Engage experiment

android/common/.gitignore

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+/build

android/common/build.gradle.kts

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+plugins {
+  id(Plugins.BuildPlugins.androidLib)
+  id(Plugins.BuildPlugins.kotlinAndroid)
+  id(Plugins.BuildPlugins.mavenPublish)
+  jacoco
+}
+
+publishing {
+  repositories {
+    maven {
+      credentials(PasswordCredentials::class)
+      url = uri("https://oss.sonatype.org/content/repositories/snapshots")
+      name = "sonatype"
+    }
+  }
+}
+
+publishArtifact(Releases.Common)
+
+createJacocoTestReportTask()
+
+android {
+  compileSdk = Sdk.compileSdk
+
+  defaultConfig {
+    minSdk = Sdk.minSdk
+    targetSdk = Sdk.targetSdk
+  }
+  compileOptions {
+    sourceCompatibility = Java.sourceCompatibility
+    targetCompatibility = Java.targetCompatibility
+  }
+  kotlinOptions { jvmTarget = Java.kotlinJvmTarget.toString() }
+  configureJacocoTestOptions()
+}
+
+configurations { all { exclude(module = "xpp3") } }
+
+dependencies {
+  api(Dependencies.HapiFhir.structuresR4)
+
+  implementation(Dependencies.fhirUcum)
+
+  testImplementation(Dependencies.Kotlin.kotlinTestJunit)
+  testImplementation(Dependencies.AndroidxTest.core)
+  testImplementation(Dependencies.junit)
+  testImplementation(Dependencies.robolectric)
+  testImplementation(Dependencies.truth)
+}

android/common/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<!--
+ Copyright 2020 Google LLC
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+<manifest
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.google.android.fhir.common"
+>
+
+</manifest>

android/common/src/main/java/com/google/android/fhir/MoreTypes.kt

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+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.fhir
+
+import java.util.Calendar
+import java.util.Date
+import java.util.Locale
+import org.hl7.fhir.r4.model.Coding
+import org.hl7.fhir.r4.model.Quantity
+import org.hl7.fhir.r4.model.StringType
+import org.hl7.fhir.r4.model.Type
+
+/**
+ * Returns whether two instances of the [Type] class are equal.
+ *
+ * Note this is not an operator because it is not possible to overload the equality operator as an
+ * extension.
+ */
+fun equals(a: Type, b: Type): Boolean {
+  if (a::class != b::class) return false
+
+  if (a === b) return true
+
+  if (a.isPrimitive) return a.primitiveValue() == b.primitiveValue()
+
+  // Codes with the same system and code values are considered equal even if they have different
+  // display values.
+  if (a is Coding && b is Coding) return a.system == b.system && a.code == b.code
+
+  throw NotImplementedError("Comparison for type ${a::class.java} not supported.")
+}
+
+operator fun Type.compareTo(value: Type): Int {
+  if (!this.fhirType().equals(value.fhirType())) {
+    throw IllegalArgumentException(
+      "Cannot compare different data types: ${this.fhirType()} and ${value.fhirType()}"
+    )
+  }
+  when {
+    this.fhirType().equals("integer") -> {
+      return this.primitiveValue().toInt().compareTo(value.primitiveValue().toInt())
+    }
+    this.fhirType().equals("decimal") -> {
+      return this.primitiveValue().toBigDecimal().compareTo(value.primitiveValue().toBigDecimal())
+    }
+    this.fhirType().equals("date") -> {
+      return clearTimeFromDateValue(this.dateTimeValue().value)
+        .compareTo(clearTimeFromDateValue(value.dateTimeValue().value))
+    }
+    this.fhirType().equals("dateTime") -> {
+      return this.dateTimeValue().value.compareTo(value.dateTimeValue().value)
+    }
+    this.fhirType().equals("Quantity") -> {
+      val quantity = UnitConverter.getCanonicalForm(UcumValue((this as Quantity).code, this.value))
+      val anotherQuantity =
+        UnitConverter.getCanonicalForm(UcumValue((value as Quantity).code, value.value))
+      if (quantity.code != anotherQuantity.code) {
+        throw IllegalArgumentException(
+          "Cannot compare different quantity codes: ${quantity.code} and ${anotherQuantity.code}"
+        )
+      }
+      return quantity.value.compareTo(anotherQuantity.value)
+    }
+    else -> {
+      throw NotImplementedError()
+    }
+  }
+  return 0
+}
+
+private fun clearTimeFromDateValue(dateValue: Date): Date {
+  val calendarValue = Calendar.getInstance()
+  calendarValue.time = dateValue
+  calendarValue.set(Calendar.HOUR_OF_DAY, 0)
+  calendarValue.set(Calendar.MINUTE, 0)
+  calendarValue.set(Calendar.SECOND, 0)
+  calendarValue.set(Calendar.MILLISECOND, 0)
+  return calendarValue.time
+}
+
+fun StringType.getLocalizedText(lang: String = Locale.getDefault().toLanguageTag()): String? {
+  return getTranslation(lang) ?: getTranslation(lang.split("-").firstOrNull()) ?: value
+}

android/common/src/main/java/com/google/android/fhir/UnitConverter.kt

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+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.fhir
+
+import java.lang.NullPointerException
+import java.math.BigDecimal
+import java.math.MathContext
+import kotlin.jvm.Throws
+import org.fhir.ucum.Decimal
+import org.fhir.ucum.Pair
+import org.fhir.ucum.UcumEssenceService
+import org.fhir.ucum.UcumException
+
+/**
+ * Canonicalizes unit values to UCUM base units.
+ *
+ * For details of UCUM, see http://unitsofmeasure.org/
+ *
+ * For using UCUM with FHIR, see https://www.hl7.org/fhir/ucum.html
+ *
+ * For the implementation of UCUM with FHIR, see https://github.com/FHIR/Ucum-java
+ */
+object UnitConverter {
+  private val ucumService by lazy {
+    UcumEssenceService(this::class.java.getResourceAsStream("/ucum-essence.xml"))
+  }
+
+  /**
+   * Returns the canonical form of a UCUM Value.
+   *
+   * The canonical form is generated by normalizing [value] to UCUM base units, used to generate
+   * canonical matches on Quantity Search
+   *
+   * For example a value of 1000 mm will return 1 m.
+   */
+  @Throws(ConverterException::class)
+  fun getCanonicalForm(value: UcumValue): UcumValue {
+    try {
+      val pair =
+        ucumService.getCanonicalForm(Pair(Decimal(value.value.toPlainString()), value.code))
+      return UcumValue(
+        pair.code,
+        pair.value.asDecimal().toBigDecimal(MathContext(value.value.precision()))
+      )
+    } catch (e: UcumException) {
+      throw ConverterException("UCUM conversion failed", e)
+    } catch (e: NullPointerException) {
+      // See https://github.com/google/android-fhir/issues/869 for why NPE needs to be caught
+      throw ConverterException("Missing numerical value in the canonical UCUM value", e)
+    }
+  }
+}
+
+class ConverterException(message: String, cause: Throwable) : Exception(message, cause)
+
+data class UcumValue(val code: String, val value: BigDecimal)