ojluni/src/main/java/com/sun/tools/hat/internal/oql/OQLEngine.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 1997, 2008, 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.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * 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.
  */


 /*
  * The Original Code is HAT. The Initial Developer of the
  * Original Code is Bill Foote, with contributions from others
  * at JavaSoft/Sun.
  */

 package com.sun.tools.hat.internal.oql;

 import com.sun.tools.hat.internal.model.*;
 import java.io.*;
 import java.lang.reflect.*;
 import java.util.*;

 /**
  * This is Object Query Language Interpreter
  *
  */
 public class OQLEngine {
     static {
         try {
             // Do we have javax.script support?
             // create ScriptEngineManager
             Class<?> managerClass = Class.forName("javax.script.ScriptEngineManager");
             Object manager = managerClass.newInstance();

             // create JavaScript engine
             Method getEngineMethod = managerClass.getMethod("getEngineByName",
                                 new Class[] { String.class });
             Object jse = getEngineMethod.invoke(manager, new Object[] {"js"});
             oqlSupported = (jse != null);
         } catch (Exception exp) {
             oqlSupported = false;
         }
     }

     // check OQL is supported or not before creating OQLEngine
     public static boolean isOQLSupported() {
         return oqlSupported;
     }

     public OQLEngine(Snapshot snapshot) {
         if (!isOQLSupported()) {
             throw new UnsupportedOperationException("OQL not supported");
         }
         init(snapshot);
     }

     /**
        Query is of the form

           select &lt;java script code to select&gt;
           [ from [instanceof] &lt;class name&gt; [&lt;identifier&gt;]
             [ where &lt;java script boolean expression&gt; ]
           ]
     */
     public synchronized void executeQuery(String query, ObjectVisitor visitor)
                                           throws OQLException {
         debugPrint("query : " + query);
         StringTokenizer st = new StringTokenizer(query);
         if (st.hasMoreTokens()) {
             String first = st.nextToken();
             if (! first.equals("select") ) {
                 // Query does not start with 'select' keyword.
                 // Just treat it as plain JavaScript and eval it.
                 try {
                     Object res = evalScript(query);
                     visitor.visit(res);
                 } catch (Exception e) {
                     throw new OQLException(e);
                 }
                 return;
             }
         } else {
             throw new OQLException("query syntax error: no 'select' clause");
         }

         String selectExpr = "";
         boolean seenFrom = false;
         while (st.hasMoreTokens()) {
             String tok = st.nextToken();
             if (tok.equals("from")) {
                 seenFrom = true;
                 break;
             }
             selectExpr += " " + tok;
         }

         if (selectExpr.equals("")) {
             throw new OQLException("query syntax error: 'select' expression can not be empty");
         }

         String className = null;
         boolean isInstanceOf = false;
         String whereExpr =  null;
         String identifier = null;

         if (seenFrom) {
             if (st.hasMoreTokens()) {
                 String tmp = st.nextToken();
                 if (tmp.equals("instanceof")) {
                     isInstanceOf = true;
                     if (! st.hasMoreTokens()) {
                         throw new OQLException("no class name after 'instanceof'");
                     }
                     className = st.nextToken();
                 } else {
                     className = tmp;
                 }
             } else {
                 throw new OQLException("query syntax error: class name must follow 'from'");
             }

             if (st.hasMoreTokens()) {
                 identifier = st.nextToken();
                 if (identifier.equals("where")) {
                     throw new OQLException("query syntax error: identifier should follow class name");
                 }
                 if (st.hasMoreTokens()) {
                     String tmp = st.nextToken();
                     if (! tmp.equals("where")) {
                         throw new OQLException("query syntax error: 'where' clause expected after 'from' clause");
                     }

                     whereExpr = "";
                     while (st.hasMoreTokens()) {
                         whereExpr += " " + st.nextToken();
                     }
                     if (whereExpr.equals("")) {
                         throw new OQLException("query syntax error: 'where' clause cannot have empty expression");
                     }
                 }
             } else {
                 throw new OQLException("query syntax error: identifier should follow class name");
             }
         }

         executeQuery(new OQLQuery(selectExpr, isInstanceOf, className,
                                   identifier, whereExpr), visitor);
     }

     private void executeQuery(OQLQuery q, ObjectVisitor visitor)
                               throws OQLException {
         JavaClass clazz = null;
         if (q.className != null) {
             clazz = snapshot.findClass(q.className);
             if (clazz == null) {
                 throw new OQLException(q.className + " is not found!");
             }
         }

