This document summarizes key points about methods common to all objects in Java. It discusses obeying the general contract when overriding equals, always overriding hashCode when equals is overridden, overriding toString for readability, overriding clone judiciously or providing an alternative copying mechanism, and considering implementing Comparable. Key aspects of implementing these methods correctly, such as symmetry for equals and hashCode, are covered.
This slideshow presents 31 examples of intranet homepage design concepts, with example screenshots.
We've pulled the screenshots from the entries in the My Beautiful Intranet 2014 competition.
Effective Java - Chapter 3: Methods Common to All Objectsİbrahim Kürce
Although object is a concrete class, it is designed primarily for extension.
All of its nonfinal methods (equals, hashCode, toString, clone, and finalize) have explicit general contracts because they are designed to be overridden.
This chapter tells you when and how to override the nonfinal Object methods. The finalize method is omitted from this chapter because it was discussed in Item 7. While not an Object method, Comparable.compareTo is discussed in this chapter because it has a similar character.
This slideshow presents 31 examples of intranet homepage design concepts, with example screenshots.
We've pulled the screenshots from the entries in the My Beautiful Intranet 2014 competition.
Effective Java - Chapter 3: Methods Common to All Objectsİbrahim Kürce
Although object is a concrete class, it is designed primarily for extension.
All of its nonfinal methods (equals, hashCode, toString, clone, and finalize) have explicit general contracts because they are designed to be overridden.
This chapter tells you when and how to override the nonfinal Object methods. The finalize method is omitted from this chapter because it was discussed in Item 7. While not an Object method, Comparable.compareTo is discussed in this chapter because it has a similar character.
Scala: Pattern matching, Concepts and ImplementationsMICHRAFY MUSTAFA
In the following slides, we attempt to present the pattern matching and its implementation in Scala.
The concepts introduced are: Basic pattern matching, Pattern alternative, Pattern guards, Pattern matching and recursive function, Typed patterns, Tuple patterns, Matching on option, Matching on immutable collection, Matching on List, Matching on case class, Nested pattern matching in case classes, and
Matching on regular expression.
Control structures in C++ Programming LanguageAhmad Idrees
The aim of this list of programming languages is to include all notable programming languages in existence, both those in current use and ... Note: This page does not list esoteric programming languages. .... Computer programming portal ...
Presented online for javaBin (2020-04-14)
Video at https://www.youtube.com/watch?v=orcSUE0Jjdc
Lambdas. All the cool kid languages have them. But does ‘lambda’ mean what Java, JavaScript, etc. mean by ‘lambda’? Where did lambdas come from? What were they originally for? What is their relationship to data abstraction?
In this session we will look into the history, the syntax and the uses of lambdas and the way in which lambda constructs in Java and other languages do (or do not) match the original construct introduced in lambda calculus.
Excel 2016 VBA PPT Slide Deck - For Basic to Adavance VBA LearningPrantikMaity6
Title: Mastering Excel VBA 2016
Introduction:
Unlock the full potential of Microsoft Excel with Visual Basic for Applications (VBA) 2016. This PowerPoint presentation is designed to guide you through the fundamentals and advanced techniques of Excel VBA, empowering you to automate tasks, enhance productivity, and unleash the true power of data manipulation.
1. Understanding VBA Basics:
Explore the foundational concepts of VBA programming, including variables, data types, control structures, and procedures. Gain insights into the VBA editor and learn how to write and execute your first macro.
2. Automating Tasks with Macros:
Discover how to record macros to automate repetitive tasks effortlessly. Learn best practices for editing and debugging macros, and customize them to suit your specific needs. Harness the power of macros to streamline your workflow and save valuable time.
3. Working with Objects and Methods:
Delve into the world of objects and methods in Excel VBA. Learn how to manipulate worksheets, ranges, cells, and other Excel objects programmatically. Master essential techniques for navigating through workbooks, formatting data, and performing calculations with precision.
4. Event-Driven Programming:
Unlock the potential of event-driven programming in Excel VBA. Explore how to trigger macros automatically in response to specific user actions or worksheet events. Enhance interactivity and user experience by leveraging event-driven techniques effectively.
5. Advanced Topics in Excel VBA:
Take your VBA skills to the next level with advanced topics such as error handling, user-defined functions (UDFs), and interacting with external data sources. Dive deep into the intricacies of VBA programming and empower yourself to tackle complex challenges with confidence.
