From 56a2be7ea85a2acbec382621c2f0126220f58683 Mon Sep 17 00:00:00 2001 From: Xevion Date: Fri, 6 Mar 2020 19:18:09 -0600 Subject: [PATCH] basic work in collections, TOC, Hiearchy, Methods of Collection Interface --- study/COLLECTIONS.MD | 44 +++++++++++++++++++++++++++++++++++++++++++- study/STUDY.MD | 2 +- 2 files changed, 44 insertions(+), 2 deletions(-) diff --git a/study/COLLECTIONS.MD b/study/COLLECTIONS.MD index 323cf89..30f723d 100644 --- a/study/COLLECTIONS.MD +++ b/study/COLLECTIONS.MD @@ -2,4 +2,46 @@ Java contains many object based data structures, some sorted, some limited, some simple, some complex. -Not all of them work in familiar ways, and their methods can be confusing without proper usage, study, and a quick explanation over how they're used. \ No newline at end of file +Not all of them work in familiar ways, and their methods can be confusing without proper usage, study, and a quick explanation over how they're used. + +This page will be using [javaTpoint](https://www.javatpoint.com/collections-in-java) for sources regarding all interfaces and classes referenced in this file. + +## Table of Contents + + + +- [Collections](#collections) + - [Table of Contents](#table-of-contents) + - [Hierarchy of Collection Framework](#hierarchy-of-collection-framework) + - [Methods of the Collection Interface](#methods-of-the-collection-interface) + + + +## Hierarchy of Collection Framework + +All datastructures referenced here can be imported using `import java.util.;`, or just `import java.util.*;` (I recommend making more direct import statements as a 'good practice' but it does not matter in the end). + +[![Hierarchy of Interfaces and Classes from Collection (Iterable)](https://i.imgur.com/fifX1Ek.png)](https://static.javatpoint.com/images/java-collection-hierarchy.png) + +## Methods of the Collection Interface + +| Method | Description | +|-----------------------------|-----------------------------------------------------| +| **public boolean add(E e)** | It is used to insert an element in this collection. | +| **public boolean addAll(Collection c)** | It is used to insert the specified collection elements in the invoking collection. | +| **public boolean remove(Object element)** | It is used to delete an element from the collection. || **public boolean removeAll(Collection c)** | It is used to delete all the elements of the specified collection from the invoking collection. | +| **default boolean removeIf(Predicate filter)** | It is used to delete all the elements of the collection that satisfy the specified predicate. | +| **public boolean retainAll(Collection c)** | It is used to delete all the elements of invoking collection except the specified collection. | +| **public int size()** | It returns the total number of elements in the collection. | +| **public void clear()** | It removes the total number of elements from the collection. | +| **public boolean contains(Object element)** | It is used to search an element. | +| **public boolean containsAll(Collection c)** | It is used to search the specified collection in the collection. | +| **public Iterator iterator()** | It returns an iterator. | +| **public Object[] toArray()** | It converts collection into array. | +| **public T[] toArray(T[] a)** | It converts collection into array. Here, the runtime type of the returned array is that of the specified array. | +| **public boolean isEmpty()** | It checks if collection is empty. | +| **default Stream parallelStream()** | It returns a possibly parallel Stream with the collection as its source. | +| **default Stream stream()** | It returns a sequential Stream with the collection as its source. | +| **default Spliterator spliterator()** | It generates a Spliterator over the specified elements in the collection. | +| **public boolean equals(Object element)** | It matches two collections. | +| **public int hashCode()** | It returns the hash code number of the collection. | \ No newline at end of file diff --git a/study/STUDY.MD b/study/STUDY.MD index 4c8cf52..a32de79 100644 --- a/study/STUDY.MD +++ b/study/STUDY.MD @@ -443,7 +443,7 @@ For lists, one can use `Collections.sort` to sort any class that implements the ### !!! char And int Are Interchangeable -``` +```java void method(int a, char b) method('c', 44) // method('g', 78900)