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- /*
- * Javassist, a Java-bytecode translator toolkit.
- * Copyright (C) 1999-2007 Shigeru Chiba. All Rights Reserved.
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. Alternatively, the contents of this file may be used under
- * the terms of the GNU Lesser General Public License Version 2.1 or later.
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- */
-
- package javassist;
-
- import javassist.bytecode.*;
- import javassist.compiler.Javac;
- import javassist.compiler.CompileError;
-
- /**
- * An instance of CtConstructor represents a constructor.
- * It may represent a static constructor
- * (class initializer). To distinguish a constructor and a class
- * initializer, call <code>isClassInitializer()</code>.
- *
- * <p>See the super class <code>CtBehavior</code> as well since
- * a number of useful methods are in <code>CtBehavior</code>.
- *
- * @see CtClass#getDeclaredConstructors()
- * @see CtClass#getClassInitializer()
- * @see CtNewConstructor
- */
- public final class CtConstructor extends CtBehavior {
- protected CtConstructor(MethodInfo minfo, CtClass declaring) {
- super(declaring, minfo);
- }
-
- /**
- * Creates a constructor with no constructor body.
- * The created constructor
- * must be added to a class with <code>CtClass.addConstructor()</code>.
- *
- * <p>The created constructor does not include a constructor body,
- * which must be specified with <code>setBody()</code>.
- *
- * @param declaring the class to which the created method is added.
- * @param parameters a list of the parameter types
- *
- * @see CtClass#addConstructor(CtConstructor)
- * @see CtConstructor#setBody(String)
- * @see CtConstructor#setBody(CtConstructor,ClassMap)
- */
- public CtConstructor(CtClass[] parameters, CtClass declaring) {
- this((MethodInfo)null, declaring);
- ConstPool cp = declaring.getClassFile2().getConstPool();
- String desc = Descriptor.ofConstructor(parameters);
- methodInfo = new MethodInfo(cp, "<init>", desc);
- setModifiers(Modifier.PUBLIC);
- }
-
- /**
- * Creates a copy of a <code>CtConstructor</code> object.
- * The created constructor must be
- * added to a class with <code>CtClass.addConstructor()</code>.
- *
- * <p>All occurrences of class names in the created constructor
- * are replaced with names specified by
- * <code>map</code> if <code>map</code> is not <code>null</code>.
- *
- * <p>By default, all the occurrences of the names of the class
- * declaring <code>src</code> and the superclass are replaced
- * with the name of the class and the superclass that
- * the created constructor is added to.
- * This is done whichever <code>map</code> is null or not.
- * To prevent this replacement, call <code>ClassMap.fix()</code>
- * or <code>put()</code> to explicitly specify replacement.
- *
- * <p><b>Note:</b> if the <code>.class</code> notation (for example,
- * <code>String.class</code>) is included in an expression, the
- * Javac compiler may produce a helper method.
- * Since this constructor never
- * copies this helper method, the programmers have the responsiblity of
- * copying it. Otherwise, use <code>Class.forName()</code> in the
- * expression.
- *
- * @param src the source method.
- * @param declaring the class to which the created method is added.
- * @param map the hashtable associating original class names
- * with substituted names.
- * It can be <code>null</code>.
- *
- * @see CtClass#addConstructor(CtConstructor)
- * @see ClassMap#fix(String)
- */
- public CtConstructor(CtConstructor src, CtClass declaring, ClassMap map)
- throws CannotCompileException
- {
- this((MethodInfo)null, declaring);
- copy(src, true, map);
- }
-
- /**
- * Returns true if this object represents a constructor.
- */
- public boolean isConstructor() {
- return methodInfo.isConstructor();
- }
-
- /**
- * Returns true if this object represents a static initializer.
- */
- public boolean isClassInitializer() {
- return methodInfo.isStaticInitializer();
- }
-
- /**
- * Returns the constructor name followed by parameter types
- * such as <code>javassist.CtConstructor(CtClass[],CtClass)</code>.
- *
- * @since 3.5
- */
- public String getLongName() {
- return getDeclaringClass().getName()
- + (isConstructor() ? Descriptor.toString(getSignature())
- : ("." + MethodInfo.nameClinit + "()"));
- }
-
- /**
- * Obtains the name of this constructor.
- * It is the same as the simple name of the class declaring this
- * constructor. If this object represents a class initializer,
- * then this method returns <code>"<clinit>"</code>.
