com.khubla.pragmatach.plugin.jsp.JSPCompiler Maven / Gradle / Ivy
package com.khubla.pragmatach.plugin.jsp;
import java.io.File;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.jasper.EmbeddedServletOptions;
import org.apache.jasper.JspCompilationContext;
import org.apache.jasper.Options;
import org.apache.jasper.compiler.Compiler;
import org.apache.jasper.compiler.JspRuntimeContext;
import org.apache.jasper.runtime.HttpJspBase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.khubla.pragmatach.framework.api.PragmatachException;
/**
* Simple JSP compiler
*
* http://javasourcecode.org/html/open-source/tomcat/tomcat-7.0.29/org/apache/jasper/JspCompilationContext.java.html
*
*
* http://javasourcecode.org/html/open-source/tomcat/tomcat-6.0.32/org/apache/jasper/JspC.java.html
*
*
* http://javasourcecode.org/html/open-source/tomcat/tomcat-7.0.29/org/apache/jasper/JspC.java.html
*
*
* @author tome
*/
public class JSPCompiler {
/**
* class cache
*/
private static JSPClassCache jspClassCache = new JSPClassCache();
/**
* namespace
*/
private static final String JSP_NAMESPACE = "com.khubla.pragmatach.jsp";
/**
* servlet context
*/
private final ServletContext servletContext;
/**
* servlet config
*/
private final ServletConfig servletConfig;
/**
* logger
*/
private final Logger logger = LoggerFactory.getLogger(this.getClass());
/**
* classloader
*/
private URLClassLoader compilerClassLoader;
/**
* options
*/
private final Options options;
/**
* file
*/
private final String jspFile;
/**
* the classname
*/
final String className;
/**
* the class package
*/
final String packageName;
/**
* the fully qualified classname
*/
final String fullyQualifiedClassName;
/**
* the path to the classfile
*/
final String classFilePath;
/**
* ctor
*/
public JSPCompiler(String jspFile, ServletConfig servletConfig, ServletContext servletContext) {
this.servletContext = servletContext;
this.servletConfig = servletConfig;
options = new EmbeddedServletOptions(servletConfig, servletContext);
this.jspFile = jspFile;
compilerClassLoader = createCompilerClassLoader(jspFile);
className = makeClassName();
packageName = getPackage();
fullyQualifiedClassName = getFullyQualifiedClassName();
classFilePath = getClassFilePath();
}
/**
* compile a jspFile and return the class type
*/
private void compile() throws PragmatachException {
ClassLoader originalClassLoader = null;
try {
/*
* get description of the class we want to create
*/
final String className = makeClassName();
final String packageName = getPackage();
final String fullyQualifiedClassName = getFullyQualifiedClassName();
/*
* log
*/
logger.info("Compiling '" + jspFile + "' to '" + fullyQualifiedClassName + "' in directory '" + getPackageDir(packageName) + "'");
/*
* options
*/
final Options options = new EmbeddedServletOptions(servletConfig, servletContext);
/*
* runtime context
*/
final JspRuntimeContext jspRuntimeContext = new JspRuntimeContext(servletContext, options);
/*
* set up class compilation context
*/
final String jspUri = jspFile.replace('\\', '/');
final JspCompilationContext jspCompilationContext = new JspCompilationContext(jspUri, false, options, servletContext, null, jspRuntimeContext);
jspCompilationContext.setServletClassName(className);
jspCompilationContext.setServletPackageName(packageName);
/*
* save the class loader and set new class loader
*/
originalClassLoader = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(compilerClassLoader);
jspCompilationContext.setClassLoader(compilerClassLoader);
/*
* compile
*/
final Compiler compiler = jspCompilationContext.createCompiler();
if (null != compiler) {
compiler.compile();
} else {
throw new Exception("Unable to create compiler");
}
/*
* refresh the classloader
*/
compilerClassLoader = createCompilerClassLoader(jspUri);
} catch (final Exception e) {
