/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2006, University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.ba.generic;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.annotation.CheckForNull;
import org.apache.bcel.generic.ArrayType;
import org.apache.bcel.generic.ObjectType;
import org.apache.bcel.generic.ReferenceType;
import org.apache.bcel.generic.Type;
import edu.umd.cs.findbugs.ba.AnalysisContext;
import edu.umd.cs.findbugs.ba.type.NullType;
import edu.umd.cs.findbugs.util.Util;
/**
* Utilities for adding support for generics. Most of these methods can be
* applied to generic and non generic type information.
*
* @author Nat Ayewah
*/
public class GenericUtilities {
public static enum TypeCategory {
/** A simple (non-generic ObjectType) */
PLAIN_OBJECT_TYPE {
@Override
public ReferenceType produce(GenericObjectType obj) {
return obj;
}
@Override
public String asString(GenericObjectType obj) {
// obj.getTypeCategory() does not return PLAIN_OBJECT_TYPE
return GenericUtilities.getString(obj);
}
},
/** A array */
ARRAY_TYPE {
@Override
public ReferenceType produce(GenericObjectType obj) {
return obj;
}
@Override
public String asString(GenericObjectType obj) {
// obj.getTypeCategory() does not return ARRAY_TYPE
return GenericUtilities.getString(obj);
}
},
/** A parameterized class e.g. <code>List<String></code> */
PARAMETERIZED {
@Override
public ReferenceType produce(GenericObjectType obj) {
return obj;
}
@Override
public String asString(GenericObjectType obj) {
StringBuilder b = new StringBuilder(obj.toPlainString());
b.append("<");
boolean first = true;
for (Type t : obj.parameters) {
if (!first)
b.append(",");
first = false;
b.append(GenericUtilities.getString(t));
}
b.append(">");
return b.toString();
}
},
/**
* A simple type variable e.g. <code>E</code>. Underlying ObjectType is
* <code>java.lang.Object</code>
*/
TYPE_VARIABLE {
@Override
public ReferenceType produce(GenericObjectType obj) {
return Type.OBJECT;
}
@Override
public String asString(GenericObjectType obj) {
return obj.variable;
}
},
/**
* A simple wildcard i.e. <code>?</code>. Underlying ObjectType is
* <code>java.lang.Object</code>
*/
WILDCARD {
@Override
public ReferenceType produce(GenericObjectType obj) {
return Type.OBJECT;
}
@Override
public String asString(GenericObjectType obj) {
return "?";
}
},
/**
* A wildcard that extends another ObjectType e.g.
* <code>? extends Comparable</code>. Underlying ObjectType is
* <code>java.lang.Object</code>. The extended type can be an ObjectType
* or a GenericObjectType
*/
WILDCARD_EXTENDS {
@Override
public ReferenceType produce(GenericObjectType obj) {
return obj.extension;
}
@Override
public String asString(GenericObjectType obj) {
Type extension = obj.extension;
assert extension != null;
return "? extends " + GenericUtilities.getString(extension);
}
},
/**
* A wildcard that is extended by another ObjectType e.g.
* <code>? super Comparable</code>. Underlying ObjectType is
* <code>java.lang.Object</code>. The super type can be an ObjectType or
* a GenericObjectType
*/
WILDCARD_SUPER {
@Override
public ReferenceType produce(GenericObjectType obj) {
return Type.OBJECT;
}
@Override
public String asString(GenericObjectType obj) {
Type extension = obj.extension;
assert extension != null;
return "? super " + GenericUtilities.getString(extension);
}
};
public abstract String asString(GenericObjectType obj);
public abstract ReferenceType produce(GenericObjectType obj);
public static String asString(ArrayType atype) {
Type obj = atype.getBasicType();
String result = GenericUtilities.getString(obj);
return result + Util.repeat("[]", atype.getDimensions());
}
}
/**
* Get the TypeCategory that represents this Object
*
* @see GenericUtilities.TypeCategory
*/
public static final TypeCategory getTypeCategory(Type type) {
if (type instanceof GenericObjectType)
return ((GenericObjectType) type).getTypeCategory();
if (type instanceof ObjectType || type instanceof NullType)
return TypeCategory.PLAIN_OBJECT_TYPE;
if (type instanceof ArrayType)
return TypeCategory.ARRAY_TYPE;
throw new IllegalArgumentException("Not a reference type: " + type);
}
public static final boolean isPlainObject(Type type) {
return getTypeCategory(type) == TypeCategory.PLAIN_OBJECT_TYPE;
}
/**
* Get String representation of a Type including Generic information
*/
public static final String getString(Type type) {
if (type instanceof GenericObjectType)
return ((GenericObjectType) type).toString(true);
else if (type instanceof ArrayType)
return TypeCategory.asString((ArrayType) type);
else
return type.toString();
}
static String stripAngleBrackets(String s) {
if (s.indexOf('<') == -1)
return s;
StringBuilder result = new StringBuilder(s.length());
int nesting = 0;
boolean seenLeftBracket = false;
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c == '<') {
nesting++;
seenLeftBracket = true;
} else if (c == '>')
nesting--;
else if (nesting == 0) {
if (seenLeftBracket && c == '.')
result.append('$');
else
result.append(c);
}
}
return result.toString();
}
public static GenericObjectType getType(String className, List<? extends ReferenceType> parameters) {
return new GenericObjectType(className, parameters);
}
/**
* This method is analogous to <code>Type.getType(String)</code>, except
* that it also accepts signatures with generic information. e.g.
