001: /*
002: * Licensed to the Apache Software Foundation (ASF) under one or more
003: * contributor license agreements. See the NOTICE file distributed with
004: * this work for additional information regarding copyright ownership.
005: * The ASF licenses this file to You under the Apache License, Version 2.0
006: * (the "License"); you may not use this file except in compliance with
007: * the License. You may obtain a copy of the License at
008: *
009: * http://www.apache.org/licenses/LICENSE-2.0
010: *
011: * Unless required by applicable law or agreed to in writing, software
012: * distributed under the License is distributed on an "AS IS" BASIS,
013: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014: * See the License for the specific language governing permissions and
015: * limitations under the License.
016: *
017: */
018: package org.apache.tools.ant.taskdefs.optional.depend;
019:
020: import java.io.DataInputStream;
021: import java.io.IOException;
022: import java.io.InputStream;
023: import java.util.Vector;
024: import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ClassCPInfo;
025: import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ConstantPool;
026: import org.apache.tools.ant.taskdefs.optional.depend.constantpool.ConstantPoolEntry;
027:
028: /**
029: * A ClassFile object stores information about a Java class. The class may
030: * be read from a DataInputStream.and written to a DataOutputStream. These
031: * are usually streams from a Java class file or a class file component of a
032: * Jar file.
033: *
034: */
035: public class ClassFile {
036:
037: /** The Magic Value that marks the start of a Java class file */
038: private static final int CLASS_MAGIC = 0xCAFEBABE;
039:
040: /** This class' constant pool. */
041: private ConstantPool constantPool;
042:
043: /** The class name for this class. */
044: private String className;
045:
046: /**
047: * Read the class from a data stream. This method takes an InputStream
048: * as input and parses the class from the stream. <p>
049: *
050: *
051: *
052: * @param stream an InputStream from which the class will be read
053: * @exception IOException if there is a problem reading from the given
054: * stream.
055: * @exception ClassFormatError if the class cannot be parsed correctly
056: */
057: public void read(InputStream stream) throws IOException,
058: ClassFormatError {
059: DataInputStream classStream = new DataInputStream(stream);
060:
061: if (classStream.readInt() != CLASS_MAGIC) {
062: throw new ClassFormatError("No Magic Code Found "
063: + "- probably not a Java class file.");
064: }
065:
066: // right we have a good looking class file.
067: /* int minorVersion = */classStream.readUnsignedShort();
068: /* int majorVersion = */classStream.readUnsignedShort();
069:
070: // read the constant pool in and resolve it
071: constantPool = new ConstantPool();
072:
073: constantPool.read(classStream);
074: constantPool.resolve();
075:
076: /* int accessFlags = */classStream.readUnsignedShort();
077: int this ClassIndex = classStream.readUnsignedShort();
078: /* int superClassIndex = */classStream.readUnsignedShort();
079: ClassCPInfo classInfo = (ClassCPInfo) constantPool
080: .getEntry(this ClassIndex);
081: className = classInfo.getClassName();
082: }
083:
084: /**
085: * Get the classes which this class references.
086: *
087: * @return a vector of class names which this class references
088: */
089: public Vector getClassRefs() {
090:
091: Vector classRefs = new Vector();
092:
093: for (int i = 0; i < constantPool.size(); ++i) {
094: ConstantPoolEntry entry = constantPool.getEntry(i);
095:
096: if (entry != null
097: && entry.getTag() == ConstantPoolEntry.CONSTANT_CLASS) {
098: ClassCPInfo classEntry = (ClassCPInfo) entry;
099:
100: if (!classEntry.getClassName().equals(className)) {
101: classRefs
102: .addElement(ClassFileUtils
103: .convertSlashName(classEntry
104: .getClassName()));
105: }
106: }
107: }
108:
109: return classRefs;
110: }
111:
112: /**
113: * Get the class' fully qualified name in dot format.
114: *
115: * @return the class name in dot format (eg. java.lang.Object)
116: */
117: public String getFullClassName() {
118: return ClassFileUtils.convertSlashName(className);
119: }
120: }
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