YangTools从YANG生成Java类(Maven)
1.说明
ODL提供了Yang Tools工具从YANG文件生成Java类，
本文介绍使用Maven插件的方式生成，
基于yang-maven-plugin这个插件。
2.创建Maven工程
Eclipse -> File -> New -> Other… -> Maven -> Maven Project
创建一个简单Maven工程，
pom.xml如下：
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.ai.prd.yang</groupId>
<artifactId>generate-yang-tools</artifactId>
<version>0.0.1-SNAPSHOT</version>
<description>使用ODL的Yang Tools工具，从yang文件生成Java类</description>
</project>3.增加父pom
在pom.xml增加mdsal-parent作为父pom：
<parent>
<groupId>org.opendaylight.controller</groupId>
<artifactId>mdsal-parent</artifactId>
<version>1.10.4</version>
<relativePath>../../parent</relativePath>
</parent>查看父pom，发现依赖了yang-maven-plugin插件：
<dependency>
<groupId>org.opendaylight.yangtools</groupId>
<artifactId>yang-maven-plugin</artifactId>
<version>3.0.16</version>
</dependency>以及在build配置了这个插件从YANG生成Java类：
<plugin>
<groupId>org.opendaylight.yangtools</groupId>
<artifactId>yang-maven-plugin</artifactId>
<version>3.0.16</version>
<executions>
<execution>
<id>binding</id>
<goals>
<goal>generate-sources</goal>
</goals>
<configuration>
<codeGenerators>
<generator>
<codeGeneratorClass>org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl</codeGeneratorClass>
<outputBaseDir>D:\Code\Work\ODL-Netconf\yang-demos\generate-yang-tools\target-ide/generated-sources/mdsal-binding</outputBaseDir>
<resourceBaseDir>D:\Code\Work\ODL-Netconf\yang-demos\generate-yang-tools\target-ide/generated-sources/spi</resourceBaseDir>
</generator>
</codeGenerators>
<inspectDependencies>true</inspectDependencies>
</configuration>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.opendaylight.mdsal</groupId>
<artifactId>maven-sal-api-gen-plugin</artifactId>
<version>2.0.17</version>
<scope>compile</scope>
</dependency>
</dependencies>
</plugin>4.创建YANG文件
由于插件默认的YANG文件位置是src\main\yang，
所有在src\main\yang目录下新建文件acme-system.yang：
module acme-system {
namespace "http://acme.example.com/system";
prefix "acme";
organization "ACME Inc.";
contact "joe@acme.example.com";
description
"The module for entities implementing the ACME system.";
revision 2007-06-09 {
description "Initial revision.";
}
container system {
leaf host-name {
type string;
description "Hostname for this system";
}
leaf-list domain-search {
type string;
description "List of domain names to search";
}
container login {
leaf message {
type string;
description
"Message given at start of login session";
}
list user {
key "name";
leaf name {
type string;
}
leaf full-name {
type string;
}
leaf class {
type string;
}
}
}
}
}对该YANG文件的解读请参考：对YANG的解读(一)
5.运行Maven插件
运行Maven命令，
执行插件功能,
从YANG文件生成Java类：
mvn clean generate-sourcesMaven编译成功日志：
[INFO] Scanning for projects...
