Java pseudocode: interface ObjCopier { String getId(); void copyToObjZ(ObjZ z); } e.g. Start with a These ArrayLists are NOT the type of "String". If you don't want to have duplicates (implies you have implemented equals() correctly) then you could use a HashSet, for example, but that implies you don't need a specific order of elements. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6). Use those elements to create an instance of the merged type, and add to the output List. If you're talking about an extremely large data set, and there is no overlap in fields across the various ObjA-ObjD, you could consider using a thread pool where each of the mergeObj() methods is run in a different thread. A sci-fi prison break movie where multiple people die while trying to break out. Asking for help, clarification, or responding to other answers. java - Merge multiple list of different Objects with a common field Can ultraproducts avoid all "factor structures"? Combine Two List and Get Another New List of Object, How to get Romex between two garage doors. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How does the theory of evolution make it less likely that the world is designed? Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. rev2023.7.7.43526. Add this method to your POJO, then use it like myObject.merge(newObject). (Ep. How much space did the 68000 registers take up? You can assume the objects are mutually exclusive. Let us start one by one approach. Can we use work equation to derive Ohm's law? please share It. Now, the report screen we are working needs to look at all these records (which are replicas of original record) and identify who inserted first and what date as well as who inserted last and last updated date etc.. Do I remove the screw keeper on a self-grounding outlet? What is the significance of Headband of Intellect et al setting the stat to 19? 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Spring REST controller partial update existing resource, C# Reflection - merge two objects together, How to merge two java object list at once in java, How to "merge" two objects of the same class, Merge multiple object in a single instance of java.lang.Object. Why free-market capitalism has became more associated to the right than to the left, to which it originally belonged? There are a few good answers already. To learn more, see our tips on writing great answers. What does that mean? What is the Modified Apollo option for a potential LEO transport? Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. Since it does use recursion and the potential is there for infinite recursion I did place in a safety against. We can merge different objects into one using the spread () operator. All source objects get merged into the first object. but you can still use the same thing for the inner level as well, docs.spring.io/spring/docs/2.5.6/api/org/springframework/beans/, Why on earth are people paying for digital real estate? If you want a String key, then you can concatenate all the field values that we care about (including a separator to prevent values from one field flowing into another). How do countries vote when appointing a judge to the European Court of Justice? Use a Map instead of a List, and make all the Objs implement an interface that defines getId() which you use as the key. Now you can iterate over the other List, and for each element, search if the Map contains a matching element. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Let us explore the different ways to merge the streams using java 8 stream api. I am having two lists of two different types of objects, which share some properties. How to merge properties of two JavaScript objects dynamically? @kosa I updated my answer based on your feedback. rev2023.7.7.43526. For example: For ArrayList : Objects 2: returns by setting up some properties (fields) or it may return new objects of the type which it holds but not returned by object 1. Merge multiple list of different Objects with a common field into another list, Why on earth are people paying for digital real estate? How to update a value, given a key in a hashmap? For a deeper merge, write a custom function or use a 3rd-party library like Lodash. have you even tried some code? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Using C# with LINQ, how can I merge two lists of different objects, say, Seminar and Conference? The issue seems to be more that of having a viable primary key, which could be a collection of real-world items or a unique computer generated id. Why did Indiana Jones contradict himself? In other words, I know what these fields are. The neuroscientist says "Baby approved!" Is there a distinction between the diminutive suffices -l and -chen? Note: In this solution you have possibility to select witch item is added to meregeResult. -the first api request returns a list of object that contains (user_id,content,date,title) -the second response returns list of object too that contains (user_id,user_name). I am being challenged (or confused) by this problem: I have a List in which each element has around 20 fields/attributes. How merge two lists of different objects? Can ultraproducts avoid all "factor structures"? The loop runs until the shorter length of both the lists. Merging two objects in Java Ask Question Asked 11 years, 11 months ago Modified 1 year, 2 months ago Viewed 94k times 24 I have two objects of same type. Try it Syntax concat() concat(value0) concat(value0, value1) concat(value0, value1, /* ,*/ valueN) Parameters valueN Optional Arrays and/or values to concatenate into a new array. They have some common and some different fields/properties and do not share unique id. Making statements based on opinion; back them up with references or personal experience. Oh nice call on the long compare, didn't know that existed. Languages which give you access to the AST to modify during compilation? Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. ObjB : String id; String address; String x; Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, Yes, a code snippet would definitely be a great help, Your definition of merge is far more important than our definition. What could cause the Nikon D7500 display to look like a cartoon/colour blocking? A.merge might return a new A object instead of modifing current. It's best to address this with the database, but it sounds like you can't in your circumstances. But there is a way to make the process faster. (Ep. Just accommodating boolean sync. How do countries vote when appointing a judge to the European Court of Justice? Connect and share knowledge within a single location that is structured and easy to search. You could make it quite generic. In other words, if any field is null in b, take it from a if there its not null. You can merge/concatenate/combine two Java String fields using the + operator, as shown in this example code: // define two strings String firstName = "Fred"; String lastName = "Flinstone"; // concatenate the strings String fullName = firstName + lastName; The String fullName now contains "FredFlinstone". By null check, do you mean an if statement to check that timedObject isn't null? Want to improve this question? May the real question be how to produce a "sort of key/id" ? As we perform twice the same operation we could create a utilities class. Would it be possible for a civilization to create machines before wheels? What would stop a large spaceship from looking like a flying brick? But there are other options with java 8 api and apache commons library. You can then write : Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Asking for help, clarification, or responding to other answers. Lest do it on example, we will have three lists: You have various option to insert all data from list1 and 'list2' into mergeResult. Why free-market capitalism has became more associated to the right than to the left, to which it originally belonged? What is the Modified Apollo option for a potential LEO transport? It will copy just values with a getter AND a setter. