Package ognl.enhance
Class ExpressionCompiler
- java.lang.Object
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- ognl.enhance.ExpressionCompiler
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- All Implemented Interfaces:
OgnlExpressionCompiler
public class ExpressionCompiler extends java.lang.Object implements OgnlExpressionCompiler
Responsible for managing/providing functionality related to compiling generated java source expressions via bytecode enhancements for a given ognl expression.
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Field Summary
Fields Modifier and Type Field Description protected int
_classCounter
protected java.util.Map
_loaders
ClassLoader
instances.protected javassist.ClassPool
_pool
Javassist class definition poool.static java.lang.String
PRE_CAST
Key used to store any java source string casting statements in theOgnlContext
during class compilation.-
Fields inherited from interface ognl.enhance.OgnlExpressionCompiler
ROOT_TYPE
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Constructor Summary
Constructors Constructor Description ExpressionCompiler()
Default constructor, does nothing.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static void
addCastString(OgnlContext context, java.lang.String cast)
Used bycastExpression(ognl.OgnlContext, ognl.Node, String)
to store the cast java source string in to the currentOgnlContext
.java.lang.String
castExpression(OgnlContext context, Node expression, java.lang.String body)
Used primarily by AST types likeASTChain
wherefoo.bar.id
type references may need to be cast multiple times in order to properly resolve the members in a compiled statement.void
compileExpression(OgnlContext context, Node expression, java.lang.Object root)
The core method executed to compile a specific expression.boolean
containsMethod(java.lang.reflect.Method m, java.lang.Class clazz)
Helper utility method used by compiler to help resolve class->method mappings during method calls toOgnlExpressionCompiler.getSuperOrInterfaceClass(java.lang.reflect.Method, Class)
.java.lang.String
createLocalReference(OgnlContext context, java.lang.String expression, java.lang.Class type)
Method is used for expressions where multiple inner parameter method calls in generated java source strings cause javassit failures.protected java.lang.String
generateGetter(OgnlContext context, javassist.CtClass newClass, javassist.CtClass objClass, javassist.ClassPool pool, javassist.CtMethod valueGetter, Node expression, java.lang.Object root)
protected java.lang.String
generateOgnlGetter(javassist.CtClass clazz, javassist.CtMethod valueGetter, javassist.CtField node)
Fail safe getter creation when normal compilation fails.protected java.lang.String
generateOgnlSetter(javassist.CtClass clazz, javassist.CtMethod valueSetter, javassist.CtField node)
Fail safe setter creation when normal compilation fails.protected java.lang.String
generateSetter(OgnlContext context, javassist.CtClass newClass, javassist.CtClass objClass, javassist.ClassPool pool, javassist.CtMethod valueSetter, Node expression, java.lang.Object root)
static java.lang.String
getCastString(java.lang.Class type)
Returns the appropriate casting expression (minus parens) for the specified class type.protected EnhancedClassLoader
getClassLoader(OgnlContext context)
Creates aClassLoader
instance compatible with the javassist classloader and normal OGNL class resolving semantics.java.lang.String
getClassName(java.lang.Class clazz)
Gets a javassist safe class string for the given class instance.protected javassist.ClassPool
getClassPool(OgnlContext context, EnhancedClassLoader loader)
Gets either a new or existingClassPool
for use in compiling javassist classes.protected javassist.CtClass
getCtClass(java.lang.Class searchClass)
Loads a new class definition via javassist for the specified class.java.lang.Class
getInterfaceClass(java.lang.Class clazz)
Used in places where the preferredOgnlExpressionCompiler.getSuperOrInterfaceClass(java.lang.reflect.Method, Class)
isn't possible because the method isn't known for a class.static java.lang.String
getRootExpression(Node expression, java.lang.Object root, OgnlContext context)
Convenience method called by many different property/method resolving AST types to get a root expression resolving string for the given node.java.lang.Class
getRootExpressionClass(Node rootNode, OgnlContext context)
For a given root object type returns the base class type to be used in root referenced expressions.java.lang.Class
getSuperOrInterfaceClass(java.lang.reflect.Method m, java.lang.Class clazz)
For the givenMethod
and class finds the highest level interface class this combination can be cast to.static boolean
shouldCast(Node expression)
Used bygetRootExpression(ognl.Node, Object, ognl.OgnlContext)
to determine if the expression needs to be cast at all.
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Field Detail
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PRE_CAST
public static final java.lang.String PRE_CAST
Key used to store any java source string casting statements in theOgnlContext
during class compilation.- See Also:
- Constant Field Values
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_loaders
protected java.util.Map _loaders
ClassLoader
instances.
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_pool
protected javassist.ClassPool _pool
Javassist class definition poool.
