Class ExpressionEvaluator
- java.lang.Object
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- org.codehaus.commons.compiler.Cookable
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- org.codehaus.commons.compiler.jdk.SimpleCompiler
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- org.codehaus.commons.compiler.jdk.ClassBodyEvaluator
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- org.codehaus.commons.compiler.jdk.ScriptEvaluator
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- org.codehaus.commons.compiler.jdk.ExpressionEvaluator
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- All Implemented Interfaces:
IClassBodyEvaluator
,ICookable
,IExpressionEvaluator
,IScriptEvaluator
,ISimpleCompiler
public class ExpressionEvaluator extends ScriptEvaluator implements IExpressionEvaluator
ThisIExpressionEvaluator
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
ScriptEvaluator.createFastEvaluator(String, Class, String[])
. Expression evaluation is faster than throughScriptEvaluator.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: TheinterfaceToImplement
must either be declaredpublic
, 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
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Field Summary
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Fields inherited from class org.codehaus.commons.compiler.jdk.ScriptEvaluator
optionalMethodNames, optionalOverrideMethod, optionalParameterNames, optionalParameterTypes, optionalReturnTypes, optionalStaticMethod, optionalThrownExceptions
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Fields inherited from interface org.codehaus.commons.compiler.IClassBodyEvaluator
DEFAULT_CLASS_NAME
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Fields inherited from interface org.codehaus.commons.compiler.ICookable
BOOT_CLASS_LOADER, SYSTEM_PROPERTY_SOURCE_DEBUGGING_DIR, SYSTEM_PROPERTY_SOURCE_DEBUGGING_ENABLE
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Fields inherited from interface org.codehaus.commons.compiler.IExpressionEvaluator
ANY_TYPE
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Constructor Summary
Constructors Constructor Description ExpressionEvaluator()
ExpressionEvaluator(java.lang.String expression, java.lang.Class<?> expressionType, java.lang.String[] parameterNames, java.lang.Class<?>[] parameterTypes)
Equivalent toExpressionEvaluator(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 toExpressionEvaluator(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
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
cook(java.lang.String[] optionalFileNames, java.io.Reader[] readers)
Same asICookable.cook(String, Reader)
, but cooks a set of scripts into one class.protected java.lang.Class<?>
getDefaultReturnType()
void
setExpressionType(java.lang.Class expressionType)
Define the type of the expression.void
setExpressionTypes(java.lang.Class[] expressionTypes)
Same asIExpressionEvaluator.setExpressionType(Class)
, but for multiple expressions.void
setReturnType(java.lang.Class returnType)
Deprecated.void
setReturnTypes(java.lang.Class[] returnTypes)
Deprecated.-
Methods inherited from class org.codehaus.commons.compiler.jdk.ScriptEvaluator
cook, cook, cook, cook, cook, createFastEvaluator, createFastEvaluator, createInstance, evaluate, evaluate, getMethod, getMethod, setMethodName, setMethodNames, setOverrideMethod, setOverrideMethod, setParameters, setParameters, setStaticMethod, setStaticMethod, setThrownExceptions, setThrownExceptions
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Methods inherited from class org.codehaus.commons.compiler.jdk.ClassBodyEvaluator
cook, getClazz, parseImportDeclarations, setClassName, setDefaultImports, setExtendedClass, setExtendedType, setImplementedInterfaces, setImplementedTypes
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Methods inherited from class org.codehaus.commons.compiler.jdk.SimpleCompiler
assertCooked, assertNotCooked, cook, getClassLoader, setDebuggingInformation, setParentClassLoader, setParentClassLoader
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Methods inherited from class org.codehaus.commons.compiler.Cookable
cook, cook, cook, cook, cook, cook, cook, cookFile, cookFile, cookFile, cookFile, readString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.codehaus.commons.compiler.IClassBodyEvaluator
createInstance, getClazz, setClassName, setDefaultImports, setExtendedClass, setExtendedType, setImplementedInterfaces, setImplementedTypes
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Methods inherited from interface org.codehaus.commons.compiler.ICookable
cook, cook, cook, cook, cook, cook, cook, cook, cookFile, cookFile, cookFile, cookFile, setDebuggingInformation, setParentClassLoader
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Methods inherited from interface org.codehaus.commons.compiler.IExpressionEvaluator
