Implement a class representing frequency
This resolves ONOS-1769
Change-Id: Ia4d0da59aec79bafdf7686dfad1f1952f94cefc7
diff --git a/utils/misc/src/main/java/org/onlab/util/Frequency.java b/utils/misc/src/main/java/org/onlab/util/Frequency.java
new file mode 100644
index 0000000..c6e262f
--- /dev/null
+++ b/utils/misc/src/main/java/org/onlab/util/Frequency.java
@@ -0,0 +1,165 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.util;
+
+import com.google.common.base.MoreObjects;
+
+import java.util.Objects;
+
+/**
+ * Class representing frequency. This class is intended to be used for a value whose unit is Hz
+ * and its family (KHz, MHz, etc.).
+ *
+ * <p>
+ * Note: this class is mainly intended to be used for lambda, which
+ * represents THz order. Long has enough space to represent over THz frequency as Hz,
+ * and the underlying value is long as Hz. This means this class can't represent
+ * sub-Hz accuracy.
+ * </p>
+ */
+public final class Frequency {
+
+ private static final long KHZ = 1_000L;
+ private static final long MHZ = 1_000_000L;
+ private static final long GHZ = 1_000_000_000L;
+ private static final long THZ = 1_000_000_000_000L;
+
+ private final long frequency; // frequency in Hz
+
+ /**
+ * Creates an instance representing the specified frequency in Hz.
+ *
+ * @param frequency frequency in Hz
+ */
+ private Frequency(long frequency) {
+ this.frequency = frequency;
+ }
+
+ /**
+ * Return the value this instance represents as Hz.
+ *
+ * @return frequency in Hz
+ */
+ public long asHz() {
+ return frequency;
+ }
+
+ /**
+ * Returns an instance representing the specified value in Hz.
+ *
+ * @param value frequency in Hz
+ * @return instance representing the given frequency
+ */
+ public static Frequency ofHz(long value) {
+ return new Frequency(value);
+ }
+
+ /**
+ * Returns an instance representing the specified value in KHz.
+ *
+ * @param value frequency in KHz
+ * @return instance representing the given frequency
+ */
+ public static Frequency ofKHz(double value) {
+ return new Frequency((long) (value * KHZ));
+ }
+
+ /**
+ * Returns an instance representing the specified value in MHz.
+ *
+ * @param value frequency in MHz
+ * @return instance representing the given frequency
+ */
+ public static Frequency ofMHz(double value) {
+ return new Frequency((long) (value * MHZ));
+ }
+
+ /**
+ * Returns an instance representing the specified value in GHz.
+ *
+ * @param value frequency in GHz
+ * @return instance representing the given frequency
+ */
+ public static Frequency ofGHz(double value) {
+ return new Frequency((long) (value * GHZ));
+ }
+
+ /**
+ * Returns an instance representing the specified value in THz.
+ *
+ * @param value frequency in THz
+ * @return instance representing the given frequency
+ */
+ public static Frequency ofTHz(double value) {
+ return new Frequency((long) (value * THZ));
+ }
+
+ /**
+ * Returns a Frequency whose value is (this + value).
+ *
+ * @param value value to be added to this Frequency
+ * @return this + value
+ */
+ public Frequency add(Frequency value) {
+ return new Frequency(this.frequency + value.frequency);
+ }
+
+ /**
+ * Returns a Frequency whose value is (this - value).
+ *
+ * @param value value to be subtracted from this Frequency
+ * @return this - value
+ */
+ public Frequency subtract(Frequency value) {
+ return new Frequency(this.frequency - value.frequency);
+ }
+
+ /**
+ * Returns a Frequency whose value is (this * value).
+ *
+ * @param value value to be multiplied by this Frequency
+ * @return this * value
+ */
+ public Frequency multiply(long value) {
+ return new Frequency(this.frequency * value);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(frequency);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) {
+ return true;
+ }
+
+ if (!(obj instanceof Frequency)) {
+ return false;
+ }
+
+ final Frequency other = (Frequency) obj;
+ return this.frequency == other.frequency;
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(this)
+ .add("frequency", frequency + "Hz")
+ .toString();
+ }
+}