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/**
* Copyright (c) 2013, impossibl.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of impossibl.com nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package com.impossibl.postgres.system;
import static com.impossibl.postgres.utils.guava.Preconditions.checkArgument;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.regex.Pattern;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.CLASS;
import static java.util.stream.Collectors.toSet;
/**
* Completely defined setting that can be transformed to/from text, use alternate
* names, carries a description and optional default value.
*
* Settings belong to {@link Setting.Group groups} that determine where they are
* valid. Groups can be global or local. If a group is global, all of its settings
* are global.
*
* Each setting requires a "primary" name (available via {@link #getName()}. This name
* is used when storing settings and when displaying information about the setting.
*
* Each setting is allowed to have alternate names that can be used when searching a source
* for an setting's value. For example, the {@link #getSystem()} method searches for a value
* in the system properties by looking up the primary name & then alternate names in turn
* until it finds a non-null value.
*
* All settings in global groups are required to have unique names (including their alternate
* names); it is enforced during instantiation and will throw an exception is duplicates are
* found.
*
*
* Getting Started:
*
* To declare a setting you need 3 things. A factory class, a {@link Setting.Group}, and
* a static field that holds the setting. Because the settings are used by annotation
* processing this is done via annotations.
*
* Factory:
* A setting factory is a simple class that holds one or more group and setting definitions
* and is annotated with the {@link Setting.Factory} annotation.
*
*
* \@Setting.Factory
* public class MySettings {
* // declare groups & settings here
* }
*
*
* Group:
* Each settings is required to belong to a group. Groups are declared using the
* {@link Setting.Group.Info} annotation and the {@link Group#declare()} initializer.
*
*
* \@Setting.Factory
* public class MySettings {
*
* \@Setting.Group.Info(id="my", desc="My Settings")
* public static final MY_GROUP = Setting.Group.declare();
*
* }
*
*
* Setting:
* Now that you have a factory and a group you can define settings. It's done similarly
* to the group declaration but requires different information.
*
*
* \@Setting.Factory
* public class MySettings {
*
* \@Setting.Group.Info(id="my", desc="My Settings")
* public static final MY_GROUP = Setting.Group.declare();
*
* \@Setting.Info(name="a.setting", group="my", desc"A Setting", def="10")
* public static final A = Setting.declare()
* }
*
*
*
* Annotation Processing:
*
* {@link Setting} & {@link Setting.Group} are designed to work with the "settingsgen"
* annotation processor. It generates documentation and an abstract JDBC datasource
* named {@link com.impossibl.postgres.jdbc.AbstractGeneratedDataSource} from all
* of the global settings groups.
*
* NOTE: Settings can be defined in code without annotations and thus without
* the support of the annotation processor. This is required for settings with types
* not supported by the processor.
*
*
* Annotation Supported Types:
*
* Although any type can be used with a setting only the following types can be
* declared via annotations using the annotation processor
*
* - {@link Boolean}
* - {@link Integer}
* - {@link String}
* - Any {@link Enum}
* - Any {@link Class}
* - {@link Version}
*
*
* @param Type of the setting
*/
public class Setting {
/**
* Setting group.
*
* A group can be global or local. All settings in a global group are required
* to be unique system wide, while settings in a local group only need to be
* unique within the group. Nothing else is unique about local groups.
*
*/
public static class Group {
/**
* Group definition annotation.
*
* The annotation must be used on a "declared" static final field
* named inside a setting factory (i.e. a classed annotated with
* {@link Setting.Factory}).
*
* A declared group field is one initialized with
* {@link Setting.Group#declare()}.
*
*
* \@Setting.Factory
* class MySettings {
*
* \@Setting.Group.Info(id="a", desc="A group")
* static final A_GROUP = Setting.Group.declare()
*
* }
*
* @see Setting
*/
@Target(FIELD)
@Retention(CLASS)
public @interface Info {
String id();
String desc();
boolean global() default true;
int order() default Integer.MAX_VALUE;
}
/**
* Forward declare a group that will be initialized by annotation processing.
*
* @see Setting
* @return Uninitialized group instance
*/
public static Group declare() {
return new Setting.Group(null, null);
}
private static final Map ALL = new LinkedHashMap<>();
/**
* Name base map of all defined setting groups
* @return Map of defined setting groups
*/
public static Map getAll() {
return Collections.unmodifiableMap(ALL);
}
private String name;
private String description;
private boolean global;
private Map> allNamed = new LinkedHashMap<>();
private Set> all = new LinkedHashSet<>();
public Group(String name, String description) {
this(name, description, true);
}
public Group(String name, String description, boolean global) {
init(name, description, global);
}
/**
* Initialize a previously {@link #declare() declared} group.
