org.weakref.jmx.internal.paranamer.JavadocParanamer Maven / Gradle / Ivy
/*
* Copyright 2007 Paul Hammant
* Copyright 2007 ThinkTank Maths Limited
*
* ThinkTank Maths Limited grants a non-revocable, perpetual licence
* to Paul Hammant for unlimited use, relicensing and redistribution. No
* explicit permission is required from ThinkTank Maths Limited for
* any future decisions made with regard to this file.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.weakref.jmx.internal.paranamer;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.GZIPInputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
/**
* Implementation of {@link Paranamer} which can access Javadocs at runtime to extract
* parameter names of methods. Works with:-
*
* - Javadoc in zip file
* - Javadoc in directory
* - Javadoc at remote URL
*
* Future implementations may be able to take multiple sources, but this version must be
* instantiated with the correct location of the Javadocs for the package you wish to
* extract the parameter names. Note that if a zip archive contains multiple
* "package-list" files, the first one will be used to index the packages which may be
* queried.
*
* Note that this does not perform any caching of entries (except what it finds in the
* package-list file, which is very lightweight)... every lookup will involve a disc hit.
* If you want to speed up performance, use a {@link CachingParanamer}.
*
* Implementation note: the constructors of this implementation let the client know if I/O
* problems will stop the recovery of parameter names. It might be preferable to suppress
* exceptions and simply return NO_PARAMETER_NAMES_LIST.
*
* TODO: example use code
*
* Known issues:-
*
* - Only tested with Javadoc 1.3 - 1.6
* - Doesn't handle methods that declare the generic type as a parameter (rare use case)
* - Some "erased" generic methods fail, e.g. File.compareTo(File), which is erased to
* File.compareTo(Object).
* - URL implementation is really slow
* - Doesn't support nested classes (due to limitations in the Java 1.4 reflection API)
*
*
* @author Samuel Halliday, ThinkTank Maths Limited
*/
public class JavadocParanamer implements Paranamer {
private static final String IE =
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)";
private static final ParameterNamesNotFoundException CLASS_NOT_SUPPORTED =
new ParameterNamesNotFoundException("class not supported");
/** In the case of an archive, this stores the path up to the base of the Javadocs */
private String base = null;
private final boolean isArchive;
private final boolean isDirectory;
private final boolean isURI;
/**
* Regardless of the implementation, this stores the base location of the remote or
* local file or directory.
*/
private final URI location;
/** The packages which are supported by this instance. Contains Strings */
private final Set packages = new HashSet();
/**
* Construct a Javadoc reading implementation of {@link Paranamer} using a local
* directory or zip archive as a source.
*
* @param archiveOrDirectory
* either a zip archive of Javadocs or the base directory of Javadocs.
* @throws IOException
* if there was an error when reading from either the archive or the
* package-list file.
* @throws FileNotFoundException
* if the archive, directory or package-list file does not
* exist.
* @throws NullPointerException
* if any parameter is null
* @throws IllegalArgumentException
* If the given parameter is not a file or directory or if it is a file
* but not a javadoc zip archive.
*/
public JavadocParanamer(File archiveOrDirectory) throws IOException {
if (archiveOrDirectory == null)
throw new NullPointerException();
if (!archiveOrDirectory.exists())
throw new FileNotFoundException(
archiveOrDirectory.getAbsolutePath());
isURI = false;
location = archiveOrDirectory.toURI();
if (archiveOrDirectory.isDirectory()) {
// is a directory
isArchive = false;
isDirectory = true;
// check that "package-list" exists
File dir = archiveOrDirectory;
File packageList =
new File(dir.getAbsolutePath() + "/package-list");
if (!packageList.isFile())
throw new FileNotFoundException("No package-list found at "
+ dir.getAbsolutePath()
+ ". Not a valid Javadoc directory.");
// it appear to be a valid Javadoc directory
FileInputStream input = new FileInputStream(packageList);
try {
String packageListString = streamToString(input);
parsePackageList(packageListString);
} finally {
input.close();
}
} else if (archiveOrDirectory.isFile()) {
// is a file
isArchive = true;
isDirectory = false;
File archive = archiveOrDirectory;
if (!archive.getAbsolutePath().toLowerCase().endsWith(".zip"))
throw new IllegalArgumentException(archive.getAbsolutePath()
+ " is not a zip file.");
// check that a "package-list" exists somewhere in the archive
ZipFile zip = new ZipFile(archive);
try {
// we need to check for a file named "package-list".
