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1 files changed, 220 insertions, 0 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/rendering/SectionedRenderer.java b/container-search/src/main/java/com/yahoo/search/rendering/SectionedRenderer.java
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+++ b/container-search/src/main/java/com/yahoo/search/rendering/SectionedRenderer.java
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+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.rendering;
+
+import com.yahoo.search.Result;
+import com.yahoo.search.grouping.result.Group;
+import com.yahoo.search.grouping.result.GroupList;
+import com.yahoo.search.grouping.result.HitList;
+import com.yahoo.search.query.context.QueryContext;
+import com.yahoo.search.result.ErrorHit;
+import com.yahoo.search.result.ErrorMessage;
+import com.yahoo.search.result.Hit;
+import com.yahoo.search.result.HitGroup;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+
+/**
+ * Renders each part of a result to a writer.
+ * The renderers are cloned just before rendering,
+ * and must therefore obey the following contract:
+ * <ol>
+ *   <li>At construction time, only final members shall be initialized,
+ *       and these must refer to immutable data only.
+ *   <li>State mutated during rendering shall be initialized in the init method.
+ * </ol>
+ *
+ * @author tonytv
+ */
+abstract public class SectionedRenderer<WRITER> extends Renderer {
+    /**
+     * Wraps the Writer instance.
+     * The result is given as a parameter to all the callback methods.
+     * Must be overridden if the generic parameter WRITER != java.io.Writer.
+     */
+    @SuppressWarnings("unchecked")
+    public WRITER wrapWriter(Writer writer) {
+        return (WRITER)writer;
+    }
+
+    /**
+     * Called at the start of rendering.
+     */
+    abstract public void beginResult(WRITER writer, Result result) throws IOException;
+
+    /**
+     * Called at the end of rendering.
+     */
+    abstract public void endResult(WRITER writer, Result result) throws IOException;
+
+    /**
+     * Called if there are errors in the result.
+     */
+    abstract public void error(WRITER writer, Collection<ErrorMessage> errorMessages) throws IOException;
+
+    /**
+     * Called if there are no hits in the result.
+     */
+    abstract public void emptyResult(WRITER writer, Result result) throws IOException;
+
+    /**
+     * Called if there is a non-null query context for the query of the result.
+     */
+    abstract public void queryContext(WRITER writer, QueryContext queryContext) throws IOException;
+
+    /**
+     * Called when a HitGroup is encountered. After all its children have been provided
+     * to methods of this class, endHitGroup is called.
+     */
+    abstract public void beginHitGroup(WRITER writer, HitGroup hitGroup) throws IOException;
+
+    /**
+     * Called after all the children of the HitGroup have been provided to methods of this class.
+     * See beginHitGroup.
+     */
+    abstract public void endHitGroup(WRITER writer, HitGroup hitGroup) throws IOException;
+
+    /**
+     * Called when a Hit is encountered.
+     */
+    abstract public void hit(WRITER writer, Hit hit) throws IOException;
+
+    /**
+     * Called when an errorHit is encountered.
+     * Forwards to hit() per default.
+     */
+    public void errorHit(WRITER writer, ErrorHit errorHit) throws IOException {
+        hit(writer, (Hit)errorHit);
+    }
+
+    /* Begin Grouping */
+
+    /**
+     * Same as beginHitGroup, but for Group(grouping api).
+     * Forwards to beginHitGroup() per default.
+     */
+    public void beginGroup(WRITER writer, Group group) throws IOException {
+        beginHitGroup(writer, group);
+    }
+
+    /**
+     * Same as endHitGroup, but for Group(grouping api).
+     * Forwards to endHitGroup() per default.
+     */
+    public void endGroup(WRITER writer, Group group) throws IOException {
+        endHitGroup(writer, group);
+    }
+
+    /**
+     * Same as beginHitGroup, but for GroupList(grouping api).
+     * Forwards to beginHitGroup() per default.
+     */
+    public void beginGroupList(WRITER writer, GroupList groupList) throws IOException {
+        beginHitGroup(writer, groupList);
+    }
+
+    /**
+     * Same as endHitGroup, but for GroupList(grouping api).
