commons-compiler 3.1.12 · org.codehaus.commons.compiler.IClassBodyEvaluator

Parses a class body and returns it as a Class object ready for use with java.lang.reflect.

Example:

  import java.util.*;

  static private int a = 1;
  private int b = 2;

  public void func(int c, int d) {
      return func2(c, d);
  }

  private static void func2(int e, int f) {
      return e * f;
  }

To set up an IClassBodyEvaluator object, proceed as follows:

Create an IClassBodyEvaluator-implementing class.
Configure the IClassBodyEvaluator by calling any of the following methods:

Call any of the ICookable#cook(String, java.io.Reader) methods to scan, parse, compile and load the class body into the JVM.

To compile a class body and immediately instantiate an object, the createInstance(Reader) methods can be used.

The generated class may optionally extend/implement a given type; the returned instance can safely be type-cast to that baseType.

Example:

public interface Foo {
    int bar(int a, int b);
}
...
IClassBodyEvaluator cbe = CompilerFactoryFactory.getDefaultCompilerFactory(). newClassBodyEvaluator();
Foo f = (Foo) ClassBodyEvaluator.createFastClassBodyEvaluator(
    new Scanner(null, new StringReader("public int bar(int a, int b) { return a + b; }")),
    Foo.class,                  // Base type to extend/implement
    (ClassLoader) null          // Use current thread's context class loader
);
System.out.println("1 + 2 = " + f.bar(1, 2));

Field Summary

Modifier and Type	Field and Description
public static final String	DEFAULT_CLASS_NAME Default name for the generated class.

Method Summary

Modifier and Type	Method and Description
public Object	Returns: An object that extends the `extendedType` and implements the given `implementedTypes` createInstance(Reader Source of class body tokens reader) Scans, parses and compiles a class body from the tokens delivered by the the given `Reader`, then creates and returns an instance of that class.
public Class<?>	Returns: The generated `Class` getClazz()
public String[]	Returns: The default imports that were previously configured with `setDefaultImports(String...)` getDefaultImports()
public void	setClassName(String className) Sets the name of the generated class.
public void	setCompileErrorHandler(ErrorHandler `null` to restore the default behavior (throwing a `CompileException`) compileErrorHandler) Installs an `ErrorHandler` which is invoked during compilation on each error.
public void	setDebuggingInformation(boolean debugSource, boolean debugLines, boolean debugVars) Determines what kind of debugging information is included in the generates classes.
public void	setDefaultImports(String... defaultImports) "Default imports" add to the system import "java.lang", i.e. the evaluator may refer to classes imported by default imports without having to explicitly declare IMPORT statements.
public void	setExtendedClass(Class<?> extendedClass) Sets a particular superclass that the generated class will extend.
public void	setExtendedType(Class<?> extendedClass) Deprecated Use `setExtendedClass(Class)` instead
public void	setImplementedInterfaces(Class<?>[] implementedInterfaces) Sets a particular set of interfaces that the generated class will implement.
public void	setImplementedTypes(Class<?>[] implementedInterfaces) Deprecated Use `setImplementedInterfaces(Class[])` instead
public void	setParentClassLoader(ClassLoader parentClassLoader) The "parent class loader" is used to load referenced classes.
public void	setWarningHandler(WarningHandler `null` to indicate that no warnings be issued warningHandler) By default, warnings are discarded, but an application my install a custom `WarningHandler`.

Inherited from org.codehaus.commons.compiler.ICookable:: cook cook cook cook cook cook cook cook cookFile cookFile cookFile cookFile getBytecodes setSourceVersion setTargetVersion

Field Detail

DEFAULT_CLASS_NAME	back to summary
public static final String DEFAULT_CLASS_NAME Default name for the generated class.

Method Detail

createInstance back to summary

createInstance	back to summary
public Object createInstance(Reader reader) throws CompileException, IOException Scans, parses and compiles a class body from the tokens delivered by the the given `Reader`, then creates and returns an instance of that class. Parameters reader:Reader Source of class body tokens Returns:Object An object that extends the `extendedType` and implements the given `implementedTypes`

public Object createInstance(Reader reader) throws CompileException, IOException

Scans, parses and compiles a class body from the tokens delivered by the the given Reader, then creates and returns an instance of that class.

Parameters

reader:Reader: Source of class body tokens

Returns:Object

An object that extends the extendedType and implements the given implementedTypes

getClazz	back to summary
public Class<?> getClazz() Returns:Class<?> The generated `Class` Exceptions IllegalStateException: This `IClassBodyEvaluator` is not yet cooked

getDefaultImports	back to summary
public String[] getDefaultImports() Returns:String[] The default imports that were previously configured with `setDefaultImports(String...)`

setClassName back to summary

setClassName	back to summary
public void setClassName(String className) Sets the name of the generated class. Defaults to `DEFAULT_CLASS_NAME`. In most cases, there is no need to set this name, because the generated class is loaded into its own `java.lang.ClassLoader` where its name cannot collide with classes generated by other evaluators. One reason to use this function is to have a class name in a non-default package, which can be relevant when types and members with DEFAULT accessibility are accessed.

public void setClassName(String className)

Sets the name of the generated class. Defaults to DEFAULT_CLASS_NAME. In most cases, there is no need to set this name, because the generated class is loaded into its own java.lang.ClassLoader where its name cannot collide with classes generated by other evaluators.

