PropertySource
PropertySource主要是对属性源的抽象，抽象除了熟悉源名称和属性源内容对象。其主要方法仍然是对这两个字段进行操作。
public abstract class PropertySource<T> {
protected final Log logger = LogFactory.getLog(getClass());
protected final String name;
protected final T source;
/**
* 构造器
*/
public PropertySource(String name, T source) {
Assert.hasText(name, "Property source name must contain at least one character");
Assert.notNull(source, "Property source must not be null");
this.name = name;
this.source = source;
}
/**
* 不带source的构造器
*/
@SuppressWarnings("unchecked")
public PropertySource(String name) {
this(name, (T) new Object());
}
/**
* 获取name字段
*/
public String getName() {
return this.name;
}
/**
* 获取source字段
*/
public T getSource() {
return this.source;
}
/**
* 是否包含属性
*/
public boolean containsProperty(String name) {
return (getProperty(name) != null);
}
/**
* 获取属性值
*/
@Nullable
public abstract Object getProperty(String name);
/**
* 两个属性源对象是否相同，仅比较名称
*/
@Override
public boolean equals(@Nullable Object other) {
return (this == other || (other instanceof PropertySource &&
ObjectUtils.nullSafeEquals(this.name, ((PropertySource<?>) other).name)));
}
/**
* 根据名称生成hash码
*/
@Override
public int hashCode() {
return ObjectUtils.nullSafeHashCode(this.name);
}
/**
* 重写的toString方法
*/
@Override
public String toString() {
if (logger.isDebugEnabled()) {
return getClass().getSimpleName() + "@" + System.identityHashCode(this) +
" {name='" + this.name + "', properties=" + this.source + "}";
}
else {
return getClass().getSimpleName() + " {name='" + this.name + "'}";
}
}
/**
* 生成一个仅比较的属性源对象，不可用获取name和source
*/
public static PropertySource<?> named(String name) {
return new ComparisonPropertySource(name);
}
/**
* 存根属性源类，主要用在测试场景
*/
public static class StubPropertySource extends PropertySource<Object> {
public StubPropertySource(String name) {
super(name, new Object());
}
/**
* Always returns {@code null}.
*/
@Override
@Nullable
public String getProperty(String name) {
return null;
}
}
/**
* 可比较的属性源类，仅用作根据名称进行比较的场景
*/
static class ComparisonPropertySource extends StubPropertySource {
private static final String USAGE_ERROR =
"ComparisonPropertySource instances are for use with collection comparison only";
public ComparisonPropertySource(String name) {
super(name);
}
@Override
public Object getSource() {
throw new UnsupportedOperationException(USAGE_ERROR);
}
@Override
public boolean containsProperty(String name) {
throw new UnsupportedOperationException(USAGE_ERROR);
}
@Override
@Nullable
public String getProperty(String name) {
throw new UnsupportedOperationException(USAGE_ERROR);
}
}
}
PropertiesPropertySource
属性源抽象类有很多子类的实现，我们仅仅分析其中最常用的一个，即：PropertiesPropertySource。
其继承关系如下：
PropertiesPropertySource -> MapPropertySource -> EnumerablePropertySource -> PropertySource
逐层分析如下：
public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
public EnumerablePropertySource(String name, T source) {
super(name, source);
}
protected EnumerablePropertySource(String name) {
super(name);
}
/**
* 属性名称是否存在
*/
@Override
public boolean containsProperty(String name) {
return ObjectUtils.containsElement(getPropertyNames(), name);
}
/**
* 获取所有的熟悉名称
*/
public abstract String[] getPropertyNames();
}
public class MapPropertySource extends EnumerablePropertySource<Map<String, Object>> {
// source为Map对象
public MapPropertySource(String name, Map<String, Object> source) {
super(name, source);
}
// 在Map对象中获取指定name对应的值
@Override
@Nullable
public Object getProperty(String name) {
return this.source.get(name);
}
// 是否包含某属性，重写了`EnumerablePropertySource`的此方法，目的是为了提升查询的效率
@Override
public boolean containsProperty(String name) {
return this.source.containsKey(name);
}
// 获取熟悉名称数组
@Override
public String[] getPropertyNames() {
return StringUtils.toStringArray(this.source.keySet());
}
}
// 和`MapPropertySource`没太大区别，唯一的操作就是对source进行了加锁，从而避免并发场景下的线程不安全因素。
public class PropertiesPropertySource extends MapPropertySource {
@SuppressWarnings({"rawtypes", "unchecked"})
public PropertiesPropertySource(String name, Properties source) {
super(name, (Map) source);
}
protected PropertiesPropertySource(String name, Map<String, Object> source) {
super(name, source);
}
@Override
public String[] getPropertyNames() {
synchronized (this.source) {
return super.getPropertyNames();
}
}
}
PropertySource
PropertySource主要是对属性源的抽象，抽象除了熟悉源名称和属性源内容对象。其主要方法仍然是对这两个字段进行操作。
public abstract class PropertySource<T> {
protected final Log logger = LogFactory.getLog(getClass());
protected final String name;
protected final T source;
/**
