Add hierarchies visualization API

gradle.properties

@@ -28,6 +28,6 @@ org.gradle.jvmargs=-XX:MaxMetaspaceSize=1024m -Xmx2048m
 # Turn off README check when running check task
 skipReadmeCheck=false
 
-jupyterApiVersion=0.9.1-42
+jupyterApiVersion=0.9.1-45
 kotlin.jupyter.add.api=false
 kotlin.jupyter.add.scanner=false

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/GraphNode.kt

@@ -0,0 +1,38 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs
+
+/**
+ * Graph node which represents the object as a part of some hierarchy
+ *
+ * Classes implementing this interface should take care of [equals] and [hashCode]
+ * because they are used for testing the nodes for equality, and wrong implementation
+ * of these methods may lead to the wrong graph rendering, StackOverflow / OutOfMemory
+ * errors and so on. See example in [NodeWrapper]
+ *
+ * @param T Underlying object type
+ */
+interface GraphNode<T> {
+    /**
+     * Node label with all required information
+     */
+    val label: Label
+
+    /**
+     * Nodes which are connected with the ingoing edges to this one:
+     * {this} <- {inNode}
+     */
+    val inNodes: List<GraphNode<T>>
+
+    /**
+     * Nodes which are connected with the outgoing edges to this one:
+     * {this} -> {outNode}
+     */
+    val outNodes: List<GraphNode<T>>
+
+    /**
+     * Nodes which are connected with the undirected edges to this one:
+     * {this} -- {biNode}
+     */
+    val biNodes: List<GraphNode<T>>
+
+    companion object
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/Label.kt

@@ -0,0 +1,17 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs
+
+/**
+ * [Label] contains all information related to the node itself
+ */
+interface Label {
+    /**
+     * Node text. May be simple simple text or HTML
+     */
+    val text: String
+
+    /**
+     * Shape of this node. The full list of shapes is given
+     * [here](https://graphviz.org/doc/info/shapes.html)
+     */
+    val shape: String? get() = null
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/NodeWrapper.kt

@@ -0,0 +1,22 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.labels.TextLabel
+
+/**
+ * Use [NodeWrapper] if [T] cannot implement [GraphNode] itself for some reason
+ */
+abstract class NodeWrapper<T>(val value: T) : GraphNode<T> {
+    override val label: Label get() = TextLabel(value.toString())
+
+    override val inNodes get() = listOf<GraphNode<T>>()
+    override val outNodes get() = listOf<GraphNode<T>>()
+    override val biNodes get() = listOf<GraphNode<T>>()
+
+    override fun equals(other: Any?): Boolean {
+        return other is NodeWrapper<*> && other.value == this.value
+    }
+
+    override fun hashCode(): Int {
+        return value.hashCode()
+    }
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/labels/FilteringPropObjectLabel.kt

@@ -0,0 +1,17 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs.labels
+
+import kotlin.reflect.KProperty1
+
+/**
+ * Convenience class for creating [PropObjectLabel] if only fixed subset
+ * of properties [propertiesToRender] should be rendered
+ */
+class FilteringPropObjectLabel<T : Any>(
+    value: T,
+    override val mainText: String = value.toString(),
+    private val propertiesToRender: Collection<String> = emptyList(),
+) : PropObjectLabel<T>(value) {
+    override fun shouldRenderProperty(prop: KProperty1<out T, *>): Boolean {
+        return prop.name in propertiesToRender
+    }
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/labels/KClassLabel.kt

@@ -0,0 +1,13 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs.labels
+
+import kotlin.reflect.KClass
+
+/**
+ * Label representing [kClass] with all members in HTML table
+ */
+class KClassLabel(private val kClass: KClass<*>) : RecordTableLabel() {
+    override val mainText get() = kClass.simpleName.toString()
+
+    override val properties: Collection<Iterable<String>>
+        get() = kClass.members.map { listOf(it.name, it.returnType.toString()) }
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/labels/PropObjectLabel.kt