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_classCounter
protected int _classCounter
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Method Detail
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addCastString
public static void addCastString(OgnlContext context, java.lang.String cast)
Used bycastExpression(ognl.OgnlContext, ognl.Node, String)
to store the cast java source string in to the currentOgnlContext
. This will either add to the existing string present if it already exists or create a new instance and store it using the static key ofPRE_CAST
.- Parameters:
context
- The current execution context.cast
- The java source string to store in to the context.
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getCastString
public static java.lang.String getCastString(java.lang.Class type)
Returns the appropriate casting expression (minus parens) for the specified class type. For instance, if given anInteger
object the string"java.lang.Integer"
would be returned. For an array of primitive ints"int[]"
and so on..- Parameters:
type
- The class to cast a string expression for.- Returns:
- The converted raw string version of the class name.
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getRootExpression
public static java.lang.String getRootExpression(Node expression, java.lang.Object root, OgnlContext context)
Convenience method called by many different property/method resolving AST types to get a root expression resolving string for the given node. The callers are mostly ignorant and rely on this method to properly determine if the expression should be cast at all and take the appropriate actions if it should.- Parameters:
expression
- The node to check and generate a root expression to if necessary.root
- The root object for this execution.context
- The current execution context.- Returns:
- Either an empty string or a root path java source string compatible with javassist compilations
from the root object up to the specified
Node
.
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shouldCast
public static boolean shouldCast(Node expression)
Used bygetRootExpression(ognl.Node, Object, ognl.OgnlContext)
to determine if the expression needs to be cast at all.- Parameters:
expression
- The node to check against.- Returns:
- Yes if the node type should be cast - false otherwise.
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castExpression
public java.lang.String castExpression(OgnlContext context, Node expression, java.lang.String body)
Description copied from interface:OgnlExpressionCompiler
Used primarily by AST types likeASTChain
wherefoo.bar.id
type references may need to be cast multiple times in order to properly resolve the members in a compiled statement.This method should be using the various
OgnlContext.getCurrentType()
/OgnlContext.getCurrentAccessor()
methods to inspect the type stack and properly cast to the right classes - but only when necessary.- Specified by:
castExpression
in interfaceOgnlExpressionCompiler
- Parameters:
context
- The current execution context.expression
- The node being checked for casting.body
- The java source string generated by the given node.- Returns:
- The body string parameter plus any additional casting syntax needed to make the expression resolvable.
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getClassName
public java.lang.String getClassName(java.lang.Class clazz)
Description copied from interface:OgnlExpressionCompiler
Gets a javassist safe class string for the given class instance. This is especially useful for handling array vs. normal class casting strings.- Specified by:
getClassName
in interfaceOgnlExpressionCompiler
- Parameters:
clazz
- The class to get a string equivalent javassist compatible string reference for.- Returns:
- The string equivalent of the class.
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getSuperOrInterfaceClass
public java.lang.Class getSuperOrInterfaceClass(java.lang.reflect.Method m, java.lang.Class clazz)
Description copied from interface:OgnlExpressionCompiler
For the givenMethod
and class finds the highest level interface class this combination can be cast to.- Specified by:
getSuperOrInterfaceClass
in interfaceOgnlExpressionCompiler
- Parameters:
m
- The method the class must implement.clazz
- The current class being worked with.- Returns:
- The highest level interface / class that the referenced
Method
is declared in.
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containsMethod
public boolean containsMethod(java.lang.reflect.Method m, java.lang.Class clazz)
Helper utility method used by compiler to help resolve class->method mappings during method calls toOgnlExpressionCompiler.getSuperOrInterfaceClass(java.lang.reflect.Method, Class)
.- Parameters:
m
- The method to check for existance of.clazz
- The class to check for the existance of a matching method definition to the method passed in.- Returns:
- True if the class contains the specified method, false otherwise.
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getInterfaceClass
public java.lang.Class getInterfaceClass(java.lang.Class clazz)
Description copied from interface:OgnlExpressionCompiler
Used in places where the preferredOgnlExpressionCompiler.getSuperOrInterfaceClass(java.lang.reflect.Method, Class)
isn't possible because the method isn't known for a class. Attempts to upcast the given class to the next available non-private accessible class so that compiled expressions can reference the interface class of an instance so as not to be compiled in to overly specific statements.- Specified by:
getInterfaceClass
in interfaceOgnlExpressionCompiler
- Parameters:
clazz
- The class to attempt to find a compatible interface for.- Returns:
- The same class if no higher level interface could be matched against or the interface equivalent class.
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getRootExpressionClass
public java.lang.Class getRootExpressionClass(Node rootNode, OgnlContext context)
Description copied from interface:OgnlExpressionCompiler
For a given root object type returns the base class type to be used in root referenced expressions. This helps in some instances where the root objects themselves are compiled javassist instances that need more generic class equivalents to cast to.- Specified by:
getRootExpressionClass
in interfaceOgnlExpressionCompiler
- Parameters:
rootNode
- The root expression node.context
- The current execution context.- Returns:
- The root expression class type to cast to for this node.
