org.eclipse.birt.core.script
Class JavascriptEvalUtil

java.lang.Object
  extended by org.eclipse.birt.core.script.JavascriptEvalUtil

public class JavascriptEvalUtil
extends java.lang.Object

Utilities to faciliate the evaluation of Javascript expressions. Handles common evaluation tasks like exception handling, data type conversion and script caching


Field Summary
protected static java.util.Map compiledScriptCache
           
protected static int SCRIPT_CACHE_SIZE
           
 
Constructor Summary
JavascriptEvalUtil()
           
 
Method Summary
static java.lang.Object convertJavascriptValue(java.lang.Object inputObj)
          Handles a Rhino script evaluation result, converting Javascript object into equivalent Java objects if necessary.
static java.lang.Object[] convertToJavaObjects(java.lang.Object[] args)
           
static java.lang.Object convertToJavascriptValue(java.lang.Object value)
          If caller does not have a scope for evaluation, the caller can use this method to evaluate expression.
static java.lang.Object convertToJavascriptValue(java.lang.Object value, org.mozilla.javascript.Scriptable scope)
          Creates Javascript native wrapper for Java objects, if necessary.
static java.lang.Object evaluateRawScript(org.mozilla.javascript.Context cx, org.mozilla.javascript.Scriptable scope, java.lang.String scriptText, java.lang.String source, int lineNo)
          This method will not convert the data of return value, so it might the Java data type or that of Java Script.
static java.lang.Object evaluateScript(org.mozilla.javascript.Context cx, org.mozilla.javascript.Scriptable scope, java.lang.String scriptText, java.lang.String source, int lineNo)
          Evaluates Javascript expression and return its result, doing the necessary Javascript -> Java data type conversion if necessary
protected static org.mozilla.javascript.Script getCompiledScript(org.mozilla.javascript.Context cx, org.mozilla.javascript.Scriptable scope, java.lang.String scriptText, java.lang.String source, int lineNo)
          Gets a compiled script, using and updating the script cache if necessary
static java.lang.String transformToJsConstants(java.lang.String s)
          This method transforms a string to JS string constants.
static BirtException wrapRhinoException(org.mozilla.javascript.RhinoException e, java.lang.String scriptText, java.lang.String source, int lineNo)
          Converts Rhino exception (a runtime exception) to BirtException
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SCRIPT_CACHE_SIZE

protected static final int SCRIPT_CACHE_SIZE
See Also:
Constant Field Values

compiledScriptCache

protected static java.util.Map compiledScriptCache
Constructor Detail

JavascriptEvalUtil

public JavascriptEvalUtil()
Method Detail

evaluateRawScript

public static java.lang.Object evaluateRawScript(org.mozilla.javascript.Context cx,
                                                 org.mozilla.javascript.Scriptable scope,
                                                 java.lang.String scriptText,
                                                 java.lang.String source,
                                                 int lineNo)
                                          throws BirtException
This method will not convert the data of return value, so it might the Java data type or that of Java Script.

Parameters:
cx -
scope -
scriptText -
source -
lineNo -
Returns:
the evaluated value
Throws:
BirtException

evaluateScript

public static java.lang.Object evaluateScript(org.mozilla.javascript.Context cx,
                                              org.mozilla.javascript.Scriptable scope,
                                              java.lang.String scriptText,
                                              java.lang.String source,
                                              int lineNo)
                                       throws BirtException
Evaluates Javascript expression and return its result, doing the necessary Javascript -> Java data type conversion if necessary

Parameters:
cx - Javascript context. If null, current thread's context is used
scope - Javascript scope to evaluate script in
scriptText - text of Javascript expression
source - descriptive text of script source (for error reporting)
lineNo - line number of script in it source
Returns:
Evaluation result.
Throws:
BirtException - If evaluation failed

getCompiledScript

protected static org.mozilla.javascript.Script getCompiledScript(org.mozilla.javascript.Context cx,
                                                                 org.mozilla.javascript.Scriptable scope,
                                                                 java.lang.String scriptText,
                                                                 java.lang.String source,
                                                                 int lineNo)
Gets a compiled script, using and updating the script cache if necessary


convertToJavascriptValue

public static java.lang.Object convertToJavascriptValue(java.lang.Object value,
                                                        org.mozilla.javascript.Scriptable scope)
Creates Javascript native wrapper for Java objects, if necessary. This method currently only wraps Date/time objects. Rhino engine natively handles wrapping String, Number and Boolean objects.

Parameters:
value - Java object to convert from

convertToJavascriptValue

public static java.lang.Object convertToJavascriptValue(java.lang.Object value)
If caller does not have a scope for evaluation, the caller can use this method to evaluate expression. But if caller has its own scope which can be used, the better way is call the method of convertToJavascriptValue( Object value, Scriptable scope ).

Parameters:
value -
Returns:

convertJavascriptValue

public static java.lang.Object convertJavascriptValue(java.lang.Object inputObj)
Handles a Rhino script evaluation result, converting Javascript object into equivalent Java objects if necessary.

Parameters:
inputObj - Object returned by rhino engine.
Returns:
If inputObj is a native Javascript object, its equivalent Java object is returned; otherwise inputObj is returned

wrapRhinoException

public static BirtException wrapRhinoException(org.mozilla.javascript.RhinoException e,
                                               java.lang.String scriptText,
                                               java.lang.String source,
                                               int lineNo)
Converts Rhino exception (a runtime exception) to BirtException

Parameters:
e - Rhino exception
scriptText - Javascript code which resulted in the exception (for error reporting purpose)
source - description of the source script. If null, get this info from Rhino exception
lineNo - lineNo of error location
Throws:

convertToJavaObjects

public static java.lang.Object[] convertToJavaObjects(java.lang.Object[] args)
Parameters:
args -
Returns:

transformToJsConstants

public static java.lang.String transformToJsConstants(java.lang.String s)
This method transforms a string to JS string constants.

Parameters:
s -
Returns:


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