org.custommonkey.xmlunit.Diff Maven / Gradle / Ivy
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package org.custommonkey.xmlunit;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import javax.xml.transform.TransformerException;
import javax.xml.transform.dom.DOMSource;
import org.custommonkey.xmlunit.exceptions.XMLUnitRuntimeException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Compares and describes any difference between XML documents.
* Two documents are either:
*
* - identical: the content and sequence of the nodes in the documents
* are exactly the same
* - similar: the content of the nodes in the documents are the same,
* but minor differences exist e.g. sequencing of sibling elements, values of
* namespace prefixes, use of implied attribute values
* - different: the contents of the documents are fundamentally
* different
*
* The difference between compared documents is contained in a message buffer
* held in this class, accessible either through the appendMessage
* or toString methods. NB: When comparing documents, the
* comparison is halted as soon as the status (identical / similar / different)
* is known with certainty. For a list of all differences between the documents
* an instance of {@link DetailedDiff the DetailedDiff class} can be used
* instead.
*/
public class Diff
implements DifferenceListener, ComparisonController {
private final Document controlDoc;
private final Document testDoc;
private boolean similar = true;
private boolean identical = true;
private boolean compared = false;
private boolean haltComparison = false;
private StringBuilder messages;
private DifferenceEngineContract differenceEngine;
private DifferenceListener differenceListenerDelegate;
private ElementQualifier elementQualifierDelegate;
private MatchTracker matchTrackerDelegate;
/**
* Construct a Diff that compares the XML in two Strings
*/
public Diff(String control, String test)
throws SAXException, IOException {
this(new StringReader(control), new StringReader(test));
}
/**
* Construct a Diff that compares the XML read from two Readers
*/
public Diff(Reader control, Reader test)
throws SAXException, IOException {
this(XMLUnit.buildDocument(XMLUnit.newControlParser(), control),
XMLUnit.buildDocument(XMLUnit.newTestParser(), test));
}
/**
* Construct a Diff that compares the XML in two Documents
*/
public Diff(Document controlDoc, Document testDoc) {
this(controlDoc, testDoc, (DifferenceEngineContract) null);
}
/**
* Construct a Diff that compares the XML in a control Document against the
* result of a transformation
*/
public Diff(String control, Transform testTransform)
throws IOException, TransformerException, SAXException {
this(XMLUnit.buildControlDocument(control),
testTransform.getResultDocument());
}
/**
* Construct a Diff that compares the XML read from two JAXP InputSources
*/
public Diff(InputSource control, InputSource test)
throws SAXException, IOException {
this(XMLUnit.buildDocument(XMLUnit.newControlParser(), control),
XMLUnit.buildDocument(XMLUnit.newTestParser(), test));
}
/**
* Construct a Diff that compares the XML in two JAXP DOMSources
*/
public Diff(DOMSource control, DOMSource test) {
this(toDocument(control), toDocument(test));
}
/**
* Construct a Diff that compares the XML in two Documents using a specific
* DifferenceEngine
*/
public Diff(Document controlDoc, Document testDoc,
DifferenceEngineContract comparator) {
this(controlDoc, testDoc, comparator, new ElementNameQualifier());
}
/**
* Construct a Diff that compares the XML in two Documents using a specific
* DifferenceEngine and ElementQualifier
*/
public Diff(Document controlDoc, Document testDoc,
DifferenceEngineContract comparator,
ElementQualifier elementQualifier) {
this.controlDoc = getManipulatedDocument(controlDoc);
this.testDoc = getManipulatedDocument(testDoc);
this.elementQualifierDelegate = elementQualifier;
this.differenceEngine = comparator;
this.messages = new StringBuilder();
}
/**
* Construct a Diff from a prototypical instance.
