org.snapscript.cglib.beans.BeanMapEmitter Maven / Gradle / Ivy

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/*
 * Copyright 2003,2004 The Apache Software Foundation
 *
 *  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 org.snapscript.cglib.beans;

import java.beans.*;
import java.util.*;

import org.snapscript.asm.ClassVisitor;
import org.snapscript.asm.Label;
import org.snapscript.asm.Type;
import org.snapscript.cglib.core.*;

class BeanMapEmitter extends ClassEmitter {
    private static final Type BEAN_MAP =
      TypeUtils.parseType("org.snapscript.cglib.beans.BeanMap");
    private static final Type FIXED_KEY_SET =
      TypeUtils.parseType("org.snapscript.cglib.beans.FixedKeySet");
    private static final Signature CSTRUCT_OBJECT =
      TypeUtils.parseConstructor("Object");
    private static final Signature CSTRUCT_STRING_ARRAY =
      TypeUtils.parseConstructor("String[]");
    private static final Signature BEAN_MAP_GET =
      TypeUtils.parseSignature("Object get(Object, Object)");
    private static final Signature BEAN_MAP_PUT =
      TypeUtils.parseSignature("Object put(Object, Object, Object)");
    private static final Signature KEY_SET =
      TypeUtils.parseSignature("java.util.Set keySet()");
    private static final Signature NEW_INSTANCE =
      new Signature("newInstance", BEAN_MAP, new Type[]{ Constants.TYPE_OBJECT });
    private static final Signature GET_PROPERTY_TYPE =
      TypeUtils.parseSignature("Class getPropertyType(String)");

    public BeanMapEmitter(ClassVisitor v, String className, Class type, int require) {
        super(v);

        begin_class(Constants.V1_2, Constants.ACC_PUBLIC, className, BEAN_MAP, null, Constants.SOURCE_FILE);
        EmitUtils.null_constructor(this);
        EmitUtils.factory_method(this, NEW_INSTANCE);
        generateConstructor();
            
        Map getters = makePropertyMap(ReflectUtils.getBeanGetters(type));
        Map setters = makePropertyMap(ReflectUtils.getBeanSetters(type));
        Map allProps = new HashMap();
        allProps.putAll(getters);
        allProps.putAll(setters);

        if (require != 0) {
            for (Iterator it = allProps.keySet().iterator(); it.hasNext();) {
                String name = (String)it.next();
                if ((((require & BeanMap.REQUIRE_GETTER) != 0) && !getters.containsKey(name)) ||
                    (((require & BeanMap.REQUIRE_SETTER) != 0) && !setters.containsKey(name))) {
                    it.remove();
                    getters.remove(name);
                    setters.remove(name);
                }
            }
        }
        generateGet(type, getters);
        generatePut(type, setters);

        String[] allNames = getNames(allProps);
        generateKeySet(allNames);
        generateGetPropertyType(allProps, allNames);
        end_class();
    }

    private Map makePropertyMap(PropertyDescriptor[] props) {
        Map names = new HashMap();
        for (int i = 0; i < props.length; i++) {
            names.put(((PropertyDescriptor)props[i]).getName(), props[i]);
        }
        return names;
    }

    private String[] getNames(Map propertyMap) {
        return (String[])propertyMap.keySet().toArray(new String[propertyMap.size()]);
    }

    private void generateConstructor() {
        CodeEmitter e = begin_method(Constants.ACC_PUBLIC, CSTRUCT_OBJECT, null);
        e.load_this();
        e.load_arg(0);
        e.super_invoke_constructor(CSTRUCT_OBJECT);
        e.return_value();
        e.end_method();
    }
        
    private void generateGet(Class type, final Map getters) {
        final CodeEmitter e = begin_method(Constants.ACC_PUBLIC, BEAN_MAP_GET, null);
        e.load_arg(0);
        e.checkcast(Type.getType(type));
        e.load_arg(1);
        e.checkcast(Constants.TYPE_STRING);
        EmitUtils.string_switch(e, getNames(getters), Constants.SWITCH_STYLE_HASH, new ObjectSwitchCallback() {
            public void processCase(Object key, Label end) {
                PropertyDescriptor pd = (PropertyDescriptor)getters.get(key);
                MethodInfo method = ReflectUtils.getMethodInfo(pd.getReadMethod());
                e.invoke(method);
                e.box(method.getSignature().getReturnType());
                e.return_value();
            }
            public void processDefault() {
                e.aconst_null();
                e.return_value();
            }
        });
        e.end_method();
    }

    private void generatePut(Class type, final Map setters) {
        final CodeEmitter e = begin_method(Constants.ACC_PUBLIC, BEAN_MAP_PUT, null);
        e.load_arg(0);
        e.checkcast(Type.getType(type));
        e.load_arg(1);
        e.checkcast(Constants.TYPE_STRING);
        EmitUtils.string_switch(e, getNames(setters), Constants.SWITCH_STYLE_HASH, new ObjectSwitchCallback() {
            public void processCase(Object key, Label end) {
                PropertyDescriptor pd = (PropertyDescriptor)setters.get(key);
                if (pd.getReadMethod() == null) {
                    e.aconst_null();
                } else {
                    MethodInfo read = ReflectUtils.getMethodInfo(pd.getReadMethod());
                    e.dup();
                    e.invoke(read);
                    e.box(read.getSignature().getReturnType());
                }
                e.swap(); // move old value behind bean
                e.load_arg(2); // new value
                MethodInfo write = ReflectUtils.getMethodInfo(pd.getWriteMethod());
                e.unbox(write.getSignature().getArgumentTypes()[0]);
                e.invoke(write);
                e.return_value();
            }
            public void processDefault() {
                // fall-through
            }
        });
        e.aconst_null();
        e.return_value();
        e.end_method();
    }
            
    private void generateKeySet(String[] allNames) {
        // static initializer
        declare_field(Constants.ACC_STATIC | Constants.ACC_PRIVATE, "keys", FIXED_KEY_SET, null);

        CodeEmitter e = begin_static();
        e.new_instance(FIXED_KEY_SET);
        e.dup();
        EmitUtils.push_array(e, allNames);
        e.invoke_constructor(FIXED_KEY_SET, CSTRUCT_STRING_ARRAY);
        e.putfield("keys");
        e.return_value();
        e.end_method();

        // keySet
        e = begin_method(Constants.ACC_PUBLIC, KEY_SET, null);
        e.load_this();
        e.getfield("keys");
        e.return_value();
        e.end_method();
    }

    private void generateGetPropertyType(final Map allProps, String[] allNames) {
        final CodeEmitter e = begin_method(Constants.ACC_PUBLIC, GET_PROPERTY_TYPE, null);
        e.load_arg(0);
        EmitUtils.string_switch(e, allNames, Constants.SWITCH_STYLE_HASH, new ObjectSwitchCallback() {
            public void processCase(Object key, Label end) {
                PropertyDescriptor pd = (PropertyDescriptor)allProps.get(key);
                EmitUtils.load_class(e, Type.getType(pd.getPropertyType()));
                e.return_value();
            }
            public void processDefault() {
                e.aconst_null();
                e.return_value();
            }
        });
        e.end_method();
    }
}