*/
public void init(String name, String description, boolean global) {
this.name = name;
this.description = description;
this.global = global;
synchronized (Group.class) {
ALL.putIfAbsent(name, this);
}
}
/**
* Adds a previously declared setting to this group.
*
* Allows adding a setting with the same name to multiple
* global groups without conflict.
*/
public Setting add(Setting setting) {
synchronized (Setting.class) {
addAll(allNamed, setting);
all.add(setting);
}
return setting;
}
/**
* Get name of group
*
* @return Name of group
*/
public String getName() {
return name;
}
/**
* Get description of group
*
* @return Description of group
*/
public String getDescription() {
return description;
}
/**
* Retrieves a names based map of all settings in the group
*
* @return Map of all settings.
*/
public Map> getAllNamedSettings() {
return Collections.unmodifiableMap(allNamed);
}
/**
* Retrieves a unique set of all settings owned by the group.
*
* @return Set of all settings.
*/
public Set> getAllOwnedSettings() {
return Collections.unmodifiableSet(all).stream().filter(setting -> setting.group == this).collect(toSet());
}
/**
* Retrieves a unique set of all settings in the group.
*
* @return Set of all settings.
*/
public Set> getAllSettings() {
return Collections.unmodifiableSet(all);
}
@Override
public String toString() {
return name;
}
}
/**
* Setting factory annotation
*
* Must be applied to any class that is generating settings via
* the annotation processor.
*
* @see Setting
*/
@Target(ElementType.TYPE)
@Retention(CLASS)
public @interface Factory {
}
/**
* Setting definition annotation.
*
* The annotation must be used on a "declared" static final field
* named inside a setting factory (i.e. a classed annotated with
* {@link Setting.Factory}).
*
* A declared setting field is one initialized with {@link Setting#declare()}
*
*
* \@Setting.Factory
* class MySettings {
*
* \@Setting.Group.Info(id="a", desc="A group")
* static final A_GROUP = Setting.Group.declare()
*
* \@Setting.Info(name="a.setting", group="a", desc="A Setting", def="10")
* static final A_SETTING = Setting.declare()
*
* }
*
*/
@Target(FIELD)
@Retention(CLASS)
public @interface Info {
String NO_DEFAULT = "$$$NULL$$$";
/**
* Primary name of the setting. Must be in dot-dash format
* (e.g. this.is.a.setting-name) to ensure it
* can be translated and used via command line easily.
*/
String name();
/**
* Id of the group to which the setting belongs.
*/
String group();
/**
* Description of the setting. The text can include
* simple markup allowable in Markdown and JavaDoc.
*/
String desc();
/**
* Static default value of the setting.
*/
String def() default NO_DEFAULT;
/**
* Code that will be directly copied and used as a dynamic default value.
*
* When this value is set, {@link #def()} is treated as a description of
* the dynamic value and {@link #defStatic()} is ignored.
*
* @see Setting
*/
String defDynamic() default NO_DEFAULT;
/**
* Code that will be directly copied and used to provide an initial
* static default value. This should be used to initialize a default
* value with a non-const variable.
*
* When this value is set, {@link #def()} is treated as a description of
* the dynamic value. If {@link #defDynamic()} is provided this value
* is ignored.
*
* @see Setting
*/
String defStatic() default NO_DEFAULT;
/**
* Minimum allowed value for setting.
*
* This value is ignored if the setting's type is not an Integer.
*
* @see Setting
*/
int min() default Integer.MIN_VALUE;
/**
* Maximum allowed value for setting.
*
* This value is ignored if the setting's type is not an Integer.
*
* @see Setting
*/
int max() default Integer.MAX_VALUE;
/**
* Alternate names for the setting.
*
* @see Setting
*/
String[] alternateNames() default {};
}
/**
* Setting value description annotation.
*
* Annotation for providing a description for an individual
* value field (e.g. an enum constants).
*
*
* enum MyEnum {
* \@Setting.Description("This is A value")
* A_VALUE
* }
*
*
* Descriptions will be used when generating documentation
* for a fields allowable values.
