[New version] Update with new Kotlin version and cleanup on the inter…

…face (#62)

fuse-android/src/test/java/com/github/kittinunf/fuse/android/FuseByteCacheTest.kt

@@ -168,8 +168,9 @@ class FuseByteCacheTest : BaseTestCase() {
 
         val timestamp = cache.getTimestamp("timestamp")
 
+        assertThat(timestamp, notNullValue())
         assertThat(timestamp, not(equalTo(-1L)))
-        assertThat(System.currentTimeMillis() - timestamp, object : BaseMatcher<Long>() {
+        assertThat(System.currentTimeMillis() - timestamp!!, object : BaseMatcher<Long>() {
             override fun describeTo(description: Description?) {}
 
             override fun matches(item: Any?): Boolean {

fuse/src/main/java/com/github/kittinunf/fuse/core/Cache.kt

@@ -1,31 +1,18 @@
 package com.github.kittinunf.fuse.core
 
 import com.github.kittinunf.fuse.core.cache.Entry
-import com.github.kittinunf.fuse.core.fetch.DiskFetcher
 import com.github.kittinunf.fuse.core.fetch.Fetcher
-import com.github.kittinunf.fuse.core.fetch.NoFetcher
-import com.github.kittinunf.fuse.core.fetch.SimpleFetcher
 import com.github.kittinunf.fuse.util.md5
 import com.github.kittinunf.result.Result
 import com.github.kittinunf.result.flatMap
-import java.io.File
 
 object CacheBuilder {
 
-    fun <T : Any> config(
-        dir: String,
-        convertible: Fuse.DataConvertible<T>,
-        construct: Config<T>.() -> Unit = {}
-    ): Config<T> {
+    fun <T : Any> config(dir: String, convertible: Fuse.DataConvertible<T>, construct: Config<T>.() -> Unit = {}): Config<T> {
         return Config(dir, convertible = convertible).apply(construct)
     }
 
-    fun <T : Any> config(
-        dir: String,
-        name: String,
-        convertible: Fuse.DataConvertible<T>,
-        construct: Config<T>.() -> Unit = {}
-    ): Config<T> {
+    fun <T : Any> config(dir: String, name: String, convertible: Fuse.DataConvertible<T>, construct: Config<T>.() -> Unit = {}): Config<T> {
         return Config(dir, name, convertible).apply(construct)
     }
 }
@@ -38,11 +25,7 @@ enum class Source {
     DISK,
 }
 
-interface Cache<T : Any> :
-    Fuse.Cacheable,
-    Fuse.Cacheable.Put<T>,
-    Fuse.Cacheable.Get<T>,
-    Fuse.DataConvertible<T>
+interface Cache<T : Any> : Fuse.Cacheable, Fuse.Cacheable.Put<T>, Fuse.Cacheable.Get<T>, Fuse.DataConvertible<T>
 
 class CacheImpl<T : Any> internal constructor(
     private val config: Config<T>
@@ -147,42 +130,13 @@ class CacheImpl<T : Any> internal constructor(
         return value != null
     }
 
-    override fun getTimestamp(key: String): Long {
+    override fun getTimestamp(key: String): Long? {
         val safeKey = key.md5()
-        return memCache.getTimestamp(safeKey) ?: diskCache.getTimestamp(safeKey) ?: -1
+        return memCache.getTimestamp(safeKey) ?: diskCache.getTimestamp(safeKey) ?: null
     }
 
     private fun fetchAndPut(fetcher: Fetcher<T>): Result<T, Exception> {
         val fetchResult = fetcher.fetch()
         return fetchResult.flatMap { put(fetcher.key, it) }
     }
 }
-
-// region File
-fun <T : Any> Cache<T>.get(file: File): Result<T, Exception> = get(DiskFetcher(file, this))
-
-fun <T : Any> Cache<T>.getWithSource(file: File): Pair<Result<T, Exception>, Source> =
-    getWithSource(DiskFetcher(file, this))
-
-fun <T : Any> Cache<T>.put(file: File): Result<T, Exception> = put(DiskFetcher(file, this))
-// endregion File
-
-// region Value
-fun <T : Any> Cache<T>.get(key: String, getValue: (() -> T?)? = null): Result<T, Exception> {
-    val fetcher = if (getValue == null) NoFetcher<T>(key) else SimpleFetcher(key, getValue)
-    return get(fetcher)
-}
-
-fun <T : Any> Cache<T>.getWithSource(
-    key: String,
-    getValue: (() -> T?)? = null
-): Pair<Result<T, Exception>, Source> {
-    val fetcher = if (getValue == null) NoFetcher<T>(key) else SimpleFetcher(key, getValue)
-    return getWithSource(fetcher)
-}
-
-fun <T : Any> Cache<T>.put(key: String, putValue: T? = null): Result<T, Exception> {
-    val fetcher = if (putValue == null) NoFetcher<T>(key) else SimpleFetcher(key, { putValue })
-    return put(fetcher)
-}
-// endregion Value

