TypeReference.java

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2013 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.objectweb.asm;

/**
 * A reference to a type appearing in a class, field or method declaration, or
 * on an instruction. Such a reference designates the part of the class where
 * the referenced type is appearing (e.g. an 'extends', 'implements' or 'throws'
 * clause, a 'new' instruction, a 'catch' clause, a type cast, a local variable
 * declaration, etc).
 * 
 * @author Eric Bruneton
 */
public class TypeReference {

    /**
     * The sort of type references that target a type parameter of a generic
     * class. See {@link #getSort getSort}.
     */
    public final static int CLASS_TYPE_PARAMETER = 0x00;

    /**
     * The sort of type references that target a type parameter of a generic
     * method. See {@link #getSort getSort}.
     */
    public final static int METHOD_TYPE_PARAMETER = 0x01;

    /**
     * The sort of type references that target the super class of a class or one
     * of the interfaces it implements. See {@link #getSort getSort}.
     */
    public final static int CLASS_EXTENDS = 0x10;

    /**
     * The sort of type references that target a bound of a type parameter of a
     * generic class. See {@link #getSort getSort}.
     */
    public final static int CLASS_TYPE_PARAMETER_BOUND = 0x11;

    /**
     * The sort of type references that target a bound of a type parameter of a
     * generic method. See {@link #getSort getSort}.
     */
    public final static int METHOD_TYPE_PARAMETER_BOUND = 0x12;

    /**
     * The sort of type references that target the type of a field. See
     * {@link #getSort getSort}.
     */
    public final static int FIELD = 0x13;

    /**
     * The sort of type references that target the return type of a method. See
     * {@link #getSort getSort}.
     */
    public final static int METHOD_RETURN = 0x14;

    /**
     * The sort of type references that target the receiver type of a method.
     * See {@link #getSort getSort}.
     */
    public final static int METHOD_RECEIVER = 0x15;

    /**
     * The sort of type references that target the type of a formal parameter of
     * a method. See {@link #getSort getSort}.
     */
    public final static int METHOD_FORMAL_PARAMETER = 0x16;

    /**
     * The sort of type references that target the type of an exception declared
     * in the throws clause of a method. See {@link #getSort getSort}.
     */
    public final static int THROWS = 0x17;

    /**
     * The sort of type references that target the type of a local variable in a
     * method. See {@link #getSort getSort}.
     */
    public final static int LOCAL_VARIABLE = 0x40;

    /**
     * The sort of type references that target the type of a resource variable
     * in a method. See {@link #getSort getSort}.
     */
    public final static int RESOURCE_VARIABLE = 0x41;

    /**
     * The sort of type references that target the type of the exception of a
     * 'catch' clause in a method. See {@link #getSort getSort}.
     */
    public final static int EXCEPTION_PARAMETER = 0x42;

    /**
     * The sort of type references that target the type declared in an
     * 'instanceof' instruction. See {@link #getSort getSort}.
     */
    public final static int INSTANCEOF = 0x43;

    /**
     * The sort of type references that target the type of the object created by
     * a 'new' instruction. See {@link #getSort getSort}.
     */
    public final static int NEW = 0x44;

    /**
     * The sort of type references that target the receiver type of a
     * constructor reference. See {@link #getSort getSort}.
     */
    public final static int CONSTRUCTOR_REFERENCE = 0x45;

    /**
     * The sort of type references that target the receiver type of a method
     * reference. See {@link #getSort getSort}.
     */
    public final static int METHOD_REFERENCE = 0x46;

    /**
     * The sort of type references that target the type declared in an explicit
     * or implicit cast instruction. See {@link #getSort getSort}.
     */
    public final static int CAST = 0x47;

    /**
     * The sort of type references that target a type parameter of a generic
     * constructor in a constructor call. See {@link #getSort getSort}.
     */
    public final static int CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT = 0x48;

    /**
     * The sort of type references that target a type parameter of a generic
     * method in a method call. See {@link #getSort getSort}.
     */
    public final static int METHOD_INVOCATION_TYPE_ARGUMENT = 0x49;

    /**
     * The sort of type references that target a type parameter of a generic
     * constructor in a constructor reference. See {@link #getSort getSort}.
     */
    public final static int CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT = 0x4A;

    /**
     * The sort of type references that target a type parameter of a generic
     * method in a method reference. See {@link #getSort getSort}.
     */
    public final static int METHOD_REFERENCE_TYPE_ARGUMENT = 0x4B;

    /**
     * The type reference value in Java class file format.
     */
    private int value;

    /**
     * Creates a new TypeReference.
     * 
     * @param typeRef
     *            the int encoded value of the type reference, as received in a
     *            visit method related to type annotations, like
     *            visitTypeAnnotation.
     */
    public TypeReference(int typeRef) {
        this.value = typeRef;
    }

