OverlayPatcher.java

package com.googlecode.gwt.test.internal;

import com.google.gwt.core.client.JavaScriptObject;
import com.googlecode.gwt.test.exceptions.GwtTestPatchException;
import com.googlecode.gwt.test.utils.JavaScriptObjects;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.NotFoundException;

import java.lang.reflect.Modifier;

/**
 * {@link Patcher} decorator to use for all {@link JavaScriptObject} subclasses (also known as
 * "overlay types"). It automatically adds an implementation for getter and setter written in JSNI.
 *
 * @author Gael Lazzari
 */
class OverlayPatcher implements Patcher {

    private static CtClass STRING_TYPE;

    static {

        try {
            STRING_TYPE = GwtClassPool.get().get(String.class.getName());
        } catch (NotFoundException e) {
            // Never append
            throw new GwtTestPatchException(e);
        }
    }

    private final Patcher decoratedPatcher;

    OverlayPatcher(Patcher patcher) {
        decoratedPatcher = patcher;
    }

    public void finalizeClass(CtClass c) throws Exception {
        if (decoratedPatcher != null) {
            decoratedPatcher.finalizeClass(c);
        }
    }

    public String getNewBody(CtMethod m) throws Exception {
        String newBody = decoratedPatcher != null ? decoratedPatcher.getNewBody(m) : null;

        if (newBody != null || !Modifier.isNative(m.getModifiers())
                || Modifier.isStatic(m.getModifiers())) {
            return newBody;
        }

        String propertyName = getPropertyName(m);
        if (propertyName == null) {
            // this method has not been identified as a property
            return null;
        }

        if (m.getName().startsWith("set") && m.getReturnType() == CtClass.voidType) {
            return getCodeSetProperty("this", propertyName, "$1");
        } else {
            return "return " + getCodeGetProperty("this", propertyName, m.getReturnType());
        }
    }

    public void initClass(CtClass c) throws Exception {
        if (decoratedPatcher != null) {
            decoratedPatcher.initClass(c);
        }
    }

    private String getCodeGetProperty(String object, String fieldName, CtClass returnType) {
        if (returnType == STRING_TYPE) {
            return JavaScriptObjects.class.getName() + ".getString(" + object + ", \"" + fieldName
                    + "\")";
        } else if (returnType == CtClass.booleanType) {
            return JavaScriptObjects.class.getName() + ".getBoolean(" + object + ", \"" + fieldName
                    + "\")";
        } else if (returnType == CtClass.intType) {
            return JavaScriptObjects.class.getName() + ".getInteger(" + object + ", \"" + fieldName
                    + "\")";
        } else if (returnType == CtClass.doubleType) {
            return JavaScriptObjects.class.getName() + ".getDouble(" + object + ", \"" + fieldName
                    + "\")";
        } else if (returnType == CtClass.floatType) {
            return JavaScriptObjects.class.getName() + ".getFloat(" + object + ", \"" + fieldName
                    + "\")";

        } else if (returnType == CtClass.shortType) {
            return JavaScriptObjects.class.getName() + ".getShort(" + object + ", \"" + fieldName
                    + "\")";
        }
        return "(" + returnType.getName() + ") " + JavaScriptObjects.class.getName() + ".getObject("
                + object + ", \"" + fieldName + "\")";
    }

    private String getCodeSetProperty(String object, String propertyName, String propertyValue) {

        return JavaScriptObjects.class.getName() + ".setProperty(" + object + ", \"" + propertyName
                + "\", " + propertyValue + ")";
    }

    private String getPropertyName(CtMethod m) throws Exception {
        String fieldName = null;
        String name = m.getName();

        if (!CtClass.voidType.equals(m.getReturnType()) && m.getParameterTypes().length == 0) {
            if (name.startsWith("get")) {
                fieldName = Character.toLowerCase(name.charAt(3)) + name.substring(4);
            } else if (m.getName().startsWith("is")) {
                fieldName = Character.toLowerCase(name.charAt(2)) + name.substring(3);
            } else {
                fieldName = name;
            }
        } else if (name.startsWith("set") && m.getParameterTypes().length == 1) {
            fieldName = Character.toLowerCase(name.charAt(3)) + name.substring(4);
        }

        return fieldName;
    }
}