    001// Copyright 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.internal.plastic;
    016
    017import org.apache.tapestry5.internal.plastic.asm.Label;
    018import org.apache.tapestry5.internal.plastic.asm.Opcodes;
    019import org.apache.tapestry5.plastic.InstructionBuilder;
    020import org.apache.tapestry5.plastic.InstructionBuilderCallback;
    021import org.apache.tapestry5.plastic.SwitchBlock;
    022import org.apache.tapestry5.plastic.SwitchCallback;
    023
    024public class SwitchBlockImpl extends Lockable implements SwitchBlock, Opcodes
    025{
    026    private final InstructionBuilder builder;
    027
    028    private final InstructionBuilderState state;
    029
    030    private final int min, max;
    031
    032    private final Label defaultLabel, endSwitchLabel;
    033
    034    private final Label[] caseLabels;
    035
    036    private boolean defaultAdded = false;
    037
    038    SwitchBlockImpl(InstructionBuilder builder, InstructionBuilderState state, int min, int max)
    039    {
    040        assert min <= max;
    041
    042        this.builder = builder;
    043        this.state = state;
    044        this.min = min;
    045        this.max = max;
    046
    047        defaultLabel = new Label();
    048        endSwitchLabel = new Label();
    049
    050        caseLabels = new Label[max - min + 1];
    051
    052        for (int i = min; i <= max; i++)
    053        {
    054            caseLabels[i - min] = new Label();
    055        }
    056
    057        state.visitor.visitTableSwitchInsn(min, max, defaultLabel, caseLabels);
    058    }
    059
    060    void doCallback(SwitchCallback callback)
    061    {
    062        check();
    063
    064        callback.doSwitch(this);
    065
    066        if (!defaultAdded)
    067        {
    068            addDefault(new InstructionBuilderCallback()
    069            {
    070                @Override
    071                public void doBuild(InstructionBuilder builder)
    072                {
    073                    builder.throwException(IllegalArgumentException.class,
    074                            "Switch value not matched in case statement.");
    075                }
    076            });
    077        }
    078
    079        state.visitor.visitLabel(endSwitchLabel);
    080
    081        lock();
    082    }
    083
    084    @Override
    085    public void addCase(int caseValue, boolean jumpToEnd, InstructionBuilderCallback callback)
    086    {
    087        assert caseValue >= min;
    088        assert caseValue <= max;
    089
    090        if (defaultAdded)
    091            throw new IllegalStateException("The default block must come last.");
    092
    093        // TODO: Check that no case value is repeated
    094
    095        state.visitor.visitLabel(caseLabels[caseValue - min]);
    096
    097        callback.doBuild(builder);
    098
    099        if (jumpToEnd)
    100            state.visitor.visitJumpInsn(GOTO, endSwitchLabel);
    101    }
    102
    103    @Override
    104    public void addDefault(InstructionBuilderCallback callback)
    105    {
    106        if (defaultAdded)
    107            throw new IllegalStateException("A SwitchBlock may only have one default block.");
    108
    109        state.visitor.visitLabel(defaultLabel);
    110
    111        callback.doBuild(builder);
    112
    113        defaultAdded = true;
    114    }
    115}