         StringBuffer buf = new StringBuffer();
         buf.append("function __select__(");
         if (q.identifier != null) {
             buf.append(q.identifier);
         }
         buf.append(") { return ");
         buf.append(q.selectExpr.replace('\n', ' '));
         buf.append("; }");

         String selectCode = buf.toString();
         debugPrint(selectCode);
         String whereCode = null;
         if (q.whereExpr != null) {
             buf = new StringBuffer();
             buf.append("function __where__(");
             buf.append(q.identifier);
             buf.append(") { return ");
             buf.append(q.whereExpr.replace('\n', ' '));
             buf.append("; }");
             whereCode = buf.toString();
         }
         debugPrint(whereCode);

         // compile select expression and where condition
         try {
             evalMethod.invoke(engine, new Object[] { selectCode });
             if (whereCode != null) {
                 evalMethod.invoke(engine, new Object[] { whereCode });
             }

             if (q.className != null) {
                 Enumeration objects = clazz.getInstances(q.isInstanceOf);
                 while (objects.hasMoreElements()) {
                     JavaHeapObject obj = (JavaHeapObject) objects.nextElement();
                     Object[] args = new Object[] { wrapJavaObject(obj) };
                     boolean b = (whereCode == null);
                     if (!b) {
                         Object res = call("__where__", args);
                         if (res instanceof Boolean) {
                             b = ((Boolean)res).booleanValue();
                         } else if (res instanceof Number) {
                             b = ((Number)res).intValue() != 0;
                         } else {
                             b = (res != null);
                         }
                     }

                     if (b) {
                         Object select = call("__select__", args);
                         if (visitor.visit(select)) return;
                     }
                 }
             } else {
                 // simple "select <expr>" query
                 Object select = call("__select__", new Object[] {});
                 visitor.visit(select);
             }
         } catch (Exception e) {
             throw new OQLException(e);
         }
     }

     public Object evalScript(String script) throws Exception {
         return evalMethod.invoke(engine, new Object[] { script });
     }

     public Object wrapJavaObject(JavaHeapObject obj) throws Exception {
         return call("wrapJavaObject", new Object[] { obj });
     }

     public Object toHtml(Object obj) throws Exception {
         return call("toHtml", new Object[] { obj });
     }

     public Object call(String func, Object[] args) throws Exception {
         return invokeMethod.invoke(engine, new Object[] { func, args });
     }

     private static void debugPrint(String msg) {
         if (debug) System.out.println(msg);
     }

     private void init(Snapshot snapshot) throws RuntimeException {
         this.snapshot = snapshot;
         try {
             // create ScriptEngineManager
             Class<?> managerClass = Class.forName("javax.script.ScriptEngineManager");
             Object manager = managerClass.newInstance();

             // create JavaScript engine
             Method getEngineMethod = managerClass.getMethod("getEngineByName",
                                 new Class[] { String.class });
             engine = getEngineMethod.invoke(manager, new Object[] {"js"});

             // initialize engine with init file (hat.js)
             InputStream strm = getInitStream();
             Class<?> engineClass = Class.forName("javax.script.ScriptEngine");
             evalMethod = engineClass.getMethod("eval",
                                 new Class[] { Reader.class });
             evalMethod.invoke(engine, new Object[] {new InputStreamReader(strm)});

             // initialize ScriptEngine.eval(String) and
             // Invocable.invokeFunction(String, Object[]) methods.
             Class<?> invocableClass = Class.forName("javax.script.Invocable");

             evalMethod = engineClass.getMethod("eval",
                                   new Class[] { String.class });
             invokeMethod = invocableClass.getMethod("invokeFunction",
                                   new Class[] { String.class, Object[].class });

             // initialize ScriptEngine.put(String, Object) method
             Method putMethod = engineClass.getMethod("put",
                                   new Class[] { String.class, Object.class });

             // call ScriptEngine.put to initialize built-in heap object
             putMethod.invoke(engine, new Object[] {
                         "heap", call("wrapHeapSnapshot", new Object[] { snapshot })
                     });
         } catch (Exception e) {
             if (debug) e.printStackTrace();
             throw new RuntimeException(e);
         }
     }

     private InputStream getInitStream() {
         return getClass().getResourceAsStream("/com/sun/tools/hat/resources/hat.js");
     }

     private Object engine;
     private Method evalMethod;
     private Method invokeMethod;
     private Snapshot snapshot;
     private static boolean debug = false;
     private static boolean oqlSupported;
 }
	/*
	* Copyright (c) 1997, 2008, 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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.
	*/


