/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.bcel.generic;

Super class for JSR - Jump to subroutine
/**
 * Super class for JSR - Jump to subroutine
 *
 */
public abstract class JsrInstruction extends BranchInstruction implements UnconditionalBranch,
        TypedInstruction, StackProducer {

    JsrInstruction(final short opcode, final InstructionHandle target) {
        super(opcode, target);
    }


    
Empty constructor needed for Instruction.readInstruction.
Not to be used otherwise.
/**
     * Empty constructor needed for Instruction.readInstruction.
     * Not to be used otherwise.
     */
    JsrInstruction() {
    }


    
Returns:
return address type/** @return return address type
     */
    @Override
    public Type getType( final ConstantPoolGen cp ) {
        return new ReturnaddressType(physicalSuccessor());
    }


    
Returns an InstructionHandle to the physical successor
of this JsrInstruction. For this method to work,
this JsrInstruction object must not be shared between
multiple InstructionHandle objects!
Formally, there must not be InstructionHandle objects
i, j where i != j and i.getInstruction() == this ==
j.getInstruction().
Returns:
an InstructionHandle to the "next" instruction that
will be executed when RETurned from a subroutine./**
     * Returns an InstructionHandle to the physical successor
     * of this JsrInstruction. <B>For this method to work,
     * this JsrInstruction object must not be shared between
     * multiple InstructionHandle objects!</B>
     * Formally, there must not be InstructionHandle objects
     * i, j where i != j and i.getInstruction() == this ==
     * j.getInstruction().
     * @return an InstructionHandle to the "next" instruction that
     * will be executed when RETurned from a subroutine.
     */
    public InstructionHandle physicalSuccessor() {
        InstructionHandle ih = super.getTarget();
        // Rewind!
        while (ih.getPrev() != null) {
            ih = ih.getPrev();
        }
        // Find the handle for "this" JsrInstruction object.
        while (ih.getInstruction() != this) {
            ih = ih.getNext();
        }
        final InstructionHandle toThis = ih;
        while (ih != null) {
            ih = ih.getNext();
            if ((ih != null) && (ih.getInstruction() == this)) {
                throw new RuntimeException("physicalSuccessor() called on a shared JsrInstruction.");
            }
        }
        // Return the physical successor
        return toThis.getNext();
    }
}