*/
@Target(FIELD)
@Retention(CLASS)
public @interface Description {
String value();
}
/**
* String to {@link U} converter functional interface.
*
* A simple interface translate string values to a target
* type while allowing exception to be thrown.
*
* @param Destination type of conversion
*/
public interface Converter {
U convert(String string) throws Exception;
static Converter identity() {
return t -> t;
}
}
/**
* Forward declare a setting that will be initialized by annotation processing.
*
* @see Setting
* @return Uninitialized setting instance
*/
public static Setting declare() {
return new Setting<>(null);
}
/**
* Prefix used when looking up values via {@link System#getProperty(String)}
*/
private static final String SYSTEM_PROPERTY_PREFIX = "pgjdbc.";
private Group group;
private String[] names;
private Class type;
private T staticDefaultValue;
private Supplier dynamicDefaultSupplier;
private Converter fromString;
private Function toString;
private String description;
private Setting(Supplier dynamicDefaultSupplier) {
this.dynamicDefaultSupplier = dynamicDefaultSupplier;
}
/**
* Constructs a new setting instance with a static default value and without support via the annotation processor.
*
* @param group Group the setting belongs to.
* @param description Description of the setting.
* @param type Type of the setting.
* @param defaultValue Default value of the setting in its native type.
* @param fromString Functional that converts a string to this settings type.
* @param toString Functional that converts a native setting value to a string.
* @param names Primary & alternate names for the setting.
*/
public Setting(Group group, String description, Class type, T defaultValue, Converter fromString, Function toString, String[] names) {
this.staticDefaultValue = defaultValue;
init(group, description, type, fromString, toString, names);
}
/**
* Constructs a new setting instance with a dynamic default value and without support via the annotation processor.
*
* @param group Group the setting belongs to.
* @param description Description of the setting.
* @param type Type of the setting.
* @param dynamicDefaultSupplier Supplier of the dynamic default value for this setting.
* @param fromString Functional that converts a string to this settings type.
* @param toString Functional that converts a native setting value to a string.
* @param names Primary & alternate names for the setting.
*/
public Setting(Group group, String description, Class type, Supplier dynamicDefaultSupplier, Converter fromString, Function toString, String[] names) {
this.dynamicDefaultSupplier = dynamicDefaultSupplier;
init(group, description, type, fromString, toString, names);
}
private void init(Group group, String description, Class type, Converter fromString, Function toString, String[] names) {
checkArgument(type != null, "Setting already initialized.");
if (names.length < 1) throw new IllegalArgumentException("names must not be empty");
this.group = group;
this.names = names;
this.type = type;
this.fromString = fromString;
this.toString = toString;
this.description = description;
synchronized (Setting.class) {
if (group.global) {
if (!isSimpleNameFormat(names[0]))
throw new IllegalArgumentException(
"Duplicate setting name found '" + names[0] + "'. " +
"Settings in global groups must be unique across all groups."
);
}
addAll(group.allNamed, this);
group.all.add(this);
}
}
/**
* Initializes a forward declared setting instance. This is intended for use only by the annotation processor.
*
* @param groupId Id of the group the setting belongs to.
* @param description Description of the setting.
* @param type Type of the setting.
* @param fromString Functional that converts a string to this settings type.
* @param toString Functional that converts a native setting value to a string.
* @param names Primary & alternate names for the setting.
*/
public void init(String groupId, String description, Class type, String defaultValue,
Converter fromString, Function toString, String[] names) {
Group group = Group.ALL.get(groupId);
if (group == null) throw new IllegalArgumentException("Unknown group: " + groupId);
init(group, description, type, fromString, toString, names);
staticDefaultValue = defaultValue != null ? fromString(defaultValue) : null;
}
/**
* Initializes a forward declared setting instance. This is intended for use only by the annotation processor.
*
* @param groupId Id of the group the setting belongs to.
* @param description Description of the setting.
* @param type Type of the setting.
* @param fromString Functional that converts a string to this settings type.
* @param toString Functional that converts a native setting value to a string.
* @param names Primary & alternate names for the setting.