	/*
	* The Original Code is HAT. The Initial Developer of the
	* Original Code is Bill Foote, with contributions from others
	* at JavaSoft/Sun.
	*/

	package com.sun.tools.hat.internal.oql;

	import com.sun.tools.hat.internal.model.*;
	import java.io.*;
	import java.lang.reflect.*;
	import java.util.*;

	/**
	* This is Object Query Language Interpreter
	*
	*/
	public class OQLEngine {
	static {
	try {
	// Do we have javax.script support?
	// create ScriptEngineManager
	Class<?> managerClass = Class.forName("javax.script.ScriptEngineManager");
	Object manager = managerClass.newInstance();

	// create JavaScript engine
	Method getEngineMethod = managerClass.getMethod("getEngineByName",
	new Class[] { String.class });
	Object jse = getEngineMethod.invoke(manager, new Object[] {"js"});
	oqlSupported = (jse != null);
	} catch (Exception exp) {
	oqlSupported = false;
	}
	}

	// check OQL is supported or not before creating OQLEngine
	public static boolean isOQLSupported() {
	return oqlSupported;
	}

	public OQLEngine(Snapshot snapshot) {
	if (!isOQLSupported()) {
	throw new UnsupportedOperationException("OQL not supported");
	}
	init(snapshot);
	}

	/**
	Query is of the form

	select <java script code to select>
	[ from [instanceof] <class name> [<identifier>]
	[ where <java script boolean expression> ]
	]
	*/
	public synchronized void executeQuery(String query, ObjectVisitor visitor)
	throws OQLException {
	debugPrint("query : " + query);
	StringTokenizer st = new StringTokenizer(query);
	if (st.hasMoreTokens()) {
	String first = st.nextToken();
	if (! first.equals("select") ) {
	// Query does not start with 'select' keyword.
	// Just treat it as plain JavaScript and eval it.
	try {
	Object res = evalScript(query);
	visitor.visit(res);
	} catch (Exception e) {
	throw new OQLException(e);
	}
	return;
	}
	} else {
	throw new OQLException("query syntax error: no 'select' clause");
	}

	String selectExpr = "";
	boolean seenFrom = false;
	while (st.hasMoreTokens()) {
	String tok = st.nextToken();
	if (tok.equals("from")) {
	seenFrom = true;
	break;
	}
	selectExpr += " " + tok;
	}

	if (selectExpr.equals("")) {
	throw new OQLException("query syntax error: 'select' expression can not be empty");
	}

	String className = null;
	boolean isInstanceOf = false;
	String whereExpr = null;
	String identifier = null;

	if (seenFrom) {
	if (st.hasMoreTokens()) {
	String tmp = st.nextToken();
	if (tmp.equals("instanceof")) {
	isInstanceOf = true;
	if (! st.hasMoreTokens()) {
	throw new OQLException("no class name after 'instanceof'");
	}
	className = st.nextToken();
	} else {
	className = tmp;
	}
	} else {
	throw new OQLException("query syntax error: class name must follow 'from'");
	}

	if (st.hasMoreTokens()) {
	identifier = st.nextToken();
	if (identifier.equals("where")) {
	throw new OQLException("query syntax error: identifier should follow class name");
	}
	if (st.hasMoreTokens()) {
	String tmp = st.nextToken();
	if (! tmp.equals("where")) {
	throw new OQLException("query syntax error: 'where' clause expected after 'from' clause");
	}

	whereExpr = "";
	while (st.hasMoreTokens()) {
	whereExpr += " " + st.nextToken();
	}
	if (whereExpr.equals("")) {
	throw new OQLException("query syntax error: 'where' clause cannot have empty expression");
	}
	}
	} else {
	throw new OQLException("query syntax error: identifier should follow class name");
	}
	}

	executeQuery(new OQLQuery(selectExpr, isInstanceOf, className,
	identifier, whereExpr), visitor);
	}

	private void executeQuery(OQLQuery q, ObjectVisitor visitor)
	throws OQLException {
	JavaClass clazz = null;
	if (q.className != null) {
	clazz = snapshot.findClass(q.className);
	if (clazz == null) {
	throw new OQLException(q.className + " is not found!");
	}
	}

