public class ExpressionEvaluator extends ScriptEvaluator implements IExpressionEvaluator
IExpressionEvaluator is implemented by creating and compiling a temporary
compilation unit defining one class with one static method with one RETURN statement.
A number of "convenience constructors" exist that execute the set-up steps described for IExpressionEvaluator instantly.
If the parameter and return types of the expression are known at compile time, then a "fast"
expression evaluator can be instantiated through
createFastExpressionEvaluator(String, Class, String[], ClassLoader). Expression
evaluation is faster than through ScriptEvaluator.evaluate(Object[]), because it is not done through
reflection but through direct method invocation.
Example:
public interface Foo {
int bar(int a, int b);
}
...
Foo f = (Foo) ExpressionEvaluator.createFastExpressionEvaluator(
"a + b", // expression to evaluate
Foo.class, // interface that describes the expression's signature
new String[] { "a", "b" }, // the parameters' names
(ClassLoader) null // Use current thread's context class loader
);
System.out.println("1 + 2 = " + f.bar(1, 2)); // Evaluate the expression
Notice: The interfaceToImplement must either be declared public,
or with package scope in the root package (i.e. "no" package).
On my system (Intel P4, 2 GHz, MS Windows XP, JDK 1.4.1), expression "x + 1" evaluates as follows:
| Server JVM | Client JVM | |
|---|---|---|
| Normal EE | 23.7 ns | 64.0 ns |
| Fast EE | 31.2 ns | 42.2 ns |
optionalMethodNames, optionalOverrideMethod, optionalParameterNames, optionalParameterTypes, optionalReturnTypes, optionalStaticMethod, optionalThrownExceptionsclassName, ZERO_CLASSESdebugLines, debugSource, debugVarsANY_TYPEDEFAULT_CLASS_NAMEBOOT_CLASS_LOADER, SYSTEM_PROPERTY_SOURCE_DEBUGGING_DIR, SYSTEM_PROPERTY_SOURCE_DEBUGGING_ENABLE| Constructor and Description |
|---|
ExpressionEvaluator() |
ExpressionEvaluator(Scanner scanner,
java.lang.String className,
java.lang.Class optionalExtendedType,
java.lang.Class[] implementedTypes,
boolean staticMethod,
java.lang.Class expressionType,
java.lang.String methodName,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes,
java.lang.Class[] thrownExceptions,
java.lang.ClassLoader optionalParentClassLoader)
Equivalent to
|
ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes)
Equivalent to
|
ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes,
java.lang.Class[] thrownExceptions,
java.lang.Class optionalExtendedType,
java.lang.Class[] implementedTypes,
java.lang.ClassLoader optionalParentClassLoader)
Equivalent to
|
ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes,
java.lang.Class[] thrownExceptions,
java.lang.ClassLoader optionalParentClassLoader)
Equivalent to
|
| Modifier and Type | Method and Description |
|---|---|
static java.lang.Object |
createFastExpressionEvaluator(Scanner scanner,
java.lang.String[] optionalDefaultImports,
java.lang.String className,
java.lang.Class optionalExtendedType,
java.lang.Class interfaceToImplement,
java.lang.String[] parameterNames,
java.lang.ClassLoader optionalParentClassLoader)
Deprecated.
|
static java.lang.Object |
createFastExpressionEvaluator(Scanner scanner,
java.lang.String className,
java.lang.Class optionalExtendedType,
java.lang.Class interfaceToImplement,
java.lang.String[] parameterNames,
java.lang.ClassLoader optionalParentClassLoader)
Deprecated.
|
static java.lang.Object |
createFastExpressionEvaluator(java.lang.String expression,
java.lang.Class interfaceToImplement,
java.lang.String[] parameterNames,
java.lang.ClassLoader optionalParentClassLoader)
Deprecated.
|
protected java.lang.Class |
getDefaultReturnType() |
static java.lang.String[] |
guessParameterNames(Scanner scanner)
Guess the names of the parameters used in the given expression.
|
protected java.util.List |
makeStatements(int idx,
Parser parser)
Fill the given
block by parsing statements until EOF and adding
them to the block. |
void |
setExpressionType(java.lang.Class expressionType)
Define the type of the expression.
|
void |
setExpressionTypes(java.lang.Class[] expressionTypes)
Same as
IExpressionEvaluator.setExpressionType(Class), but for multiple expressions. |
void |
setReturnType(java.lang.Class returnType)
Deprecated.
|
void |
setReturnTypes(java.lang.Class[] returnTypes)
Deprecated.