6. Practical Applications and Case Studies:
Gain practical insights into real-world applications of Excel VBA through interactive case studies and examples. Learn how leading organizations leverage VBA to automate reporting, analyze data, and drive informed decision-making.
**7. Integrating VBA with Other Office Applications:**
Explore the seamless integration of VBA across the Microsoft Office suite. Learn how to leverage VBA to automate tasks not only in Excel but also in other Office applications such as Word, PowerPoint, Outlook, and Access. Discover how VBA can streamline workflows by enabling data exchange and manipulation between different Office programs, maximizing efficiency and productivity.
**8. Customizing User Interfaces with VBA Forms:**
Dive into the realm of user interface customization with VBA forms. Explore how to design and create user-friendly interfaces using form controls such as buttons, checkboxes, textboxes, and dropdown lists. Learn how to enhance user experience by incorporating interactive elements and guiding users through complex processes, all within the familiar environment of Excel.
Scala: Pattern matching, Concepts and ImplementationsMICHRAFY MUSTAFA
In the following slides, we attempt to present the pattern matching and its implementation in Scala.
The concepts introduced are: Basic pattern matching, Pattern alternative, Pattern guards, Pattern matching and recursive function, Typed patterns, Tuple patterns, Matching on option, Matching on immutable collection, Matching on List, Matching on case class, Nested pattern matching in case classes, and
Matching on regular expression.
Control structures in C++ Programming LanguageAhmad Idrees
The aim of this list of programming languages is to include all notable programming languages in existence, both those in current use and ... Note: This page does not list esoteric programming languages. .... Computer programming portal ...
Presented online for javaBin (2020-04-14)
Video at https://www.youtube.com/watch?v=orcSUE0Jjdc
Lambdas. All the cool kid languages have them. But does ‘lambda’ mean what Java, JavaScript, etc. mean by ‘lambda’? Where did lambdas come from? What were they originally for? What is their relationship to data abstraction?
In this session we will look into the history, the syntax and the uses of lambdas and the way in which lambda constructs in Java and other languages do (or do not) match the original construct introduced in lambda calculus.
Excel 2016 VBA PPT Slide Deck - For Basic to Adavance VBA LearningPrantikMaity6
Title: Mastering Excel VBA 2016
Introduction:
Unlock the full potential of Microsoft Excel with Visual Basic for Applications (VBA) 2016. This PowerPoint presentation is designed to guide you through the fundamentals and advanced techniques of Excel VBA, empowering you to automate tasks, enhance productivity, and unleash the true power of data manipulation.
1. Understanding VBA Basics:
Explore the foundational concepts of VBA programming, including variables, data types, control structures, and procedures. Gain insights into the VBA editor and learn how to write and execute your first macro.
2. Automating Tasks with Macros:
Discover how to record macros to automate repetitive tasks effortlessly. Learn best practices for editing and debugging macros, and customize them to suit your specific needs. Harness the power of macros to streamline your workflow and save valuable time.
3. Working with Objects and Methods:
Delve into the world of objects and methods in Excel VBA. Learn how to manipulate worksheets, ranges, cells, and other Excel objects programmatically. Master essential techniques for navigating through workbooks, formatting data, and performing calculations with precision.
4. Event-Driven Programming:
Unlock the potential of event-driven programming in Excel VBA. Explore how to trigger macros automatically in response to specific user actions or worksheet events. Enhance interactivity and user experience by leveraging event-driven techniques effectively.
5. Advanced Topics in Excel VBA:
Take your VBA skills to the next level with advanced topics such as error handling, user-defined functions (UDFs), and interacting with external data sources. Dive deep into the intricacies of VBA programming and empower yourself to tackle complex challenges with confidence.
6. Practical Applications and Case Studies:
Gain practical insights into real-world applications of Excel VBA through interactive case studies and examples. Learn how leading organizations leverage VBA to automate reporting, analyze data, and drive informed decision-making.
**7. Integrating VBA with Other Office Applications:**
Explore the seamless integration of VBA across the Microsoft Office suite. Learn how to leverage VBA to automate tasks not only in Excel but also in other Office applications such as Word, PowerPoint, Outlook, and Access. Discover how VBA can streamline workflows by enabling data exchange and manipulation between different Office programs, maximizing efficiency and productivity.
