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Apache Commons Bytecode Engineering Library, with type annotations
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/*
* 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.generic;
import java.util.ArrayList;
import java.util.List;
import org.apache.bcel.Const;
import org.apache.bcel.classfile.AnnotationEntry;
import org.apache.bcel.classfile.Annotations;
import org.apache.bcel.classfile.Attribute;
import org.apache.bcel.classfile.Constant;
import org.apache.bcel.classfile.ConstantObject;
import org.apache.bcel.classfile.ConstantPool;
import org.apache.bcel.classfile.ConstantValue;
import org.apache.bcel.classfile.Field;
import org.apache.bcel.classfile.Utility;
import org.apache.bcel.util.BCELComparator;
/*>>>
import org.checkerframework.checker.nullness.qual.Nullable;
*/
/**
* Template class for building up a field. The only extraordinary thing
* one can do is to add a constant value attribute to a field (which must of
* course be compatible with to the declared type).
*
* @version $Id$
* @see Field
*/
public class FieldGen extends FieldGenOrMethodGen {
private Object value = null;
private static BCELComparator bcelComparator = new BCELComparator() {
@Override
public boolean equals( final Object o1, final Object o2 ) {
final FieldGen THIS = (FieldGen) o1;
final FieldGen THAT = (FieldGen) o2;
return THIS.getName().equals(THAT.getName())
&& THIS.getSignature().equals(THAT.getSignature());
}
@Override
public int hashCode( final Object o ) {
final FieldGen THIS = (FieldGen) o;
return THIS.getSignature().hashCode() ^ THIS.getName().hashCode();
}
};
/**
* Declare a field. If it is static (isStatic() == true) and has a
* basic type like int or String it may have an initial value
* associated with it as defined by setInitValue().
*
* @param access_flags access qualifiers
* @param type field type
* @param name field name
* @param cp constant pool
*/
public FieldGen(final int access_flags, final Type type, final String name, final ConstantPoolGen cp) {
super(access_flags);
setType(type);
setName(name);
setConstantPool(cp);
}
/**
* Instantiate from existing field.
*
* @param field Field object
* @param cp constant pool (must contain the same entries as the field's constant pool)
*/
public FieldGen(final Field field, final ConstantPoolGen cp) {
this(field.getAccessFlags(), Type.getType(field.getSignature()), field.getName(), cp);
final Attribute[] attrs = field.getAttributes();
for (final Attribute attr : attrs) {
if (attr instanceof ConstantValue) {
setValue(((ConstantValue) attr).getConstantValueIndex());
} else if (attr instanceof Annotations) {
final Annotations runtimeAnnotations = (Annotations)attr;
final AnnotationEntry[] annotationEntries = runtimeAnnotations.getAnnotationEntries();
for (final AnnotationEntry element : annotationEntries) {
addAnnotationEntry(new AnnotationEntryGen(element,cp,false));
}
} else {
addAttribute(attr);
}
}
}
private void setValue( final int index ) {
final ConstantPool cp = super.getConstantPool().getConstantPool();
final Constant c = cp.getConstant(index);
value = ((ConstantObject) c).getConstantValue(cp);
}
/**
* Set (optional) initial value of field, otherwise it will be set to null/0/false
* by the JVM automatically.
*/
public void setInitValue( final String str ) {
checkType( ObjectType.getInstance("java.lang.String"));
if (str != null) {
value = str;
}
}
public void setInitValue( final long l ) {
checkType(Type.LONG);
if (l != 0L) {
value = Long.valueOf(l);
}
}
public void setInitValue( final int i ) {
checkType(Type.INT);
if (i != 0) {
value = Integer.valueOf(i);
}
}
public void setInitValue( final short s ) {
checkType(Type.SHORT);
if (s != 0) {
value = Integer.valueOf(s);
}
}
public void setInitValue( final char c ) {
checkType(Type.CHAR);
if (c != 0) {
value = Integer.valueOf(c);
}
}
public void setInitValue( final byte b ) {
checkType(Type.BYTE);
if (b != 0) {
value = Integer.valueOf(b);
}
}
public void setInitValue( final boolean b ) {
checkType(Type.BOOLEAN);
if (b) {
value = Integer.valueOf(1);
}
}
public void setInitValue( final float f ) {
checkType(Type.FLOAT);
if (f != 0.0) {
value = new Float(f);
}
}
public void setInitValue( final double d ) {
checkType(Type.DOUBLE);
if (d != 0.0) {
value = new Double(d);
}
}
/** Remove any initial value.
