gaspersic/java-design-patterns
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Use enums instead os switch blocks

Browse Source 
Its better to use enums instead of switch
blocks which makes the code longer and difficult
to maintain as and when new state appears.
This commit is contained in:
Rakesh Venkatesh
2020-08-05 15:50:05 +02:00
parent cd20e7a3f4
commit 0c83ccc2fe
12 changed files with 56 additions and 130 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
observer/README.md
View File

@ -13,18 +13,18 @@ tags:
Dependents, Publish-Subscribe
## Intent
Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified
Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified
and updated automatically.
## Explanation
Real world example
> In a land far away lives the races of hobbits and orcs. Both of them are mostly outdoors so they closely follow the changes in weather. One could say that they are constantly observing the weather.
> In a land far away lives the races of hobbits and orcs. Both of them are mostly outdoors so they closely follow the changes in weather. One could say that they are constantly observing the weather.
In plain words
> Register as an observer to receive state changes in the object.
> Register as an observer to receive state changes in the object.
Wikipedia says
@ -46,22 +46,7 @@ public class Orcs implements WeatherObserver {
@Override
public void update(WeatherType currentWeather) {
switch (currentWeather) {
case COLD:
LOGGER.info("The orcs are freezing cold.");
break;
case RAINY:
LOGGER.info("The orcs are dripping wet.");
break;
case SUNNY:
LOGGER.info("The sun hurts the orcs' eyes.");
break;
case WINDY:
LOGGER.info("The orc smell almost vanishes in the wind.");
break;
default:
break;
}
LOGGER.info("The hobbits are facing " + currentWeather.getDescription() + " weather now");
}
}
@ -72,21 +57,7 @@ public class Hobbits implements WeatherObserver {
@Override
public void update(WeatherType currentWeather) {
switch (currentWeather) {
case COLD:
LOGGER.info("The hobbits are shivering in the cold weather.");
break;
case RAINY:
LOGGER.info("The hobbits look for cover from the rain.");
break;
case SUNNY:
LOGGER.info("The happy hobbits bade in the warm sun.");
break;
case WINDY:
LOGGER.info("The hobbits hold their hats tightly in the windy weather.");
break;
default:
break;
}
LOGGER.info("The hobbits are facing " + currentWeather.getDescription() + " weather now");
}
}
```
@ -141,20 +112,20 @@ Here's the full example in action.
weather.timePasses();
// The weather changed to rainy.
// The orcs are dripping wet.
// The hobbits look for cover from the rain.
// The orcs are facing rainy weather now
// The hobbits are facing rainy weather now
weather.timePasses();
// The weather changed to windy.
// The orc smell almost vanishes in the wind.
// The hobbits hold their hats tightly in the windy weather.
// The orcs are facing windy weather now
// The hobbits are facing windy weather now
weather.timePasses();
// The weather changed to cold.
// The orcs are freezing cold.
// The hobbits are shivering in the cold weather.
// The orcs are facing cold weather now
// The hobbits are facing cold weather now
weather.timePasses();
// The weather changed to sunny.
// The sun hurts the orcs' eyes.
// The happy hobbits bade in the warm sun.
// The orcs are facing sunny weather now
// The hobbits are facing sunny weather now
```
## Class diagram