/*
* 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.tools.ant.filters.util;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.ConstantValue;
import org.apache.bcel.classfile.Field;
import org.apache.bcel.classfile.JavaClass;
// CheckStyle:HideUtilityClassConstructorCheck OFF - bc
/**
* Helper class that filters constants from a Java Class
*
*/
public final class JavaClassHelper {
/** System specific line separator. */
private static final String LS = System.getProperty("line.separator");
/**
* Get the constants declared in a file as name=value
*
* @param bytes the class as a array of bytes
* @return a StringBuffer contains the name=value pairs
* @exception IOException if an error occurs
*/
public static StringBuffer getConstants(byte[] bytes)
throws IOException {
final StringBuffer sb = new StringBuffer();
final ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
final ClassParser parser = new ClassParser(bis, "");
final JavaClass javaClass = parser.parse();
final Field[] fields = javaClass.getFields();
for (int i = 0; i < fields.length; i++) {
final Field field = fields[i];
if (field != null) {
final ConstantValue cv = field.getConstantValue();
if (cv != null) {
String cvs = cv.toString();
//Remove start and end quotes if field is a String
if (cvs.startsWith("\"") && cvs.endsWith("\"")) {
cvs = cvs.substring(1, cvs.length() - 1);
}
sb.append(field.getName());
sb.append('=');
sb.append(cvs);
sb.append(LS);
}
}
}
return sb;
}
}