fuse/src/main/java/com/github/kittinunf/fuse/core/Config.kt

@@ -21,9 +21,6 @@ class Config<T : Any>(
 }
 
 internal fun defaultMemoryCache(minimalSize: Int = 128): Persistence<Any> = MemCache(minimalSize)
+
 internal fun defaultDiskCache(cacheDir: String, name: String, diskCapacity: Long): Persistence<ByteArray> =
-    DiskCache.open(
-        cacheDir,
-        name,
-        diskCapacity
-    )
+    DiskCache.open(cacheDir, name, diskCapacity)

fuse/src/main/java/com/github/kittinunf/fuse/core/Fuse.kt

@@ -1,9 +1,13 @@
 package com.github.kittinunf.fuse.core
 
+import com.github.kittinunf.fuse.core.fetch.DiskFetcher
 import com.github.kittinunf.fuse.core.fetch.Fetcher
+import com.github.kittinunf.fuse.core.fetch.NeverFetcher
+import com.github.kittinunf.fuse.core.fetch.SimpleFetcher
 import com.github.kittinunf.result.Result
+import java.io.File
 
-class Fuse {
+object Fuse {
 
     interface DataConvertible<T : Any> {
         fun convertFromData(bytes: ByteArray): T
@@ -77,8 +81,89 @@ class Fuse {
         /**
          *  Retrieve the keys from all values persisted
          * @param key The key associated with the object to be persisted
-         * @return Long represents the timestamp in milliseconds since epoch 1970
+         * @return Long represents the timestamp in milliseconds since epoch 1970, or null which means that the key is not present in cache
          */
-        fun getTimestamp(key: String): Long
+        fun getTimestamp(key: String): Long?
     }
 }
+
+// region File
+/**
+ *  Get the entry associated as a Data of file content in T with its particular key as File path. If File is not there or too large, it returns as [Result.Failure]
+ *  Otherwise, it returns [Result.Success] of data of a given file in T
+ *
+ * @param file The file object that represent file data on the disk
+ * @return Result<T, Exception> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.get(file: File): Result<T, Exception> = get(DiskFetcher(file, this))
+
+/**
+ *  Get the entry associated as a Data of file content in T with its particular key as File path. If File is not there or too large, it returns as [Result.Failure]
+ *  Otherwise, it returns [Result.Success] data of a given file in T
+ *
+ * @param file The file object that represent file data on the disk
+ * @return Pair<Result<T, Exception>, Source>> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.getWithSource(file: File): Pair<Result<T, Exception>, Source> =
+    getWithSource(DiskFetcher(file, this))
+
+/**
+ *  Put the entry as a content of a file into Cache
+ *
+ * @param file The file object that represent file data on the disk
+ * @return Result<T, Exception> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.put(file: File): Result<T, Exception> = put(DiskFetcher(file, this))
+// endregion File
+
+// region Value
+/**
+ *  Get the entry associated as a value in T by using lambda getValue as a default value generator. If value for associated Key is not there, it saves with value from defaultValue.
+ *
+ * @param key The String represent key of the entry
+ * @return Result<T, Exception> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.get(key: String, defaultValue: (() -> T?)): Result<T, Exception> {
+    val fetcher = SimpleFetcher(key, defaultValue)
+    return get(fetcher)
+}
+
+/**
+ *  Get the entry associated as a value in T. Unlike [Cache<T>.get(key: String, defaultValue: (() -> T))] counterpart, if value for associated Key is not there, it returns as [Result.Failure]
+ *
+ * @param key The String represent key of the entry
+ * @return Result<T, Exception> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.get(key: String): Result<T, Exception> = get(NeverFetcher(key))
+
+/**
+ *  Get the entry associated as a value in T by using lambda as a default value generator. if value for associated key is not there, it saves with value from defaultValue.
+ *
+ * @param key The string represent key of the entry
+ * @return Pair<Result<T, Exception>, Source>> The result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.getWithSource(key: String, getValue: (() -> T?)): Pair<Result<T, Exception>, Source> {
+    val fetcher = SimpleFetcher(key, getValue)
+    return getWithSource(fetcher)
+}
+
+/**
+ *  Get the entry associated as a value in T by using lambda as a default value generator. if value for associated key is not there, it saves with value from defaultValue.
+ *
+ * @param key The string represent key of the entry
+ * @return Pair<Result<T, Exception>, Source>> The result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.getWithSource(key: String): Pair<Result<T, Exception>, Source> = getWithSource(NeverFetcher(key))
+
+/**
+ *  Put the entry as a content of a file into Cache
+ *
+ * @param key file object that represent file data on the disk
+ * @return Result<T, Exception> The Result that represents the success/failure of the operation
+ */
+fun <T : Any> Cache<T>.put(key: String, putValue: T): Result<T, Exception> {
+    val fetcher = SimpleFetcher(key, { putValue })
+    return put(fetcher)
+}
+// endregion Value
+

