com.android.ide.eclipse.apt.internal.analysis.EnumAnalyzer.java Source code

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Here is the source code for com.android.ide.eclipse.apt.internal.analysis.EnumAnalyzer.java

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/**
 * Copyright (C) Mattia Gustarini
 * 
 * Licensed 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 com.android.ide.eclipse.apt.internal.analysis;

import java.util.Collection;
import java.util.LinkedList;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.MethodNode;

import com.android.ide.eclipse.apt.internal.crawler.ClassCrawler;

/**
 * This analyzer checks if in the code are present uses of enums
 * following the guideline:<br/>
 * @see <a href="http://developer.android.com/guide/practices/design/performance.html#avoid_enums">Avoid Enums</a>
 * @author Mattia Gustarini
 *
 */
public final class EnumAnalyzer extends SpecificAnalyzer {
    private final LinkedList<String> mEnumClasseNames;
    private boolean mFirstClass;

    public EnumAnalyzer() {
        super("Avoid Enums",
                "The use of enum is discouraged, because they increase the byte code size and decrease speed!");
        mEnumClasseNames = new LinkedList<String>();
        mFirstClass = true;
    }

    /* (non-Javadoc)
     * @see com.android.ide.eclipse.apt.internal.analysis.SpecificAnalyzer#analyse(org.objectweb.asm.tree.ClassNode)
     */
    @Override
    public void analyse(final ClassNode classNode) {
        if (mFirstClass) {
            //search for all the Enum classes in the project
            final Collection<ClassNode> classes = ClassCrawler.sClassNodes;
            for (final ClassNode classNode2 : classes) {
                if ((classNode2.access & Opcodes.ACC_ENUM) != 0) {
                    mEnumClasseNames.add(classNode2.name);
                }
            }
            mFirstClass = false;
        }
        if ((classNode.access & Opcodes.ACC_ENUM) == 0) {
            super.analyse(classNode);
        }
    }

    /* (non-Javadoc)
     * @see ch.usi.inf.gustarim.apt.analysis.SpecificAnalyzer#analyzeMethod(org.objectweb.asm.tree.MethodNode)
     */
    @Override
    protected Collection<Problem> analyzeMethod(MethodNode methodNode) {
        final Collection<Problem> problems = new LinkedList<Problem>();
        final InsnList instructions = methodNode.instructions;
        for (int i = 0; i < instructions.size(); i++) {
            final AbstractInsnNode instruction = instructions.get(i);
            final int op = instruction.getOpcode();
            if (op == Opcodes.GETSTATIC) {
                final FieldInsnNode field = (FieldInsnNode) instruction;
                final String fieldDesc = field.desc;
                final int fieldDescLength = fieldDesc.length();
                if (fieldDescLength > 1) {
                    final String type = fieldDesc.substring(1, fieldDesc.length() - 1);
                    if (mEnumClasseNames.contains(type)) {
                        final Problem problem = new Problem(instruction);
                        problems.add(problem);
                    }
                }
            }
        }
        return problems;
    }

}