generator.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.compiler;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Vector;

import javax.el.MethodExpression;
import javax.el.ValueExpression;
import javax.servlet.jsp.tagext.TagAttributeInfo;
import javax.servlet.jsp.tagext.TagInfo;
import javax.servlet.jsp.tagext.TagVariableInfo;
import javax.servlet.jsp.tagext.VariableInfo;

import org.apache.jasper.Constants;
import org.apache.jasper.JasperException;
import org.apache.jasper.JspCompilationContext;
import org.apache.jasper.runtime.JspRuntimeLibrary;
import org.xml.sax.Attributes;

/**
 * Generate Java source from Nodes
 * 
 * @author Anil K. Vijendran
 * @author Danno Ferrin
 * @author Mandar Raje
 * @author Rajiv Mordani
 * @author Pierre Delisle
 * 
 * Tomcat 4.1.x and Tomcat 5:
 * @author Kin-man Chung
 * @author Jan Luehe
 * @author Shawn Bayern
 * @author Mark Roth
 * @author Denis Benoit
 * 
 * Tomcat 6.x
 * @author Jacob Hookom
 * @author Remy Maucherat
 */

class Generator {

    private static final Class[] OBJECT_CLASS = { Object.class };

    private static final String VAR_EXPRESSIONFACTORY = 
        System.getProperty("org.apache.jasper.compiler.Generator.VAR_EXPRESSIONFACTORY", "_el_expressionfactory");
    private static final String VAR_ANNOTATIONPROCESSOR = 
        System.getProperty("org.apache.jasper.compiler.Generator.VAR_ANNOTATIONPROCESSOR", "_jsp_annotationprocessor");

    private ServletWriter out;

    private ArrayList methodsBuffered;

    private FragmentHelperClass fragmentHelperClass;

    private ErrorDispatcher err;

    private BeanRepository beanInfo;

    private JspCompilationContext ctxt;

    private boolean isPoolingEnabled;

    private boolean breakAtLF;

    private String jspIdPrefix;

    private int jspId;

    private PageInfo pageInfo;

    private Vector<String> tagHandlerPoolNames;

    private GenBuffer charArrayBuffer;

    /**
     * @param s
     *            the input string
     * @return quoted and escaped string, per Java rule
     */
    static String quote(String s) {

        if (s == null)
            return "null";

        return '"' + escape(s) + '"';
    }

    /**
     * @param s
     *            the input string
     * @return escaped string, per Java rule
     */
    static String escape(String s) {

        if (s == null)
            return "";

        StringBuffer b = new StringBuffer();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '"')
                b.append('\\').append('"');
            else if (c == '\\')
                b.append('\\').append('\\');
            else if (c == '\n')
                b.append('\\').append('n');
            else if (c == '\r')
                b.append('\\').append('r');
            else
                b.append(c);
        }
        return b.toString();
    }

    /**
     * Single quote and escape a character
     */
    static String quote(char c) {

        StringBuffer b = new StringBuffer();
        b.append('\'');
        if (c == '\'')
            b.append('\\').append('\'');
        else if (c == '\\')
            b.append('\\').append('\\');
        else if (c == '\n')
            b.append('\\').append('n');
        else if (c == '\r')
            b.append('\\').append('r');
        else
            b.append(c);
        b.append('\'');
        return b.toString();
    }

    private String createJspId() throws JasperException {
        if (this.jspIdPrefix == null) {
            StringBuffer sb = new StringBuffer(32);
            String name = ctxt.getServletJavaFileName();
            sb.append("jsp_").append(Math.abs(name.hashCode())).append('_');
            this.jspIdPrefix = sb.toString();
        }
        return this.jspIdPrefix + (this.jspId++);
    }

    /**
     * Generates declarations. This includes "info" of the page directive, and
     * scriptlet declarations.
     */
    private void generateDeclarations(Node.Nodes page) throws JasperException {

        class DeclarationVisitor extends Node.Visitor {

            private boolean getServletInfoGenerated = false;

