Example usage for org.apache.commons.lang3.reflect FieldUtils readStaticField

Introduction

In this page you can find the example usage for org.apache.commons.lang3.reflect FieldUtils readStaticField.

Prototype

public static Object readStaticField(final Class<?> cls, final String fieldName) throws IllegalAccessException 

Source Link

Document

Reads the named public static Field .

Usage

From source file:com.holonplatform.core.internal.property.DefaultPropertySetRefIntrospector.java

@Override
public PropertySet<?> getPropertySet(PropertySetRef annotation) throws PropertySetIntrospectionException {
    ObjectUtils.argumentNotNull(annotation, "PropertySetRef annotation must be not null");

    // reference class
    final Class<?> cls = annotation.value();
    if (cls == null) {
        throw new PropertySetIntrospectionException("[PropertySetRef] missing value");
    }/* w  ww .j av a  2 s. co  m*/

    // field name
    String fieldName = AnnotationUtils.getStringValue(annotation.field());

    boolean wasNullFieldName = (fieldName == null);

    if (fieldName == null) {

        // check cache
        synchronized (cache) {
            final CacheKey key = new CacheKey(cls, null);
            if (cache.containsKey(key)) {
                return cache.get(key);
            }
        }

        if (PropertySet.class == cls) {
            throw new PropertySetIntrospectionException(
                    "Invalid PropertySetRef class value: [" + cls.getName() + "]");
        }

        // If the class itself is a PropertySet, try to instantiate it
        if (PropertySet.class.isAssignableFrom(cls)) {
            try {
                return (PropertySet<?>) cls.newInstance();
            } catch (InstantiationException | IllegalAccessException e) {
                throw new PropertySetIntrospectionException(
                        "[PropertySetRef] Failed to instantiate PropertySet class [" + cls.getName() + "]", e);
            }
        }

        // Look for a public static PropertySet type field
        List<String> candidateFieldNames = new LinkedList<>();
        Field[] flds = cls.getDeclaredFields();
        if (flds != null) {
            for (Field fld : flds) {
                if (Modifier.isStatic(fld.getModifiers()) && Modifier.isPublic(fld.getModifiers())
                        && PropertySet.class.isAssignableFrom(fld.getType())) {
                    candidateFieldNames.add(fld.getName());
                }
            }
        }

        if (candidateFieldNames.isEmpty()) {
            throw new PropertySetIntrospectionException(
                    "[PropertySetRef] Cannot find any valid public static PropertySet type field in class ["
                            + cls.getName() + "]");
        }

        if (candidateFieldNames.size() > 1) {
            throw new PropertySetIntrospectionException(
                    "[PropertySetRef] More than one valid PropertySet type field found in class ["
                            + cls.getName()
                            + "]: please specify the field name to use in PropertySetRef annotation. Detected PropertySet fields: ["
                            + candidateFieldNames + "]");
        }

        fieldName = candidateFieldNames.get(0);

    } else {

        // check cache
        synchronized (cache) {
            final CacheKey key = new CacheKey(cls, fieldName);
            if (cache.containsKey(key)) {
                return cache.get(key);
            }
        }

    }

    if (LOGGER.isEnabled(Level.DEBUG)) {
        final String fn = fieldName;
        LOGGER.debug(() -> "Get PropertySet using PropertySetRef annotation for class [" + cls
                + "] and field name [" + fn + "]");
    }

    // Read the PropertySet field
    try {
        Object value = FieldUtils.readStaticField(cls, fieldName);

        if (value == null) {
            throw new PropertySetIntrospectionException("[PropertySetRef] The field [" + fieldName
                    + "] in class [" + cls.getName() + "] has null value");
        }

        if (!PropertySet.class.isAssignableFrom(value.getClass())) {
            throw new PropertySetIntrospectionException(
                    "[PropertySetRef] The field [" + fieldName + "] in class [" + cls.getName()
                            + "] is not of PropertySet type but [" + value.getClass().getName() + "]");
        }

        final PropertySet<?> propertySet = (PropertySet<?>) value;

        // put in cache and return
        if (wasNullFieldName) {
            cache.putIfAbsent(new CacheKey(cls, null), propertySet);
        }
        PropertySet<?> existing = cache.putIfAbsent(new CacheKey(cls, fieldName), propertySet);
        return (existing != null ? existing : propertySet);

    } catch (IllegalAccessException e) {
        throw new PropertySetIntrospectionException(
                "[PropertySetRef] Failed to read field [" + fieldName + "] from class [" + cls.getName() + "]",
                e);
    }
}

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From source file:org.apache.servicecomb.it.junit.ITJUnitUtils.java

private static void initClasses(Class<?>[] classes) throws Throwable {
    for (Class<?> cls : classes) {
        for (Field field : FieldUtils.getAllFieldsList(cls)) {
            if (Consumers.class.isAssignableFrom(field.getType())
                    || GateRestTemplate.class.isAssignableFrom(field.getType())
                    || ITSCBRestTemplate.class.isAssignableFrom(field.getType())) {
                Object target = FieldUtils.readStaticField(field, true);
                MethodUtils.invokeMethod(target, "init");
            }// w ww .j  a v  a 2  s.  c  o  m
        }
    }
}

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