* <code>Ljava/util/ArrayList<TT;>;</code>
* <p>
*
* The signature should only contain one type. Use GenericSignatureParser to
* break up a signature with many types or call createTypes(String) to
* return a list of types
*/
public static @CheckForNull
Type getType(String signature) {
try {
// ensure signature only has one type
if (new GenericSignatureParser("(" + signature + ")V").getNumParameters() != 1)
throw new IllegalArgumentException("the following signature does not " + "contain exactly one type: " + signature);
int index = 0;
if (signature.startsWith("L")) {
index = lastMatchedLeftAngleBracket(signature);
if (index < 0)
return Type.getType(stripAngleBrackets(signature));
String typeParameters = signature.substring(index + 1, nextUnmatchedRightAngleBracket(signature, index + 1));
List<ReferenceType> parameters = GenericUtilities.getTypeParameters(typeParameters);
if (parameters == null)
return null;
String baseType = removeMatchedAngleBrackets(signature.substring(1, index)).replace('.', '$');
return new GenericObjectType(baseType, parameters);
} else if (signature.startsWith("T")) {
// can't handle type variables
return null;
} else if (signature.startsWith("[")) {
index++;
while (signature.charAt(index) == '[')
index++;
Type componentType = getType(signature.substring(index));
if (componentType == null)
return null;
return new ArrayType(componentType, index);
} else if (signature.startsWith("*")) {
return new GenericObjectType("*");
} else if (signature.startsWith("+") || signature.startsWith("-")) {
Type baseType = getType(signature.substring(1));
if (baseType == null)
return null;
return new GenericObjectType(signature.substring(0, 1), (ReferenceType) baseType);
} else
// assert signature contains no generic information
return Type.getType(signature);
} catch (IllegalStateException e) {
AnalysisContext.logError("Error parsing signature " + signature, e);
return null;
}
}
public static ObjectType merge(@CheckForNull Type t1, ObjectType t2) {
if (t1 instanceof GenericObjectType)
return merge((GenericObjectType) t1, t2);
return t2;
}
public static Type merge(@CheckForNull GenericObjectType t1, Type t2) {
if (t1 == null)
return t2;
if (t2 instanceof ObjectType)
return merge(t1,(ObjectType) t2);
if (t2 instanceof NullType)
return t1;
return t2;
}
public static ObjectType merge(@CheckForNull GenericObjectType t1, ObjectType t2) {
if (t1 == null || t2 instanceof GenericObjectType)
return t2;
List<? extends ReferenceType> parameters = t1.getParameters();
if (parameters == null)
return t2;
return new GenericObjectType(t2.getClassName(), parameters);
}
public static String removeMatchedAngleBrackets(String s) {
int first = s.indexOf('<');
if (first < 0)
return s;
StringBuilder result = new StringBuilder(s.substring(0, first));
int pos = first;
int nesting = 0;
while (pos < s.length()) {
char c = s.charAt(pos++);
if (c == '<')
nesting++;
else if (c == '>')
nesting--;
else if (nesting == 0)
result.append(c);
}
return result.toString();
}
public static int nextUnmatchedRightAngleBracket(String s, int startingAt) {
int nesting = 0;
int pos = startingAt;
while (true) {
if (pos < 0)
return -1;
char c = s.charAt(pos);
if (c == '>') {
if (nesting == 0)
return pos;
nesting--;
} else if (c == '<')
nesting++;
pos++;
}
}
public static int lastMatchedLeftAngleBracket(String s) {
int nesting = 0;
int pos = s.length() - 2;
while (true) {
if (pos < 0)
return -1;
char c = s.charAt(pos);
if (c == '<') {
nesting--;
if (nesting == 0)
return pos;
} else if (c == '>')
nesting++;
else if (nesting == 0)
return -1;
pos--;
}
}
/**
* Parse a bytecode signature that has 1 or more (possibly generic) types
* and return a list of the Types.
*
* @param signature
* bytecode signature e.g. e.g.
* <code>Ljava/util/ArrayList<Ljava/lang/String;>;Ljava/util/ArrayList<TT;>;Ljava/util/ArrayList<*>;</code>
*/
public static final @CheckForNull
List<ReferenceType> getTypeParameters(String signature) {
GenericSignatureParser parser = new GenericSignatureParser("(" + signature + ")V");
List<ReferenceType> types = new ArrayList<ReferenceType>();
Iterator<String> iter = parser.parameterSignatureIterator();
while (iter.hasNext()) {
String parameterString = iter.next();
ReferenceType t = (ReferenceType) getType(parameterString);
if (t == null)
return null;
types.add(t);
}
return types;
}
public static final List<String> split(String signature, boolean skipInitialAngleBracket) {
List<String> result = new ArrayList<String>();
if (signature.charAt(0) != '<')
skipInitialAngleBracket = false;
int depth = 0;
int start = 0;
for (int pos = start; pos < signature.length(); pos++)
switch (signature.charAt(pos)) {
case '<':
depth++;
break;
case '>':
depth--;
if (depth == 0 && skipInitialAngleBracket) {
skipInitialAngleBracket = false;
start = pos + 1;
}
break;
case ';':
if (depth > 0)
break;
String substring = signature.substring(start, pos + 1);
result.add(substring);
start = pos + 1;
}
if (depth != 0)
throw new IllegalArgumentException("Unbalanced signature: " + signature);
return result;
}
}