            /*
             * Generates getServletInfo() method that returns the value of the
             * page directive's 'info' attribute, if present.
             * 
             * The Validator has already ensured that if the translation unit
             * contains more than one page directive with an 'info' attribute,
             * their values match.
             */
            public void visit(Node.PageDirective n) throws JasperException {

                if (getServletInfoGenerated) {
                    return;
                }

                String info = n.getAttributeValue("info");
                if (info == null)
                    return;

                getServletInfoGenerated = true;
                out.printil("public String getServletInfo() {");
                out.pushIndent();
                out.printin("return ");
                out.print(quote(info));
                out.println(";");
                out.popIndent();
                out.printil("}");
                out.println();
            }

            public void visit(Node.Declaration n) throws JasperException {
                n.setBeginJavaLine(out.getJavaLine());
                out.printMultiLn(new String(n.getText()));
                out.println();
                n.setEndJavaLine(out.getJavaLine());
            }

            // Custom Tags may contain declarations from tag plugins.
            public void visit(Node.CustomTag n) throws JasperException {
                if (n.useTagPlugin()) {
                    if (n.getAtSTag() != null) {
                        n.getAtSTag().visit(this);
                    }
                    visitBody(n);
                    if (n.getAtETag() != null) {
                        n.getAtETag().visit(this);
                    }
                } else {
                    visitBody(n);
                }
            }
        }

        out.println();
        page.visit(new DeclarationVisitor());
    }

    /**
     * Compiles list of tag handler pool names.
     */
    private void compileTagHandlerPoolList(Node.Nodes page)
            throws JasperException {

        class TagHandlerPoolVisitor extends Node.Visitor {

            private Vector names;

            /*
             * Constructor
             * 
             * @param v Vector of tag handler pool names to populate
             */
            TagHandlerPoolVisitor(Vector v) {
                names = v;
            }

            /*
             * Gets the name of the tag handler pool for the given custom tag
             * and adds it to the list of tag handler pool names unless it is
             * already contained in it.
             */
            public void visit(Node.CustomTag n) throws JasperException {

                if (!n.implementsSimpleTag()) {
                    String name = createTagHandlerPoolName(n.getPrefix(), n
                            .getLocalName(), n.getAttributes(), n
                            .hasEmptyBody());
                    n.setTagHandlerPoolName(name);
                    if (!names.contains(name)) {
                        names.add(name);
                    }
                }
                visitBody(n);
            }

            /*
             * Creates the name of the tag handler pool whose tag handlers may
             * be (re)used to service this action.
             * 
             * @return The name of the tag handler pool
             */
            private String createTagHandlerPoolName(String prefix,
                    String shortName, Attributes attrs, boolean hasEmptyBody) {
                String poolName = null;

                poolName = "_jspx_tagPool_" + prefix + "_" + shortName;
                if (attrs != null) {
                    String[] attrNames = new String[attrs.getLength()];
                    for (int i = 0; i < attrNames.length; i++) {
                        attrNames[i] = attrs.getQName(i);
                    }
                    Arrays.sort(attrNames, Collections.reverseOrder());
                    for (int i = 0; i < attrNames.length; i++) {
                        poolName = poolName + "_" + attrNames[i];
                    }
                }
                if (hasEmptyBody) {
                    poolName = poolName + "_nobody";
                }
                return JspUtil.makeJavaIdentifier(poolName);
            }
        }

        page.visit(new TagHandlerPoolVisitor(tagHandlerPoolNames));
    }

    private void declareTemporaryScriptingVars(Node.Nodes page)
            throws JasperException {

        class ScriptingVarVisitor extends Node.Visitor {

            private Vector vars;

            ScriptingVarVisitor() {
                vars = new Vector();
            }

            public void visit(Node.CustomTag n) throws JasperException {

                if (n.getCustomNestingLevel() > 0) {
                    TagVariableInfo[] tagVarInfos = n.getTagVariableInfos();
                    VariableInfo[] varInfos = n.getVariableInfos();

                    if (varInfos.length > 0) {
                        for (int i = 0; i < varInfos.length; i++) {
                            String varName = varInfos[i].getVarName();
                            String tmpVarName = "_jspx_" + varName + "_"
                                    + n.getCustomNestingLevel();
                            if (!vars.contains(tmpVarName)) {
                                vars.add(tmpVarName);
                                out.printin(varInfos[i].getClassName());