Java tutorial
/* * Copyright 2007-2009 the original author or authors. * * 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 com.laxser.blitz.web.instruction; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import javax.servlet.ServletException; import org.apache.commons.lang.math.NumberUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.stereotype.Component; import org.springframework.util.ClassUtils; import com.laxser.blitz.util.SpringUtils; import com.laxser.blitz.web.Invocation; import com.laxser.blitz.web.impl.thread.InvocationBean; /** * @author [qieqie.wang@gmail.com] */ public class InstructionExecutorImpl implements InstructionExecutor { private Log logger = LogFactory.getLog(getClass()); @Override public Object render(Invocation inv, Object instruction) throws IOException, ServletException, Exception { instruction = translatesToInstructionObject((InvocationBean) inv, instruction); if (instruction != null && !Thread.currentThread().isInterrupted()) { ((Instruction) instruction).render(inv); } return instruction; } /** * @param inv * @param instruction * @return * @throws StackOverflowError */ private Instruction translatesToInstructionObject(InvocationBean inv, Object instruction) throws StackOverflowError { int count = 0; while (!(instruction instanceof Instruction)) { if (count++ > 50) { throw new StackOverflowError("Unable to parse the instruction to an" + " Instruction object less than " + count + " times. Is the instruction" + " that returned by your controller" + " action is right?"); } if (Thread.interrupted() || instruction == null) { return null; } else { if (instruction.getClass() != String.class && !ClassUtils.isPrimitiveOrWrapper(instruction.getClass()) && instruction.getClass().getComponentType() == null && instruction.getClass().getAnnotation(Component.class) != null) { SpringUtils.autowire(instruction, inv.getApplicationContext()); } instruction = parseInstruction(inv, instruction); } } return (Instruction) instruction; } protected Object parseInstruction(Invocation inv, Object ins) { if (logger.isDebugEnabled()) { logger.debug("parset instruction:" + ins.getClass().getName() + ": '" + ins + "'"); } if (ClassUtils.isPrimitiveOrWrapper(ins.getClass())) { return Text.text(ins); } else if (ins instanceof CharSequence) { String str = ins.toString(); if (str.length() == 0 || str.equals("@")) { return null; } if (str.charAt(0) == '@') { return Text.text(str.substring(1)); // content-type?@HttpFeatures } if (str.charAt(0) == '/') { return new ViewInstruction(str); } if (str.startsWith("r:") || str.startsWith("redirect:")) { StringInstruction si = new StringInstruction(false, str.substring(str.indexOf(':') + 1)); if (si.innerInstruction.startsWith("http://") || si.innerInstruction.startsWith("https://")) { return Redirect.location(si.innerInstruction); } return si; } if (str.startsWith("pr:") || str.startsWith("perm-redirect:")) { StringInstruction si = new StringInstruction(false, str.substring(str.indexOf(':') + 1)); si.permanentlyWhenRedirect = true; if (si.innerInstruction.startsWith("http://") || si.innerInstruction.startsWith("https://")) { return si.permanentlyIfNecessary(Redirect.location(si.innerInstruction)); } return si; } if (str.startsWith("f:") || str.startsWith("forward:")) { return new StringInstruction(true, str.substring(str.indexOf(':') + 1)); } if (str.startsWith("e:") || str.startsWith("error:")) { int begin = str.indexOf(':') + 1; int codeEnd = str.indexOf(';'); if (codeEnd == -1) { String text = str.substring(begin); if (text.length() > 0 && NumberUtils.isNumber(text)) { return HttpError.code(Integer.parseInt(text)); } return HttpError.code(500, text); } else { return HttpError.code(Integer.parseInt(str.substring(begin, codeEnd)), str.substring(codeEnd + 1).trim()); } } if (str.startsWith("s:") || str.startsWith("status:")) { int begin = str.indexOf(':') + 1; int codeEnd = str.indexOf(';', begin); if (codeEnd == -1) { inv.getResponse().setStatus(Integer.parseInt(str.substring(begin))); return null; } else { // setStatus(int, String)???';'??msg // sendError? inv.getResponse().setStatus(Integer.parseInt(str.substring(begin, codeEnd))); for (int i = codeEnd; i < str.length(); i++) { if (str.charAt(i) != ' ') { str = str.substring(i + 1); break; } } } } if (str.equals(":continue")) { return null; } return new StringInstruction(null, str); } else if (ins.getClass() == StringInstruction.class) { StringInstruction fr = (StringInstruction) ins; String str = fr.innerInstruction; int queryIndex = str.indexOf('?'); for (int i = (queryIndex == -1) ? str.length() - 1 : queryIndex - 1; i >= 0; i--) { if (str.charAt(i) != ':') { continue; } if (i > 0 && str.charAt(i - 1) == '\\') { // ? str = str.substring(0, i - 1) + str.substring(i); i--; continue; } int cmdEnd = i; int cmdBeforeBegin = i - 1; while (cmdBeforeBegin >= 0 && str.charAt(cmdBeforeBegin) != ':') { cmdBeforeBegin--; } String prefix = str.subSequence(cmdBeforeBegin + 1, cmdEnd).toString(); String body = str.subSequence(i + 1, str.length()).toString(); if ("a".equals(prefix) || "action".equals(prefix)) { if (fr.isReirect()) { return fr.permanentlyIfNecessary(Redirect.action(body)); } else { return Forward.action(body); } } if ("c".equals(prefix) || "controller".equals(prefix)) { if (fr.isReirect()) { return fr.permanentlyIfNecessary(Redirect.controller(body)); } else { return Forward.controller(body); } } if ("m".equals(prefix) || "module".equals(prefix)) { if (fr.isReirect()) { return fr.permanentlyIfNecessary(Redirect.module(body)); } else { return Forward.module(body); } } logger.warn("skip the prefix '" + prefix + ":' of " + str); if (fr.isReirect()) { return fr.permanentlyIfNecessary(Redirect.location(str)); } else if (fr.isForward()) { return Forward.path(str); } else { return new ViewInstruction(str); } } if (fr.isReirect()) { return fr.permanentlyIfNecessary(Redirect.location(str)); } else if (fr.isForward()) { return Forward.path(str); } return new ViewInstruction(str); } else if (ins instanceof InputStream) { return new InputStreamInstruction((InputStream) ins); } else if (ins instanceof byte[]) { return new InputStreamInstruction(new ByteArrayInputStream((byte[]) ins)); } else { return Text.text(ins.toString()); } } private class StringInstruction { Boolean forward; String innerInstruction; boolean permanentlyWhenRedirect = false; public StringInstruction(Boolean forward, String innerInstruction) { super(); this.forward = forward; this.innerInstruction = innerInstruction; } public RedirectInstruction permanentlyIfNecessary(RedirectInstruction redirectInstruction) { if (permanentlyWhenRedirect) { redirectInstruction.permanently(); } return redirectInstruction; } public boolean isReirect() { return forward != null && !forward.booleanValue(); } public boolean isForward() { return forward != null && forward.booleanValue(); } @Override public String toString() { return forward == null ? "" : (forward ? "f:" : "r:") + innerInstruction; } } }