Type DimensionSizes

1 files changed, 71 insertions, 0 deletions

diff --git a/vespajlib/src/main/java/com/yahoo/tensor/DimensionSizes.java b/vespajlib/src/main/java/com/yahoo/tensor/DimensionSizes.java
new file mode 100644
index 00000000000..76340bb7d8f
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/tensor/DimensionSizes.java
@@ -0,0 +1,71 @@
+package com.yahoo.tensor;
+
+import java.util.Arrays;
+
+/**
+ * The sizes of a set of dimensions.
+ * 
+ * @author bratseth
+ */
+public final class DimensionSizes {
+
+    private final int[] sizes;
+
+    private DimensionSizes(Builder builder) {
+        this.sizes = builder.sizes;
+        builder.sizes = null; // invalidate builder to avoid copying the array
+    }
+
+    /**
+     * Returns the length of this in the nth dimension
+     *
+     * @throws IndexOutOfBoundsException if the index is larger than the number of dimensions in this tensor minus one
+     */
+    public int size(int dimensionIndex) { return sizes[dimensionIndex]; }
+
+    /** Returns the number of dimensions this provides the size of */
+    public int dimensions() { return sizes.length; }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) return true;
+        if (!(o instanceof DimensionSizes)) return false;
+        return Arrays.equals(((DimensionSizes) o).sizes, this.sizes);
+    }
+
+    @Override
+    public int hashCode() { return Arrays.hashCode(sizes); }
+
+    /** 
+     * Builder of a set of dimension sizes.
+     * Dimensions whose size is not set before building will get size 0.
+     */
+    public final static class Builder {
+
+        private int[] sizes;
+
+        public Builder(int dimensions) {
+            this.sizes = new int[dimensions];
+        }
+
+        public Builder set(int dimensionIndex, int size) {
+            sizes[dimensionIndex] = size;
+            return this;
+        }
+
+        /**
+         * Returns the length of this in the nth dimension
+         *
+         * @throws IndexOutOfBoundsException if the index is larger than the number of dimensions in this tensor minus one
+         */
+        public int size(int dimensionIndex) { return sizes[dimensionIndex]; }
+
+        /** Returns the number of dimensions this provides the size of */
+        public int dimensions() { return sizes.length; }
+
+        /** Build this. This builder becomes invalid after calling this. */
+        public DimensionSizes build() { return new DimensionSizes(this); }
+
+    }
+
+}