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compileExpression
public void compileExpression(OgnlContext context, Node expression, java.lang.Object root) throws java.lang.Exception
Description copied from interface:OgnlExpressionCompiler
The core method executed to compile a specific expression. It is expected that this expression always return aNode
with a non nullNode.getAccessor()
instance - unless an exception is thrown by the method or the statement wasn't compilable in this instance because of missing/null objects in the expression. These instances may in some cases continue to call this compilation method until the expression is resolvable.- Specified by:
compileExpression
in interfaceOgnlExpressionCompiler
- Parameters:
context
- The context of execution.expression
- The pre-parsed root expression node to compile.root
- The root object for the expression - may be null in many instances so some implementations may exit- Throws:
java.lang.Exception
- If an error occurs compiling the expression and no strategy has been implemented to handle incremental expression compilation for incomplete expression members.
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generateGetter
protected java.lang.String generateGetter(OgnlContext context, javassist.CtClass newClass, javassist.CtClass objClass, javassist.ClassPool pool, javassist.CtMethod valueGetter, Node expression, java.lang.Object root) throws java.lang.Exception
- Throws:
java.lang.Exception
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createLocalReference
public java.lang.String createLocalReference(OgnlContext context, java.lang.String expression, java.lang.Class type)
Description copied from interface:OgnlExpressionCompiler
Method is used for expressions where multiple inner parameter method calls in generated java source strings cause javassit failures. It is hacky and cumbersome to have to generate expressions this way but it's the only current known way to make javassist happy.Takes an expression block generated by a node and creates a new method on the base object being compiled so that sufficiently complicated sub expression blocks can be broken out in to distinct methods to be referenced by the core accessor / setter methods in the base compiled root object.
- Specified by:
createLocalReference
in interfaceOgnlExpressionCompiler
- Parameters:
context
- The current execution context.expression
- The java source expression to dump in to a seperate method reference.type
- The return type that should be specified for the new method.- Returns:
- The method name that will be used to reference the sub expression in place of the actual sub expression itself.
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generateSetter
protected java.lang.String generateSetter(OgnlContext context, javassist.CtClass newClass, javassist.CtClass objClass, javassist.ClassPool pool, javassist.CtMethod valueSetter, Node expression, java.lang.Object root) throws java.lang.Exception
- Throws:
java.lang.Exception
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generateOgnlGetter
protected java.lang.String generateOgnlGetter(javassist.CtClass clazz, javassist.CtMethod valueGetter, javassist.CtField node) throws java.lang.Exception
Fail safe getter creation when normal compilation fails.- Parameters:
clazz
- The javassist class the new method should be attached to.valueGetter
- The method definition the generated code will be contained within.node
- The root expression node.- Returns:
- The generated source string for this method, the method will still be added via the javassist API either way so this is really a convenience for exception reporting / debugging.
- Throws:
java.lang.Exception
- If a javassist error occurs.
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generateOgnlSetter
protected java.lang.String generateOgnlSetter(javassist.CtClass clazz, javassist.CtMethod valueSetter, javassist.CtField node) throws java.lang.Exception
Fail safe setter creation when normal compilation fails.- Parameters:
clazz
- The javassist class the new method should be attached to.valueSetter
- The method definition the generated code will be contained within.node
- The root expression node.- Returns:
- The generated source string for this method, the method will still be added via the javassist API either way so this is really a convenience for exception reporting / debugging.
- Throws:
java.lang.Exception
- If a javassist error occurs.
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getClassLoader
protected EnhancedClassLoader getClassLoader(OgnlContext context)
Creates aClassLoader
instance compatible with the javassist classloader and normal OGNL class resolving semantics.- Parameters:
context
- The current execution context.- Returns:
- The created
ClassLoader
instance.
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getCtClass
protected javassist.CtClass getCtClass(java.lang.Class searchClass) throws javassist.NotFoundException
Loads a new class definition via javassist for the specified class.- Parameters:
searchClass
- The class to load.- Returns:
- The javassist class equivalent.
- Throws:
javassist.NotFoundException
- When the class definition can't be found.
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getClassPool
protected javassist.ClassPool getClassPool(OgnlContext context, EnhancedClassLoader loader)
Gets either a new or existingClassPool
for use in compiling javassist classes. A new class path object is inserted in to the returnedClassPool
using the passed inloader
instance if a new pool needs to be created.- Parameters:
context
- The current execution context.loader
- TheClassLoader
instance to use - as returned bygetClassLoader(ognl.OgnlContext)
.- Returns:
- The existing or new
ClassPool
instance.
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