jaxb-ri/xjc/src/main/java/com/sun/tools/xjc/generator/bean/field/UntypedListField.java

/*
 * Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package com.sun.tools.xjc.generator.bean.field;

import java.util.ArrayList;
import java.util.List;

import com.sun.codemodel.JBlock;
import com.sun.codemodel.JClass;
import com.sun.codemodel.JExpr;
import com.sun.codemodel.JExpression;
import com.sun.codemodel.JMethod;
import com.sun.codemodel.JVar;
import com.sun.tools.xjc.generator.bean.ClassOutlineImpl;
import com.sun.tools.xjc.generator.bean.MethodWriter;
import com.sun.tools.xjc.model.CPropertyInfo;
import org.glassfish.jaxb.core.api.impl.NameConverter;

/**
 * Realizes a property as an untyped {@link List}.
 * 
 * <pre>
 * List getXXX();
 * </pre>
 * 
 * <h2>Default value handling</h2>
 * <p>
 * Since unmarshaller just adds new values into the storage,
 * we can't fill the storage by default values at the time of
 * instanciation. (or oherwise values found in the document will
 * be appended to default values, where it should overwrite them.)
 * <p>
 * Therefore, when the object is created, the storage will be empty.
 * When the getXXX method is called, we'll check if the storage is
 * modified in anyway. If it is modified, it must mean that the values
 * are found in the document, so we just return it.
 * 
 * Otherwise we will fill in default values and return it to the user.
 * 
 * <p>
 * When a list has default values, its dirty flag is set to true.
 * Marshaller will check this and treat it appropriately.
 * 
 * 
 * @author
 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
 */
public class UntypedListField extends AbstractListField {

    /**
     * A concrete class that implements the List interface.
     * An instance of this class will be used to store data
     * for this field.
     */
    private final JClass coreList;


    /** List getFIELD() method. */
    private JMethod $get;

    /**
     * @param coreList
     *      A concrete class that implements the List interface.
     *      An instance of this class will be used to store data
     *      for this field.
     */
    protected UntypedListField(ClassOutlineImpl context, CPropertyInfo prop, JClass coreList) {
        // the JAXB runtime picks ArrayList if the signature is List,
        // so don't do eager allocation if it's ArrayList.
        // otherwise we need to do eager allocation so that the collection type specified by the user
        // will be used.
        super(context, prop, !coreList.fullName().equals("java.util.ArrayList"));
        this.coreList = coreList.narrow(exposedType.boxify());
        generate();
    }

    protected final JClass getCoreListType() {
        return coreList;
    }

    @Override
    public void generateAccessors() {
        final MethodWriter writer = outline.createMethodWriter();
        final Accessor acc = create(JExpr._this());

        // [RESULT]
        // List getXXX() {
        //     return <ref>;
        // }
        $get = writer.declareMethod(listT,"get"+prop.getName(true));
        writer.javadoc().append(prop.javadoc);
        JBlock block = $get.body();
        fixNullRef(block);  // avoid using an internal getter
        block._return(acc.ref(true));

        String pname = NameConverter.standard.toVariableName(prop.getName(true));
        writer.javadoc().append(
            "Gets the value of the "+pname+" property.\n\n"+
            "<p>\n" +
            "This accessor method returns a reference to the live list,\n" +
            "not a snapshot. Therefore any modification you make to the\n" +
            "returned list will be present inside the Jakarta XML Binding object.\n" +
            "This is why there is not a <CODE>set</CODE> method for the " +pname+ " property.\n" +
            "\n"+
            "<p>\n" +
            "For example, to add a new item, do as follows:\n"+
            "<pre>\n"+
            "   get"+prop.getName(true)+"().add(newItem);\n"+
            "</pre>\n"+
            "\n\n"
        );

        writer.javadoc().append(
            "<p>\n" +
            "Objects of the following type(s) are allowed in the list\n")
            .append(listPossibleTypes(prop));
    }

    public Accessor create(JExpression targetObject) {
        return new Accessor(targetObject);
    }

    class Accessor extends AbstractListField.Accessor {
        protected Accessor( JExpression $target ) {
            super($target);
        }

        public void toRawValue(JBlock block, JVar $var) {
            // [RESULT]
            // $<var>.addAll(bean.getLIST());
            // list.toArray( array );
            block.assign($var,JExpr._new(codeModel.ref(ArrayList.class).narrow(exposedType.boxify())).arg(
                $target.invoke($get)
            ));
        }

        public void fromRawValue(JBlock block, String uniqueName, JExpression $var) {
            // [RESULT]
            // bean.getLIST().addAll($<var>);
            JVar $list = block.decl(listT,uniqueName+'l',$target.invoke($get));
            block.invoke($list,"addAll").arg($var);
        }
    }
}