Add support relative url for image

Author: anton-knyazev

omegatypes/src/main/java/com/omega_r/libs/omegatypes/image/UrlImage.kt

@@ -6,21 +6,33 @@ import com.omega_r.libs.omegatypes.decoders.toBitmap
 import java.io.IOException
 import java.net.HttpURLConnection
 import java.net.URL
+import java.util.regex.Pattern
 
 
 /**
  * Created by Anton Knyazev on 2019-10-03.
  */
-data class UrlImage(val url: String) : BaseBitmapImage() {
+data class UrlImage(val baseUrl: String? = null, val relativeUrl: String) : BaseBitmapImage() {
 
     companion object {
+        private val PATTERN_ABSOLUTE_URL = Pattern.compile("\\A[a-z0-9.+-]+://.*", Pattern.CASE_INSENSITIVE)
+
+        var defaultBaseUrl : String? = null
 
         init {
             ImageProcessors.default.addImageProcessor(UrlImage::class, Processor())
         }
 
+        private fun String.isAbsoluteUrl(): Boolean = PATTERN_ABSOLUTE_URL.matcher(this).matches()
+
     }
 
+
+    val url: String
+        get() = if (relativeUrl.isAbsoluteUrl()) relativeUrl else (baseUrl ?: defaultBaseUrl ?: "") + relativeUrl
+
+    constructor(url: String): this(null, url)
+
     class Processor : BaseBitmapImage.Processor<UrlImage>(true) {