- */
- public String getName() {
- if (methodInfo.isStaticInitializer())
- return MethodInfo.nameClinit;
- else
- return declaringClass.getSimpleName();
- }
-
- /**
- * Returns true if the constructor (or static initializer)
- * is the default one. This method returns true if the constructor
- * takes some arguments but it does not perform anything except
- * calling <code>super()</code> (the no-argument constructor of
- * the super class).
- */
- public boolean isEmpty() {
- CodeAttribute ca = getMethodInfo2().getCodeAttribute();
- if (ca == null)
- return false; // native or abstract??
- // they are not allowed, though.
-
- ConstPool cp = ca.getConstPool();
- CodeIterator it = ca.iterator();
- try {
- int pos, desc;
- int op0 = it.byteAt(it.next());
- return op0 == Opcode.RETURN // empty static initializer
- || (op0 == Opcode.ALOAD_0
- && it.byteAt(pos = it.next()) == Opcode.INVOKESPECIAL
- && (desc = cp.isConstructor(getSuperclassName(),
- it.u16bitAt(pos + 1))) != 0
- && "()V".equals(cp.getUtf8Info(desc))
- && it.byteAt(it.next()) == Opcode.RETURN
- && !it.hasNext());
- }
- catch (BadBytecode e) {}
- return false;
- }
-
- private String getSuperclassName() {
- ClassFile cf = declaringClass.getClassFile2();
- return cf.getSuperclass();
- }
-
- /**
- * Returns true if this constructor calls a constructor
- * of the super class. This method returns false if it
- * calls another constructor of this class by <code>this()</code>.
- */
- public boolean callsSuper() throws CannotCompileException {
- CodeAttribute codeAttr = methodInfo.getCodeAttribute();
- if (codeAttr != null) {
- CodeIterator it = codeAttr.iterator();
- try {
- int index = it.skipSuperConstructor();
- return index >= 0;
- }
- catch (BadBytecode e) {
- throw new CannotCompileException(e);
- }
- }
-
- return false;
- }
-
- /**
- * Sets a constructor body.
- *
- * @param src the source code representing the constructor body.
- * It must be a single statement or block.
- * If it is <code>null</code>, the substituted
- * constructor body does nothing except calling
- * <code>super()</code>.
- */
- public void setBody(String src) throws CannotCompileException {
- if (src == null)
- if (isClassInitializer())
- src = ";";
- else
- src = "super();";
-
- super.setBody(src);
- }
-
- /**
- * Copies a constructor body from another constructor.
- *
- * <p>All occurrences of the class names in the copied body
- * are replaced with the names specified by
- * <code>map</code> if <code>map</code> is not <code>null</code>.
- *
- * @param src the method that the body is copied from.
- * @param map the hashtable associating original class names
- * with substituted names.
- * It can be <code>null</code>.
- */
- public void setBody(CtConstructor src, ClassMap map)
- throws CannotCompileException
- {
- setBody0(src.declaringClass, src.methodInfo,
- declaringClass, methodInfo, map);
- }
-
- /**
- * Inserts bytecode just after another constructor in the super class
- * or this class is called.
- * It does not work if this object represents a class initializer.
- *
- * @param src the source code representing the inserted bytecode.
- * It must be a single statement or block.
- */
- public void insertBeforeBody(String src) throws CannotCompileException {
- CtClass cc = declaringClass;
- cc.checkModify();
- if (isClassInitializer())
- throw new CannotCompileException("class initializer");
-
- CodeAttribute ca = methodInfo.getCodeAttribute();
- CodeIterator iterator = ca.iterator();
- Bytecode b = new Bytecode(methodInfo.getConstPool(),
- ca.getMaxStack(), ca.getMaxLocals());
- b.setStackDepth(ca.getMaxStack());
- Javac jv = new Javac(b, cc);
- try {
- jv.recordParams(getParameterTypes(), false);
- jv.compileStmnt(src);
- ca.setMaxStack(b.getMaxStack());
- ca.setMaxLocals(b.getMaxLocals());
- iterator.skipConstructor();
- int pos = iterator.insertEx(b.get());
- iterator.insert(b.getExceptionTable(), pos);
- methodInfo.rebuildStackMapIf6(cc.getClassPool(), cc.getClassFile2());
- }
- catch (NotFoundException e) {
- throw new CannotCompileException(e);
- }
- catch (CompileError e) {
- throw new CannotCompileException(e);
- }
- catch (BadBytecode e) {
- throw new CannotCompileException(e);
- }
- }
-
- /* This method is called by addCatch() in CtBehavior.
