groovy.lang.TracingInterceptor 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 groovy.lang;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
/*
* This {@link Interceptor} traces method calls on the proxied object to a log.
* By default, the log is simply System.out
; however, that can be
* changed with the setWriter(Writer)
method.
*
* A message will be written to output before a method is invoked and after a method
* is invoked. If methods are nested, and invoke one another, then indentation
* of two spaces is written.
*
* Here is an example usage on the ArrayList object:
*
* def proxy = ProxyMetaClass.getInstance(ArrayList.class)
* proxy.interceptor = new TracingInterceptor()
* proxy.use {
* def list = [1, 2, 3]
* assert 3 == list.size()
* assert list.contains(1)
* }
*
* Running this code produces this output:
*
* before java.util.ArrayList.size()
* after java.util.ArrayList.size()
* before java.util.ArrayList.contains(java.lang.Integer)
* after java.util.ArrayList.contains(java.lang.Integer)
*
*/
public class TracingInterceptor implements Interceptor {
protected Writer writer = new PrintWriter(System.out);
private int indent = 0;
/**
* Returns the writer associated with this interceptor.
*/
public Writer getWriter() {
return writer;
}
/**
* Changes the writer associated with this interceptor.
*/
public void setWriter(Writer writer) {
this.writer = writer;
}
public Object beforeInvoke(Object object, String methodName, Object[] arguments) {
write(object, methodName, arguments, "before");
indent++ ;
return null;
}
public Object afterInvoke(Object object, String methodName, Object[] arguments, Object result) {
indent--;
write(object, methodName, arguments, "after ");
return result;
}
public boolean doInvoke() {
return true;
}
private String indent(){
StringBuilder result = new StringBuilder();
for (int i=0; i 0) writer.write(", ");
Object argument = arguments[i];
writer.write(argument.getClass().getName());
}
writer.write(")");
}
}