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Merging two arrays in Java is similar to concatenate or combine two arrays in a single array object. To learn more, see our tips on writing great answers. Not the answer you're looking for? The first thing you should do is to write a class to hold the data items: The next thing you need to do is to write an IEqualityComparer that you can use to compare the items (you will need this to use Intersect() and Except(): Now write a class to receive the comparison data: (I've added a ToString() to that class for convenience.). I can't think of any good solution other than iterating over both lists and comparing with the other, building three different lists and merging them int the end and eventually even sorting them. Thank you! Overview In this tutorial, we're going to discuss how to concatenate two arrays in Java. critical chance, does it have any reason to exist? critical chance, does it have any reason to exist? if its in both i want to mark it as changed (Status) and store the old and new value (Amount/ NewAmount). I tried with above solution getting the below output [Employee [id=1, name=EPPI CF3, timstamp=1507543156000], Employee [id=3, name=EPPI CF, timstamp=1507542925000], Employee [id=2, name=EPPI CF2, timstamp=1507542924000], Staff [id=1, staffName=Parnamya, timestamp=1507724760000], Staff [id=2, staffName=Sreenu, timestamp=1507623378000], Staff [id=3, staffName=Joseph, timestamp=1507621774000], Staff [id=4, staffName=Dolores,timestamp=1507547700000], Staff [id=5, staffName=Molly, timestamp=1507541100000]] but expected output updated in the Question. 2. i want to sort final list which is allObj based on timestamp(long value) in both the objects common property is timestamp. Will mark this answer as solution after testing in my code. RSS Feed. This is an example of a possible implementation. Could look like something like this (map the lists by user id, get all the user ids - or get the intersections of user ids, then go over all the user ids, get the matching value in each map, create your third type): First of all, it would improve performance to transform one of the Lists (let's say List) to a Map indexed by the userId (I assumed it's a String). By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. They have some common and some different fields/properties and do not share unique id. Twitter How do countries vote when appointing a judge to the European Court of Justice? The function returns a merged object which is good to go. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How to Merge Two Arrays in Java - Javatpoint @user2078315, ArrayList is just implementation of List interface. Its pretty easy to do using the org.springframework.beans.BeanUtils class provided by spring. 6 fields are date fields, remaining are group codes. Can I still have hopes for an offer as a software developer, Brute force open problems in graph theory. @ug_ I think the nullAwareBeanCopy is not support nested object merging. Merging two List of objects in java 8 - Stack Overflow Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Why add an increment/decrement operator when compound assignnments exist? How to merge two ordered list of objects? Will just the increase in height of water column increase pressure or does mass play any role in it? This will take a O(n) and O(m) time complexity respectively. When are complicated trig functions used? Can Visa, Mastercard credit/debit cards be used to receive online payments? Can I ask a specific person to leave my defence meeting? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Then create a stream over the key sets of these maps. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. The problem of detecting duplicates is hard. consider buying me a coffee ($5) or two ($10). What is the Modified Apollo option for a potential LEO transport? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I have classes like below, class Employee and Class Staff both classes implements the Comparable and sorting based on timestamp which is long value. List<String> newList = new LinkedList<> (listOne); newList.addAll (listTwo); Prefer to use a LinkedList for efficient add operations. Languages which give you access to the AST to modify during compilation? Connect and share knowledge within a single location that is structured and easy to search. Then store the "sort of duplicates" in separate lists per "key". Using Java 8: List<Parent> result = Stream.concat(list1.stream(), list2.stream()) .distinct() .collect(Collectors.toList()); If they have common properties, then ideally they share an, What are you trying to accomplish? Java 8 - How to merge/concatenate/join two lists into single list Asking for help, clarification, or responding to other answers. dictOne and dictTwo. Languages which give you access to the AST to modify during compilation? Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. Thanks for contributing an answer to Stack Overflow! Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. I want to create a single list out of the two making sure that if a human is superhuman, it only appears once in the list using java 8. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6). reflection - Merging two objects in Java - Stack Overflow 1. Are there ethnically non-Chinese members of the CCP right now? How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device? But your lists are JSON, not DTOs. You need to make them extend the same super class or implement the same interface to compare. I just didn't want to complicate the question here and paste unneccesary code, @dymanoid because my lists come from entities stored in my db. Making statements based on opinion; back them up with references or personal experience. To learn more, see our tips on writing great answers. How do I sort elements of 2 lists by their id which have been merged? How do countries vote when appointing a judge to the European Court of Justice? So you've decided to stick our objects in a Set. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. // { name: 'John Doe', age: 25, profession: 'IT Engineer' }, // merge the object into the target object, // iterate through all objects and merge them with target, // deep merge the object into the target object. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. It supports nested object copying, objects 1+ level deep will no longer be copied by reference, instead Nested objects will be cloned or their properties be copied individually. Making statements based on opinion; back them up with references or personal experience. How can I learn wizard spells as a warlock without multiclassing? Approach: The following approach is adopted to store elements alternatively in a merged list. How to passive amplify signal from outside to inside?