Spring CompositePropertySource

  • Author: HuiFer

  • 源码阅读仓库: SourceHot-spring

  • 全路径: org.springframework.core.env.CompositePropertySource

  • 整体代码如下

  1. public class CompositePropertySource extends EnumerablePropertySource<Object> {
  3.     /**
  4.      * set 集合
  5.      */
  6.     private final Set<PropertySource<?>> propertySources = new LinkedHashSet<>();
  9.     /**
  10.      * Create a new {@code CompositePropertySource}.
  11.      * @param name the name of the property source
  12.      */
  13.     public CompositePropertySource(String name) {
  14.         super(name);
  15.     }
  18.     @Override
  19.     @Nullable
  20.     public Object getProperty(String name) {
  21.         // 循环
  22.         for (PropertySource<?> propertySource : this.propertySources) {
  23.             // 获取存储内容
  24.             Object candidate = propertySource.getProperty(name);
  25.             if (candidate != null) {
  26.                 return candidate;
  27.             }
  28.         }
  29.         return null;
  30.     }
  32.     @Override
  33.     public boolean containsProperty(String name) {
  34.         for (PropertySource<?> propertySource : this.propertySources) {
  35.             // 是否存在name
  36.             if (propertySource.containsProperty(name)) {
  37.                 return true;
  38.             }
  39.         }
  40.         return false;
  41.     }
  43.     @Override
  44.     public String[] getPropertyNames() {
  45.         Set<String> names = new LinkedHashSet<>();
  46.         for (PropertySource<?> propertySource : this.propertySources) {
  47.             // 类型不同抛出异常
  48.             if (!(propertySource instanceof EnumerablePropertySource)) {
  49.                 throw new IllegalStateException(
  50.                         "Failed to enumerate property names due to non-enumerable property source: " + propertySource);
  51.             }
  52.             // 批量添加
  53.             names.addAll(Arrays.asList(((EnumerablePropertySource<?>) propertySource).getPropertyNames()));
  54.         }
  55.         // 转换成 array
  56.         return StringUtils.toStringArray(names);
  57.     }
  60.     /**
  61.      * Add the given {@link PropertySource} to the end of the chain.
  62.      * @param propertySource the PropertySource to add
  63.      */
  64.     public void addPropertySource(PropertySource<?> propertySource) {
  65.         this.propertySources.add(propertySource);
  66.     }
  68.     /**
  69.      * Add the given {@link PropertySource} to the start of the chain.
  70.      * @param propertySource the PropertySource to add
  71.      * @since 4.1
  72.      */
  73.     public void addFirstPropertySource(PropertySource<?> propertySource) {
  74.         // 头插
  75.         List<PropertySource<?>> existing = new ArrayList<>(this.propertySources);
  76.         this.propertySources.clear();
  77.         this.propertySources.add(propertySource);
  78.         this.propertySources.addAll(existing);
  79.     }
  81.     /**
  82.      * Return all property sources that this composite source holds.
  83.      * @since 4.1.1
  84.      */
  85.     public Collection<PropertySource<?>> getPropertySources() {
  86.         return this.propertySources;
  87.     }
  90.     @Override
  91.     public String toString() {
  92.         return getClass().getSimpleName() + " {name='" + this.name + "', propertySources=" + this.propertySources + "}";
  93.     }
  95. }