fuse/src/main/java/com/github/kittinunf/fuse/core/fetch/DiskFetcher.kt

@@ -5,8 +5,7 @@ import com.github.kittinunf.result.Result
 import com.github.kittinunf.result.map
 import java.io.File
 
-class DiskFetcher<T : Any>(private val file: File, private val convertible: Fuse.DataConvertible<T>) :
-    Fetcher<T>,
+class DiskFetcher<T : Any>(private val file: File, private val convertible: Fuse.DataConvertible<T>) : Fetcher<T>,
     Fuse.DataConvertible<T> by convertible {
 
     override val key: String = file.path
@@ -15,7 +14,7 @@ class DiskFetcher<T : Any>(private val file: File, private val convertible: Fuse
 
     override fun fetch(): Result<T, Exception> {
         val readFileResult = Result.of<ByteArray, Exception> { file.readBytes() }
-        if (cancelled) return Result.error(RuntimeException("Fetch got cancelled"))
+        if (cancelled) return Result.failure(RuntimeException("Fetch got cancelled"))
         return readFileResult.map { convertFromData(it) }
     }
 

fuse/src/main/java/com/github/kittinunf/fuse/core/fetch/Fetcher.kt

@@ -12,14 +12,15 @@ interface Fetcher<out T : Any> {
     }
 }
 
-class NotFoundException(key: String) : RuntimeException("value from $key is not found")
+class NotFoundException(key: String) : RuntimeException("Value with key: $key is not found in cache")
 
 internal class SimpleFetcher<out T : Any>(override val key: String, private val getValue: () -> T?) : Fetcher<T> {
 
-    override fun fetch(): Result<T, Exception> = Result.of(getValue(), { NotFoundException(key) })
+    override fun fetch(): Result<T, Exception> =
+        if (getValue() == null) Result.failure(RuntimeException("Fetch with Key: $key is failure")) else Result.of(getValue)
 }
 
-internal class NoFetcher<out T : Any>(override val key: String) : Fetcher<T> {
+internal class NeverFetcher<out T : Any>(override val key: String) : Fetcher<T> {
 
-    override fun fetch(): Result<T, Exception> = Result.error(NotFoundException(key))
+    override fun fetch(): Result<T, Exception> = Result.failure(NotFoundException(key))
 }

fuse/src/main/java/com/github/kittinunf/fuse/core/scenario/ExpirableCache.kt

@@ -1,16 +1,15 @@
 package com.github.kittinunf.fuse.core.scenario
 
 import com.github.kittinunf.fuse.core.Cache
-import com.github.kittinunf.fuse.core.Fuse
 import com.github.kittinunf.fuse.core.Source
 import com.github.kittinunf.fuse.core.fetch.Fetcher
-import com.github.kittinunf.fuse.core.fetch.NoFetcher
+import com.github.kittinunf.fuse.core.fetch.NeverFetcher
 import com.github.kittinunf.fuse.core.fetch.SimpleFetcher
 import com.github.kittinunf.result.Result
 import kotlin.time.Duration
-import kotlin.time.ExperimentalTime
+import kotlin.time.Duration.Companion.milliseconds
 
-class ExpirableCache<T : Any>(private val cache: Cache<T>) : Fuse.Cacheable by cache, Fuse.Cacheable.Put<T> by cache {
+class ExpirableCache<T : Any>(private val cache: Cache<T>) : Cache<T> by cache {
 
     /**
      *  Get the entry associated with its particular key which provided by the persistence.
@@ -26,7 +25,6 @@ class ExpirableCache<T : Any>(private val cache: Cache<T>) : Fuse.Cacheable by c
      * @param useEntryEvenIfExpired The flag indicates whether we still want to use the entry or not
      * @return Result<T, Exception> The Result that represents the success/failure of the operation
      */
-    @OptIn(ExperimentalTime::class)
     fun get(
         fetcher: Fetcher<T>,
         timeLimit: Duration = Duration.INFINITE,
@@ -47,7 +45,6 @@ class ExpirableCache<T : Any>(private val cache: Cache<T>) : Fuse.Cacheable by c
      * @param useEntryEvenIfExpired The flag indicates whether we still want to use the entry or not
      * @return Pair<Result<T, Exception>, Cache.Source> The Pair of the result that represents the success/failure of the operation and The source of the entry
      */
-    @OptIn(ExperimentalTime::class)
     fun getWithSource(
         fetcher: Fetcher<T>,
         timeLimit: Duration = Duration.INFINITE,
@@ -57,7 +54,7 @@ class ExpirableCache<T : Any>(private val cache: Cache<T>) : Fuse.Cacheable by c
         val persistedTimestamp = getTimestamp(key)
 
