Package org.apache.openjpa.util.asm

Class AsmHelper

java.lang.Object
org.apache.openjpa.util.asm.AsmHelper
public final class AsmHelper extends Object
Utility methods to deal with ASM bytecode
Author:
Mark Struberg

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final org.apache.xbean.asm9.Attribute[]
    ATTRS
     
    static final org.apache.xbean.asm9.Type
    TYPE_OBJECT
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static Class<?>
    getClass(ClassLoader classLoader, String internalTypeName)
     
    static byte[]
    getClassBytes(String typeName)
     
    static int
    getCorrespondingLoadInsn(int storeInsnOpcode)
    Get the corresponding LOAD instruction for the given STORE instruction.
    static int
    getCorrespondingStoreInsn(int loadInsnOpcode)
    Get the corresponding STORE instruction for the given LOAD instruction.
    static Class<?>
    getDescribedClass(ClassLoader classLoader, String typeDesc)
    Get the class from the described type
    static String[]
    getInternalNames(Class<?>[] classes)
    Get the internal names for the given classes
    static org.apache.xbean.asm9.tree.AbstractInsnNode
    getLoadConstantInsn(Object val)
     
    static int
    getLoadInsn(Class<?> type)
    Calclates the proper LOAD instruction opcode for the given type.
    static int
    getLocalVarPos(org.apache.xbean.asm9.tree.MethodNode meth)
    Calculate the next local variable position.
    static Optional<org.apache.xbean.asm9.tree.MethodNode>
    getMethodNode(org.apache.xbean.asm9.tree.ClassNode classNode, Method meth)
     
    static Optional<org.apache.xbean.asm9.tree.MethodNode>
    getMethodNode(org.apache.xbean.asm9.tree.ClassNode classNode, String methodName, Class<?> returnType, Class<?>... paramTypes)
     
    static int
    getParamIndex(org.apache.xbean.asm9.tree.MethodNode methodNode, int varPos)
    Determine the 0-based index of the parameter of LOAD or STORE position varPos
    static org.apache.xbean.asm9.Type[]
    getParamTypes(Class<?>[] params)
    get the ASM Types for the given classes
    static int
    getReturnInsn(Class<?> type)
    Calclates the proper Return instruction opcode for the given class
    static int
    getStoreInsn(Class<?> type)
    Calclates the proper STORE instruction opcode for the given type
    static boolean
    isLoadInsn(org.apache.xbean.asm9.tree.AbstractInsnNode insn)
     
    static boolean
    isPrimitive(String typeDesc, boolean includeVoid)
     
    static boolean
    isThisInsn(org.apache.xbean.asm9.tree.AbstractInsnNode insn)
     
    static org.apache.xbean.asm9.tree.ClassNode
    readClassNode(Class<?> clazz)
    Read the binary bytecode from the class with the given name
    static org.apache.xbean.asm9.tree.ClassNode
    readClassNode(ClassLoader classLoader, String className)
    Read the binary bytecode from the class with the given name
    static org.apache.xbean.asm9.tree.InsnList
    throwException(Class type)
    Helper method to add the code necessary to throw the given exception type, sans message.
    static org.apache.xbean.asm9.tree.InsnList
    throwException(Class type, String msg)
    Helper method to add the code necessary to throw the given exception type, sans message.
    static byte[]
    toByteArray(ClassNodeTracker cnt)
    Create a byte[] of that class represented by the ClassNodeTracker

    Methods inherited from class java.lang.Object

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

  • Field Details

    • TYPE_OBJECT

      public static final org.apache.xbean.asm9.Type TYPE_OBJECT

    • ATTRS

      public static final org.apache.xbean.asm9.Attribute[] ATTRS

  • Method Details

    • readClassNode

      public static org.apache.xbean.asm9.tree.ClassNode readClassNode(Class<?> clazz)
      Read the binary bytecode from the class with the given name
      Parameters:
      clazz - the class to read into the ClassNode
      Returns:
      the ClassNode constructed from that class

    • readClassNode

      public static org.apache.xbean.asm9.tree.ClassNode readClassNode(ClassLoader classLoader, String className) throws ClassNotFoundException
      Read the binary bytecode from the class with the given name
      Parameters:
      classLoader - the ClassLoader to use
      className - the fully qualified class name to read. e.g. "org.mycorp.mypackage.MyEntity"
      Returns:
      the ClassNode constructed from that class
      Throws:
      ClassNotFoundException

    • getClassBytes

      public static byte[] getClassBytes(String typeName)

    • toByteArray

      public static byte[] toByteArray(ClassNodeTracker cnt)
      Create a byte[] of that class represented by the ClassNodeTracker

