1 files changed, 126 insertions, 0 deletions
diff --git a/simplemetrics/src/main/java/com/yahoo/metrics/simple/PointBuilder.java b/simplemetrics/src/main/java/com/yahoo/metrics/simple/PointBuilder.java
new file mode 100644
index 00000000000..7f6b797c601
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+++ b/simplemetrics/src/main/java/com/yahoo/metrics/simple/PointBuilder.java
@@ -0,0 +1,126 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.metrics.simple;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Single-use builder for the immutable Point instances used to set dimensions
+ * for a metric. Get a fresh instance either from a corresponding Gauge or Counter,
+ * or through the MetricReceiver API.
+ *
+ * @author steinar
+ */
+@Beta
+public final class PointBuilder {
+    private ArrayList<String> dimensions;
+    private ArrayList<Value> location;
+    private static final String[] dimensionsTypeArgument = new String[0];
+    private static final Value[] locationTypeArgument = new Value[0];
+
+    public enum Discriminator {
+        LONG, DOUBLE, STRING;
+    }
+
+    PointBuilder() {
+        this(null);
+    }
+
+    PointBuilder(Point p) {
+        dimensions = new ArrayList<>();
+        location = new ArrayList<>();
+        if (p != null) {
+            int size = p.dimensionality();
+            dimensions = new ArrayList<>(size);
+            location = new ArrayList<>(size);
+            for (String dimensionName : p.getDimensions()) {
+                dimensions.add(dimensionName);
+            }
+            for (Value dimensionValue : p.getLocation()) {
+                location.add(dimensionValue);
+            }
+        } else {
+            dimensions = new ArrayList<>(4);
+            location = new ArrayList<>(4);
+        }
+    }
+
+    /**
+     * Set a named dimension to an integer value.
+     *
+     * @param dimensionName the name of the dimension to set
+     * @param dimensionValue to value for the given dimension
+     * @return this, to facilitate chaining
+     */
+    public PointBuilder set(String dimensionName, long dimensionValue) {
+        return set(dimensionName, Value.of(dimensionValue));
+    }
+
+    /**
+     * Set a named dimension to a floating point value.
+     *
+     * @param dimensionName the name of the dimension to set
+     * @param dimensionValue to value for the given dimension
+     * @return this, to facilitate chaining
+     */
+    public PointBuilder set(String dimensionName, double dimensionValue) {
+        return set(dimensionName, Value.of(dimensionValue));
+    }
+
+    /**
+     * Set a named dimension to a string value.
+     *
+     * @param dimensionName the name of the dimension to set
+     * @param dimensionValue to value for the given dimension
+     * @return this, to facilitate chaining
+     */
+    public PointBuilder set(String dimensionName, String dimensionValue) {
+        return set(dimensionName, Value.of(dimensionValue));
+    }
+
+    private PointBuilder set(String axisName, Value w) {
+        // handle setting same axis multiple times nicely
+        int i = Collections.binarySearch(dimensions, axisName);
+        if (i < 0) {
+            dimensions.add(~i, axisName);
+            location.add(~i, w);
+        } else {
+            // only set location, dim obviously exists
+            location.set(i, w);
+        }
+        return this;
+    }
+
+    /**
+     * Create a new Point instance using the settings stored in this
+     * PointBuilder. PointBuilder instances cannot be re-used after build() has
+     * been invoked.
+     *
+     * @return a Point instance reflecting this builder
+     */
+    public Point build() {
+        Point p;
+        if (dimensions.size() == 0) {
+            p = null;
+        } else {
+            p = new Point(dimensions.toArray(dimensionsTypeArgument), location.toArray(locationTypeArgument));
+        }
+        // deny builder re-use
+        dimensions = null;
+        location = null;
+        return p;
+    }
+
+    @Override
+    public String toString() {
+        final int maxLen = 3;
+        StringBuilder builder = new StringBuilder();
+        builder.append("PointBuilder [dimensions=")
+                .append(dimensions != null ? dimensions.subList(0, Math.min(dimensions.size(), maxLen)) : null)
+                .append(", location=").append(location != null ? location.subList(0, Math.min(location.size(), maxLen)) : null)
+                .append("]");
+        return builder.toString();
+    }
+}