    /**
     * Returns a type reference of the given sort.
     * 
     * @param sort
     *            {@link #FIELD FIELD}, {@link #METHOD_RETURN METHOD_RETURN},
     *            {@link #METHOD_RECEIVER METHOD_RECEIVER},
     *            {@link #LOCAL_VARIABLE LOCAL_VARIABLE},
     *            {@link #RESOURCE_VARIABLE RESOURCE_VARIABLE},
     *            {@link #INSTANCEOF INSTANCEOF}, {@link #NEW NEW},
     *            {@link #CONSTRUCTOR_REFERENCE CONSTRUCTOR_REFERENCE}, or
     *            {@link #METHOD_REFERENCE METHOD_REFERENCE}.
     * @return a type reference of the given sort.
     */
    public static TypeReference newTypeReference(int sort) {
        return new TypeReference(sort << 24);
    }

    /**
     * Returns a reference to a type parameter of a generic class or method.
     * 
     * @param sort
     *            {@link #CLASS_TYPE_PARAMETER CLASS_TYPE_PARAMETER} or
     *            {@link #METHOD_TYPE_PARAMETER METHOD_TYPE_PARAMETER}.
     * @param paramIndex
     *            the type parameter index.
     * @return a reference to the given generic class or method type parameter.
     */
    public static TypeReference newTypeParameterReference(int sort,
            int paramIndex) {
        return new TypeReference((sort << 24) | (paramIndex << 16));
    }

    /**
     * Returns a reference to a type parameter bound of a generic class or
     * method.
     * 
     * @param sort
     *            {@link #CLASS_TYPE_PARAMETER CLASS_TYPE_PARAMETER} or
     *            {@link #METHOD_TYPE_PARAMETER METHOD_TYPE_PARAMETER}.
     * @param paramIndex
     *            the type parameter index.
     * @param boundIndex
     *            the type bound index within the above type parameters.
     * @return a reference to the given generic class or method type parameter
     *         bound.
     */
    public static TypeReference newTypeParameterBoundReference(int sort,
            int paramIndex, int boundIndex) {
        return new TypeReference((sort << 24) | (paramIndex << 16)
                | (boundIndex << 8));
    }

    /**
     * Returns a reference to the super class or to an interface of the
     * 'implements' clause of a class.
     * 
     * @param itfIndex
     *            the index of an interface in the 'implements' clause of a
     *            class, or -1 to reference the super class of the class.
     * @return a reference to the given super type of a class.
     */
    public static TypeReference newSuperTypeReference(int itfIndex) {
        itfIndex &= 0xFFFF;
        return new TypeReference((CLASS_EXTENDS << 24) | (itfIndex << 8));
    }

    /**
     * Returns a reference to the type of a formal parameter of a method.
     * 
     * @param paramIndex
     *            the formal parameter index.
     * 
     * @return a reference to the type of the given method formal parameter.
     */
    public static TypeReference newFormalParameterReference(int paramIndex) {
        return new TypeReference((METHOD_FORMAL_PARAMETER << 24)
                | (paramIndex << 16));
    }

    /**
     * Returns a reference to the type of an exception, in a 'throws' clause of
     * a method.
     * 
     * @param exceptionIndex
     *            the index of an exception in a 'throws' clause of a method.
     * 
     * @return a reference to the type of the given exception.
     */
    public static TypeReference newExceptionReference(int exceptionIndex) {
        return new TypeReference((THROWS << 24) | (exceptionIndex << 8));
    }

    /**
     * Returns a reference to the type of the exception declared in a 'catch'
     * clause of a method.
     * 
     * @param tryCatchBlockIndex
     *            the index of a try catch block (using the order in which they
     *            are visited with visitTryCatchBlock).
     * 
     * @return a reference to the type of the given exception.
     */
    public static TypeReference newTryCatchReference(int tryCatchBlockIndex) {
        return new TypeReference((EXCEPTION_PARAMETER << 24)
                | (tryCatchBlockIndex << 8));
    }

    /**
     * Returns a reference to the type of a type argument in a constructor or
     * method call or reference.
     * 
     * @param sort
     *            {@link #CAST CAST},
     *            {@link #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
     *            CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT},
     *            {@link #METHOD_INVOCATION_TYPE_ARGUMENT
     *            METHOD_INVOCATION_TYPE_ARGUMENT},
     *            {@link #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
     *            CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or
     *            {@link #METHOD_REFERENCE_TYPE_ARGUMENT
     *            METHOD_REFERENCE_TYPE_ARGUMENT}.
     * @param argIndex
     *            the type argument index.
     * 
     * @return a reference to the type of the given type argument.
     */
    public static TypeReference newTypeArgumentReference(int sort, int argIndex) {
        return new TypeReference((sort << 24) | argIndex);
    }