// There may be multiple files in the archive
// but we cannot use ZipFile.getEntry for suffix names
// so we have to look through all the entries.
// We then pick the largest file.
Enumeration entries = zip.entries();
// grr... http://javablog.co.uk/2007/11/25/enumeration-and-iterable
// Set
SortedMap packageLists = new TreeMap();
while (entries.hasMoreElements()) {
ZipEntry entry = (ZipEntry) entries.nextElement();
String name = entry.getName();
if (name.endsWith("package-list")) {
Long size = new Long(entry.getSize());
packageLists.put(size, entry);
}
}
if (packageLists.size() == 0)
throw new FileNotFoundException(
"no package-list found in archive");
// pick the largest package-list file, it's most likely the one we want
ZipEntry entry =
(ZipEntry) packageLists.get(packageLists.lastKey());
String name = entry.getName();
base =
name.substring(0, name.length()
- "package-list".length());
InputStream input = zip.getInputStream(entry);
try {
String packageListString = streamToString(input);
parsePackageList(packageListString);
} finally {
input.close();
}
} finally {
zip.close();
}
} else
throw new IllegalArgumentException(
archiveOrDirectory.getAbsolutePath()
+ " is neither a directory nor a file.");
}
/**
* @param url
* @throws IOException
* if there was a problem connecting to the remote Javadocs
* @throws FileNotFoundException
* if the url does not have a /package-list
* @throws NullPointerException
* if any parameter is null
*/
public JavadocParanamer(URL url) throws IOException {
if (url == null)
throw new NullPointerException();
isArchive = false;
isDirectory = false;
isURI = true;
try {
location = new URI(url.toString());
} catch (URISyntaxException e) {
throw new IOException(e.getMessage());
}
// check the package-list
URL packageListURL = new URL(url.toString() + "/package-list");
InputStream input = urlToInputStream(packageListURL);
try {
String packageList = streamToString(input);
parsePackageList(packageList);
} finally {
input.close();
}
}
public String[] lookupParameterNames(AccessibleObject methodOrConstructor) {
return lookupParameterNames(methodOrConstructor, true);
}
public String[] lookupParameterNames(AccessibleObject methodOrConstructor, boolean throwExceptionIfMissing) {
if (methodOrConstructor == null)
throw new NullPointerException();
Class klass;
String name;
Class[] types;
if (methodOrConstructor instanceof Constructor) {
Constructor constructor = (Constructor) methodOrConstructor;
klass = constructor.getDeclaringClass();
name = constructor.getName();
types = constructor.getParameterTypes();
} else if (methodOrConstructor instanceof Method) {
Method method = (Method) methodOrConstructor;
klass = method.getDeclaringClass();
name = method.getName();
types = method.getParameterTypes();
} else
throw new IllegalArgumentException();
// quick check to see if we support the package
if (!packages.contains(klass.getPackage().getName()))
throw CLASS_NOT_SUPPORTED;
try {
String[] names = getParameterNames(klass, name, types);
if (names == null) {
if (throwExceptionIfMissing) {
throw new ParameterNamesNotFoundException(
methodOrConstructor.toString());
} else {
return Paranamer.EMPTY_NAMES;
}
}
return names;
} catch (IOException e) {
if (throwExceptionIfMissing) {
throw new ParameterNamesNotFoundException(
methodOrConstructor.toString() + " due to an I/O error: "
+ e.getMessage());
} else {
return Paranamer.EMPTY_NAMES;
}
}
}
// throws CLASS_NOT_SUPPORTED if the class file is not found in the javadocs
// return null if the parameter names were not found
private String[] getParameterNames(Class klass,
String constructorOrMethodName, Class[] types) throws IOException {
// silly request for names of a parameterless method/constructor!
