com.greenpepper.shaded.org.apache.tools.ant.filters.ClassConstants Maven / Gradle / Ivy
/*
* 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 com.greenpepper.shaded.org.apache.tools.ant.filters;
import java.io.IOException;
import java.io.Reader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import com.greenpepper.shaded.org.apache.tools.ant.BuildException;
/**
* Assembles the constants declared in a Java class in
* key1=value1(line separator)key2=value2
* format.
*
* Notes:
*
* - This filter uses the BCEL external toolkit.
*
- This assembles only those constants that are not created
* using the syntax
new whatever()
* - This assembles constants declared using the basic datatypes
* and String only.
* - The access modifiers of the declared constants do not matter.
*
* Example:
* <classconstants/>
* Or:
* <filterreader
* classname="com.greenpepper.shaded.org.apache.tools.ant.filters.ClassConstants"/>
*/
public final class ClassConstants
extends BaseFilterReader
implements ChainableReader {
/** Data that must be read from, if not null. */
private String queuedData = null;
/** Helper Class to be invoked via reflection. */
private static final String JAVA_CLASS_HELPER =
"com.greenpepper.shaded.org.apache.tools.ant.filters.util.JavaClassHelper";
/**
* Constructor for "dummy" instances.
*
* @see BaseFilterReader#BaseFilterReader()
*/
public ClassConstants() {
super();
}
/**
* Creates a new filtered reader. The contents of the passed-in reader
* are expected to be the name of the class from which to produce a
* list of constants.
*
* @param in A Reader object providing the underlying stream.
* Must not be null.
*/
public ClassConstants(final Reader in) {
super(in);
}
/**
* Reads and assembles the constants declared in a class file.
*
* @return the next character in the list of constants, or -1
* if the end of the resulting stream has been reached
*
* @exception IOException if the underlying stream throws an IOException
* during reading, or if the constants for the specified class cannot
* be read (for example due to the class not being found).
*/
public int read() throws IOException {
int ch = -1;
if (queuedData != null && queuedData.length() == 0) {
queuedData = null;
}
if (queuedData != null) {
ch = queuedData.charAt(0);
queuedData = queuedData.substring(1);
if (queuedData.length() == 0) {
queuedData = null;
}
} else {
final String clazz = readFully();
if (clazz == null) {
ch = -1;
} else {
final byte[] bytes = clazz.getBytes("ISO-8859-1");
try {
final Class javaClassHelper =
Class.forName(JAVA_CLASS_HELPER);
if (javaClassHelper != null) {
final Class[] params = {
byte[].class
};
final Method getConstants =
javaClassHelper.getMethod("getConstants", params);
final Object[] args = {
bytes
};
// getConstants is a static method, no need to
// pass in the object
final StringBuffer sb = (StringBuffer)
getConstants.invoke(null, args);
if (sb.length() > 0) {
queuedData = sb.toString();
return read();
}
}
} catch (NoClassDefFoundError ex) {
throw ex;
} catch (RuntimeException ex) {
throw ex;
} catch (InvocationTargetException ex) {
Throwable t = ex.getTargetException();
if (t instanceof NoClassDefFoundError) {
throw (NoClassDefFoundError) t;
}
if (t instanceof RuntimeException) {
throw (RuntimeException) t;
}
throw new BuildException(t);
} catch (Exception ex) {
throw new BuildException(ex);
}
}
}
return ch;
}
/**
* Creates a new ClassConstants using the passed in
* Reader for instantiation.
*
* @param rdr A Reader object providing the underlying stream.
* Must not be null.
*
* @return a new filter based on this configuration, but filtering
* the specified reader
*/
public Reader chain(final Reader rdr) {
ClassConstants newFilter = new ClassConstants(rdr);
return newFilter;
}
}