*/
public void cancelInitValue() {
value = null;
}
private void checkType( final Type atype ) {
final Type superType = super.getType();
if (superType == null) {
throw new ClassGenException("You haven't defined the type of the field yet");
}
if (!isFinal()) {
throw new ClassGenException("Only final fields may have an initial value!");
}
if (!superType.equals(atype)) {
throw new ClassGenException("Types are not compatible: " + superType + " vs. " + atype);
}
}
/**
* Get field object after having set up all necessary values.
*/
public Field getField() {
final String signature = getSignature();
final int name_index = super.getConstantPool().addUtf8(super.getName());
final int signature_index = super.getConstantPool().addUtf8(signature);
if (value != null) {
checkType(super.getType());
final int index = addConstant();
addAttribute(new ConstantValue(super.getConstantPool().addUtf8("ConstantValue"), 2, index,
super.getConstantPool().getConstantPool())); // sic
}
addAnnotationsAsAttribute(super.getConstantPool());
return new Field(super.getAccessFlags(), name_index, signature_index, getAttributes(),
super.getConstantPool().getConstantPool()); // sic
}
private void addAnnotationsAsAttribute(final ConstantPoolGen cp) {
final Attribute[] attrs = AnnotationEntryGen.getAnnotationAttributes(cp, super.getAnnotationEntries());
for (final Attribute attr : attrs) {
addAttribute(attr);
}
}
private int addConstant() {
switch (super.getType().getType()) { // sic
case Const.T_INT:
case Const.T_CHAR:
case Const.T_BYTE:
case Const.T_BOOLEAN:
case Const.T_SHORT:
return super.getConstantPool().addInteger(((Integer) value).intValue());
case Const.T_FLOAT:
return super.getConstantPool().addFloat(((Float) value).floatValue());
case Const.T_DOUBLE:
return super.getConstantPool().addDouble(((Double) value).doubleValue());
case Const.T_LONG:
return super.getConstantPool().addLong(((Long) value).longValue());
case Const.T_REFERENCE:
return super.getConstantPool().addString((String) value);
default:
throw new RuntimeException("Oops: Unhandled : " + super.getType().getType()); // sic
}
}
@Override
public String getSignature() {
return super.getType().getSignature();
}
private List observers;
/** Add observer for this object.
*/
public void addObserver( final FieldObserver o ) {
if (observers == null) {
observers = new ArrayList<>();
}
observers.add(o);
}
/** Remove observer for this object.
*/
public void removeObserver( final FieldObserver o ) {
if (observers != null) {
observers.remove(o);
}
}
/** Call notify() method on all observers. This method is not called
* automatically whenever the state has changed, but has to be
* called by the user after he has finished editing the object.
*/
public void update() {
if (observers != null) {
for (final FieldObserver observer : observers ) {
observer.notify(this);
}
}
}
public /*@Nullable*/ String getInitValue() {
if (value != null) {
return value.toString();
}
return null;
}
/**
* Return string representation close to declaration format,
* `public static final short MAX = 100', e.g..
*
* @return String representation of field
*/
@Override
public final String toString() {
String name;
String signature;
String access; // Short cuts to constant pool
access = Utility.accessToString(super.getAccessFlags());
access = access.isEmpty() ? "" : (access + " ");
signature = super.getType().toString();
name = getName();
final StringBuilder buf = new StringBuilder(32); // CHECKSTYLE IGNORE MagicNumber
buf.append(access).append(signature).append(" ").append(name);
final String value = getInitValue();
if (value != null) {
buf.append(" = ").append(value);
}
return buf.toString();
}
/** @return deep copy of this field
*/
public FieldGen copy( final ConstantPoolGen cp ) {
final FieldGen fg = (FieldGen) clone();
fg.setConstantPool(cp);
return fg;
}
/**
* @return Comparison strategy object
*/
public static BCELComparator getComparator() {
return bcelComparator;
}
/**
* @param comparator Comparison strategy object
*/
public static void setComparator( final BCELComparator comparator ) {
bcelComparator = comparator;
}
/**
* Return value as defined by given BCELComparator strategy.
* By default two FieldGen objects are said to be equal when
* their names and signatures are equal.
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( final /*@Nullable*/ Object obj ) {
return bcelComparator.equals(this, obj);
}
/**
* Return value as defined by given BCELComparator strategy.
* By default return the hashcode of the field's name XOR signature.
*
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return bcelComparator.hashCode(this);
}
}