*/
public void init(String groupId, String description, Class type, Supplier defaultValue,
Converter fromString, Function toString, String[] names) {
Group group = Group.ALL.get(groupId);
if (group == null) throw new IllegalArgumentException("Unknown group: " + groupId);
init(group, description, type, fromString, toString, names);
dynamicDefaultSupplier = defaultValue;
}
private static final Pattern SIMPLE_NAME_PATTERN = Pattern.compile("(?:[a-z][a-z0-9\\-]+)(?:\\.[a-z0-9][a-z0-9\\-]+)*");
/**
* Validate primary name as being all lowercase and compatible with generating
* a JavaBean property name (doesn't start with a number, dash or dot).
*/
private static boolean isSimpleNameFormat(String name) {
return SIMPLE_NAME_PATTERN.matcher(name).matches();
}
private static void addAll(Map> settings, Setting instance) {
for (String name : instance.names) {
if (settings.containsKey(name)) {
throw new IllegalStateException("Setting with name '" + name + "' already exists");
}
settings.put(name, instance);
}
}
/**
* Retrieve the setting's group
*
* @return Group this setting belongs to
*/
public Group getGroup() {
return group;
}
/**
* Retrieve the primary name of this setting.
*
* @return Primary name of the setting.
*/
public String getName() {
return names[0];
}
/**
* Get all names for this setting; including
* primary and alternate names.
*
* @return All names for this setting.
*/
public String[] getNames() {
return names;
}
/**
* Retrieve the type of this setting.
*
* @return Type of this setting.
*/
public Class getType() {
return type;
}
/**
* Flag that tells whether the setting
* uses a dynamic or static default value.
*
* @return true if the default value is dynamic, false otherwise.
*/
public boolean isDefaultDynamic() {
return dynamicDefaultSupplier != null;
}
/**
* Retrieve the default value of this setting.
*
* @return Default value of this setting.
*/
public T getDefault() {
if (isDefaultDynamic()) {
String value = dynamicDefaultSupplier.get();
if (value == null) return null;
return fromString(value);
}
return staticDefaultValue;
}
/**
* Retrieve the default value of this setting as text.
*
* @return Text version of the default value of this setting.
*/
public String getDefaultText() {
if (isDefaultDynamic()) {
return dynamicDefaultSupplier.get();
}
if (staticDefaultValue != null) {
return toString(staticDefaultValue);
}
return null;
}
/**
* Retrieve the description of this setting.
*
* @return Description of this setting.
*/
public String getDescription() {
return description;
}
/**
* Convert a string to the setting's native type.
*
* @param value String value to parse.
* @return Value in the settings native type.
* @throws IllegalArgumentException If the value cannot be parsed.
*/
public T fromString(String value) {
try {
return fromString.convert(value);
}
catch (Exception e) {
throw new IllegalArgumentException("Unable to parse setting \"" + getName() + "\" from '" + value + "'");
}
}
/**
* Convert a native type to a string value.
*
* @param value Native value to convert into text.
* @return Value in text form.
*/
public String toString(T value) {
return toString.apply(value);
}
/**
* Looks up the setting in system properties.
*
* This method tries all names (primary & alternates) in the
* order in which they were defined and returns the first
* non-null value.
*
* If no value is found the settings {@link #getDefault() default}
* value is returned.
*
* @return System property value of the setting or its default value.
*/
public T getSystem() {
for (String name : names) {
String value = System.getProperty(SYSTEM_PROPERTY_PREFIX + name);
if (value != null) {
return fromString(value);
}
}
return getDefault();
}
/**
* Looks up the setting in the provided {@code properties}.
*
* This method tries all names (primary & alternates) in the
* order in which they were defined and returns the first
* non-null value.
*
* If no value is found the setting's {@link #getDefault()} default)
* value is returned.
*
* @return Property value of the setting or its default value.
*/
public T get(Properties properties) {
for (String name : names) {
String value = properties.getProperty(name);
if (value != null) {
return fromString(value);
}
}
return getDefault();
}
/**
* Looks up the setting in the provided {@code properties}, returning
* it as a text value.
*
* This method tries all names (primary & alternates) in the
* order in which they were defined and returns the first
* non-null value.
*
* If no value is found the setting's {@link #getDefaultText()} default)
* value is returned.
*
* @return Property value of the setting or its default text value.
*/
public String getText(Properties properties) {
for (String name : names) {
String value = properties.getProperty(name);
if (value != null) {
return value;
}
}
return getDefaultText();
}
@Override
public String toString() {
String defaultValue = getDefaultText();
return group + ": " + Arrays.toString(names) + " (" + type + ") = " + (defaultValue != null ? defaultValue : "null") + " : " + description;
}
}