createFastEvaluator, createFastEvaluator, evaluate
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Methods inherited from interface org.codehaus.commons.compiler.IScriptEvaluator
cook, cook, cook, evaluate, getMethod, getMethod, setMethodName, setMethodNames, setOverrideMethod, setOverrideMethod, setParameters, setParameters, setStaticMethod, setStaticMethod, setThrownExceptions, setThrownExceptions
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Constructor Detail
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ExpressionEvaluator
public ExpressionEvaluator(java.lang.String expression, java.lang.Class<?> expressionType, java.lang.String[] parameterNames, java.lang.Class<?>[] parameterTypes) throws CompileException
Equivalent toExpressionEvaluator ee = new ExpressionEvaluator(); ee.setExpressionType(expressionType); ee.setParameters(parameterNames, parameterTypes); ee.cook(expression);
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ExpressionEvaluator
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
Equivalent toExpressionEvaluator ee = new ExpressionEvaluator(); ee.setExpressionType(expressionType); ee.setParameters(parameterNames, parameterTypes); ee.setThrownExceptions(thrownExceptions); ee.setParentClassLoader(optionalParentClassLoader); ee.cook(expression);
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ExpressionEvaluator
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
Equivalent toExpressionEvaluator 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);
- Throws:
CompileException
- See Also:
ExpressionEvaluator()
,setExpressionType(Class)
,ScriptEvaluator.setParameters(String[], Class[])
,ScriptEvaluator.setThrownExceptions(Class[])
,ClassBodyEvaluator.setExtendedClass(Class)
,ClassBodyEvaluator.setImplementedInterfaces(Class[])
,SimpleCompiler.setParentClassLoader(ClassLoader)
,Cookable.cook(String)
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ExpressionEvaluator
public ExpressionEvaluator()
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Method Detail
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setExpressionType
public void setExpressionType(java.lang.Class expressionType)
Description copied from interface:IExpressionEvaluator
Define the type of the expression. The special typeIExpressionEvaluator.ANY_TYPE
allows the expression to return any type (primitive or reference).If
expressionType
isVoid.TYPE
, then the expression must be an invocation of avoid
method.Defaults to
IExpressionEvaluator.ANY_TYPE
.- Specified by:
setExpressionType
in interfaceIExpressionEvaluator
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setExpressionTypes
public void setExpressionTypes(java.lang.Class[] expressionTypes)
Description copied from interface:IExpressionEvaluator
Same asIExpressionEvaluator.setExpressionType(Class)
, but for multiple expressions.- Specified by:
setExpressionTypes
in interfaceIExpressionEvaluator
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setReturnType
@Deprecated public final void setReturnType(java.lang.Class returnType)
Deprecated.Description copied from interface:IScriptEvaluator
Defines the return type of the generated method. The meaning of anull
value is implementation-dependent.- Specified by:
setReturnType
in interfaceIExpressionEvaluator
- Specified by:
setReturnType
in interfaceIScriptEvaluator
- Overrides:
setReturnType
in classScriptEvaluator
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setReturnTypes
@Deprecated public final void setReturnTypes(java.lang.Class[] returnTypes)
Deprecated.Description copied from interface:IScriptEvaluator
Defines the return types of the generated methods. The meaning ofnull
values is implementation-dependent.- Specified by:
setReturnTypes
in interfaceIExpressionEvaluator
- Specified by:
setReturnTypes
in interfaceIScriptEvaluator
- Overrides:
setReturnTypes
in classScriptEvaluator
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getDefaultReturnType
protected java.lang.Class<?> getDefaultReturnType()
- Overrides:
getDefaultReturnType
in classScriptEvaluator
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cook
public void cook(java.lang.String[] optionalFileNames, java.io.Reader[] readers) throws CompileException, java.io.IOException
Description copied from interface:IScriptEvaluator
Same asICookable.cook(String, Reader)
, but cooks a set of scripts into one class. Notice that if any of the scripts causes trouble, the entire compilation will fail. If you need to report which of the scripts causes the exception, you may want to use theoptionalFileNames
parameter to distinguish between the individual token sources.If and only if the number of scanners is one, then that single script may contain leading IMPORT directives.
- Specified by:
cook
in interfaceIScriptEvaluator
- Overrides:
cook
in classScriptEvaluator
- Throws:
CompileException
java.io.IOException
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