+     * Forwards to endHitGroup() per default.
+     */
+    public void endGroupList(WRITER writer, GroupList groupList) throws IOException {
+        endHitGroup(writer, groupList);
+    }
+
+    /**
+     * Same as beginHitGroup, but for HitList(grouping api).
+     * Forwards to beginHitGroup() per default.
+     */
+    public void beginHitList(WRITER writer, HitList hitList) throws IOException {
+        beginHitGroup(writer, hitList);
+    }
+
+    /**
+     * Same as endHitGroup, but for HitList(grouping api).
+     * Forwards to endHitGroup() per default.
+     */
+    public void endHitList(WRITER writer, HitList hitList) throws IOException {
+        endHitGroup(writer, hitList);
+    }
+    /* End Grouping */
+
+    /**
+     * Picks apart the result and feeds it to the other methods.
+     */
+    @Override
+    public final void render(Writer writer, Result result) throws IOException {
+        WRITER wrappedWriter = wrapWriter(writer);
+
+        beginResult(wrappedWriter, result);
+        renderResultContent(wrappedWriter, result);
+        endResult(wrappedWriter, result);
+    }
+
+    private  void renderResultContent(WRITER writer, Result result) throws IOException {
+        if (result.hits().getError() != null || result.hits().getQuery().errors().size() > 0) {
+            error(writer, asUnmodifiableSearchErrorList(result.hits().getQuery().errors(), result.hits().getError()));
+        }
+
+        if (result.getConcreteHitCount() == 0) {
+            emptyResult(writer, result);
+        }
+
+        if (result.getContext(false) != null) {
+            queryContext(writer, result.getContext(false));
+        }
+
+        renderHitGroup(writer, result.hits());
+    }
+
+    private Collection<ErrorMessage> asUnmodifiableSearchErrorList(List<com.yahoo.processing.request.ErrorMessage> queryErrors,ErrorMessage resultError) {
+        if (queryErrors.size() == 0)
+            return Collections.singletonList(resultError);
+        List<ErrorMessage> searchErrors = new ArrayList<>(queryErrors.size() + (resultError != null ? 1 :0) );
+        for (int i=0; i<queryErrors.size(); i++)
+            searchErrors.add(ErrorMessage.from(queryErrors.get(i)));
+        if (resultError != null)
+            searchErrors.add(resultError);
+        return Collections.unmodifiableCollection(searchErrors);
+    }
+
+    private void renderHitGroup(WRITER writer, HitGroup hitGroup) throws IOException {
+        if (hitGroup instanceof GroupList) {
+            beginGroupList(writer, (GroupList) hitGroup);
+            renderHitGroupContent(writer, hitGroup);
+            endGroupList(writer, (GroupList) hitGroup);
+        } else if (hitGroup instanceof HitList) {
+            beginHitList(writer, (HitList) hitGroup);
+            renderHitGroupContent(writer, hitGroup);
+            endHitList(writer, (HitList) hitGroup);
+        } else if (hitGroup instanceof Group) {
+            beginGroup(writer, (Group) hitGroup);
+            renderHitGroupContent(writer, hitGroup);
+            endGroup(writer, (Group) hitGroup);
+        } else {
+            beginHitGroup(writer, hitGroup);
+            renderHitGroupContent(writer, hitGroup);
+            endHitGroup(writer, hitGroup);
+        }
+    }
+
+    private void renderHitGroupContent(WRITER writer, HitGroup hitGroup) throws IOException {
+        for (Hit hit : hitGroup.asList()) {
+            renderHit(writer, hit);
+        }
+    }
+
+    private void renderHit(WRITER writer, Hit hit) throws IOException {
+        if (hit instanceof  HitGroup) {
+            renderHitGroup(writer, (HitGroup) hit);
+        } else if (hit instanceof ErrorHit) {
+            errorHit(writer, (ErrorHit) hit);
+        } else {
+            hit(writer, hit);
+        }
+    }
+}