- * super() and this() must not be in a try statement.
- */
- int getStartPosOfBody(CodeAttribute ca) throws CannotCompileException {
- CodeIterator ci = ca.iterator();
- try {
- ci.skipConstructor();
- return ci.next();
- }
- catch (BadBytecode e) {
- throw new CannotCompileException(e);
- }
- }
-
- /**
- * Makes a copy of this constructor and converts it into a method.
- * The signature of the mehtod is the same as the that of this constructor.
- * The return type is <code>void</code>. The resulting method must be
- * appended to the class specified by <code>declaring</code>.
- * If this constructor is a static initializer, the resulting method takes
- * no parameter.
- *
- * <p>An occurrence of another constructor call <code>this()</code>
- * or a super constructor call <code>super()</code> is
- * eliminated from the resulting method.
- *
- * <p>The immediate super class of the class declaring this constructor
- * must be also a super class of the class declaring the resulting method.
- * If the constructor accesses a field, the class declaring the resulting method
- * must also declare a field with the same name and type.
- *
- * @param name the name of the resulting method.
- * @param declaring the class declaring the resulting method.
- */
- public CtMethod toMethod(String name, CtClass declaring)
- throws CannotCompileException
- {
- return toMethod(name, declaring, null);
- }
-
- /**
- * Makes a copy of this constructor and converts it into a method.
- * The signature of the method is the same as the that of this constructor.
- * The return type is <code>void</code>. The resulting method must be
- * appended to the class specified by <code>declaring</code>.
- * If this constructor is a static initializer, the resulting method takes
- * no parameter.
- *
- * <p>An occurrence of another constructor call <code>this()</code>
- * or a super constructor call <code>super()</code> is
- * eliminated from the resulting method.
- *
- * <p>The immediate super class of the class declaring this constructor
- * must be also a super class of the class declaring the resulting method
- * (this is obviously true if the second parameter <code>declaring</code> is
- * the same as the class declaring this constructor).
- * If the constructor accesses a field, the class declaring the resulting method
- * must also declare a field with the same name and type.
- *
- * @param name the name of the resulting method.
- * @param declaring the class declaring the resulting method.
- * It is normally the same as the class declaring this
- * constructor.
- * @param map the hash table associating original class names
- * with substituted names. The original class names will be
- * replaced while making a copy.
- * <code>map</code> can be <code>null</code>.
- */
- public CtMethod toMethod(String name, CtClass declaring, ClassMap map)
- throws CannotCompileException
- {
- CtMethod method = new CtMethod(null, declaring);
- method.copy(this, false, map);
- if (isConstructor()) {
- MethodInfo minfo = method.getMethodInfo2();
- CodeAttribute ca = minfo.getCodeAttribute();
- if (ca != null) {
- removeConsCall(ca);
- try {
- methodInfo.rebuildStackMapIf6(declaring.getClassPool(),
- declaring.getClassFile2());
- }
- catch (BadBytecode e) {
- throw new CannotCompileException(e);
- }
- }
- }
-
- method.setName(name);
- return method;
- }
-
- private static void removeConsCall(CodeAttribute ca)
- throws CannotCompileException
- {
- CodeIterator iterator = ca.iterator();
- try {
- int pos = iterator.skipConstructor();
- if (pos >= 0) {
- int mref = iterator.u16bitAt(pos + 1);
- String desc = ca.getConstPool().getMethodrefType(mref);
- int num = Descriptor.numOfParameters(desc) + 1;
- if (num > 3)
- iterator.insertGap(pos, num - 3);
-
- iterator.writeByte(Opcode.POP, pos++); // this
- iterator.writeByte(Opcode.NOP, pos);
- iterator.writeByte(Opcode.NOP, pos + 1);
- Descriptor.Iterator it = new Descriptor.Iterator(desc);
- while (true) {
- it.next();
- if (it.isParameter())
- iterator.writeByte(it.is2byte() ? Opcode.POP2 : Opcode.POP,
- pos++);
- else
- break;
- }
- }
- }
- catch (BadBytecode e) {
- throw new CannotCompileException(e);
- }
- }
- }
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