    • getMethodNode

      public static Optional<org.apache.xbean.asm9.tree.MethodNode> getMethodNode(org.apache.xbean.asm9.tree.ClassNode classNode, Method meth)

    • getMethodNode

      public static Optional<org.apache.xbean.asm9.tree.MethodNode> getMethodNode(org.apache.xbean.asm9.tree.ClassNode classNode, String methodName, Class<?> returnType, Class<?>... paramTypes)

    • getReturnInsn

      public static int getReturnInsn(Class<?> type)
      Calclates the proper Return instruction opcode for the given class
      Parameters:
      type - the type to get returned
      Returns:
      the proper Opcode RETURN, ARETURN, IRETURN, etc

    • getLoadConstantInsn

      public static org.apache.xbean.asm9.tree.AbstractInsnNode getLoadConstantInsn(Object val)

    • getStoreInsn

      public static int getStoreInsn(Class<?> type)
      Calclates the proper STORE instruction opcode for the given type
      Parameters:
      type - the type to get stored
      Returns:
      the proper Opcode ISTORE, ASTORE, LSTORE, etc

    • getLoadInsn

      public static int getLoadInsn(Class<?> type)
      Calclates the proper LOAD instruction opcode for the given type. This is the appropriate bytecode instruction to load a value from a variable to the stack.
      Parameters:
      type - the type to get loaded
      Returns:
      the proper Opcode ILOAD, ALOAD, LLOAD, etc

    • getInternalNames

      public static String[] getInternalNames(Class<?>[] classes)
      Get the internal names for the given classes
      See Also:
      • Type.getInternalName(Class)

    • getParamTypes

      public static org.apache.xbean.asm9.Type[] getParamTypes(Class<?>[] params)
      get the ASM Types for the given classes
      See Also:
      • Type.getType(Method)

    • getParamIndex

      public static int getParamIndex(org.apache.xbean.asm9.tree.MethodNode methodNode, int varPos)
      Determine the 0-based index of the parameter of LOAD or STORE position varPos
      Parameters:
      methodNode -
      varPos - the position on the stack
      Returns:
      the index of the parameter which corresponds to this varPos

    • isLoadInsn

      public static boolean isLoadInsn(org.apache.xbean.asm9.tree.AbstractInsnNode insn)
      Returns:
      true if the instruction is an LOAD instruction

    • isThisInsn

      public static boolean isThisInsn(org.apache.xbean.asm9.tree.AbstractInsnNode insn)
      Returns:
      true if the instruction is an ALOAD_0

    • getCorrespondingLoadInsn

      public static int getCorrespondingLoadInsn(int storeInsnOpcode)
      Get the corresponding LOAD instruction for the given STORE instruction.
      Parameters:
      storeInsnOpcode - e.g. Opcodes.ISTORE
      Throws:
      IllegalArgumentException - if the given opcode is not a STORE instruction

    • getCorrespondingStoreInsn

      public static int getCorrespondingStoreInsn(int loadInsnOpcode)
      Get the corresponding STORE instruction for the given LOAD instruction.
      Parameters:
      loadInsnOpcode - e.g. Opcodes.FLOAD
      Throws:
      IllegalArgumentException - if the given opcode is not a STORE instruction

    • isPrimitive

      public static boolean isPrimitive(String typeDesc, boolean includeVoid)
      Parameters:
      typeDesc - the internal type descriptor from the bytecode. See ClassNode.name
      includeVoid - if the Void.class type also counts as primitive

    • getDescribedClass

      public static Class<?> getDescribedClass(ClassLoader classLoader, String typeDesc)
      Get the class from the described type
      Parameters:
      typeDesc -
      Returns:
      described class or null if it could not be loaded

    • throwException

      public static org.apache.xbean.asm9.tree.InsnList throwException(Class type)
      Helper method to add the code necessary to throw the given exception type, sans message.

    • throwException

      public static org.apache.xbean.asm9.tree.InsnList throwException(Class type, String msg)
      Helper method to add the code necessary to throw the given exception type, sans message.

    • getClass

      public static Class<?> getClass(ClassLoader classLoader, String internalTypeName)

    • getLocalVarPos

      public static int getLocalVarPos(org.apache.xbean.asm9.tree.MethodNode meth)
      Calculate the next local variable position. For a non-static method the position 0 on the stack is the this pointer. After that there are all the method parameters. For a static method the method parameters begin at position zero. This method does calculate the first unused stack position which can be used for xLOAD/xSTORE opterations, e.g. int nextVarPos = AsmHelper.getLocalVarPos(myMethodNode); instructions.add(AsmHelper.getLoadConstantInsn(4711)); instructions.add(new VarInsnNode(Opcodes.ISTORE, nextVarPos);
      Returns:
      the 0-based position on the stack at which the local variables can be located.