JStaticJavaFile.java
/*
* Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.codemodel.fmt;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.text.ParseException;
import java.util.Iterator;
import java.util.List;
import com.sun.codemodel.JClass;
import com.sun.codemodel.JPackage;
import com.sun.codemodel.JResourceFile;
import com.sun.codemodel.JTypeVar;
/**
* Statically generated Java soruce file.
*
* <p>
* This {@link JResourceFile} implementation will generate a Java source
* file by copying the source code from a resource.
* <p>
* While copying a resource, we look for a package declaration and
* replace it with the target package name. This allows the static Java
* source code to have an arbitrary package declaration.
* <p>
* You can also use the getJClass method to obtain a {@link JClass}
* object that represents the static file. This allows the client code
* to refer to the class from other CodeModel generated code.
* <p>
* Note that because we don't parse the static Java source code,
* the returned {@link JClass} object doesn't respond to methods like
* "isInterface" or "_extends",
*
* @author
* Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
*/
public final class JStaticJavaFile extends JResourceFile {
private final JPackage pkg;
private final String className;
private final ResourceLoader source;
private final JStaticClass clazz;
private final LineFilter filter;
public JStaticJavaFile(JPackage _pkg, String _className, Class<?> loadingClass, LineFilter _filter) {
super(_className + ".java");
if (loadingClass == null) throw new NullPointerException();
this.pkg = _pkg;
this.clazz = new JStaticClass();
this.className = _className;
this.source = new ResourceLoader(_className, loadingClass);
this.filter = _filter;
}
/**
* Returns a class object that represents a statically generated code.
*/
public JClass getJClass() {
return clazz;
}
@Override
protected boolean isResource() {
return false;
}
@Override
protected void build(OutputStream os) throws IOException {
int lineNumber=1;
try (
InputStream is = source.getResourceAsStream();
BufferedReader r = new BufferedReader(new InputStreamReader(is));
PrintWriter w = new PrintWriter(new BufferedWriter(new OutputStreamWriter(os)))
) {
LineFilter filter = createLineFilter();
String line;
while((line=r.readLine())!=null) {
line = filter.process(line);
if(line!=null)
w.println(line);
lineNumber++;
}
} catch( ParseException e ) {
throw new IOException("unable to process "+source+" line:"+lineNumber+"\n"+e.getMessage());
}
}
/**
* Creates a {@link LineFilter}.
* <p>
* A derived class can override this method to process
* the contents of the source file.
*/
private LineFilter createLineFilter() {
// this filter replaces the package declaration.
LineFilter f = new LineFilter() {
@Override
public String process(String line) {
if(!line.startsWith("package ")) return line;
// replace package decl
if( pkg.isUnnamed() )
return null;
else
return "package "+pkg.name()+";";
}
};
if( filter!=null )
return new ChainFilter(filter,f);
else
return f;
}
/**
* Filter that alters the Java source code.
* <p>
* By implementing this interface, derived classes
* can modify the Java source file before it's written out.
*/
public interface LineFilter {
/**
* @param line
* a non-null valid String that corresponds to one line.
* No '\n' included.
* @return
* null to strip the line off. Otherwise the returned
* String will be written out. Do not add '\n' at the end
* of this string.
*
* @exception ParseException
* when for some reason there's an error in the line.
*/
String process(String line) throws ParseException;
}
/**
* A {@link LineFilter} that combines two {@link LineFilter}s.
*/
public static final class ChainFilter implements LineFilter {
private final LineFilter first,second;
public ChainFilter( LineFilter first, LineFilter second ) {
this.first=first;
this.second=second;
}
@Override
public String process(String line) throws ParseException {
line = first.process(line);
if(line==null) return null;
return second.process(line);
}
}
private class JStaticClass extends JClass {
private final JTypeVar[] typeParams;
JStaticClass() {
super(pkg.owner());
// TODO: allow those to be specified
typeParams = new JTypeVar[0];
}
@Override
public String name() {
return className;
}
@Override
public String fullName() {
if(pkg.isUnnamed())
return className;
else
return pkg.name()+'.'+className;
}
@Override
public JPackage _package() {
return pkg;
}
@Override
public JClass _extends() {
throw new UnsupportedOperationException();
}
@Override
public Iterator<JClass> _implements() {
throw new UnsupportedOperationException();
}
@Override
public boolean isInterface() {
throw new UnsupportedOperationException();
}
@Override
public boolean isAbstract() {
throw new UnsupportedOperationException();
}
@Override
public JTypeVar[] typeParams() {
return typeParams;
}
@Override
protected JClass substituteParams(JTypeVar[] variables, List<JClass> bindings) {
return this;
}
}
static class ResourceLoader {
Class<?> loadingClass;
String shortName;
ResourceLoader(String shortName, Class<?> loadingClass) {
this.loadingClass = loadingClass;
this.shortName = shortName;
}
InputStream getResourceAsStream() {
// some people didn't like our jars to contain files with .java extension,
// so when we build jars, we'' use ".java_". But when we run from the workspace,
// we want the original source code to be used, so we check both here.
// see bug 6211503.
InputStream stream = loadingClass.getResourceAsStream(shortName + ".java");
if (stream == null) {
stream = loadingClass.getResourceAsStream(shortName + ".java_");
}
if (stream == null) {
throw new InternalError("Unable to load source code of " + loadingClass.getName() + " as a resource");
}
return stream;
}
}
}