LineNumber.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.bcel.classfile;
import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.bcel.util.Args;
/**
* This class represents a (PC offset, line number) pair, i.e., a line number in the source that corresponds to a
* relative address in the byte code. This is used for debugging purposes.
*
* @see LineNumberTable
*/
public final class LineNumber implements Cloneable, Node {
static final LineNumber[] EMPTY_ARRAY = {};
/** Program Counter (PC) corresponds to line */
private int startPc;
/** Number in source file */
private int lineNumber;
/**
* Constructs object from file stream.
*
* @param file Input stream
* @throws IOException if an I/O Exception occurs in readUnsignedShort
*/
LineNumber(final DataInput file) throws IOException {
this(file.readUnsignedShort(), file.readUnsignedShort());
}
/**
* @param startPc Program Counter (PC) corresponds to
* @param lineNumber line number in source file
*/
public LineNumber(final int startPc, final int lineNumber) {
this.startPc = Args.requireU2(startPc, "startPc");
this.lineNumber = Args.requireU2(lineNumber, "lineNumber");
}
/**
* Initialize from another object.
*
* @param c the object to copy
*/
public LineNumber(final LineNumber c) {
this(c.getStartPC(), c.getLineNumber());
}
/**
* Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
* I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
*
* @param v Visitor object
*/
@Override
public void accept(final Visitor v) {
v.visitLineNumber(this);
}
/**
* @return deep copy of this object
*/
public LineNumber copy() {
try {
return (LineNumber) clone();
} catch (final CloneNotSupportedException e) {
// TODO should this throw?
}
return null;
}
/**
* Dump line number/pc pair to file stream in binary format.
*
* @param file Output file stream
* @throws IOException if an I/O Exception occurs in writeShort
*/
public void dump(final DataOutputStream file) throws IOException {
file.writeShort(startPc);
file.writeShort(lineNumber);
}
/**
* @return Corresponding source line
*/
public int getLineNumber() {
return lineNumber & 0xffff;
}
/**
* @return PC in code
*/
public int getStartPC() {
return startPc & 0xffff;
}
/**
* @param lineNumber the source line number
*/
public void setLineNumber(final int lineNumber) {
this.lineNumber = (short) lineNumber;
}
/**
* @param startPc the pc for this line number
*/
public void setStartPC(final int startPc) {
this.startPc = (short) startPc;
}
/**
* @return String representation
*/
@Override
public String toString() {
return "LineNumber(" + getStartPC() + ", " + getLineNumber() + ")";
}
}