    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
    015    package org.apache.tapestry5.internal.plastic;
    016
    017    import org.apache.tapestry5.internal.plastic.asm.Label;
    018    import org.apache.tapestry5.internal.plastic.asm.Opcodes;
    019    import org.apache.tapestry5.plastic.InstructionBuilder;
    020    import org.apache.tapestry5.plastic.InstructionBuilderCallback;
    021    import org.apache.tapestry5.plastic.SwitchBlock;
    022    import org.apache.tapestry5.plastic.SwitchCallback;
    023
    024    public 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                    public void doBuild(InstructionBuilder builder)
    071                    {
    072                        builder.throwException(IllegalArgumentException.class,
    073                                "Switch value not matched in case statement.");
    074                    }
    075                });
    076            }
    077
    078            state.visitor.visitLabel(endSwitchLabel);
    079
    080            lock();
    081        }
    082
    083        public void addCase(int caseValue, boolean jumpToEnd, InstructionBuilderCallback callback)
    084        {
    085            assert caseValue >= min;
    086            assert caseValue <= max;
    087
    088            if (defaultAdded)
    089                throw new IllegalStateException("The default block must come last.");
    090
    091            // TODO: Check that no case value is repeated
    092
    093            state.visitor.visitLabel(caseLabels[caseValue - min]);
    094
    095            callback.doBuild(builder);
    096
    097            if (jumpToEnd)
    098                state.visitor.visitJumpInsn(GOTO, endSwitchLabel);
    099        }
    100
    101        public void addDefault(InstructionBuilderCallback callback)
    102        {
    103            if (defaultAdded)
    104                throw new IllegalStateException("A SwitchBlock may only have one default block.");
    105
    106            state.visitor.visitLabel(defaultLabel);
    107
    108            callback.doBuild(builder);
    109
    110            defaultAdded = true;
    111        }
    112    }