>();
stories.forEach(s -> {
Tags tags = tagsById.computeIfAbsent(s.id, v -> new Tags(s));
tags.getKeywords().add(s.getKeyword());
tags.getTargetings().add(s.getTargeting());
});
return tagsById;
}
Class used to represent the Story:
public class Story {
private final long id;
private final String title;
private final String keyword;
private final String targeting;
public Story(long id, String title, String keyword, String targeting) {
this.id = id;
this.title = title;
this.keyword = keyword;
this.targeting = targeting;
}
public long getId() {
return id;
}
public String getTitle() {
return title;
}
public String getKeyword() {
return keyword;
}
public String getTargeting() {
return targeting;
}
#Override
public String toString() {
return String.format("Story %s, title=%s, keyword=%s, targeting=%s", id, title, keyword, targeting);
}
}
Class used to represent the Tags:
public class Tags {
private final long id;
private final String title;
private final List<String> keywords = new ArrayList<>();
private final List<String> targetings = new ArrayList<>();
Tags(Story story) {
this.id = story.id;
this.title = story.title;
}
public List<String> getKeywords() {
return keywords;
}
public List<String> getTargetings() {
return targetings;
}
#Override
public String toString() {
return String.format("Tags for id %s, title:%s: keywords=%s, targetings=%s", id, title, keywords, targetings);
}
}
Output
[Story 1, title=Onboarding, keyword=new joinee, targeting=finance, Story 1, title=Onboarding, keyword=training, targeting=HR]
Tags for id 1, title:Onboarding: keywords=[new joinee, training], targetings=[finance, HR]
Yes, you can do that with a Multimap. First I would define a pojo for Story in order to make things clearer:
public class Story {
private int id;
private String title;
private String keyword;
private String targeting;
//getters setters
}
Second you need to define a key with hashcode and equals.
public static class StoryKey {
private final int id;
private final String title;
public StoryKey(int id, String title) {
this.id = id;
this.title = title;
}
//getters
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
StoryKey storyKey = (StoryKey) o;
if (id != storyKey.id) return false;
return title != null ? title.equals(storyKey.title) : storyKey.title == null;
}
#Override
public int hashCode() {
int result = id;
result = 31 * result + (title != null ? title.hashCode() : 0);
return result;
}
The code will look like:
ArrayListMultimap<StoryKey, Story> multiMap = ArrayListMultimap.create();
List<Story> stories = new ArrayList();
Story story1 = new Story();
story1.setId(1);
story1.setTitle("Onboarding");
story1.setKeyword("training");
story1.setTargeting("HR");
Story story2 = new Story();
story2.setId(1);
story2.setTitle("Onboarding");
story2.setKeyword("new joinee,");
story2.setTargeting("finance");
stories.add(story1);
stories.add(story2);
System.out.println(stories);
stories.
forEach((story) -> {
multiMap.put(new StoryKey(story.getId(), story.getTitle()), story);
});
multiMap.keys().forEach(key ->
System.out.println(
"id =" + key.getId() +
" title =" + key.getTitle()+
"keyword =" + multiMap.get(key).stream().map(story->story.getKeyword()).collect(Collectors.toList()).toString()+
"targeting ="+ multiMap.get(key).stream().map(story->story.getTargeting()).collect(Collectors.toList()).toString())
);
I have to update a table with two columns and I have created a class
public class Country {
private String url;
private String search;
public Country(String url, String search) {
this.url = url;
this.search = search;
}
// ...
}
List<Country> countries = new ArrayList<Country>();
countries.add(new Country(urls, txt));
...
Countries has a data {java.com.main#yfxse34567}
Could be {www.google.com, main string...}
How can I put a proper data into countries list
Override the toString() method
Example
List<Country> countries = new ArrayList<Country>() {
#Override
public String toString() {
String result = "{";
for (int index= 0; index < size(); index++){
result = result.concat(this.get(index).url);
if (index != size()-1) {
result = result.concat(", ");
}
}
result = result.concat("}");
return result;
}
};
For me your solution should work, however try to instantiate the parent first and then add the instance ... Something like
Country instanceCountry = new Country();
instanceCountry.setUrl("www.google.com");
instanceCountry.setSearch("xpto");
countries.add(instanceCountry);
Do not forget to generate the Getters and Setters