ClassConstant.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;

import java.io.IOException;

import org.eclipse.persistence.tools.workbench.utility.classfile.descriptor.FieldType;
import org.eclipse.persistence.tools.workbench.utility.classfile.tools.ClassFileDataInputStream;
import org.eclipse.persistence.tools.workbench.utility.io.IndentingPrintWriter;


/**
 * This class models a class file class (or interface) constant:
 *     u1 tag;
 *     u2 name_index;
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public class ClassConstant extends Constant {
    private short nameIndex;
    private FieldType fieldDescriptor;        // lazy-initialized - so use the getter

    /**
     * Construct a class file constant from the specified stream
     * of byte codes.
     */
    ClassConstant(ConstantPool pool, byte tag, ClassFileDataInputStream stream) throws IOException {
        super(pool, tag, stream);
    }

    void initialize(ClassFileDataInputStream stream) throws IOException {
        this.nameIndex = stream.readU2();
    }

    public void displayStringOn(IndentingPrintWriter writer) {
        super.displayStringOn(writer);
        writer.print(" name: ");
        writer.println(this.name());
    }

    public String description() {
        return "class";
    }

    /**
     * Return the human-readable version of the class's name.
     */
    public String name() {
        return this.getFieldDescriptor().declaration();
    }

    private String internalName() {
        return this.utf8String(this.nameIndex);
    }

    /**
     * Return the name that matches the name returned by
     * java.lang.Class.getName().
     */
    public String javaTypeName() {
        return this.getFieldDescriptor().javaName();
    }

    /**
     * Return the class's Java class, if possible.
     */
    public Class javaType() throws ClassNotFoundException {
        return this.getFieldDescriptor().javaClass();
    }

    /**
     * Return the class's array depth. If the class is
     * not an array, the array depth is zero.
     */
    public int arrayDepth() {
        return this.getFieldDescriptor().arrayDepth();
    }

    /**
     * Return the class's element type name.
     */
    public String elementTypeName() {
        return this.getFieldDescriptor().elementTypeName();
    }

    public short getNameIndex() {
        return this.nameIndex;
    }

    public Object value() {
        return this.name();
    }

    public void accept(Visitor visitor) {
        visitor.visit(this);
        this.getFieldDescriptor().accept(visitor);
    }

    public FieldType getFieldDescriptor() {
        if (this.fieldDescriptor == null) {
            this.fieldDescriptor = FieldType.createFieldTypeForClassConstant(this.internalName());
        }
        return this.fieldDescriptor;
    }

}