Overview
The PhraseService class provides phrase management functionality including creating, reading, updating, and deleting phrases. It includes input validation and error handling.
Location: com.demodogo.ev_sum_2.services.PhraseService
Constructor
class PhraseService(
private val repo: PhraseRepository = PhraseRepository()
)
repo
PhraseRepository
default:"PhraseRepository()"
The phrase repository instance. Defaults to a new PhraseRepository instance.
Methods
add
Adds a new phrase to the repository.
suspend fun add(text: String)
The phrase text to add. Will be trimmed before validation.
IllegalArgumentException if the trimmed text is blankException if saving the phrase fails
The input text is automatically trimmed before validation and storage.
Usage Example
val phraseService = PhraseService()
try {
phraseService.add("Hola, ¿cómo estás?")
// Phrase successfully added
} catch (e: IllegalArgumentException) {
println("Invalid phrase: ${e.message}")
} catch (e: Exception) {
println("Error saving phrase: ${e.message}")
}
get
Retrieves all phrases from the repository.
suspend fun get(): List<Phrase>
List<Phrase> - A list of all saved phrases
Throws: Exception if loading phrases fails
Usage Example
val phraseService = PhraseService()
try {
val phrases = phraseService.get()
phrases.forEach { phrase ->
println("${phrase.id}: ${phrase.text}")
}
} catch (e: Exception) {
println("Error loading phrases: ${e.message}")
}
update
Updates an existing phrase with new text.
suspend fun update(id: String, newText: String)
The unique identifier of the phrase to update
The new text for the phrase. Will be trimmed before validation.
IllegalArgumentException if the trimmed text is blank
The update method does not catch repository exceptions. Ensure proper error handling when calling this method.
Usage Example
val phraseService = PhraseService()
try {
phraseService.update("phrase-id-123", "Updated phrase text")
// Phrase successfully updated
} catch (e: IllegalArgumentException) {
println("Invalid phrase: ${e.message}")
} catch (e: Exception) {
println("Error updating phrase: ${e.message}")
}
delete
Deletes a phrase from the repository.
suspend fun delete(id: String)
The unique identifier of the phrase to delete. Must not be blank.
IllegalArgumentException if the id is blankException if deletion fails
Usage Example
val phraseService = PhraseService()
try {
phraseService.delete("phrase-id-123")
// Phrase successfully deleted
} catch (e: IllegalArgumentException) {
println("Invalid ID: ${e.message}")
} catch (e: Exception) {
println("Error deleting phrase: ${e.message}")
}
Data Models
Phrase
The Phrase model represents a saved phrase:
data class Phrase(
val id: String,
val text: String
)
Validation Rules
All text inputs are trimmed before validation. The following validation rules apply:
- add(): Text cannot be blank after trimming
- update(): New text cannot be blank after trimming
- delete(): ID cannot be blank
Error Handling
The service provides two types of error handling:
- Validation Errors: Throw
IllegalArgumentException with descriptive messages in Spanish
- Operation Errors: Wrap repository exceptions with user-friendly messages
Error Messages
"La frase no puede estar vacía" - Phrase cannot be empty (add/update)"Error al guardar la frase" - Error saving phrase (add)"Error al cargar las frases" - Error loading phrases (get)"Error al eliminar la frase" - Error deleting phrase (delete)"Id inválido" - Invalid ID (delete)
Complete Usage Example
class PhraseViewModel : ViewModel() {
private val phraseService = PhraseService()
private val _phrases = MutableStateFlow<List<Phrase>>(emptyList())
val phrases: StateFlow<List<Phrase>> = _phrases.asStateFlow()
init {
loadPhrases()
}
fun loadPhrases() {
viewModelScope.launch {
try {
_phrases.value = phraseService.get()
} catch (e: Exception) {
// Handle error
}
}
}
fun addPhrase(text: String) {
viewModelScope.launch {
try {
phraseService.add(text)
loadPhrases() // Reload list
} catch (e: Exception) {
// Handle error
}
}
}
fun updatePhrase(id: String, newText: String) {
viewModelScope.launch {
try {
phraseService.update(id, newText)
loadPhrases()
} catch (e: Exception) {
// Handle error
}
}
}
fun deletePhrase(id: String) {
viewModelScope.launch {
try {
phraseService.delete(id)
loadPhrases()
} catch (e: Exception) {
// Handle error
}
}
}
}
See Also