**8. Customizing User Interfaces with VBA Forms:**
Dive into the realm of user interface customization with VBA forms. Explore how to design and create user-friendly interfaces using form controls such as buttons, checkboxes, textboxes, and dropdown lists. Learn how to enhance user experience by incorporating interactive elements and guiding users through complex processes, all within the familiar environment of Excel.
4. Best Approach – Avoid! Works if
Each instance of a class is unique
You don’t care if class has logical equality
The superclass equals is satisfactory
Class is not public and equals method never will be
invoked
5. Best Approach – Avoid! Works if
Each instance of a class is unique
You don’t care if class has logical equality
The superclass equals is satisfactory
Class is not public and equals method never will be
invoked
6. General Contract for equals
Reflexive
x.equals(x) must return true
Symmetric
x.equals(y) iff y.equals(x)
Transitive
x.equals(y) && y.equals(z)
Then x.equals(z)
Consistency
Null values
x.equals(null) must return false
11. How to Implement equals()
Use == to see if argument is a reference to this
object
Use instanceof to check if argument is of the correct
type
Cast the argument to the correct type
Check each “significant field”
Check symmetric, transitive, consistent
12. What to Do
Always override hashCode when override equals
Don’t substitute another type for Object
Don’t throw NullPointerException or
ClassCastException
14. Contract
hashCode() must return same interger on different
calls, as long as equals() unchanged
If x.equals(y) is true, then x, y must have same
hashcode
It is not required that unequal objects have different
hashcodes
18. Simple Recipe
Start with some nonzero value
Say, result = 17;
(Repeatedly) compute in hashCode “c” for each
“significant field”
Apply various rules for each data type
Combine
result = result*37 + c;
21. “It is recommended that all subclasses override this
method.” Good advice, indeed!
Providing a good toString implementation makes
your class much more pleasant to use
Return all of the interesting information contained in
the object
Clearly document your intentions
Provide getters for values toString() provides
23. Contract
x.clone() != x
x.clone().getClass() = x.getClass()
x.clone().equals(x) will be true
No constructors are called
24. The role of mutability
If a class has only primitive fields or immutable
references as fields, super.clone() returns exactly
what you want
For objects with mutable references, “deep copies”
are required
25. Cloning Problems
Cloning may be a problem with final fields
Cloning recursively may not be sufficient
26. Other Mechanism
Better off not implementing Cloneable
Provide a separate copy mechanism
Copy Constructor:
public ClassA ( ClassA a )
Factory
public static ClassA newInstance ( ClassA a )
28. Contract
x.compareTo(y) = - y.compareTo(x)
If x.compareTo(y)>0 && y.compareTo(z)>0, then
x.compareTo(z) must be greater than 0
If x.compareTo(y)==0, then
sign(x.compareTo(z))==sign(y.compareTo(z))
It is strongly recommended, but not strictly required
that
(x.compareTo(y)==0) == (x.equals(y))
# This is true for classes such as Thread that represent active entities rather than values.# For example, java.util.Random could have overridden equals to check whether two Random instances would produce the same sequence of random numbers going forward, but the designers didn’t think that clients would need or want this functionality. # For example, most Set implementations inherit their equals implementation from AbstractSet, List implementations from AbstractList, and Map implementations from AbstractMap.@
# This is true for classes such as Thread that represent active entities rather than values.# For example, java.util.Random could have overridden equals to check whether two Random instances would produce the same sequence of random numbers going forward, but the designers didn’t think that clients would need or want this functionality. # For example, most Set implementations inherit their equals implementation from AbstractSet, List implementations from AbstractList, and Map implementations from AbstractMap.
# This is just a performance optimization
Notice that two PhoneNumber instances are involved: one is used for insertion into the HashMap, and a second, equal, instance is used for (attempted) retrieval. The PhoneNumber class’s failure to override hashCode causes the two equal instances to have unequal hash codes, in violation of the hashCode contract. Therefore the get method is likely to look for the phone number in a different hash bucket from the one in which it was stored by the put method. Even if the two instances happen to hash to the same bucket, the get method will almost certainly return null, as HashMap has an optimization that caches the hash code associated with each entry and doesn’t bother checking for object equality if the hash codes don’t match.
# It’s legal because it ensures that equal objects have the same hash code. It’s atrocious because it ensures that every object has the same hash code. Therefore, every object hashes to the same bucket, and hash tables degenerate to linked lists. Programs that should run in linear time instead run in quadratic time. For large hash tables, this is the difference between working and not working.