throw new PragmatachException("Exception in compile", e);
} finally {
if (originalClassLoader != null) {
Thread.currentThread().setContextClassLoader(originalClassLoader);
}
}
}
/**
* set up the class loader for the JSP compiler
*/
private URLClassLoader createCompilerClassLoader(String jspFile) {
try {
/*
* the urls
*/
final List urls = new ArrayList();
/*
* find the files in /WEB-INF/classes/
*/
final String rootURI = servletContext.getRealPath(File.separator);
final File classesDir = new File(rootURI + "/WEB-INF/classes/");
if (classesDir.exists()) {
final Collection jars = FileUtils.listFiles(classesDir, new String[] { "jar" }, true);
for (final File jar : jars) {
urls.add(new URL("file://" + jar.getAbsolutePath()));
}
}
/*
* find the files in /WEB-INF/lib/
*/
final File libsDir = new File(rootURI + "/WEB-INF/lib/");
if (libsDir.exists()) {
final Collection jars = FileUtils.listFiles(libsDir, new String[] { "jar" }, true);
for (final File jar : jars) {
urls.add(new URL("file://" + jar.getAbsolutePath()));
}
}
/*
* show all urls
*/
for (final URL url : urls) {
logger.debug(url.getPath());
}
/*
* done
*/
final URL[] u = new URL[urls.size()];
urls.toArray(u);
return new URLClassLoader(u);
} catch (final Exception e) {
logger.error("Exception in createCompilerClassLoader", e);
return null;
}
}
private URLClassLoader createJSPClassLoader() {
try {
return new URLClassLoader(new URL[] { new URL("file://" + options.getScratchDir().getAbsolutePath() + "/") }, Thread.currentThread().getContextClassLoader());
} catch (final Exception e) {
logger.error("Exception in createJSPClassLoader", e);
return null;
}
}
private final String getClassFilePath() {
return getPackageDir(getPackage()) + "/" + makeClassName() + ".class";
}
/**
* get a Class for the jspFile
*/
private Class getClazz() throws PragmatachException {
try {
/*
* get from cache
*/
Class ret = jspClassCache.find(fullyQualifiedClassName);
if (null == ret) {
/*
* compile
*/
compile();
/*
* get it
*/
final URLClassLoader jspClassLoader = createJSPClassLoader();
if (null != jspClassLoader) {
ret = jspClassLoader.loadClass(fullyQualifiedClassName);
/*
* cache it
*/
jspClassCache.add(ret, fullyQualifiedClassName);
}
}
/*
* done
*/
return ret;
} catch (final Exception e) {
throw new PragmatachException("Exception in getClazz", e);
}
}
/**
* get jspFile fully qualified name
*/
private String getFullyQualifiedClassName() {
return getPackage() + "." + makeClassName();
}
/**
* get jspFile package
*/
private String getPackage() {
final String classPart = jspFile.replaceAll(File.separator, ".");
final int i = classPart.lastIndexOf(File.separator);
if (-1 != i) {
return JSP_NAMESPACE + "." + classPart.substring(0, i);
} else {
return JSP_NAMESPACE;
}
}
/**
* get the absolute dir that files in a specific package will end up in
*/
private String getPackageDir(String packageName) {
return options.getScratchDir().getAbsolutePath() + File.separator + StringUtils.replace(packageName, ".", File.separator);
}
/**
* given a JSP file relative path, return a Servlet
*/
public HttpJspBase getServlet() throws PragmatachException {
try {
final Class clazz = getClazz();
if (null != clazz) {
final Object o = clazz.newInstance();
return (HttpJspBase) o;
} else {
return null;
}
} catch (final Exception e) {
throw new PragmatachException("Exception in getServlet", e);
}
}
/**
* create classname from jspFile
*/
private String makeClassName() {
/*
* get the part after the last dot
*/
String ret = jspFile.substring(0, jspFile.indexOf("."));
final int i = ret.lastIndexOf(File.separator);
if (-1 != i) {
ret = ret.substring(i + 1);
}
/*
* capitalize first letter
*/
ret = ret.substring(0, 1).toUpperCase() + ret.substring(1);
/*
* done
*/
return ret;
}
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