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Groovy: A powerful, dynamic language for the JVM
/*
* 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 org.codehaus.groovy.runtime.powerassert;
import java.util.*;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
/**
* Creates a string representation of an assertion and its recorded values.
*
* @author Peter Niederwieser
*/
public final class AssertionRenderer {
private final String text;
private final ValueRecorder recorder;
private final List lines = new ArrayList();
// startColumns.get(i) is the first non-empty column of lines.get(i)
private final List startColumns = new ArrayList();
private AssertionRenderer(String text, ValueRecorder recorder) {
if (text.contains("\n"))
throw new IllegalArgumentException("source text may not contain line breaks");
this.text = text;
this.recorder = recorder;
}
/**
* Creates a string representation of an assertion and its recorded values.
*
* @param text the assertion's source text
* @param recorder a recorder holding the values recorded during evaluation
* of the assertion
* @return a string representation of the assertion and its recorded values
*/
public static String render(String text, ValueRecorder recorder) {
return new AssertionRenderer(text, recorder).render();
}
private String render() {
renderText();
sortValues();
renderValues();
return linesToString();
}
private void renderText() {
lines.add(new StringBuilder(text));
startColumns.add(0);
lines.add(new StringBuilder()); // empty line
startColumns.add(0);
}
private void sortValues() {
// it's important to use a stable sort here, otherwise
// renderValues() will skip the wrong values
Collections.sort(recorder.getValues(),
new Comparator() {
public int compare(Value v1, Value v2) {
return v2.getColumn() - v1.getColumn();
}
}
);
}
private void renderValues() {
List values = recorder.getValues();
int valuesSize = values.size();
nextValue:
for (int i = 0; i < valuesSize; i++) {
final Value value = values.get(i);
final int startColumn = value.getColumn();
if (startColumn < 1) continue; // skip values with unknown source position
// if multiple values are associated with the same column, only
// render the value which was recorded last (i.e. the value
// corresponding to the outermost expression)
// important for GROOVY-4344
Value next = i + 1 < valuesSize ? values.get(i + 1) : null;
if (next != null && next.getColumn() == startColumn) continue;
String str = valueToString(value.getValue());
if (str == null) continue; // null signals the value shouldn't be rendered
String[] strs = str.split("\r\n|\r|\n");
int endColumn = strs.length == 1 ?
startColumn + str.length() : // exclusive
Integer.MAX_VALUE; // multi-line strings are always placed on new lines
for (int j = 1; j < lines.size(); j++)
if (endColumn < startColumns.get(j)) {
placeString(lines.get(j), str, startColumn);
startColumns.set(j, startColumn);
continue nextValue;
} else {
placeString(lines.get(j), "|", startColumn);
if (j > 1) // make sure that no values are ever placed on empty line
startColumns.set(j, startColumn + 1); // + 1: no whitespace required between end of value and "|"
}
// value could not be placed on existing lines, so place it on new line(s)
for (String s : strs) {
StringBuilder newLine = new StringBuilder();
lines.add(newLine);
placeString(newLine, s, startColumn);
startColumns.add(startColumn);
}
}
}
private String linesToString() {
StringBuilder firstLine = lines.get(0);
for (int i = 1; i < lines.size(); i++)
firstLine.append('\n').append(lines.get(i).toString());
return firstLine.toString();
}
private static void placeString(StringBuilder line, String str, int column) {
while (line.length() < column)
line.append(' ');
line.replace(column - 1, column - 1 + str.length(), str);
}
/**
* Returns a string representation of the given value, or null if
* the value should not be included (because it does not add any valuable
* information).
*
* @param value a value
* @return a string representation of the given value
*/
private static String valueToString(Object value) {
String toString;
try {
toString = DefaultGroovyMethods.toString(value);
} catch (Exception e) {
return String.format("%s (toString() threw %s)",
javaLangObjectToString(value), e.getClass().getName());
}
if (toString == null) {
return String.format("%s (toString() == null)", javaLangObjectToString(value));
}
if (toString.equals("")) {
if (hasStringLikeType(value)) return "\"\"";
return String.format("%s (toString() == \"\")", javaLangObjectToString(value));
}
return toString;
}
private static boolean hasStringLikeType(Object value) {
Class clazz = value.getClass();
return clazz == String.class || clazz == StringBuffer.class || clazz == StringBuilder.class;
}
private static String javaLangObjectToString(Object value) {
String hash = Integer.toHexString(System.identityHashCode(value));
return value.getClass().getName() + "@" + hash;
}
}