    /**
     * Returns the sort of this type reference.
     * 
     * @return {@link #CLASS_TYPE_PARAMETER CLASS_TYPE_PARAMETER},
     *         {@link #METHOD_TYPE_PARAMETER METHOD_TYPE_PARAMETER},
     *         {@link #CLASS_EXTENDS CLASS_EXTENDS},
     *         {@link #CLASS_TYPE_PARAMETER_BOUND CLASS_TYPE_PARAMETER_BOUND},
     *         {@link #METHOD_TYPE_PARAMETER_BOUND METHOD_TYPE_PARAMETER_BOUND},
     *         {@link #FIELD FIELD}, {@link #METHOD_RETURN METHOD_RETURN},
     *         {@link #METHOD_RECEIVER METHOD_RECEIVER},
     *         {@link #METHOD_FORMAL_PARAMETER METHOD_FORMAL_PARAMETER},
     *         {@link #THROWS THROWS}, {@link #LOCAL_VARIABLE LOCAL_VARIABLE},
     *         {@link #RESOURCE_VARIABLE RESOURCE_VARIABLE},
     *         {@link #EXCEPTION_PARAMETER EXCEPTION_PARAMETER},
     *         {@link #INSTANCEOF INSTANCEOF}, {@link #NEW NEW},
     *         {@link #CONSTRUCTOR_REFERENCE CONSTRUCTOR_REFERENCE},
     *         {@link #METHOD_REFERENCE METHOD_REFERENCE}, {@link #CAST CAST},
     *         {@link #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
     *         CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT},
     *         {@link #METHOD_INVOCATION_TYPE_ARGUMENT
     *         METHOD_INVOCATION_TYPE_ARGUMENT},
     *         {@link #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
     *         CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or
     *         {@link #METHOD_REFERENCE_TYPE_ARGUMENT
     *         METHOD_REFERENCE_TYPE_ARGUMENT}.
     */
    public int getSort() {
        return value >>> 24;
    }

    /**
     * Returns the index of the type parameter referenced by this type
     * reference. This method must only be used for type references whose sort
     * is {@link #CLASS_TYPE_PARAMETER CLASS_TYPE_PARAMETER},
     * {@link #METHOD_TYPE_PARAMETER METHOD_TYPE_PARAMETER},
     * {@link #CLASS_TYPE_PARAMETER_BOUND CLASS_TYPE_PARAMETER_BOUND} or
     * {@link #METHOD_TYPE_PARAMETER_BOUND METHOD_TYPE_PARAMETER_BOUND}.
     * 
     * @return a type parameter index.
     */
    public int getTypeParameterIndex() {
        return (value & 0x00FF0000) >> 16;
    }

    /**
     * Returns the index of the type parameter bound, within the type parameter
     * {@link #getTypeParameterIndex}, referenced by this type reference. This
     * method must only be used for type references whose sort is
     * {@link #CLASS_TYPE_PARAMETER_BOUND CLASS_TYPE_PARAMETER_BOUND} or
     * {@link #METHOD_TYPE_PARAMETER_BOUND METHOD_TYPE_PARAMETER_BOUND}.
     * 
     * @return a type parameter bound index.
     */
    public int getTypeParameterBoundIndex() {
        return (value & 0x0000FF00) >> 8;
    }

    /**
     * Returns the index of the "super type" of a class that is referenced by
     * this type reference. This method must only be used for type references
     * whose sort is {@link #CLASS_EXTENDS CLASS_EXTENDS}.
     * 
     * @return the index of an interface in the 'implements' clause of a class,
     *         or -1 if this type reference references the type of the super
     *         class.
     */
    public int getSuperTypeIndex() {
        return (short) ((value & 0x00FFFF00) >> 8);
    }

    /**
     * Returns the index of the formal parameter whose type is referenced by
     * this type reference. This method must only be used for type references
     * whose sort is {@link #METHOD_FORMAL_PARAMETER METHOD_FORMAL_PARAMETER}.
     * 
     * @return a formal parameter index.
     */
    public int getFormalParameterIndex() {
        return (value & 0x00FF0000) >> 16;
    }

    /**
     * Returns the index of the exception, in a 'throws' clause of a method,
     * whose type is referenced by this type reference. This method must only be
     * used for type references whose sort is {@link #THROWS THROWS}.
     * 
     * @return the index of an exception in the 'throws' clause of a method.
     */
    public int getExceptionIndex() {
        return (value & 0x00FFFF00) >> 8;
    }

    /**
     * Returns the index of the try catch block (using the order in which they
     * are visited with visitTryCatchBlock), whose 'catch' type is referenced by
     * this type reference. This method must only be used for type references
     * whose sort is {@link #EXCEPTION_PARAMETER EXCEPTION_PARAMETER} .
     * 
     * @return the index of an exception in the 'throws' clause of a method.
     */
    public int getTryCatchBlockIndex() {
        return (value & 0x00FFFF00) >> 8;
    }

    /**
     * Returns the index of the type argument referenced by this type reference.
     * This method must only be used for type references whose sort is
     * {@link #CAST CAST}, {@link #CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
     * CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT},
     * {@link #METHOD_INVOCATION_TYPE_ARGUMENT METHOD_INVOCATION_TYPE_ARGUMENT},
     * {@link #CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
     * CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or
     * {@link #METHOD_REFERENCE_TYPE_ARGUMENT METHOD_REFERENCE_TYPE_ARGUMENT}.
     * 
     * @return a type parameter index.
     */
    public int getTypeArgumentIndex() {
        return value & 0xFF;
    }

    /**
     * Returns the int encoded value of this type reference, suitable for use in
     * visit methods related to type annotations, like visitTypeAnnotation.
     * 
     * @return the int encoded value of this type reference.
     */
    public int getValue() {
        return value;
    }
}