* 构造器
*/
public PropertySource(String name, T source) {
Assert.hasText(name, "Property source name must contain at least one character");
Assert.notNull(source, "Property source must not be null");
this.name = name;
this.source = source;
}
/**
* 不带source的构造器
*/
@SuppressWarnings("unchecked")
public PropertySource(String name) {
this(name, (T) new Object());
}
/**
* 获取name字段
*/
public String getName() {
return this.name;
}
/**
* 获取source字段
*/
public T getSource() {
return this.source;
}
/**
* 是否包含属性
*/
public boolean containsProperty(String name) {
return (getProperty(name) != null);
}
/**
* 获取属性值
*/
@Nullable
public abstract Object getProperty(String name);
/**
* 两个属性源对象是否相同，仅比较名称
*/
@Override
public boolean equals(@Nullable Object other) {
return (this == other || (other instanceof PropertySource &&
ObjectUtils.nullSafeEquals(this.name, ((PropertySource<?>) other).name)));
}
/**
* 根据名称生成hash码
*/
@Override
public int hashCode() {
return ObjectUtils.nullSafeHashCode(this.name);
}
/**
* 重写的toString方法
*/
@Override
public String toString() {
if (logger.isDebugEnabled()) {
return getClass().getSimpleName() + "@" + System.identityHashCode(this) +
" {name='" + this.name + "', properties=" + this.source + "}";
}
else {
return getClass().getSimpleName() + " {name='" + this.name + "'}";
}
}
/**
* 生成一个仅比较的属性源对象，不可用获取name和source
*/
public static PropertySource<?> named(String name) {
return new ComparisonPropertySource(name);
}
/**
* 存根属性源类，主要用在测试场景
*/
public static class StubPropertySource extends PropertySource<Object> {
public StubPropertySource(String name) {
super(name, new Object());
}
/**
* Always returns {@code null}.
*/
@Override
@Nullable
public String getProperty(String name) {
return null;
}
}
/**
* 可比较的属性源类，仅用作根据名称进行比较的场景
*/
static class ComparisonPropertySource extends StubPropertySource {
private static final String USAGE_ERROR =
"ComparisonPropertySource instances are for use with collection comparison only";
public ComparisonPropertySource(String name) {
super(name);
}
@Override
public Object getSource() {
throw new UnsupportedOperationException(USAGE_ERROR);
}
@Override
public boolean containsProperty(String name) {
throw new UnsupportedOperationException(USAGE_ERROR);
}
@Override
@Nullable
public String getProperty(String name) {
throw new UnsupportedOperationException(USAGE_ERROR);
}
}
}
PropertiesPropertySource
属性源抽象类有很多子类的实现，我们仅仅分析其中最常用的一个，即：PropertiesPropertySource。
其继承关系如下：
PropertiesPropertySource -> MapPropertySource -> EnumerablePropertySource -> PropertySource
逐层分析如下：
public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
public EnumerablePropertySource(String name, T source) {
super(name, source);
}
protected EnumerablePropertySource(String name) {
super(name);
}
/**
* 属性名称是否存在
*/
@Override
public boolean containsProperty(String name) {
return ObjectUtils.containsElement(getPropertyNames(), name);
}
/**
* 获取所有的熟悉名称
*/
public abstract String[] getPropertyNames();
}
public class MapPropertySource extends EnumerablePropertySource<Map<String, Object>> {
// source为Map对象
public MapPropertySource(String name, Map<String, Object> source) {
super(name, source);
}
// 在Map对象中获取指定name对应的值
@Override
@Nullable
public Object getProperty(String name) {
return this.source.get(name);
}
// 是否包含某属性，重写了`EnumerablePropertySource`的此方法，目的是为了提升查询的效率
@Override
public boolean containsProperty(String name) {
return this.source.containsKey(name);
}
// 获取熟悉名称数组
@Override
public String[] getPropertyNames() {
return StringUtils.toStringArray(this.source.keySet());
}
}
// 和`MapPropertySource`没太大区别，唯一的操作就是对source进行了加锁，从而避免并发场景下的线程不安全因素。
public class PropertiesPropertySource extends MapPropertySource {
@SuppressWarnings({"rawtypes", "unchecked"})
public PropertiesPropertySource(String name, Properties source) {
super(name, (Map) source);
}
protected PropertiesPropertySource(String name, Map<String, Object> source) {
super(name, source);
}
@Override
public String[] getPropertyNames() {
synchronized (this.source) {
return super.getPropertyNames();
}
}
}
PropertySources
PropertySources是对属性源列表操作的封装。主要加入了迭代器、可变性和集合操作。这个类有一个唯一的子类，即：MutablePropertySources。
// 在迭代器的基础上，增加了判断属性源是否存在，以及根据属性源名称获取属性源的操作。
public interface PropertySources extends Iterable<PropertySource<?>> {
/**
* Return a sequential {@link Stream} containing the property sources.
* @since 5.1
*/
default Stream<PropertySource<?>> stream() {
return StreamSupport.stream(spliterator(), false);
}
/**
* Return whether a property source with the given name is contained.
