lombok.patcher.scripts.AddFieldScript.java Source code

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Here is the source code for lombok.patcher.scripts.AddFieldScript.java

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/*
 * Copyright (C) 2009-2014 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.patcher.scripts;

import java.util.Collection;
import java.util.List;

import lombok.patcher.MethodTarget;
import lombok.patcher.PatchScript;
import lombok.patcher.TransplantMapper;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.Opcodes;

/**
 * Adds a field to any class.
 */
public class AddFieldScript extends PatchScript {
    private final int accessFlags;
    private final List<String> targetClasses;
    private final String fieldName;
    private final String fieldType;
    private final Object value;

    /**
     * @param targetClasses The class(es) to add the field to, separated with dots (e.g. java.lang.String).
     * @param fieldName the name of the field to create.
     * @param typeSpec the type of the field, in JVM spec (e.g. [I for an int array).
     */
    AddFieldScript(List<String> targetClasses, int accessFlags, String fieldName, String fieldType, Object value) {
        if (targetClasses == null)
            throw new NullPointerException("targetClass");
        if (fieldName == null)
            throw new NullPointerException("fieldName");
        if (fieldType == null)
            throw new NullPointerException("typeSpec");
        this.accessFlags = accessFlags;
        this.targetClasses = targetClasses;
        this.fieldName = fieldName;
        this.fieldType = fieldType;
        this.value = value;
    }

    @Override
    public byte[] patch(String className, byte[] byteCode, TransplantMapper transplantMapper) {
        for (String tc : targetClasses)
            if (MethodTarget.typeMatches(className, tc))
                return runASM(byteCode, false, transplantMapper);
        return null;
    }

    @Override
    protected ClassVisitor createClassVisitor(ClassWriter writer, String classSpec,
            TransplantMapper transplantMapper) {
        return new ClassVisitor(Opcodes.ASM4, writer) {
            private boolean alreadyAdded = false;

            @Override
            public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
                if (name != null && name.equals(fieldName))
                    alreadyAdded = true;
                return super.visitField(access, name, desc, signature, value);
            }

            @Override
            public void visitEnd() {
                if (!alreadyAdded) {
                    FieldVisitor fv = cv.visitField(accessFlags, fieldName, fieldType, null, value);
                    fv.visitEnd();
                }
                super.visitEnd();
            }
        };
    }

    @Override
    public Collection<String> getClassesToReload() {
        return targetClasses;
    }
}