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


/**
 * This class models an exceptions attribute:
 *     u2 attribute_name_index;
 *     u4 attribute_length;
 *     u2 number_of_exceptions;
 *     u2[number_of_exceptions] exception_index_table
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public class ExceptionsAttribute extends Attribute {
    private short count;
    private short[] exceptionIndexes;


    /**
     * Construct an exceptions attribute from the specified stream
     * of byte codes.
     */
    ExceptionsAttribute(ClassFileDataInputStream stream, short nameIndex, AttributePool pool) throws IOException {
        super(stream, nameIndex, pool);
    }

    void initializeInfo(ClassFileDataInputStream stream) throws IOException {
        this.count = stream.readU2();
        short cnt = this.count;
        this.exceptionIndexes = new short[cnt];
        short[] indexes = this.exceptionIndexes;
        for (short i = 0; i < cnt; i++) {
            indexes[i] = stream.readU2();
        }
    }

    void displayInfoStringOn(IndentingPrintWriter writer) {
        short cnt = this.count;
        for (short i = 0; i < cnt; i++) {
            writer.println(this.exceptionClassName(i));
        }
    }

    public String exceptionClassName(short index) {
        return this.constantPool().getClassConstant(this.exceptionIndexes[index]).name();
    }

    public String[] exceptionClassNames() {
        short cnt = this.count;
        if (cnt == 0) {
            return EMPTY_STRING_ARRAY;
        }
        String[] exceptionClassNames = new String[cnt];
        for (short i = 0; i < cnt; i++) {
            exceptionClassNames[i] = this.exceptionClassName(i);
        }
        return exceptionClassNames;
    }

    public void printThrowsClauseOn(PrintWriter writer) {
        short cnt = this.count;
        if (cnt == 0) {
            return;
        }
        writer.print(" throws ");
        for (short i = 0; i < cnt; i++) {
            if (i != 0) {
                writer.print(", ");
            }
            writer.print(this.exceptionClassName(i));
        }
    }

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

    public short getCount() {
        return this.count;
    }

    public short[] getExceptionIndexes() {
        return this.exceptionIndexes;
    }

    public short getExceptionIndex(short index) {
        return this.exceptionIndexes[index];
    }

    void toString(StringBuffer sb) {
        sb.append(this.count);
        sb.append(" exception(s)");
    }

}