[INFO]
[INFO] ----------------< com.ai.prd.yang:generate-yang-tools >-----------------
[INFO] Building generate-yang-tools 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ generate-yang-tools ---
[INFO]
[INFO] --- maven-enforcer-plugin:3.0.0-M2:enforce (enforce-maven) @ generate-yang-tools ---
[INFO]
[INFO] --- maven-enforcer-plugin:3.0.0-M2:enforce (enforce-banned-dependencies) @ generate-yang-tools ---
[INFO]
[INFO] --- git-commit-id-plugin:3.0.1:revision (get-git-infos) @ generate-yang-tools ---
[INFO]
[INFO] --- jacoco-maven-plugin:0.8.5:prepare-agent (pre-unit-test) @ generate-yang-tools ---
[INFO] argLine set to -javaagent:C:\\developtools\\maven-repository\\org\\jacoco\\org.jacoco.agent\\0.8.5\\org.jacoco.agent-0.8.5-runtime.jar=destfile=D:\\Code\\Work\\ODL-Netconf\\yang-demos\\generate-yang-tools\\target\\code-coverage\\jacoco.exec,excludes=**/gen/**:**/generated-sources/**:**/generated-test-sources/**:**/yang-gen/**:**/yang-gen-config/**:**/yang-gen-sal/**:**/yang-gen-code/**:**/pax/**
[INFO]
[INFO] --- yang-maven-plugin:3.0.16:generate-sources (binding) @ generate-yang-tools ---
[INFO] yang-to-sources: Code generator instantiated from org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl
[INFO] yang-to-sources: Inspecting D:\Code\Work\ODL-Netconf\yang-demos\generate-yang-tools\src\main\yang
[INFO] yang-to-sources: Found 0 dependencies in 40.39 ms
[INFO] yang-to-sources: Project model files found: 1
[INFO] yang-to-sources: 1 YANG models processed in 110.2 ms
[INFO] yang-to-sources: Sources will be generated to D:\Code\Work\ODL-Netconf\yang-demos\generate-yang-tools\target\generated-sources\mdsal-binding
[INFO] Found 5 Binding types in 58.11 ms
[INFO] Generating 8 Binding source files into 3 directories
[INFO] yang-to-sources: Sources generated by org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl: 11 in 136.5 ms
[INFO]
[INFO] --- build-helper-maven-plugin:3.0.0:add-source (add-yang-sources) @ generate-yang-tools ---
[INFO] Source directory: D:\Code\Work\ODL-Netconf\yang-demos\generate-yang-tools\target\generated-sources\mdsal-binding added.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.983 s
[INFO] Finished at: 2021-01-27T15:47:28+08:00
[INFO] ------------------------------------------------------------------------6.查看生成的Java类
Maven命令执行成功后，
生成的Java类在工程的target\generated-sources\mdsal-binding目录下，
然后是Java类的包路径：org\opendaylight\yang\gen\v1\http\acme\example\com\system\rev070609，
目录rev070609的详细文件如下：
.:
system/ '$YangModelBindingProvider.java' '$YangModuleInfoImpl.java'
AcmeSystemData.java System.java SystemBuilder.java
./system:
login/ Login.java LoginBuilder.java
./system/login:
User.java UserBuilder.java UserKey.java原始的YANG文件也会输出到target\generated-sources\yang\META-INF\yang下面，
并且重命名为acme-system@2007-06-09.yang。
由于生成的Java类都比较大，
这里仅贴出Login.java和LoginBuilder.java两个类。
Login.java:
package org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system;
import java.lang.Class;
import java.lang.Override;
import java.lang.String;
import java.util.List;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.$YangModuleInfoImpl;
import org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.System;
import org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system.login.User;
import org.opendaylight.yangtools.yang.binding.Augmentable;
import org.opendaylight.yangtools.yang.binding.ChildOf;
import org.opendaylight.yangtools.yang.binding.CodeHelpers;
import org.opendaylight.yangtools.yang.common.QName;
/**
*
* <p>
* This class represents the following YANG schema fragment defined in module <b>acme-system</b>
* <pre>
* container login {
* leaf message {
* type string;
* }
* list user {
* key name;
* leaf name {
* type string;
* }
* leaf full-name {
* type string;
* }
* leaf class {
* type string;
* }
* }
* }
* </pre>The schema path to identify an instance is
* <i>acme-system/system/login</i>
*
* <p>To create instances of this class use {@link LoginBuilder}.
* @see LoginBuilder
*
*/
public interface Login
extends
ChildOf<System>,
Augmentable<Login>
{
public static final @NonNull QName QNAME = $YangModuleInfoImpl.qnameOf("login");
@Override
default Class<org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system.Login> implementedInterface() {
return org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system.Login.class;
}
/**
* Message given at start of login session
*
*
*
* @return java.lang.String message, or null if not present
*/
@Nullable String getMessage();
/**
* @return java.util.List user, or null if not present
*/
@Nullable List<User> getUser();
/**
* @return java.util.List user, or an empty list if it is not present
*/
default @NonNull List<User> nonnullUser() {
return CodeHelpers.nonnull(getUser());
}
}LoginBuilder.java:
package org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system;
import com.google.common.base.MoreObjects;
import java.lang.Class;
import java.lang.Object;
import java.lang.Override;
import java.lang.String;
import java.lang.SuppressWarnings;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import org.opendaylight.yang.gen.v1.http.acme.example.com.system.rev070609.system.login.User;
import org.opendaylight.yangtools.concepts.Builder;
import org.opendaylight.yangtools.yang.binding.AbstractAugmentable;
import org.opendaylight.yangtools.yang.binding.Augmentation;
import org.opendaylight.yangtools.yang.binding.AugmentationHolder;
import org.opendaylight.yangtools.yang.binding.CodeHelpers;
import org.opendaylight.yangtools.yang.binding.DataObject;
/**
* Class that builds {@link LoginBuilder} instances. Overall design of the class is that of a
* <a href="https://en.wikipedia.org/wiki/Fluent_interface">fluent interface</a>, where method chaining is used.