@@ -0,0 +1,28 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs.labels
+
+import kotlin.reflect.KProperty1
+import kotlin.reflect.full.memberProperties
+import kotlin.reflect.jvm.isAccessible
+
+/**
+ * Renders [value] object with its properties for
+ * those [shouldRenderProperty] returns `true`
+ */
+open class PropObjectLabel<T : Any>(val value: T) : RecordTableLabel() {
+    override val mainText get() = value.toString()
+
+    override val properties: Collection<Iterable<String>> get() {
+        val kClass = value::class
+
+        return kClass.memberProperties
+            .filter(::shouldRenderProperty)
+            .map { prop ->
+                @Suppress("UNCHECKED_CAST")
+                prop as KProperty1<T, *>
+                prop.isAccessible = true
+                listOf(prop.name, prop.invoke(value).toString())
+            }
+    }
+
+    open fun shouldRenderProperty(prop: KProperty1<out T, *>) = true
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/labels/RecordTableLabel.kt

@@ -0,0 +1,42 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs.labels
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.Label
+
+/**
+ * Renders as n-column table
+ * First column consists of one cell containing [mainText].
+ * Next `(n-1)` columns contain values from [properties]. It is
+ * supposed that all element in [properties] collection would
+ * have `(n-1)` elements.
+ */
+abstract class RecordTableLabel : Label {
+    override val text: String get() {
+        val nProperties = properties.size
+
+        fun inTable(builderAction: StringBuilder.() -> Unit) = buildString {
+            append("<<table>")
+            builderAction()
+            append("</table>>")
+        }
+
+        if (nProperties == 0) return inTable { append("<tr><td>$mainText</td></tr>") }
+        return inTable {
+            properties.forEachIndexed { i, prop ->
+                append("<tr>")
+                if (i == 0 && mainText != null) {
+                    append("""<td rowspan="$nProperties">$mainText</td>""")
+                }
+                prop.forEach { value ->
+                    append("""<td>$value</td>""")
+                }
+                appendLine("</tr>")
+            }
+        }
+    }
+
+    override val shape: String? get() = "plaintext"
+
+    abstract val mainText: String?
+
+    abstract val properties: Collection<Iterable<String>>
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/graphs/labels/TextLabel.kt

@@ -0,0 +1,10 @@
+package org.jetbrains.kotlinx.jupyter.api.graphs.labels
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.Label
+
+/**
+ * Label representing a plain text inside a given [shape]
+ */
+class TextLabel(value: String, override val shape: String? = "ellipse") : Label {
+    override val text: String = "\"${value.replace("\"", "\\\"")}\""
+}

jupyter-lib/lib-ext/build.gradle.kts

@@ -32,6 +32,8 @@ dependencies {
     implementation("org.apache.xmlgraphics:fop:2.6")
     implementation("org.apache.xmlgraphics:batik-codec:1.14")
     implementation("org.apache.xmlgraphics:xmlgraphics-commons:2.6")
+
+    implementation("guru.nidi:graphviz-java:0.18.1")
 }
 
 tasks.test {

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/DirectedEdge.kt

@@ -0,0 +1,8 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+data class DirectedEdge<T>(
+    val fromNode: GraphNode<T>,
+    val toNode: GraphNode<T>,
+)

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/Graph.kt

@@ -0,0 +1,22 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+interface Graph<T> : MultiGraph<T> {
+    override val directedEdges: Set<DirectedEdge<T>>
+    override val undirectedEdges: Set<UndirectedEdge<T>>
+
+    companion object {
+        fun <T> of(elements: Iterable<GraphNode<T>>): Graph<T> {
+            val nodes = mutableSetOf<GraphNode<T>>()
+            val directedEdges = mutableSetOf<DirectedEdge<T>>()
+            val undirectedEdges = mutableSetOf<UndirectedEdge<T>>()
+
+            for (element in elements) element.populate(nodes, directedEdges, undirectedEdges)
+
+            return GraphImpl(nodes, directedEdges, undirectedEdges)
+        }
+
+        fun <T> of(vararg elements: GraphNode<T>): Graph<T> = of(elements.toList())
+    }
+}

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/GraphImpl.kt

@@ -0,0 +1,9 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+class GraphImpl<T>(
+    override val nodes: Set<GraphNode<T>>,
+    override val directedEdges: Set<DirectedEdge<T>>,
+    override val undirectedEdges: Set<UndirectedEdge<T>>,
+) : Graph<T>

