XtemplatesCreateHandler.java

package com.googlecode.gwt.test.gxt3.internal.handlers;

import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.googlecode.gwt.test.GwtCreateHandler;
import com.googlecode.gwt.test.exceptions.GwtTestException;
import com.sencha.gxt.core.client.XTemplates;
import com.sencha.gxt.core.client.XTemplates.XTemplate;
import freemarker.template.Configuration;
import freemarker.template.ObjectWrapper;
import freemarker.template.Template;

import java.io.*;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.Map;

public class XtemplatesCreateHandler implements GwtCreateHandler {

    private class XTemplatesInvocationHandler implements InvocationHandler {

        private final Class<?> proxiedClass;

        private XTemplatesInvocationHandler(Class<?> proxiedClass) {
            this.proxiedClass = proxiedClass;

        }

        public Object invoke(Object proxy, Method method, Object[] args)
                throws Throwable {

            Template template = templates.get(method);
            if (template == null) {
                template = createTemplate(method);
            }

            String[] paramNames = JavaFileParanamer.get().lookupParameterNames(method);

            Map<String, Object> dataModel = new HashMap<String, Object>();
            for (int i = 0; i < paramNames.length; i++) {
                dataModel.put(paramNames[i], args[i]);
            }

            StringWriter writer = new StringWriter();
            template.process(dataModel, writer);

            if (method.getReturnType() == String.class) {
                return writer.toString();
            } else {
                return SafeHtmlUtils.fromTrustedString(writer.toString());
            }

        }

        private Template createTemplate(Method method) {
            Configuration cfg = new Configuration();
            cfg.setObjectWrapper(ObjectWrapper.DEFAULT_WRAPPER);

            XTemplate xTemplate = method.getAnnotation(XTemplate.class);
            if (xTemplate == null) {
                throw new GwtTestException(
                        "gwt-test-utils expects to find a @XTemplate annotation on method "
                                + method.toString());
            }

            String templateName = method.toGenericString();

            if (xTemplate.source().length() > 0) {
                InputStream in = method.getDeclaringClass().getResourceAsStream(
                        xTemplate.source());

                if (in == null) {
                    throw new GwtTestException("Cannot find file @Template source file "
                            + xTemplate.source() + " declared for method " + method);
                }
                BufferedReader br = new BufferedReader(new InputStreamReader(in));
                try {
                    return new Template(templateName, br, cfg);
                } catch (IOException e) {
                    throw new GwtTestException(
                            "Error while trying to get template for method " + method);
                }
            } else {
                return Template.getPlainTextTemplate(templateName, xTemplate.value(),
                        cfg);
            }

        }

    }

    private static final XtemplatesCreateHandler INSTANCE = new XtemplatesCreateHandler();

    public static final XtemplatesCreateHandler get() {
        return INSTANCE;
    }

    private final Configuration config;
    private final Map<Method, Template> templates;

    private XtemplatesCreateHandler() {
        this.config = new Configuration();
        this.templates = new HashMap<Method, Template>();
    }

    public Object create(Class<?> classLiteral) throws Exception {
        if (!XTemplates.class.isAssignableFrom(classLiteral)) {
            return null;
        }

        return Proxy.newProxyInstance(classLiteral.getClassLoader(),
                new Class<?>[]{classLiteral}, new XTemplatesInvocationHandler(
                        classLiteral));

    }

}