*
* <p>
* In general, this class is supposed to be used like this template:
* <pre>
*
* LoginBuilder createTarget(int fooXyzzy, int barBaz) {
* return new LoginBuilderBuilder()
* .setFoo(new FooBuilder().setXyzzy(fooXyzzy).build())
* .setBar(new BarBuilder().setBaz(barBaz).build())
* .build();
* }
*
* </pre>
*
* <p>
* This pattern is supported by the immutable nature of LoginBuilder, as instances can be freely passed around without
* worrying about synchronization issues.
*
* <p>
* As a side note: method chaining results in:
* <ul>
* <li>very efficient Java bytecode, as the method invocation result, in this case the Builder reference, is
* on the stack, so further method invocations just need to fill method arguments for the next method
* invocation, which is terminated by {@link #build()}, which is then returned from the method</li>
* <li>better understanding by humans, as the scope of mutable state (the builder) is kept to a minimum and is
* very localized</li>
* <li>better optimization oportunities, as the object scope is minimized in terms of invocation (rather than
* method) stack, making <a href="https://en.wikipedia.org/wiki/Escape_analysis">escape analysis</a> a lot
* easier. Given enough compiler (JIT/AOT) prowess, the cost of th builder object can be completely
* eliminated</li>
* </ul>
*
* @see LoginBuilder
* @see Builder
*
*/
public class LoginBuilder implements Builder<Login> {
private String _message;
private List<User> _user;
Map<Class<? extends Augmentation<Login>>, Augmentation<Login>> augmentation = Collections.emptyMap();
public LoginBuilder() {
}
public LoginBuilder(Login base) {
if (base instanceof AugmentationHolder) {
@SuppressWarnings("unchecked")
Map<Class<? extends Augmentation<Login>>, Augmentation<Login>> aug =((AugmentationHolder<Login>) base).augmentations();
if (!aug.isEmpty()) {
this.augmentation = new HashMap<>(aug);
}
}
this._message = base.getMessage();
this._user = base.getUser();
}
public String getMessage() {
return _message;
}
public List<User> getUser() {
return _user;
}
@SuppressWarnings({ "unchecked", "checkstyle:methodTypeParameterName"})
public <E$$ extends Augmentation<Login>> E$$ augmentation(Class<E$$> augmentationType) {
return (E$$) augmentation.get(CodeHelpers.nonNullValue(augmentationType, "augmentationType"));
}
public LoginBuilder setMessage(final String value) {
this._message = value;
return this;
}
public LoginBuilder setUser(final List<User> values) {
this._user = values;
return this;
}
public LoginBuilder addAugmentation(Class<? extends Augmentation<Login>> augmentationType, Augmentation<Login> augmentationValue) {
if (augmentationValue == null) {
return removeAugmentation(augmentationType);
}
if (!(this.augmentation instanceof HashMap)) {
this.augmentation = new HashMap<>();
}
this.augmentation.put(augmentationType, augmentationValue);
return this;
}
public LoginBuilder removeAugmentation(Class<? extends Augmentation<Login>> augmentationType) {
if (this.augmentation instanceof HashMap) {
this.augmentation.remove(augmentationType);
}
return this;
}
@Override
public Login build() {
return new LoginImpl(this);
}
private static final class LoginImpl
extends AbstractAugmentable<Login>
implements Login {
private final String _message;
private final List<User> _user;
LoginImpl(LoginBuilder base) {
super(base.augmentation);
this._message = base.getMessage();
this._user = base.getUser();
}
@Override
public String getMessage() {
return _message;
}
@Override
public List<User> getUser() {
return _user;
}
private int hash = 0;
private volatile boolean hashValid = false;
@Override
public int hashCode() {
if (hashValid) {
return hash;
}
final int prime = 31;
int result = 1;
result = prime * result + Objects.hashCode(_message);
result = prime * result + Objects.hashCode(_user);
result = prime * result + Objects.hashCode(augmentations());
hash = result;
hashValid = true;
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof DataObject)) {
return false;
}
if (!Login.class.equals(((DataObject)obj).implementedInterface())) {
return false;
}
Login other = (Login)obj;
if (!Objects.equals(_message, other.getMessage())) {
return false;
}
if (!Objects.equals(_user, other.getUser())) {
return false;
}
if (getClass() == obj.getClass()) {
// Simple case: we are comparing against self
LoginImpl otherImpl = (LoginImpl) obj;
if (!Objects.equals(augmentations(), otherImpl.augmentations())) {
return false;
}
} else {
// Hard case: compare our augments with presence there...
