jspruntimelibrary.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.jasper.runtime;

import java.beans.PropertyEditor;
import java.beans.PropertyEditorManager;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyContent;

import org.apache.jasper.Constants;
import org.apache.jasper.JasperException;
import org.apache.jasper.compiler.Localizer;

/**
 * Bunch of util methods that are used by code generated for useBean,
 * getProperty and setProperty.  
 *
 * The __begin, __end stuff is there so that the JSP engine can
 * actually parse this file and inline them if people don't want
 * runtime dependencies on this class. However, I'm not sure if that
 * works so well right now. It got forgotten at some point. -akv
 *
 * @author Mandar Raje
 * @author Shawn Bayern
 */
public class JspRuntimeLibrary {
    
    private static final String SERVLET_EXCEPTION
	= "javax.servlet.error.exception";
    private static final String JSP_EXCEPTION
	= "javax.servlet.jsp.jspException";

    protected static class PrivilegedIntrospectHelper
	implements PrivilegedExceptionAction {

	private Object bean;
	private String prop;
	private String value;
	private ServletRequest request;
	private String param;
	private boolean ignoreMethodNF;

        PrivilegedIntrospectHelper(Object bean, String prop,
                                   String value, ServletRequest request,
                                   String param, boolean ignoreMethodNF)
        {
	    this.bean = bean;
	    this.prop = prop;
	    this.value = value;
            this.request = request;
	    this.param = param;
	    this.ignoreMethodNF = ignoreMethodNF;
        }
         
        public Object run() throws JasperException {
	    internalIntrospecthelper(
                bean,prop,value,request,param,ignoreMethodNF);
            return null;
        }
    }

    /**
     * Returns the value of the javax.servlet.error.exception request
     * attribute value, if present, otherwise the value of the
     * javax.servlet.jsp.jspException request attribute value.
     *
     * This method is called at the beginning of the generated servlet code
     * for a JSP error page, when the "exception" implicit scripting language
     * variable is initialized.
     */
    public static Throwable getThrowable(ServletRequest request) {
	Throwable error = (Throwable) request.getAttribute(SERVLET_EXCEPTION);
	if (error == null) {
	    error = (Throwable) request.getAttribute(JSP_EXCEPTION);
	    if (error != null) {
		/*
		 * The only place that sets JSP_EXCEPTION is
		 * PageContextImpl.handlePageException(). It really should set
		 * SERVLET_EXCEPTION, but that would interfere with the 
		 * ErrorReportValve. Therefore, if JSP_EXCEPTION is set, we
		 * need to set SERVLET_EXCEPTION.
		 */
		request.setAttribute(SERVLET_EXCEPTION, error);
	    }
	}

	return error;
    }

    public static boolean coerceToBoolean(String s) {
	if (s == null || s.length() == 0)
	    return false;
	else
	    return Boolean.valueOf(s).booleanValue();
    }

    public static byte coerceToByte(String s) {
	if (s == null || s.length() == 0)
	    return (byte) 0;
	else
	    return Byte.valueOf(s).byteValue();
    }

    public static char coerceToChar(String s) {
	if (s == null || s.length() == 0) {
	    return (char) 0;
	} else {
	    // this trick avoids escaping issues
	    return (char)(int) s.charAt(0);
	}
    }

    public static double coerceToDouble(String s) {
	if (s == null || s.length() == 0)
	    return (double) 0;
	else
	    return Double.valueOf(s).doubleValue();
    }

    public static float coerceToFloat(String s) {
	if (s == null || s.length() == 0)
	    return (float) 0;
	else
	    return Float.valueOf(s).floatValue();
    }

    public static int coerceToInt(String s) {
	if (s == null || s.length() == 0)
	    return 0;
	else
	    return Integer.valueOf(s).intValue();
    }

    public static short coerceToShort(String s) {
	if (s == null || s.length() == 0)
	    return (short) 0;
	else
	    return Short.valueOf(s).shortValue();
    }

    public static long coerceToLong(String s) {
	if (s == null || s.length() == 0)
	    return (long) 0;
	else
	    return Long.valueOf(s).longValue();
    }

    public static Object coerce(String s, Class target) {

	boolean isNullOrEmpty = (s == null || s.length() == 0);

	if (target == Boolean.class) {
	    if (isNullOrEmpty) {
		s = "false";
	    }
	    return new Boolean(s);
	} else if (target == Byte.class) {
	    if (isNullOrEmpty)
		return new Byte((byte) 0);
	    else
		return new Byte(s);
	} else if (target == Character.class) {
	    if (isNullOrEmpty)
		return new Character((char) 0);
	    else 
		return new Character(s.charAt(0));
	} else if (target == Double.class) {
	    if (isNullOrEmpty)
		return new Double(0);
	    else
		return new Double(s);
	} else if (target == Float.class) {
	    if (isNullOrEmpty)
		return new Float(0);
	    else
		return new Float(s);
	} else if (target == Integer.class) {
	    if (isNullOrEmpty)
		return new Integer(0);
	    else
		return new Integer(s);
	} else if (target == Short.class) {
	    if (isNullOrEmpty)
		return new Short((short) 0);
	    else
		return new Short(s);
	} else if (target == Long.class) {
	    if (isNullOrEmpty)
		return new Long(0);
	    else
		return new Long(s);
	} else {
	    return null;
	}
    }

