com.google.gerrit.metrics.Field Maven / Gradle / Ivy
// Copyright (C) 2015 The Android Open Source Project
//
// 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 com.google.gerrit.metrics;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.common.base.Function;
import com.google.common.base.Functions;
/**
* Describes a bucketing field used by a metric.
*
* @param type of field
*/
public class Field {
/**
* Break down metrics by boolean true/false.
*
* @param name field name
* @return boolean field
*/
public static Field ofBoolean(String name) {
return ofBoolean(name, null);
}
/**
* Break down metrics by boolean true/false.
*
* @param name field name
* @param description field description
* @return boolean field
*/
public static Field ofBoolean(String name, String description) {
return new Field<>(name, Boolean.class, description);
}
/**
* Break down metrics by cases of an enum.
*
* @param enumType type of enum
* @param name field name
* @return enum field
*/
public static > Field ofEnum(Class enumType, String name) {
return ofEnum(enumType, name, null);
}
/**
* Break down metrics by cases of an enum.
*
* @param enumType type of enum
* @param name field name
* @param description field description
* @return enum field
*/
public static > Field ofEnum(
Class enumType, String name, String description) {
return new Field<>(name, enumType, description);
}
/**
* Break down metrics by string.
*
* Each unique string will allocate a new submetric. Do not use user content as a field
* value as field values are never reclaimed.
*
* @param name field name
* @return string field
*/
public static Field ofString(String name) {
return ofString(name, null);
}
/**
* Break down metrics by string.
*
* Each unique string will allocate a new submetric. Do not use user content as a field
* value as field values are never reclaimed.
*
* @param name field name
* @param description field description
* @return string field
*/
public static Field ofString(String name, String description) {
return new Field<>(name, String.class, description);
}
/**
* Break down metrics by integer.
*
* Each unique integer will allocate a new submetric. Do not use user content as a field
* value as field values are never reclaimed.
*
* @param name field name
* @return integer field
*/
public static Field ofInteger(String name) {
return ofInteger(name, null);
}
/**
* Break down metrics by integer.
*
* Each unique integer will allocate a new submetric. Do not use user content as a field
* value as field values are never reclaimed.
*
* @param name field name
* @param description field description
* @return integer field
*/
public static Field ofInteger(String name, String description) {
return new Field<>(name, Integer.class, description);
}
private final String name;
private final Class keyType;
private final Function formatter;
private final String description;
private Field(String name, Class keyType, String description) {
checkArgument(name.matches("^[a-z_]+$"), "name must match [a-z_]");
this.name = name;
this.keyType = keyType;
this.formatter = initFormatter(keyType);
this.description = description;
}
/** @return name of this field within the metric. */
public String getName() {
return name;
}
/** @return type of value used within the field. */
public Class getType() {
return keyType;
}
/** @return description text for the field explaining its range of values. */
public String getDescription() {
return description;
}
public Function formatter() {
return formatter;
}
@SuppressWarnings("unchecked")
private static Function initFormatter(Class keyType) {
if (keyType == String.class) {
return (Function) Functions.identity();
} else if (keyType == Integer.class || keyType == Boolean.class) {
return (Function) Functions.toStringFunction();
} else if (Enum.class.isAssignableFrom(keyType)) {
return in -> ((Enum) in).name();
}
throw new IllegalStateException("unsupported type " + keyType.getName());
}
}