One reason to use this function is to have a class name in a non-default package, which can be relevant when types and members with DEFAULT accessibility are accessed.

setCompileErrorHandler back to summary

setCompileErrorHandler	back to summary
public void setCompileErrorHandler(ErrorHandler compileErrorHandler) Installs an `ErrorHandler` which is invoked during compilation on each error. (By default, the compilation throws a `CompileException` on the first error and terminates.) If the given `ErrorHandler` throws a `CompileException`, then the compilation terminates and the exception is propagated. If the given `ErrorHandler` does not throw a `CompileException` but completes normally, then the compilation may or may not continue, depending on the error. Iff the compilation completes normally but errors were reported, then it will throw a `CompileException` indicating the number of errors. In other words: The `ErrorHandler` may throw a `CompileException` or not, but the compilation will definitely throw a `CompileException` if one or more compile errors have occurred. Parameters compileErrorHandler:ErrorHandler `null` to restore the default behavior (throwing a `CompileException`)

public void setCompileErrorHandler(ErrorHandler compileErrorHandler)

Installs an ErrorHandler which is invoked during compilation on each error. (By default, the compilation throws a CompileException on the first error and terminates.)

If the given ErrorHandler throws a CompileException, then the compilation terminates and the exception is propagated.

If the given ErrorHandler does not throw a CompileException but completes normally, then the compilation may or may not continue, depending on the error. Iff the compilation completes normally but errors were reported, then it will throw a CompileException indicating the number of errors.

In other words: The ErrorHandler may throw a CompileException or not, but the compilation will definitely throw a CompileException if one or more compile errors have occurred.

Parameters

compileErrorHandler:ErrorHandler: null to restore the default behavior (throwing a CompileException)

setDebuggingInformation	back to summary
public void setDebuggingInformation(boolean debugSource, boolean debugLines, boolean debugVars) Determines what kind of debugging information is included in the generates classes. The default is typically "`-g:none`".

setDefaultImports	back to summary
public void setDefaultImports(String... defaultImports) "Default imports" add to the system import "java.lang", i.e. the evaluator may refer to classes imported by default imports without having to explicitly declare IMPORT statements. Notice that JDK 5 "static imports" are also supported, as shown here: sc.setDefaultImports( "java.util.Map", // Single type import "java.io.", // Type-import-on-demand "static java.util.Collections.EMPTY_MAP", // Single static import "static java.util.Collections.", // Static-import-on-demand );

setDefaultImports

back to summary

public void setDefaultImports(String... defaultImports)

"Default imports" add to the system import "java.lang", i.e. the evaluator may refer to classes imported by default imports without having to explicitly declare IMPORT statements.

Notice that JDK 5 "static imports" are also supported, as shown here:

    sc.setDefaultImports(
        "java.util.Map",                          // Single type import
        "java.io.*",                              // Type-import-on-demand
        "static java.util.Collections.EMPTY_MAP", // Single static import
        "static java.util.Collections.*",         // Static-import-on-demand
    );

setExtendedClass back to summary

setExtendedClass	back to summary
public void setExtendedClass(Class<?> extendedClass) Sets a particular superclass that the generated class will extend. If `extendedClass` is `null`, the generated class will extend `Object`. The usual reason to set a base class for an evaluator is that the generated class can directly access the superclass's (non-private) members.

public void setExtendedClass(Class<?> extendedClass)

Sets a particular superclass that the generated class will extend. If extendedClass is null, the generated class will extend Object.

The usual reason to set a base class for an evaluator is that the generated class can directly access the superclass's (non-private) members.

setExtendedType	back to summary
public void setExtendedType(Class<?> extendedClass) Deprecated Use `setExtendedClass(Class)` instead Annotations @Deprecated

setImplementedInterfaces	back to summary
public void setImplementedInterfaces(Class<?>[] implementedInterfaces) Sets a particular set of interfaces that the generated class will implement.

setImplementedTypes	back to summary
public void setImplementedTypes(Class<?>[] implementedInterfaces) Deprecated Use `setImplementedInterfaces(Class[])` instead Annotations @Deprecated

setParentClassLoader back to summary

public void setParentClassLoader(ClassLoader parentClassLoader)

The "parent class loader" is used to load referenced classes. Useful values are:

`System.getSystemClassLoader()`	The running JVM's class path
`Thread.currentThread().getContextClassLoader()` or `null`	The class loader effective for the invoking thread
`ClassLoaders#BOOTCLASSPATH_CLASS_LOADER`	The running JVM's boot class path

The parent class loader defaults to the current thread's context class loader.

setWarningHandler back to summary

setWarningHandler	back to summary
public void setWarningHandler(WarningHandler warningHandler) By default, warnings are discarded, but an application my install a custom `WarningHandler`. Parameters warningHandler:WarningHandler `null` to indicate that no warnings be issued

public void setWarningHandler(WarningHandler warningHandler)

By default, warnings are discarded, but an application my install a custom WarningHandler.

Parameters

warningHandler:WarningHandler: null to indicate that no warnings be issued

public Interface IClassBodyEvaluator

Field Summary

Method Summary

Field Detail

Method Detail