Member.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 java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Modifier;

import org.eclipse.persistence.tools.workbench.utility.ClassTools;
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 member (field or method):
 *     u2 access_flags;
 *     u2 name_index;
 *     u2 descriptor_index;
 *     u2 attributes_count;
 *     attribute_info[attributes_count] attributes;
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public abstract class Member {
    private Pool pool;
    private short accessFlags;
    /** these flags will match those returned by java.lang.Field/Method#getModifiers() */
    private short standardAccessFlags;
    private short nameIndex;
    private short descriptorIndex;
    private AttributePool attributePool;

    /** constants defined in "The Java Virtual Machine Specification" */
    public static final short ACC_SYNTHETIC = 0x1000;


    /**
     * Construct a class file member from the specified stream
     * of byte codes.
     */
    Member(ClassFileDataInputStream stream, Pool pool) throws IOException {
        super();
        this.pool = pool;
        this.initialize(stream);
    }

    void initialize(ClassFileDataInputStream stream) throws IOException {
        this.accessFlags = stream.readU2();
        this.standardAccessFlags = this.buildStandardAccessFlags();
        this.nameIndex = stream.readU2();
        this.descriptorIndex = stream.readU2();
        this.attributePool = new AttributePool(stream, this.classFile());
    }

    private short buildStandardAccessFlags() {
        short result = this.accessFlags;
        // clear any unsupported bits
        result &= this.visibleAccessFlagsMask();
        return result;
    }

    /**
     * Return a mask that will preserve only those bits properly recognized
     * by the java.lang.reflect.Modifier.toString() method.
     */
    abstract short visibleAccessFlagsMask();

    public String displayString() {
        StringWriter sw = new StringWriter(1000);
        IndentingPrintWriter writer = new IndentingPrintWriter(sw);
        this.displayStringOn(writer);
        return sw.toString();
    }

    public void displayStringOn(IndentingPrintWriter writer) {
        this.printDeclarationOn(writer);
//        writer.print(" (");
//        writer.print(this.descriptor());
//        writer.print(")");
        writer.println();

        writer.indent();
        this.attributePool.displayStringOn(writer);
        writer.undent();
    }

    public abstract void printDeclarationOn(PrintWriter writer);

    void printModifierOn(PrintWriter writer) {
        String modifierString = this.modifierString();
        if (modifierString.length() != 0) {
            writer.print(modifierString);
            writer.print(' ');
        }
    }

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

    public String modifierString() {
        return Modifier.toString(this.standardAccessFlags);
    }

    public String name() {
        return this.constantPool().getUTF8String(this.nameIndex);
    }

    public String descriptor() {
        return this.constantPool().getUTF8String(this.descriptorIndex);
    }

    public boolean isDeprecated() {
        return this.attributePool.isDeprecated();
    }

    /**
     * "A class member that does not appear in the source code
     * must be marked using a Synthetic attribute, or else it must
     * have its ACC_SYNTHETIC bit set."
     */
    public boolean isSynthetic() {
        return this.isMarkedSyntheticByAccessFlag() || this.isMarkedSyntheticByAttribute();
    }

    /**
     * Check a bit that cannot (yet?) be interpreted by the
     * Modifier static methods. This bit indicates the member
     * is "not present in the source code".
     */
    public boolean isMarkedSyntheticByAccessFlag() {
        return (this.accessFlags & ACC_SYNTHETIC) != 0;
    }

    public boolean isMarkedSyntheticByAttribute() {
        return this.attributePool.isSynthetic();
    }

    public Pool getPool() {
        return this.pool;
    }

    public ClassFile classFile() {
        return this.pool.getClassFile();
    }

    public String declaringClassName() {
        return this.classFile().className();
    }

    public ConstantPool constantPool() {
        return this.classFile().getConstantPool();
    }

    /**
     * Return the set of flags that will match those
     * returned by java.lang.Class#getModifiers()
     */
    public short standardAccessFlags() {
        return this.standardAccessFlags;
    }

    public short getAccessFlags() {
        return this.accessFlags;
    }

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

    public short getDescriptorIndex() {
        return this.descriptorIndex;
    }

    public AttributePool getAttributePool() {
        return this.attributePool;
    }

    public final String toString() {
        StringWriter sw = new StringWriter(200);
        PrintWriter pw = new PrintWriter(sw);
        pw.print(ClassTools.shortClassNameForObject(this));
        pw.print('(');
        this.printDeclarationOn(pw);
        pw.print(')');
        return sw.toString();
    }


    // ********** member interface **********

    /**
     * backpointer interface for members (fields and methods)
     */
    public interface Pool {
        ClassFile getClassFile();
    }

}