be.wolkmaan.klimtoren.shared.ViewInjectingReturnValueHandler.java Source code

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Here is the source code for be.wolkmaan.klimtoren.shared.ViewInjectingReturnValueHandler.java

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package be.wolkmaan.klimtoren.shared;

import be.wolkmaan.klimtoren.shared.view.BaseView;
import be.wolkmaan.klimtoren.shared.view.PojoView;
import be.wolkmaan.klimtoren.shared.view.ResponseView;
import org.springframework.core.MethodParameter;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.ModelAndViewContainer;

/**
 *
 * @author karl
 */
public class ViewInjectingReturnValueHandler implements HandlerMethodReturnValueHandler {

    private final HandlerMethodReturnValueHandler delegate;

    public ViewInjectingReturnValueHandler(HandlerMethodReturnValueHandler delegate) {
        this.delegate = delegate;
    }

    @Override
    public boolean supportsReturnType(MethodParameter returnType) {
        return delegate.supportsReturnType(returnType);
    }

    @Override
    public void handleReturnValue(Object returnValue, MethodParameter returnType,
            ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {

        Class<? extends BaseView> viewClass = getDeclaredViewClass(returnType);
        if (viewClass != null) {
            returnValue = wrapResult(returnValue, viewClass);
        }

        delegate.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
    }

    /**
     * Returns the view class declared on the method, if it exists.
     * Otherwise, returns null.
     * @param returnType
     * @return
     */
    private Class<? extends BaseView> getDeclaredViewClass(MethodParameter returnType) {
        ResponseView annotation = returnType.getMethodAnnotation(ResponseView.class);
        if (annotation != null) {
            return annotation.value();
        } else {
            return null;
        }
    }

    private Object wrapResult(Object result, Class<? extends BaseView> viewClass) {
        PojoView response = new PojoView(result, viewClass);
        return response;
    }
}