   // __begin convertMethod
    public static Object convert(String propertyName, String s, Class t,
				 Class propertyEditorClass) 
       throws JasperException 
    {
        try {
            if (s == null) {
                if (t.equals(Boolean.class) || t.equals(Boolean.TYPE))
                    s = "false";
                else
                    return null;
            }
	    if (propertyEditorClass != null) {
		return getValueFromBeanInfoPropertyEditor(
				    t, propertyName, s, propertyEditorClass);
	    } else if ( t.equals(Boolean.class) || t.equals(Boolean.TYPE) ) {
                if (s.equalsIgnoreCase("on") || s.equalsIgnoreCase("true"))
                    s = "true";
                else
                    s = "false";
                return new Boolean(s);
            } else if ( t.equals(Byte.class) || t.equals(Byte.TYPE) ) {
                return new Byte(s);
            } else if (t.equals(Character.class) || t.equals(Character.TYPE)) {
                return s.length() > 0 ? new Character(s.charAt(0)) : null;
            } else if ( t.equals(Short.class) || t.equals(Short.TYPE) ) {
                return new Short(s);
            } else if ( t.equals(Integer.class) || t.equals(Integer.TYPE) ) {
                return new Integer(s);
            } else if ( t.equals(Float.class) || t.equals(Float.TYPE) ) {
                return new Float(s);
            } else if ( t.equals(Long.class) || t.equals(Long.TYPE) ) {
                return new Long(s);
            } else if ( t.equals(Double.class) || t.equals(Double.TYPE) ) {
                return new Double(s);
            } else if ( t.equals(String.class) ) {
                return s;
            } else if ( t.equals(java.io.File.class) ) {
                return new java.io.File(s);
            } else if (t.getName().equals("java.lang.Object")) {
                return new Object[] {s};
	    } else {
		return getValueFromPropertyEditorManager(
                                            t, propertyName, s);
            }
        } catch (Exception ex) {
            throw new JasperException(ex);
        }
    }
    // __end convertMethod

    // __begin introspectMethod
    public static void introspect(Object bean, ServletRequest request)
                                  throws JasperException
    {
	Enumeration e = request.getParameterNames();
	while ( e.hasMoreElements() ) {
	    String name  = (String) e.nextElement();
	    String value = request.getParameter(name);
	    introspecthelper(bean, name, value, request, name, true);
	}
    }
    // __end introspectMethod
    
    // __begin introspecthelperMethod
    public static void introspecthelper(Object bean, String prop,
                                        String value, ServletRequest request,
                                        String param, boolean ignoreMethodNF)
                                        throws JasperException
    {
        if( Constants.IS_SECURITY_ENABLED ) {
            try {
                PrivilegedIntrospectHelper dp =
		    new PrivilegedIntrospectHelper(
			bean,prop,value,request,param,ignoreMethodNF);
                AccessController.doPrivileged(dp);
            } catch( PrivilegedActionException pe) {
                Exception e = pe.getException();
                throw (JasperException)e;
            }
        } else {
            internalIntrospecthelper(
		bean,prop,value,request,param,ignoreMethodNF);
        }
    }

    private static void internalIntrospecthelper(Object bean, String prop,
					String value, ServletRequest request,
					String param, boolean ignoreMethodNF) 
					throws JasperException
    {
        Method method = null;
        Class type = null;
        Class propertyEditorClass = null;
	try {
	    java.beans.BeanInfo info
		= java.beans.Introspector.getBeanInfo(bean.getClass());
	    if ( info != null ) {
		java.beans.PropertyDescriptor pd[]
		    = info.getPropertyDescriptors();
		for (int i = 0 ; i < pd.length ; i++) {
		    if ( pd[i].getName().equals(prop) ) {
			method = pd[i].getWriteMethod();
			type   = pd[i].getPropertyType();
			propertyEditorClass = pd[i].getPropertyEditorClass();
			break;
		    }
		}
	    }
	    if ( method != null ) {
		if (type.isArray()) {
                    if (request == null) {
			throw new JasperException(
		            Localizer.getMessage("jsp.error.beans.setproperty.noindexset"));
                    }
		    Class t = type.getComponentType();
		    String[] values = request.getParameterValues(param);
		    //XXX Please check.
		    if(values == null) return;
		    if(t.equals(String.class)) {
			method.invoke(bean, new Object[] { values });
		    } else {
			Object tmpval = null;
			createTypedArray (prop, bean, method, values, t,