if ((types != null) && (types.length == 0))
return new String[0];
String path = getCanonicalName(klass).replace('.', '/');
if (isArchive) {
ZipFile archive = new ZipFile(new File(location));
ZipEntry entry = archive.getEntry(base + path + ".html");
if (entry == null)
throw CLASS_NOT_SUPPORTED;
InputStream input = archive.getInputStream(entry);
return getParameterNames2(input, constructorOrMethodName, types);
} else if (isDirectory) {
File file = new File(location.getPath() + "/" + path + ".html");
if (!file.isFile())
throw CLASS_NOT_SUPPORTED;
FileInputStream input = new FileInputStream(file);
return getParameterNames2(input, constructorOrMethodName, types);
} else if (isURI) {
try {
URL url = new URL(location.toString() + "/" + path + ".html");
InputStream input = urlToInputStream(url);
return getParameterNames2(input, constructorOrMethodName, types);
} catch (FileNotFoundException e) {
throw CLASS_NOT_SUPPORTED;
}
}
throw new RuntimeException(
"bug in JavadocParanamer. Should not reach here.");
}
/*
* Parse the Javadoc String and return the parameter names for the given constructor
* or method. Return null if no method/constructor is found. Note that types will
* never have length zero... we already deal with that situation higher up in the
* chain. Don't forget to close the input!
*/
private String[] getParameterNames2(InputStream input,
String constructorOrMethodName, Class[] types) throws IOException {
String javadoc = streamToString(input);
input.close();
// String we're looking for is like
//
// NAME="constructorOrMethodName(obj.ClassName, ...)"...noise...
// Parameters: parameter_name_1...noise...
// parameter_name_2...noise...
// ...
// parameter_name_N...noise...
//
// We cannot rely on the Parameters line existing as it depends on the author
// having correctly marked-up their code. The NAME element is auto-generated
// and should be checked for aggressively.
//
// Also note that Javadoc parameter names may differ from the names in the source.
// we don't have Pattern/Matcher :-(
StringBuffer regex = new StringBuffer();
regex.append("NAME=\"");
regex.append(constructorOrMethodName);
// quotes needed to escape array brackets
regex.append("\\(\\Q");
for (int i = 0; i < types.length; i++) {
if (i != 0)
regex.append(", ");
// canonical name deals with arrays
regex.append(getCanonicalName(types[i]));
}
regex.append("\\E\\)\"");
// FIXME: handle Javadoc 1.3, 1.4 and 1.5 as well (this is 1.6)
Pattern pattern = Pattern.compile(regex.toString());
Matcher matcher = pattern.matcher(javadoc);
if (!matcher.find())
// not found
return Paranamer.EMPTY_NAMES;
// found it. Lookup the parameter names.
String[] names = new String[types.length];
// now we're sure we have the right method, find the parameter names!
String regexParams = "([^<]*)";
Pattern patternParams = Pattern.compile(regexParams);
int start = matcher.end();
Matcher matcherParams = patternParams.matcher(javadoc);
for (int i = 0; i < types.length; i++) {
boolean find = matcherParams.find(start);
if (!find)
return Paranamer.EMPTY_NAMES;
start = matcherParams.end();
names[i] = matcherParams.group(1);
}
return names;
}
// doesn't support names of nested classes
private String getCanonicalName(Class klass) {
if (klass.isArray())
return getCanonicalName(klass.getComponentType()) + "[]";
return klass.getName();
}
// storing the list of packages that we support is very lightweight
private void parsePackageList(String packageList) throws IOException {
StringReader reader = new StringReader(packageList);
BufferedReader breader = new BufferedReader(reader);
String line;
while ((line = breader.readLine()) != null) {
packages.add(line);
}
}
// read an InputStream into a UTF-8 String
private String streamToString(InputStream input) throws IOException {
InputStreamReader reader;
try {
reader = new InputStreamReader(input, "UTF-8");
} catch (UnsupportedEncodingException e) {
// this should never happen
reader = new InputStreamReader(input);
}
BufferedReader breader = new BufferedReader(reader);
String line;
StringBuffer builder = new StringBuffer();
while ((line = breader.readLine()) != null) {
builder.append(line);
builder.append("\n");
}
return builder.toString();
}
private InputStream urlToInputStream(URL url) throws IOException {
URLConnection conn = url.openConnection();
// pretend to be IE6
conn.setRequestProperty("User-Agent", IE);
// allow both GZip and Deflate (ZLib) encodings
conn.setRequestProperty("Accept-Encoding", "gzip, deflate");
conn.connect();
String encoding = conn.getContentEncoding();
if ((encoding != null) && encoding.equalsIgnoreCase("gzip"))
return new GZIPInputStream(conn.getInputStream());
else if ((encoding != null) && encoding.equalsIgnoreCase("deflate"))
return new InflaterInputStream(conn.getInputStream(), new Inflater(
true));
else
return conn.getInputStream();
}
}