|
compileToMethods, cook, cook, cook, cook, cook, cook, cook, createFastEvaluator, createFastEvaluator, createFastEvaluator, createFastScriptEvaluator, createFastScriptEvaluator, createFastScriptEvaluator, createFastScriptEvaluator, createInstance, evaluate, evaluate, getMethod, getMethod, makeMethodDeclaration, setMethodName, setMethodNames, setOverrideMethod, setOverrideMethod, setParameters, setParameters, setStaticMethod, setStaticMethod, setThrownExceptions, setThrownExceptionsaddPackageMemberClassDeclaration, compileToClass, createFastClassBodyEvaluator, createFastClassBodyEvaluator, getClazz, makeCompilationUnit, setClassName, setDefaultImports, setExtendedClass, setExtendedType, setImplementedInterfaces, setImplementedTypesassertNotCooked, classesToTypes, classToType, compileToClassLoader, cook, cook, equals, getClassLoader, hashCode, main, setDebuggingInformation, setParentClassLoadercook, cook, cook, cook, cook, cook, cook, cookFile, cookFile, cookFile, cookFile, readStringclone, finalize, getClass, notify, notifyAll, toString, wait, wait, waitcreateFastEvaluator, createFastEvaluator, evaluatecook, cook, cook, cook, evaluate, getMethod, getMethod, setMethodName, setMethodNames, setOverrideMethod, setOverrideMethod, setParameters, setParameters, setStaticMethod, setStaticMethod, setThrownExceptions, setThrownExceptionscreateInstance, getClazz, setClassName, setDefaultImports, setExtendedClass, setExtendedType, setImplementedInterfaces, setImplementedTypespublic ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes)
throws CompileException
ExpressionEvaluator ee = new ExpressionEvaluator(); ee.setExpressionType(expressionType); ee.setParameters(parameterNames, parameterTypes); ee.cook(expression);
public ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes,
java.lang.Class[] thrownExceptions,
java.lang.ClassLoader optionalParentClassLoader)
throws CompileException
ExpressionEvaluator ee = new ExpressionEvaluator(); ee.setExpressionType(expressionType); ee.setParameters(parameterNames, parameterTypes); ee.setThrownExceptions(thrownExceptions); ee.setParentClassLoader(optionalParentClassLoader); ee.cook(expression);
public ExpressionEvaluator(java.lang.String expression,
java.lang.Class expressionType,
java.lang.String[] parameterNames,
java.lang.Class[] parameterTypes,
java.lang.Class[] thrownExceptions,
java.lang.Class optionalExtendedType,
java.lang.Class[] implementedTypes,
java.lang.ClassLoader optionalParentClassLoader)
throws CompileException
ExpressionEvaluator ee = new ExpressionEvaluator(); ee.setExpressionType(expressionType); ee.setParameters(parameterNames, parameterTypes); ee.setThrownExceptions(thrownExceptions); ee.setExtendedType(optionalExtendedType); ee.setImplementedTypes(implementedTypes); ee.setParentClassLoader(optionalParentClassLoader); ee.cook(expression);
CompileExceptionExpressionEvaluator(),
setExpressionType(Class),
ScriptEvaluator.setParameters(String[], Class[]),
ScriptEvaluator.setThrownExceptions(Class[]),
ClassBodyEvaluator.setExtendedClass(Class),
ClassBodyEvaluator.setImplementedInterfaces(Class[]),
SimpleCompiler.setParentClassLoader(ClassLoader),
Cookable.cook(String)public ExpressionEvaluator(Scanner scanner, java.lang.String className, java.lang.Class optionalExtendedType, java.lang.Class[] implementedTypes, boolean staticMethod, java.lang.Class expressionType, java.lang.String methodName, java.lang.String[] parameterNames, java.lang.Class[] parameterTypes, java.lang.Class[] thrownExceptions, java.lang.ClassLoader optionalParentClassLoader) throws CompileException, java.io.IOException
ExpressionEvaluator ee = new ExpressionEvaluator(); ee.setClassName(className); ee.setExtendedType(optionalExtendedType); ee.setImplementedTypes(implementedTypes); ee.setStaticMethod(staticMethod); ee.setExpressionType(expressionType); ee.setMethodName(methodName); ee.setParameters(parameterNames, parameterTypes); ee.setThrownExceptions(thrownExceptions); ee.setParentClassLoader(optionalParentClassLoader); ee.cook(scanner);
CompileExceptionjava.io.IOExceptionIExpressionEvaluator,
IClassBodyEvaluator.setClassName(String),
IClassBodyEvaluator.setExtendedClass(Class),
IClassBodyEvaluator.setImplementedInterfaces(Class[]),
IScriptEvaluator.setStaticMethod(boolean),
IExpressionEvaluator.setExpressionType(Class),
IScriptEvaluator.setMethodName(String),
IScriptEvaluator.setParameters(String[], Class[]),
IScriptEvaluator.setThrownExceptions(Class[]),
ICookable.setParentClassLoader(ClassLoader),
ICookable.cook(Reader)public ExpressionEvaluator()
public void setExpressionType(java.lang.Class expressionType)
IExpressionEvaluatorIExpressionEvaluator.ANY_TYPE allows the expression
to return any type (primitive or reference).
