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Java example source code file (SOQL.java)

This example Java source code file (SOQL.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

address, bufferedreader, exception, instanceklass, ioexception, jsjavaobject, oop, soql, string, stringbuffer, stringtokenizer, symbol, u2array, unknown, util

The SOQL.java Java example source code

/*
 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

package sun.jvm.hotspot.tools.soql;

import java.io.*;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.tools.*;
import sun.jvm.hotspot.utilities.*;
import sun.jvm.hotspot.utilities.soql.*;

/**
  This is command line SOQL (Simple Object Query Language) interpreter.
*/

public class SOQL extends Tool {
   public static void main(String[] args) {
      SOQL soql = new SOQL();
      soql.execute(args);
   }

   public SOQL() {
      super();
   }

   public SOQL(JVMDebugger d) {
      super(d);
   }

   protected SOQLEngine soqlEngine;
   protected BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   protected PrintStream out       = System.out;
   static protected String prompt       = "soql> ";
   static protected String secondPrompt = "> ";

   public void run() {
      soqlEngine = SOQLEngine.getEngine();
      while (true) {
         try {
            out.print(prompt);
            String line = in.readLine();
            if (line == null) {
               return;
            }
            StringTokenizer st = new StringTokenizer(line);
            if (st.hasMoreTokens()) {
               String cmd = st.nextToken();
               if (cmd.equals("select")) {
                  handleSelect(line);
               } else if (cmd.equals("classes")) {
                  handleClasses(line);
               } else if (cmd.equals("class")) {
                  handleClass(line);
               } else if (cmd.equals("object")) {
                  handleObject(line);
               } else if (cmd.equals("quit")) {
                  out.println("Bye!");
                  return;
               } else if (cmd.equals("")) {
                  // do nothing ...
               } else {
                  handleUnknown(line);
               }
            }
         } catch (IOException e) {
            e.printStackTrace();
            return;
         }
      }
   }

   protected void handleSelect(String query) {
      StringBuffer buf = new StringBuffer(query);
      String tmp = null;
      while (true) {
         out.print(secondPrompt);
         try {
            tmp = in.readLine();
         } catch (IOException ioe) {
            break;
         }
         if (tmp.equals("") || tmp.equals("go"))
            break;
         buf.append('\n');
         buf.append(tmp);
      }
      query = buf.toString();

      try {
         soqlEngine.executeQuery(query,
                           new ObjectVisitor() {
                              public void visit(Object o) {
                                 if (o != null && o instanceof JSJavaObject) {
                                     String oopAddr = ((JSJavaObject)o).getOop().getHandle().toString();
                                     out.println(oopAddr);
                                 } else {
                                     out.println((o == null)? "null" : o.toString());
                                 }
                              }
                           });
      } catch (SOQLException se) {
         se.printStackTrace();
      }
   }

   protected void handleClasses(String line) {
      // just list all InstanceKlasses
      InstanceKlass[] klasses = SystemDictionaryHelper.getAllInstanceKlasses();
      for (int i = 0; i < klasses.length; i++) {
         out.print(klasses[i].getName().asString().replace('/', '.'));
         out.print(" @");
         out.println(klasses[i].getAddress());
      }
   }

   protected void handleClass(String line) {
      StringTokenizer st = new StringTokenizer(line);
      st.nextToken(); // ignore "class"
      if (st.hasMoreTokens()) {
         String className = st.nextToken();
         InstanceKlass klass = SystemDictionaryHelper.findInstanceKlass(className);
         if (klass == null) {
            out.println("class " + className + " not found");
         } else {
            // klass.iterate(new OopPrinter(out), true);

            // base class
            InstanceKlass base = (InstanceKlass) klass.getSuper();
            if (base != null) {
               out.println("super");
               out.print("\t");
               out.println(base.getName().asString().replace('/', '.'));
            }

            // list immediate fields only
            U2Array fields = klass.getFields();
            int numFields = (int) fields.length();
            ConstantPool cp = klass.getConstants();
            out.println("fields");
            if (numFields != 0) {
              for (int f = 0; f < numFields; f++){
                 Symbol f_name = klass.getFieldName(f);
                 Symbol f_sig  = klass.getFieldSignature(f);
                 StringBuffer sigBuf = new StringBuffer();
                 new SignatureConverter(f_sig, sigBuf).dispatchField();
                 out.print('\t');
                 out.print(sigBuf.toString().replace('/', '.'));
                 out.print(' ');
                 out.println(f_name.asString());
               }
            } else {
               out.println("\tno fields in this class");
            }
         }
      } else {
         out.println("usage: class <name of the class>");
      }
   }

   protected Oop getOopAtAddress(Address addr) {
      OopHandle oopHandle = addr.addOffsetToAsOopHandle(0);
      return VM.getVM().getObjectHeap().newOop(oopHandle);
   }

   protected void handleObject(String line) {
      StringTokenizer st = new StringTokenizer(line);
      st.nextToken(); // ignore "object"
      if (st.hasMoreTokens()) {
         String addrStr = st.nextToken();
         Address addr = null;
         Debugger dbg = VM.getVM().getDebugger();
         try {
            addr = dbg.parseAddress(addrStr);
         } catch (Exception e) {
            out.println("invalid address : " + e.getMessage());
            return;
         }

         Oop oop = null;
         try {
            oop = getOopAtAddress(addr);
         } catch (Exception e) {
            out.println("invalid object : " + e.getMessage());
         }

         if (oop != null) {
            oop.iterate(new OopPrinter(out), true);
         } else {
            out.println("null object!");
         }
      } else {
         out.println("usage: object <address>");
      }
   }

   protected void handleUnknown(String line) {
      out.println("Unknown command!");
   }
}

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