1 files changed, 95 insertions, 0 deletions
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/SourceGroup.java b/config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/SourceGroup.java
new file mode 100644
index 00000000000..799bba45b04
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/vespa/model/container/search/searchchain/SourceGroup.java
@@ -0,0 +1,95 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.model.container.search.searchchain;
+
+import com.yahoo.component.ComponentId;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+/**
+ * A set of sources with the same name,
+ * each associated with a different provider,
+ * that fills the same role.
+ * @author tonytv
+ */
+final class SourceGroup {
+    private final ComponentId id;
+    private Source leader;
+    private final Set<Source> participants =
+            new LinkedHashSet<>();
+
+    private void setLeader(Source leader) {
+        assert (validMember(leader));
+
+        if (this.leader != null) {
+            throw new IllegalStateException(
+                    "There can not be two default providers for the source "
+                            + id);
+        }
+
+        this.leader = leader;
+    }
+
+    private void addParticipant(Source source) {
+        assert (validMember(source));
+        assert (!source.equals(leader));
+
+        if (!participants.add(source)) {
+            throw new RuntimeException("Source added twice to the same group "
+                    + source);
+        }
+    }
+
+    private boolean validMember(Source leader) {
+        return leader.getComponentId().equals(id);
+    }
+
+    public ComponentId getComponentId() {
+        return id;
+    }
+
+    public SourceGroup(ComponentId id) {
+        this.id = id;
+    }
+
+    public void add(Source source) {
+        assert source.getComponentId().equals(getComponentId()):
+                "Ids differ: " + source.getComponentId() + " -- " + getComponentId();
+
+        if (Source.GroupOption.leader == source.groupOption) {
+            setLeader(source);
+        } else {
+            addParticipant(source);
+        }
+    }
+
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append("Source id: ").append(id).append("\n").
+                append("Leader provider: ").append(
+                leader.getParentProvider().getComponentId()).append("\n").
+                append("Participants:");
+
+        for (Source participant : participants) {
+            builder.append("\n").append("    Provider: ").append(
+                    participant.getParentProvider().getComponentId());
+        }
+        return builder.toString();
+    }
+
+    public Source leader() {
+        return leader;
+    }
+
+    public Collection<Source> participants() {
+        return Collections.unmodifiableCollection(participants);
+    }
+
+    public void validate() {
+        if (leader == null)
+            throw new IllegalStateException("Missing leader for the source " + getComponentId() +
+                    ". One of the sources must use the attribute id instead of idref.");
+    }
+}