    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 org.apache.commons.compress.harmony.pack200.Pack200Exception;
    020import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
    021import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
    022import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
    023import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
    024
    025/**
    026 * Abstract class of all ByteCodeForms which add a nested entry from the globalConstantPool.
    027 */
    028public abstract class ReferenceForm extends ByteCodeForm {
    029
    030    public ReferenceForm(final int opcode, final String name, final int[] rewrite) {
    031        super(opcode, name, rewrite);
    032    }
    033
    034    protected abstract int getPoolID();
    035
    036    protected abstract int getOffset(OperandManager operandManager);
    037
    038    protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset)
    039        throws Pack200Exception {
    040        final SegmentConstantPool globalPool = operandManager.globalConstantPool();
    041        ClassFileEntry[] nested = null;
    042        nested = new ClassFileEntry[] {globalPool.getConstantPoolEntry(getPoolID(), offset)};
    043        if (nested[0] == null) {
    044            throw new NullPointerException("Null nested entries are not allowed");
    045        }
    046        byteCode.setNested(nested);
    047        byteCode.setNestedPositions(new int[][] {{0, 2}});
    048    }
    049
    050    /*
    051     * (non-Javadoc)
    052     *
    053     * @see
    054     * org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons.
    055     * compress.harmony.unpack200.bytecode.ByteCode,
    056     * org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable,
    057     * org.apache.commons.compress.harmony.unpack200.Segment)
    058     */
    059    @Override
    060    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager,
    061        final int codeLength) {
    062        final int offset = getOffset(operandManager);
    063        try {
    064            setNestedEntries(byteCode, operandManager, offset);
    065        } catch (final Pack200Exception ex) {
    066            throw new Error("Got a pack200 exception. What to do?");
    067        }
    068    }
    069}