	StringBuffer buf = new StringBuffer();
	buf.append("function __select__(");
	if (q.identifier != null) {
	buf.append(q.identifier);
	}
	buf.append(") { return ");
	buf.append(q.selectExpr.replace('\n', ' '));
	buf.append("; }");

	String selectCode = buf.toString();
	debugPrint(selectCode);
	String whereCode = null;
	if (q.whereExpr != null) {
	buf = new StringBuffer();
	buf.append("function __where__(");
	buf.append(q.identifier);
	buf.append(") { return ");
	buf.append(q.whereExpr.replace('\n', ' '));
	buf.append("; }");
	whereCode = buf.toString();
	}
	debugPrint(whereCode);

	// compile select expression and where condition
	try {
	evalMethod.invoke(engine, new Object[] { selectCode });
	if (whereCode != null) {
	evalMethod.invoke(engine, new Object[] { whereCode });
	}

	if (q.className != null) {
	Enumeration objects = clazz.getInstances(q.isInstanceOf);
	while (objects.hasMoreElements()) {
	JavaHeapObject obj = (JavaHeapObject) objects.nextElement();
	Object[] args = new Object[] { wrapJavaObject(obj) };
	boolean b = (whereCode == null);
	if (!b) {
	Object res = call("__where__", args);
	if (res instanceof Boolean) {
	b = ((Boolean)res).booleanValue();
	} else if (res instanceof Number) {
	b = ((Number)res).intValue() != 0;
	} else {
	b = (res != null);
	}
	}

	if (b) {
	Object select = call("__select__", args);
	if (visitor.visit(select)) return;
	}
	}
	} else {
	// simple "select <expr>" query
	Object select = call("__select__", new Object[] {});
	visitor.visit(select);
	}
	} catch (Exception e) {
	throw new OQLException(e);
	}
	}

	public Object evalScript(String script) throws Exception {
	return evalMethod.invoke(engine, new Object[] { script });
	}

	public Object wrapJavaObject(JavaHeapObject obj) throws Exception {
	return call("wrapJavaObject", new Object[] { obj });
	}

	public Object toHtml(Object obj) throws Exception {
	return call("toHtml", new Object[] { obj });
	}

	public Object call(String func, Object[] args) throws Exception {
	return invokeMethod.invoke(engine, new Object[] { func, args });
	}

	private static void debugPrint(String msg) {
	if (debug) System.out.println(msg);
	}

	private void init(Snapshot snapshot) throws RuntimeException {
	this.snapshot = snapshot;
	try {
	// create ScriptEngineManager
	Class<?> managerClass = Class.forName("javax.script.ScriptEngineManager");
	Object manager = managerClass.newInstance();

	// create JavaScript engine
	Method getEngineMethod = managerClass.getMethod("getEngineByName",
	new Class[] { String.class });
	engine = getEngineMethod.invoke(manager, new Object[] {"js"});

	// initialize engine with init file (hat.js)
	InputStream strm = getInitStream();
	Class<?> engineClass = Class.forName("javax.script.ScriptEngine");
	evalMethod = engineClass.getMethod("eval",
	new Class[] { Reader.class });
	evalMethod.invoke(engine, new Object[] {new InputStreamReader(strm)});

	// initialize ScriptEngine.eval(String) and
	// Invocable.invokeFunction(String, Object[]) methods.
	Class<?> invocableClass = Class.forName("javax.script.Invocable");

	evalMethod = engineClass.getMethod("eval",
	new Class[] { String.class });
	invokeMethod = invocableClass.getMethod("invokeFunction",
	new Class[] { String.class, Object[].class });

	// initialize ScriptEngine.put(String, Object) method
	Method putMethod = engineClass.getMethod("put",
	new Class[] { String.class, Object.class });

	// call ScriptEngine.put to initialize built-in heap object
	putMethod.invoke(engine, new Object[] {
	"heap", call("wrapHeapSnapshot", new Object[] { snapshot })
	});
	} catch (Exception e) {
	if (debug) e.printStackTrace();
	throw new RuntimeException(e);
	}
	}

	private InputStream getInitStream() {
	return getClass().getResourceAsStream("/com/sun/tools/hat/resources/hat.js");
	}

	private Object engine;
	private Method evalMethod;
	private Method invokeMethod;
	private Snapshot snapshot;
	private static boolean debug = false;
	private static boolean oqlSupported;
	}