    001/*
    002 *  Licensed to the Apache Software Foundation (ASF) under one or more
    003 *  contributor license agreements.  See the NOTICE file distributed with
    004 *  this work for additional information regarding copyright ownership.
    005 *  The ASF licenses this file to You under the Apache License, Version 2.0
    006 *  (the "License"); you may not use this file except in compliance with
    007 *  the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017package org.apache.commons.compress.harmony.unpack200.bytecode.forms;
    018
    019import java.util.Objects;
    020
    021import org.apache.commons.compress.harmony.pack200.Pack200Exception;
    022import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
    023import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
    024import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
    025import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
    026
    027/**
    028 * Abstract class of all ByteCodeForms which add a nested entry from the globalConstantPool.
    029 */
    030public abstract class ReferenceForm extends ByteCodeForm {
    031
    032    public ReferenceForm(final int opcode, final String name, final int[] rewrite) {
    033        super(opcode, name, rewrite);
    034    }
    035
    036    protected abstract int getOffset(OperandManager operandManager);
    037
    038    protected abstract int getPoolID();
    039
    040    /*
    041     * (non-Javadoc)
    042     *
    043     * @see
    044     * org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons.
    045     * compress.harmony.unpack200.bytecode.ByteCode,
    046     * org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable,
    047     * org.apache.commons.compress.harmony.unpack200.Segment)
    048     */
    049    @Override
    050    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager,
    051        final int codeLength) {
    052        final int offset = getOffset(operandManager);
    053        try {
    054            setNestedEntries(byteCode, operandManager, offset);
    055        } catch (final Pack200Exception ex) {
    056            throw new Error("Got a pack200 exception. What to do?");
    057        }
    058    }
    059
    060    protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset)
    061        throws Pack200Exception {
    062        final SegmentConstantPool globalPool = operandManager.globalConstantPool();
    063        ClassFileEntry[] nested = null;
    064        nested = new ClassFileEntry[] {globalPool.getConstantPoolEntry(getPoolID(), offset)};
    065        Objects.requireNonNull(nested[0], "Null nested entries are not allowed");
    066        byteCode.setNested(nested);
    067        byteCode.setNestedPositions(new int[][] {{0, 2}});
    068    }
    069}