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

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Here is the source code for com.android.ide.eclipse.apt.internal.analysis.ConstantFinalAnalyzer.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 java.util.List;

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.FieldNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.MethodNode;

/**
 * This analyzer checks if there are possible constant declarations that are not final
 * following the guideline:<br/>
 * @see <a href="http://developer.android.com/guide/practices/design/performance.html#use_final">Declare Constants Final</a>
 * @author Mattia Gustarini
 */
public final class ConstantFinalAnalyzer extends SpecificAnalyzer {
    private ClassNode mCurrentClass;

    public ConstantFinalAnalyzer() {
        super("Declare Constants Final", "If it is a constant declare it final!");
    }

    /* (non-Javadoc)
     * @see com.android.ide.eclipse.apt.internal.analysis.SpecificAnalyzer#analyzeClass(org.objectweb.asm.tree.ClassNode)
     */
    @SuppressWarnings("unchecked")
    @Override
    protected Collection<Problem> analyzeClass(final ClassNode classNode) {
        final Collection<Problem> problems = new LinkedList<Problem>();
        if ((classNode.access & Opcodes.ACC_ENUM) == 0) {
            final List<MethodNode> methodNodes = (List<MethodNode>) classNode.methods;
            for (final MethodNode methodNode : methodNodes) {
                if (methodNode.name.equals("<clinit>")) {
                    mCurrentClass = classNode;
                    final Collection<Problem> foundProblems = analyzeMethod(methodNode);
                    problems.addAll(foundProblems);
                }
            }
        }
        return problems;
    }

    /* (non-Javadoc)
     * @see ch.usi.inf.gustarim.apt.analysis.SpecificAnalyzer#analyzeMethod(org.objectweb.asm.tree.MethodNode)
     */
    @Override
    protected Collection<Problem> analyzeMethod(final MethodNode methodNode) {
        final LinkedList<Problem> problems = new LinkedList<Problem>();
        final InsnList instructions = methodNode.instructions;
        for (int i = 0; i < instructions.size(); i++) {
            final AbstractInsnNode insnNode = instructions.get(i);
            if (insnNode.getOpcode() == Opcodes.PUTSTATIC) {
                final FieldInsnNode field = (FieldInsnNode) insnNode;
                final String fieldName = field.name;
                if (!isFinal(fieldName)) {
                    final Problem problem = new Problem(insnNode);
                    problems.add(problem);
                }
            }
        }
        return problems;
    }

    /**
     * Check if a given field of a class is final or not
     * @param fieldName Field name of a class
     * @return true if the field is final, false otherwise
     */
    @SuppressWarnings("unchecked")
    private boolean isFinal(final String fieldName) {
        boolean isFinal = false;
        final List<FieldNode> fields = (List<FieldNode>) mCurrentClass.fields;
        for (final FieldNode fieldNode : fields) {
            if (fieldNode.name.equals(fieldName)) {
                isFinal = (fieldNode.access & Opcodes.ACC_FINAL) != 0;
                break;
            }
        }
        return isFinal;
    }
}