If expressionType is Void.TYPE, then the expression must be an
invocation of a void method.
Defaults to IExpressionEvaluator.ANY_TYPE.
setExpressionType in interface IExpressionEvaluatorpublic void setExpressionTypes(java.lang.Class[] expressionTypes)
IExpressionEvaluatorIExpressionEvaluator.setExpressionType(Class), but for multiple expressions.setExpressionTypes in interface IExpressionEvaluator@Deprecated public final void setReturnType(java.lang.Class returnType)
IScriptEvaluatornull value is implementation-dependent.setReturnType in interface IExpressionEvaluatorsetReturnType in interface IScriptEvaluatorsetReturnType in class ScriptEvaluator@Deprecated public final void setReturnTypes(java.lang.Class[] returnTypes)
ScriptEvaluatorsetReturnTypes in interface IExpressionEvaluatorsetReturnTypes in interface IScriptEvaluatorsetReturnTypes in class ScriptEvaluatorreturnTypes - The methods' return types; null values mean the "default return type", which is the
type returned by ScriptEvaluator.getDefaultReturnType() (void.class for ScriptEvaluator and Object.class for ExpressionEvaluator)ScriptEvaluator.getDefaultReturnType(),
getDefaultReturnType()protected java.lang.Class getDefaultReturnType()
getDefaultReturnType in class ScriptEvaluatorvoid.classScriptEvaluator.setReturnTypes(Class[])protected java.util.List makeStatements(int idx,
Parser parser)
throws CompileException,
java.io.IOException
ScriptEvaluatorblock by parsing statements until EOF and adding
them to the block.makeStatements in class ScriptEvaluatorCompileExceptionjava.io.IOException@Deprecated
public static java.lang.Object createFastExpressionEvaluator(java.lang.String expression,
java.lang.Class interfaceToImplement,
java.lang.String[] parameterNames,
java.lang.ClassLoader optionalParentClassLoader)
throws CompileException
ScriptEvaluator.createFastEvaluator(String, Class, String[]) instead:IExpressionEvaluatoree =CompilerFactoryFactory.getDefaultCompilerFactory().newExpressionEvaluator(); ee.setParentClassLoader(optionalParentClassLoader); return ee.createFastEvaluator(expression, interfaceToImplement, parameterNames);
CompileException@Deprecated public static java.lang.Object createFastExpressionEvaluator(Scanner scanner, java.lang.String className, java.lang.Class optionalExtendedType, java.lang.Class interfaceToImplement, java.lang.String[] parameterNames, java.lang.ClassLoader optionalParentClassLoader) throws CompileException, java.io.IOException
ScriptEvaluator.createFastEvaluator(Reader, Class, String[]) insteadIExpressionEvaluator, and is hence only available in this
implementation of org.codehaus.commons.compiler. To be independent from this particular
implementation, try to switch to ScriptEvaluator.createFastEvaluator(Reader, Class, String[]).CompileExceptionjava.io.IOException@Deprecated public static java.lang.Object createFastExpressionEvaluator(Scanner scanner, java.lang.String[] optionalDefaultImports, java.lang.String className, java.lang.Class optionalExtendedType, java.lang.Class interfaceToImplement, java.lang.String[] parameterNames, java.lang.ClassLoader optionalParentClassLoader) throws CompileException, java.io.IOException
ScriptEvaluator.createFastEvaluator(Reader, Class, String[]) insteadIExpressionEvaluator, and is hence only available in this
implementation of org.codehaus.commons.compiler. To be independent from this particular
implementation, try to switch to ScriptEvaluator.createFastEvaluator(Reader, Class, String[]).CompileExceptionjava.io.IOExceptionpublic static java.lang.String[] guessParameterNames(Scanner scanner) throws CompileException, java.io.IOException
CompileExceptionjava.io.IOExceptionScanner.Scanner(String, Reader)