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/MultiGraph.kt

@@ -0,0 +1,23 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+interface MultiGraph<T> {
+    val nodes: Set<GraphNode<T>>
+    val directedEdges: Collection<DirectedEdge<T>>
+    val undirectedEdges: Collection<UndirectedEdge<T>>
+
+    companion object {
+        fun <T> of(elements: Iterable<GraphNode<T>>): MultiGraph<T> {
+            val nodes = mutableSetOf<GraphNode<T>>()
+            val directedEdges = mutableListOf<DirectedEdge<T>>()
+            val undirectedEdges = mutableListOf<UndirectedEdge<T>>()
+
+            for (element in elements) element.populate(nodes, directedEdges, undirectedEdges)
+
+            return MultiGraphImpl(nodes, directedEdges, undirectedEdges)
+        }
+
+        fun <T> of(vararg elements: GraphNode<T>): MultiGraph<T> = of(elements.toList())
+    }
+}

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/MultiGraphImpl.kt

@@ -0,0 +1,9 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+class MultiGraphImpl<T>(
+    override val nodes: Set<GraphNode<T>>,
+    override val directedEdges: List<DirectedEdge<T>>,
+    override val undirectedEdges: List<UndirectedEdge<T>>,
+) : MultiGraph<T>

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/UndirectedEdge.kt

@@ -0,0 +1,22 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+data class UndirectedEdge<T>(
+    val fromNode: GraphNode<T>,
+    val toNode: GraphNode<T>,
+) {
+    override fun equals(other: Any?): Boolean {
+        return other is UndirectedEdge<*> && (
+            (fromNode == other.fromNode) && (toNode == other.toNode) ||
+                (fromNode == other.toNode) && (toNode == other.fromNode)
+            )
+    }
+
+    override fun hashCode(): Int {
+        var h1 = fromNode.hashCode()
+        var h2 = toNode.hashCode()
+        if (h1 > h2) { val t = h2; h2 = h1; h1 = t }
+        return 31 * h1 + h2
+    }
+}

jupyter-lib/lib-ext/src/main/kotlin/org/jetbrains/kotlinx/jupyter/ext/graph/structure/util.kt

@@ -0,0 +1,51 @@
+package org.jetbrains.kotlinx.jupyter.ext.graph.structure
+
+import org.jetbrains.kotlinx.jupyter.api.graphs.GraphNode
+
+val <T> GraphNode<T>.allParents: Iterable<GraphNode<T>> get() {
+    return IterablesView(listOf(inNodes, outNodes, biNodes))
+}
+
+private class IterablesView<T>(private val iterables: Iterable<Iterable<T>>) : Iterable<T> {
+    override fun iterator(): Iterator<T> {
+        return MyIterator(iterables)
+    }
+
+    class MyIterator<T>(iterables: Iterable<Iterable<T>>) : Iterator<T> {
+        private val outerIterator = iterables.iterator()
+        private var innerIterator: Iterator<T>? = null
+
+        override fun hasNext(): Boolean {
+            while (innerIterator?.hasNext() != true) {
+                if (!outerIterator.hasNext()) return false
+                innerIterator = outerIterator.next().iterator()
+            }
+            return true
+        }
+
+        override fun next(): T {
+            if (!hasNext()) throw IndexOutOfBoundsException()
+            return innerIterator!!.next()
+        }
+    }
+}
+
+fun <T> GraphNode<T>.populate(
+    nodes: MutableSet<GraphNode<T>>,
+    directedEdges: MutableCollection<DirectedEdge<T>>,
+    undirectedEdges: MutableCollection<UndirectedEdge<T>>,
+) {
+    nodes.add(this)
+    for (parent in inNodes) {
+        directedEdges.add(DirectedEdge(parent, this))
+    }
+    for (parent in outNodes) {
+        directedEdges.add(DirectedEdge(this, parent))
+    }
+    for (parent in this.biNodes) {
+        undirectedEdges.add(UndirectedEdge(this, parent))
+    }
+    for (parent in allParents) {
+        if (parent !in nodes) parent.populate(nodes, directedEdges, undirectedEdges)
+    }
+}