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


/**
 * This class models a local variable table attribute:
 *     u2 attribute_name_index;
 *     u4 attribute_length;
 *     u2 local_variable_table_length;
 *     {
 *         u2 start_pc;
 *         u2 length;
 *         u2 name_index;
 *         u2 descriptor_index;
 *         u2 index;
 *     }[local_variable_table_length] local_variable_table;
 *
 * See "The Java Virtual Machine Specification" Chapter 4.
 */
public class LocalVariableTableAttribute extends Attribute {
    private short count;
    private LocalVariable[] localVariables;

    /**
     * Construct a local variable table attribute from the specified stream
     * of byte codes.
     */
    LocalVariableTableAttribute(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.localVariables = new LocalVariable[cnt];
        LocalVariable[] variables = this.localVariables;
        for (short i = 0; i < cnt; i++) {
            variables[i] = new LocalVariable(stream, this.constantPool());
        }
    }

    public void displayNameOn(IndentingPrintWriter writer) {
        super.displayNameOn(writer);
        writer.print(" (count: ");
        writer.print(this.count);
        writer.print(")");
    }

    void displayInfoStringOn(IndentingPrintWriter writer) {
        short cnt = this.count;
        LocalVariable[] variables = this.localVariables;
        for (short i = 0; i < cnt; i++) {
            writer.print(i);
            writer.print(": ");
            variables[i].displayStringOn(writer);
        }
    }

    public String localVariableName(short index) {
        return this.localVariables[index].name();
    }

    public LocalVariable localVariableNamed(String name) {
        short cnt = this.count;
        LocalVariable[] variables = this.localVariables;
        for (short i = 0; i < cnt; i++) {
            LocalVariable localVariable = variables[i];
            if (localVariable.isNamed(name)) {
                return localVariable;
            }
        }
        return null;
    }

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

    public void accept(Visitor visitor) {
        visitor.visit(this);
        short cnt = this.count;
        LocalVariable[] variables = this.localVariables;
        for (short i = 0; i < cnt; i++) {
            variables[i].accept(visitor);
        }
    }

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

    public LocalVariable[] getLocalVariables() {
        return this.localVariables;
    }

    public LocalVariable getLocalVariable(short index) {
        return this.localVariables[index];
    }

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

}