* @param name the {@linkplain PropertySource#getName() name of the property source} to find
*/
boolean contains(String name);
/**
* Return the property source with the given name, {@code null} if not found.
* @param name the {@linkplain PropertySource#getName() name of the property source} to find
*/
@Nullable
PropertySource<?> get(String name);
}
MutablePropertySources
MutablePropertySources在PropertySources的基础上，增加了可变性和集合操作。
public class MutablePropertySources implements PropertySources {
// 使用`CopyOnWriteArrayList`，保持集合操作的线程安全性。
private final List<PropertySource<?>> propertySourceList = new CopyOnWriteArrayList<>();
/**
* 构造空集合
*/
public MutablePropertySources() {
}
/**
* 构造指定集合
*/
public MutablePropertySources(PropertySources propertySources) {
this();
for (PropertySource<?> propertySource : propertySources) {
addLast(propertySource);
}
}
// ******
// 以下所有方法都是集合操作，主要包括：
// 增、删、改、查、替换、断言存在性等操作
// 非常简单
// ******
@Override
public Iterator<PropertySource<?>> iterator() {
return this.propertySourceList.iterator();
}
@Override
public Spliterator<PropertySource<?>> spliterator() {
return Spliterators.spliterator(this.propertySourceList, 0);
}
@Override
public Stream<PropertySource<?>> stream() {
return this.propertySourceList.stream();
}
@Override
public boolean contains(String name) {
return this.propertySourceList.contains(PropertySource.named(name));
}
@Override
@Nullable
public PropertySource<?> get(String name) {
int index = this.propertySourceList.indexOf(PropertySource.named(name));
return (index != -1 ? this.propertySourceList.get(index) : null);
}
/**
* Add the given property source object with highest precedence.
*/
public void addFirst(PropertySource<?> propertySource) {
removeIfPresent(propertySource);
this.propertySourceList.add(0, propertySource);
}
/**
* Add the given property source object with lowest precedence.
*/
public void addLast(PropertySource<?> propertySource) {
removeIfPresent(propertySource);
this.propertySourceList.add(propertySource);
}
/**
* Add the given property source object with precedence immediately higher
* than the named relative property source.
*/
public void addBefore(String relativePropertySourceName, PropertySource<?> propertySource) {
assertLegalRelativeAddition(relativePropertySourceName, propertySource);
removeIfPresent(propertySource);
int index = assertPresentAndGetIndex(relativePropertySourceName);
addAtIndex(index, propertySource);
}
/**
* Add the given property source object with precedence immediately lower
* than the named relative property source.
*/
public void addAfter(String relativePropertySourceName, PropertySource<?> propertySource) {
assertLegalRelativeAddition(relativePropertySourceName, propertySource);
removeIfPresent(propertySource);
int index = assertPresentAndGetIndex(relativePropertySourceName);
addAtIndex(index + 1, propertySource);
}
/**
* Return the precedence of the given property source, {@code -1} if not found.
*/
public int precedenceOf(PropertySource<?> propertySource) {
return this.propertySourceList.indexOf(propertySource);
}
/**
* Remove and return the property source with the given name, {@code null} if not found.
* @param name the name of the property source to find and remove
*/
@Nullable
public PropertySource<?> remove(String name) {
int index = this.propertySourceList.indexOf(PropertySource.named(name));
return (index != -1 ? this.propertySourceList.remove(index) : null);
}
/**
* Replace the property source with the given name with the given property source object.
* @param name the name of the property source to find and replace
* @param propertySource the replacement property source
* @throws IllegalArgumentException if no property source with the given name is present
* @see #contains
*/
public void replace(String name, PropertySource<?> propertySource) {
int index = assertPresentAndGetIndex(name);
this.propertySourceList.set(index, propertySource);
}
/**
* Return the number of {@link PropertySource} objects contained.
*/
public int size() {
return this.propertySourceList.size();
}
@Override
public String toString() {
return this.propertySourceList.toString();
}
/**
* Ensure that the given property source is not being added relative to itself.
*/
protected void assertLegalRelativeAddition(String relativePropertySourceName, PropertySource<?> propertySource) {
String newPropertySourceName = propertySource.getName();
if (relativePropertySourceName.equals(newPropertySourceName)) {
throw new IllegalArgumentException(
"PropertySource named '" + newPropertySourceName + "' cannot be added relative to itself");
}
}
/**
* Remove the given property source if it is present.
*/
protected void removeIfPresent(PropertySource<?> propertySource) {
this.propertySourceList.remove(propertySource);
}
/**
* Add the given property source at a particular index in the list.
*/
private void addAtIndex(int index, PropertySource<?> propertySource) {
removeIfPresent(propertySource);
this.propertySourceList.add(index, propertySource);
}
/**
* Assert that the named property source is present and return its index.
* @param name {@linkplain PropertySource#getName() name of the property source} to find
* @throws IllegalArgumentException if the named property source is not present
*/
private int assertPresentAndGetIndex(String name) {
int index = this.propertySourceList.indexOf(PropertySource.named(name));
if (index == -1) {
throw new IllegalArgumentException("PropertySource named '" + name + "' does not exist");
}
return index;
}
}