for (Map.Entry<Class<? extends Augmentation<Login>>, Augmentation<Login>> e : augmentations().entrySet()) {
if (!e.getValue().equals(other.augmentation(e.getKey()))) {
return false;
}
}
// .. and give the other one the chance to do the same
if (!obj.equals(this)) {
return false;
}
}
return true;
}
@Override
public String toString() {
final MoreObjects.ToStringHelper helper = MoreObjects.toStringHelper("Login");
CodeHelpers.appendValue(helper, "_message", _message);
CodeHelpers.appendValue(helper, "_user", _user);
CodeHelpers.appendValue(helper, "augmentation", augmentations().values());
return helper.toString();
}
}
}7.问题解决
在Eclipse缺少某些插件时，
会报Maven的一些goals无法执行的错误，
下面配置去掉Eclipse中的pom报错，
并且不影响Maven命令执行结果:
<build>
<pluginManagement>
<plugins>
<!--This plugin's configuration is used to store Eclipse m2e settings only. It has no influence on the Maven build itself.-->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>
com.github.spotbugs
</groupId>
<artifactId>
spotbugs-maven-plugin
</artifactId>
<versionRange>
[3.1.12.2,)
</versionRange>
<goals>
<goal>check</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore></ignore>
</action>
</pluginExecution>
<pluginExecution>
<pluginExecutionFilter>
<groupId>
org.apache.maven.plugins
</groupId>
<artifactId>
maven-checkstyle-plugin
</artifactId>
<versionRange>
[3.1.1,)
</versionRange>
<goals>
<goal>check</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore></ignore>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>8.使用ODL提供的样例工程
ODL提供了一个和上面类似的工程，
下载地址：https://github.com/opendaylight/controller/releases?after=v2.0.5
选择下载版本release/sodium-sr4，
这个是钠版本的稳定发布版本，
且支持JDK 1.8和Maven 3.6.9，
这是由于在父pom中指定了requireJavaVersion为1.8.0，
以及requireMavenVersion大于等于3.5.0。
<plugin>
<artifactId>maven-enforcer-plugin</artifactId>
<version>3.0.0-M2</version>
<executions>
<execution>
<id>enforce-maven</id>
<goals>
<goal>enforce</goal>
</goals>
<configuration>
<rules>
<requireJavaVersion>
<version>1.8.0</version>
</requireJavaVersion>
<requireMavenVersion>
<version>[3.5.0,)</version>
</requireMavenVersion>
</rules>
</configuration>
</execution>
<execution>
<id>enforce-banned-dependencies</id>
<goals>
<goal>enforce</goal>
</goals>
<configuration>
<rules>
<bannedDependencies>
<message>Please always use mockito-core instead of mockito-all (see https://bugs.opendaylight.org/show_bug.cgi?id=7662), and spotbugs:annotations instead of findbugs:annotations</message>
<excludes>
<exclude>org.mockito:mockito-all</exclude>
<exclude>com.google.code.findbugs:annotations</exclude>
</excludes>
</bannedDependencies>
</rules>
<fail>true</fail>
</configuration>
</execution>
</executions>
</plugin>9.使用样例工程
下载的controller-release-sodium-sr4.zip解压到本地，
找到toaster工程：
D:\temp\controller-release-sodium-sr4\opendaylight\md-sal\samples\toaster
然后在工程下面执行编译命令即可:
mvn clean generate-sources也可以把工程复制出来单独编译，
也可以把工程导入Eclipse编译，
生成的结果和上面类似。
10.参考文章
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