         // no timestamp fetch, we need to just fetch the new data
-        return if (persistedTimestamp == -1L) {
+        return if (persistedTimestamp == null) {
             put(fetcher) to Source.ORIGIN
         } else {
             val isExpired = hasExpired(persistedTimestamp, timeLimit)
@@ -82,39 +79,44 @@ class ExpirableCache<T : Any>(private val cache: Cache<T>) : Fuse.Cacheable by c
         }
     }
 
-    @OptIn(ExperimentalTime::class)
     private fun hasExpired(persistedTimestamp: Long, timeLimit: Duration): Boolean {
         val now = System.currentTimeMillis()
-        val durationSincePersisted = Duration.milliseconds((now - persistedTimestamp))
+        val durationSincePersisted = (now - persistedTimestamp).milliseconds
         return durationSincePersisted > timeLimit
     }
 }
 
 // region Value
-@OptIn(ExperimentalTime::class)
 fun <T : Any> ExpirableCache<T>.get(
     key: String,
-    getValue: (() -> T?)? = null,
+    getValue: (() -> T),
     timeLimit: Duration = Duration.INFINITE,
     useEntryEvenIfExpired: Boolean = false
 ): Result<T, Exception> {
-    val fetcher = if (getValue == null) NoFetcher(key) else SimpleFetcher(key, getValue)
+    val fetcher = SimpleFetcher(key, getValue)
     return get(fetcher, timeLimit, useEntryEvenIfExpired)
 }
 
-@OptIn(ExperimentalTime::class)
+fun <T : Any> ExpirableCache<T>.get(
+    key: String,
+    timeLimit: Duration = Duration.INFINITE,
+    useEntryEvenIfExpired: Boolean = false
+): Result<T, Exception> = get(NeverFetcher(key), timeLimit, useEntryEvenIfExpired)
+
 fun <T : Any> ExpirableCache<T>.getWithSource(
     key: String,
-    getValue: (() -> T?)? = null,
+    getValue: (() -> T),
     timeLimit: Duration = Duration.INFINITE,
     useEntryEvenIfExpired: Boolean = false
 ): Pair<Result<T, Exception>, Source> {
-    val fetcher = if (getValue == null) NoFetcher(key) else SimpleFetcher(key, getValue)
+    val fetcher = SimpleFetcher(key, getValue)
     return getWithSource(fetcher, timeLimit, useEntryEvenIfExpired)
 }
 
-fun <T : Any> ExpirableCache<T>.put(key: String, putValue: T? = null): Result<T, Exception> {
-    val fetcher = if (putValue == null) NoFetcher(key) else SimpleFetcher(key, { putValue })
-    return put(fetcher)
-}
+fun <T : Any> ExpirableCache<T>.getWithSource(
+    key: String,
+    timeLimit: Duration = Duration.INFINITE,
+    useEntryEvenIfExpired: Boolean = false
+): Pair<Result<T, Exception>, Source> = getWithSource(NeverFetcher(key), timeLimit, useEntryEvenIfExpired)
+
 // endregion

fuse/src/main/java/com/github/kittinunf/fuse/util/MD5.kt

@@ -2,7 +2,7 @@ package com.github.kittinunf.fuse.util
 
 import java.security.MessageDigest
 
-fun String.md5(): String {
+internal fun String.md5(): String {
     val md = MessageDigest.getInstance("MD5")
     val digested = md.digest(toByteArray())
     return digested.joinToString("") {

fuse/src/test/java/com/github/kittinunf/fuse/FuseByteCacheTest.kt

@@ -170,11 +170,12 @@ class FuseByteCacheTest : BaseTestCase() {
 
         val timestamp = cache.getTimestamp("timestamp")
 
+        assertThat(timestamp, notNullValue())
         assertThat(timestamp, not(equalTo(-1L)))
 
         val timeLimit = 2000L
         assertThat(
-            System.currentTimeMillis() - timestamp,
+            System.currentTimeMillis() - timestamp!!,
             object : BaseMatcher<Long>() {
                 override fun describeTo(description: Description) {
                     description.appendText("$timestamp is over than $timeLimit")