FieldType.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.classfile.descriptor;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringReader;

import org.eclipse.persistence.tools.workbench.utility.ClassTools;
import org.eclipse.persistence.tools.workbench.utility.classfile.Visitor;


/**
 * This class models a class file Descriptor Field Type.
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public abstract class FieldType {


    // ********** static factory methods **********

    public static FieldType createFieldType(String fieldDescriptor) {
        try {
            return createFieldType(new StringReader(fieldDescriptor));
        } catch (IOException ex) {
            // highly unlikely when using a StringReader...
            throw new RuntimeException(ex);
        }
    }

    public static FieldType createFieldType(Reader reader) throws IOException {
        int c = reader.read();
        switch (c) {
            case 'L':    return new ObjectType(reader);
            case '[':    return new ArrayType(reader);
            default: return new BaseType(c);
        }
    }

    /**
     * Array classes are stored like descriptors; while non-array
     * classes are simply stored as a name (without the surrounding
     * "L   ;").
     */
    public static FieldType createFieldTypeForClassConstant(String internalName) {
        if (internalName.charAt(0) == '[') {
            return FieldType.createFieldType(internalName);
        }
        return new ObjectType(internalName);
    }


    // ********** public API **********

    /**
     * Accept the specified visitor.
     */
    public abstract void accept(Visitor visitor);

    /**
     * Return the field type's "array depth".
     */
    public abstract int arrayDepth();

    /**
     * Return the field type's "element type name".
     */
    public abstract String elementTypeName();

    /**
     * Return the name that matches the name returned by
     * java.lang.Class.getName().
     */
    public abstract String javaName();

    /**
     * Return the Java class corresponding to the
     * type declaration, if possible.
     */
    public abstract Class javaClass() throws ClassNotFoundException;

    /**
     * Return the declaration used to define the field type in Java
     * source code.
     */
    public String declaration() {
        StringBuffer sb = new StringBuffer(200);
        this.appendDeclarationTo(sb);
        return sb.toString();
    }

    /**
     * Append the Java source code that would define
     * the field type on the specified string buffer.
     */
    public abstract void appendDeclarationTo(StringBuffer sb);

    /**
     * Print the Java source code that would define
     * the field type on the specified writer.
     */
    public abstract void printDeclarationOn(PrintWriter writer);

    /**
     * Return the name that matches the name used internally by the JVM.
     */
    public abstract String internalName();

    public String toString() {
        StringBuffer sb = new StringBuffer(200);
        sb.append(ClassTools.shortClassNameForObject(this));
        sb.append('(');
        this.appendDeclarationTo(sb);
        sb.append(')');
        return sb.toString();
    }


    // ********** internal API **********

    FieldType() {
        super();
    }

    abstract void appendArrayJavaNameTo(StringBuffer sb);

    abstract void appendArrayInternalNameTo(StringBuffer sb);

}