ClassWriter (Drools 4.0.0.11754MR2 API) - JBoss RULES 4.0.0.11754MR2 API 英文版文档

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org.drools.asm
Class ClassWriter

java.lang.Object
  org.drools.asm.ClassWriter

All Implemented Interfaces:: ClassVisitor

public class ClassWriter
extends Object
implements ClassVisitor
extends Object
implements ClassVisitor

A ClassVisitor that generates classes in bytecode form. More precisely this visitor generates a byte array conforming to the Java class file format. It can be used alone, to generate a Java class "from scratch", or with one or more ClassReader and adapter class visitor to generate a modified class from one or more existing Java classes.

Author:: Eric Bruneton

Constructor Summary

ClassWriter(boolean computeMaxs)
          Constructs a new ClassWriter object.

ClassWriter(boolean computeMaxs, boolean skipUnknownAttributes)
          Constructs a new ClassWriter object.

ClassWriter(ClassReader classReader, boolean computeMaxs)
          Constructs a new ClassWriter object and enables optimizations for "mostly add" bytecode transformations.

Method Summary

int newClass(String value)
          Adds a class reference to the constant pool of the class being build.

int newConst(Object cst)
          Adds a number or string constant to the constant pool of the class being build.

int newField(String owner, String name, String desc)
          Adds a field reference to the constant pool of the class being build.

int newMethod(String owner, String name, String desc, boolean itf)
          Adds a method reference to the constant pool of the class being build.

int newNameType(String name, String desc)
          Adds a name and type to the constant pool of the class being build.

int newUTF8(String value)
          Adds an UTF8 string to the constant pool of the class being build.

byte[] toByteArray()
          Returns the bytecode of the class that was build with this class writer.

void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
          Visits the header of the class.

AnnotationVisitor visitAnnotation(String desc, boolean visible)
          Visits an annotation of the class.

void visitAttribute(Attribute attr)
          Visits a non standard attribute of the class.

void visitEnd()
          Visits the end of the class.

FieldVisitor visitField(int access, String name, String desc, String signature, Object value)
          Visits a field of the class.

void visitInnerClass(String name, String outerName, String innerName, int access)
          Visits information about an inner class.

MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions)
          Visits a method of the class.

void visitOuterClass(String owner, String name, String desc)
          Visits the enclosing class of the class.

void visitSource(String file, String debug)
          Visits the source of the class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Summary
`ClassWriter(boolean computeMaxs)` Constructs a new `ClassWriter` object.
`ClassWriter(boolean computeMaxs, boolean skipUnknownAttributes)` Constructs a new `ClassWriter` object.
`ClassWriter(ClassReader classReader, boolean computeMaxs)` Constructs a new `ClassWriter` object and enables optimizations for "mostly add" bytecode transformations.

Method Summary
`int`	`newClass(String value)` Adds a class reference to the constant pool of the class being build.
`int`	`newConst(Object cst)` Adds a number or string constant to the constant pool of the class being build.
`int`	`newField(String owner, String name, String desc)` Adds a field reference to the constant pool of the class being build.
`int`	`newMethod(String owner, String name, String desc, boolean itf)` Adds a method reference to the constant pool of the class being build.
`int`	`newNameType(String name, String desc)` Adds a name and type to the constant pool of the class being build.
`int`	`newUTF8(String value)` Adds an UTF8 string to the constant pool of the class being build.
`byte[]`	`toByteArray()` Returns the bytecode of the class that was build with this class writer.
`void`	`visit(int version, int access, String name, String signature, String superName, String[] interfaces)` Visits the header of the class.
`AnnotationVisitor`	`visitAnnotation(String desc, boolean visible)` Visits an annotation of the class.
`void`	`visitAttribute(Attribute attr)` Visits a non standard attribute of the class.
`void`	`visitEnd()` Visits the end of the class.
`FieldVisitor`	`visitField(int access, String name, String desc, String signature, Object value)` Visits a field of the class.
`void`	`visitInnerClass(String name, String outerName, String innerName, int access)` Visits information about an inner class.
`MethodVisitor`	`visitMethod(int access, String name, String desc, String signature, String[] exceptions)` Visits a method of the class.
`void`	`visitOuterClass(String owner, String name, String desc)` Visits the enclosing class of the class.
`void`	`visitSource(String file, String debug)` Visits the source of the class.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

ClassWriter

public ClassWriter(boolean computeMaxs)

Constructs a new ClassWriter object.

Parameters:: computeMaxs - true if the maximum stack size and the maximum number of local variables must be automatically computed. If this flag is true, then the arguments of the visitMaxs method of the MethodVisitor returned by the visitMethod method will be ignored, and computed automatically from the signature and the bytecode of each method.

ClassWriter

public ClassWriter(boolean computeMaxs,
                   boolean skipUnknownAttributes)

Constructs a new ClassWriter object.

Parameters:: computeMaxs - true if the maximum stack size and the maximum number of local variables must be automatically computed. If this flag is true, then the arguments of the visitMaxs method of the MethodVisitor returned by the visitMethod method will be ignored, and computed automatically from the signature and the bytecode of each method.; skipUnknownAttributes - Deprecated. The value of this parameter is ignored.

ClassWriter

public ClassWriter(ClassReader classReader,
                   boolean computeMaxs)

Constructs a new ClassWriter object and enables optimizations for "mostly add" bytecode transformations. These optimizations are the following:

The constant pool from the original class is copied as is in the new class, which saves time. New constant pool entries will be added at the end if necessary, but unused constant pool entries won't be removed.
Methods that are not transformed are copied as is in the new class, directly from the original class bytecode (i.e. without emitting visit events for all the method instructions), which saves a lot of time. Untransformed methods are detected by the fact that the ClassReader receives MethodVisitor objects that come from a ClassWriter (and not from a custom ClassAdapter or any other ClassVisitor instance).

Parameters:: classReader - the ClassReader used to read the original class. It will be used to copy the entire constant pool from the original class and also to copy other fragments of original bytecode where applicable.; computeMaxs - true if the maximum stack size and the maximum number of local variables must be automatically computed. If this flag is true, then the arguments of the visitMaxs method of the MethodVisitor returned by the visitMethod method will be ignored, and computed automatically from the signature and the bytecode of each method.

Method Detail