org.apache.tools.ant.taskdefs.optional.depend.ClassFile Maven / Gradle / Ivy
/*
* 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.taskdefs.optional.depend;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Vector;
import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ClassCPInfo;
import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ConstantPool;
import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ConstantPoolEntry;
/**
* A ClassFile object stores information about a Java class. The class may
* be read from a DataInputStream.and written to a DataOutputStream. These
* are usually streams from a Java class file or a class file component of a
* Jar file.
*
*/
public class ClassFile {
/** The Magic Value that marks the start of a Java class file */
private static final int CLASS_MAGIC = 0xCAFEBABE;
/** This class' constant pool. */
private ConstantPool constantPool;
/** The class name for this class. */
private String className;
/**
* Read the class from a data stream. This method takes an InputStream
* as input and parses the class from the stream.
*
*
*
* @param stream an InputStream from which the class will be read
* @exception IOException if there is a problem reading from the given
* stream.
* @exception ClassFormatError if the class cannot be parsed correctly
*/
public void read(InputStream stream) throws IOException, ClassFormatError {
DataInputStream classStream = new DataInputStream(stream);
if (classStream.readInt() != CLASS_MAGIC) {
throw new ClassFormatError("No Magic Code Found "
+ "- probably not a Java class file.");
}
// right we have a good looking class file.
/* int minorVersion = */ classStream.readUnsignedShort();
/* int majorVersion = */ classStream.readUnsignedShort();
// read the constant pool in and resolve it
constantPool = new ConstantPool();
constantPool.read(classStream);
constantPool.resolve();
/* int accessFlags = */ classStream.readUnsignedShort();
int thisClassIndex = classStream.readUnsignedShort();
/* int superClassIndex = */ classStream.readUnsignedShort();
ClassCPInfo classInfo
= (ClassCPInfo) constantPool.getEntry(thisClassIndex);
className = classInfo.getClassName();
}
/**
* Get the classes which this class references.
*
* @return a vector of class names which this class references
*/
public Vector getClassRefs() {
Vector classRefs = new Vector();
final int size = constantPool.size();
for (int i = 0; i < size; ++i) {
ConstantPoolEntry entry = constantPool.getEntry(i);
if (entry != null
&& entry.getTag() == ConstantPoolEntry.CONSTANT_CLASS) {
ClassCPInfo classEntry = (ClassCPInfo) entry;
if (!classEntry.getClassName().equals(className)) {
classRefs.addElement(
ClassFileUtils.convertSlashName(classEntry.getClassName()));
}
}
}
return classRefs;
}
/**
* Get the class' fully qualified name in dot format.
*
* @return the class name in dot format (eg. java.lang.Object)
*/
public String getFullClassName() {
return ClassFileUtils.convertSlashName(className);
}
}