VarParameterResolver.java

/*
 * Copyright 2008-2010 the T2 Project ant the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.t2framework.confeito.parameter.impl;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;

import org.t2framework.confeito.action.ActionContext;
import org.t2framework.confeito.annotation.Var;
import org.t2framework.confeito.contexts.Request;
import org.t2framework.confeito.exception.VarParameterNotFoundRuntimeException;
import org.t2framework.confeito.parameter.AbstractParameterResolver;
import org.t2framework.confeito.util.ConverterUtil;
import org.t2framework.confeito.util.Logger;
import org.t2framework.confeito.util.URLUtil;

/**
 * <#if locale="en">
 * <p>
 * VarParameterResolver is a resolver class to inject a part of url which is
 * described by annotation value. For example, consider the page class like
 * below:
 * 
 * <pre>
 * 	@Page("{s}/vartest")
 * 	public static class VarPage {
 * 		public Navigation aaa(@Var("s") String s) {
 * 			......
 * </pre>
 * 
 * The point is that {s} annotated with @Page takes any value like
 * aaa/vartest or bbb/vartest.VarParameterResolver is enbale to get that value,
 * aaa or bbb.
 * 
 * </p>
 * <#else>
 * <p>
 * 
 * </p>
 * </#if>
 * 
 * @author shot
 */
public class VarParameterResolver extends AbstractParameterResolver {

	protected static Logger logger = Logger
			.getLogger(VarParameterResolver.class);

	public VarParameterResolver() {
		setTargetAnnotationClass(Var.class);
	}

	/**
	 * <#if locale="en">
	 * <p>
	 * Find and resolve templated value(with {@literal aaa -> aaa} ) which is
	 * specified by {@link Var#value()}, then return.The returned value is
	 * decoded by {@link URLUtil#decode(String, String)} with character encoding
	 * specified by web.xml.
	 * 
	 * </p>
	 * <#else>
	 * <p>
	 * 
	 * </p>
	 * </#if>
	 * 
	 * @return string : templated value.
	 * @throws VarParameterNotFoundRuntimeException
	 *             value is not found and {@link Var#nullable()} is false
	 */
	@Override
	public Object resolve(final ActionContext actionContext, final Method md,
			final int paramIndex, final Annotation[] paramAnnotations,
			final Class<?> paramClass) {
		final Var var = findTargetAnnotation(paramAnnotations,
				getTargetAnnotationClass());
		if (var == null) {
			throw new IllegalStateException("must have @Var annotation.");
		}
		final String templateKey = "{" + var.value() + "}";
		final boolean nullable = var.nullable();
		final String value = actionContext.getVariables(templateKey);
		if (value != null) {
			final Request request = actionContext.getRequest();
			final String encoding = request.getCharacterEncoding();
			String ret = URLUtil.decode(value, encoding);
			return ConverterUtil.convert(ret, paramClass);
		} else if (nullable) {
			return null;
		} else {
			throw new VarParameterNotFoundRuntimeException(templateKey);
		}
	}
}