* Used by extension subclasses
* @param prototype a prototypical instance
*/
protected Diff(Diff prototype) {
this(prototype.controlDoc, prototype.testDoc, prototype.differenceEngine,
prototype.elementQualifierDelegate);
this.differenceListenerDelegate = prototype.differenceListenerDelegate;
}
/**
* If {@link XMLUnit#getIgnoreWhitespace whitespace is ignored} in
* differences then manipulate the content to strip the redundant
* whitespace
* @param originalDoc a document making up one half of this difference
* @return the original document with redundant whitespace removed if
* differences ignore whitespace
*/
private Document getWhitespaceManipulatedDocument(Document originalDoc) {
return XMLUnit.getIgnoreWhitespace()
? XMLUnit.getWhitespaceStrippedDocument(originalDoc)
: originalDoc;
}
/**
* Manipulates the given document according to the setting in the
* XMLUnit class.
*
* This may involve:
*
* - {@link XMLUnit#setIgnoreWhitespace stripping redundant
* whitespace}
* - {@link XMLUnit#setIgnoreComments stripping comments}
* - {@link XMLUnit#setNormalize normalizing Text nodes}
*
*
* @param orig a document making up one half of this difference
* @return manipulated doc
*/
private Document getManipulatedDocument(Document orig) {
return getNormalizedDocument(getCommentlessDocument(getWhitespaceManipulatedDocument(orig)));
}
/**
* Removes all comment nodes if {@link XMLUnit#getIgnoreComments
* comments are ignored}.
*
* @param orig a document making up one half of this difference
* @return manipulated doc
*/
private Document getCommentlessDocument(Document orig) {
if (!XMLUnit.getIgnoreComments()) {
return orig;
}
try {
Transform commentStripper = XMLUnit.getStripCommentsTransform(orig);
return commentStripper.getResultDocument();
} catch (TransformerException e) {
throw new XMLUnitRuntimeException(e.getMessage(), e.getCause());
}
}
private Document getNormalizedDocument(Document orig) {
if (!XMLUnit.getNormalize()) {
return orig;
}
Document d = (Document) orig.cloneNode(true);
d.normalize();
return d;
}
/**
* Top of the recursive comparison execution tree
*/
protected final void compare() {
if (compared) {
return;
}
getDifferenceEngine().compare(controlDoc, testDoc, this,
elementQualifierDelegate);
compared = true;
}
/**
* Return the result of a comparison. Two documents are considered
* to be "similar" if they contain the same elements and attributes
* regardless of order.
*/
public boolean similar(){
compare();
return similar;
}
/**
* Return the result of a comparison. Two documents are considered
* to be "identical" if they contain the same elements and attributes
* in the same order.
*/
public boolean identical(){
compare();
return identical;
}
/**
* Append a meaningful message to the buffer of messages
* @param appendTo the messages buffer
* @param difference
*/
private void appendDifference(StringBuilder appendTo, Difference difference) {
appendTo.append(' ').append(difference).append('\n');
}
/**
* DifferenceListener implementation.
* If the {@link Diff#overrideDifferenceListener overrideDifferenceListener}
* method has been called then the interpretation of the difference
* will be delegated.
* @param difference
* @return a DifferenceListener.RETURN_... constant indicating how the
* difference was interpreted.
* Always RETURN_ACCEPT_DIFFERENCE if the call is not delegated.
*/
public int differenceFound(Difference difference) {
int returnValue = evaluate(difference);
switch (returnValue) {
case RETURN_IGNORE_DIFFERENCE_NODES_IDENTICAL:
return returnValue;
case RETURN_IGNORE_DIFFERENCE_NODES_SIMILAR:
identical = false;
haltComparison = false;
break;
case RETURN_ACCEPT_DIFFERENCE:
identical = false;
if (difference.isRecoverable()) {
haltComparison = false;
} else {
similar = false;
haltComparison = true;
}
break;
case RETURN_UPGRADE_DIFFERENCE_NODES_DIFFERENT:
identical = similar = false;
haltComparison = true;
break;
default:
throw new IllegalArgumentException(returnValue
+ " is not a defined DifferenceListener.RETURN_... value");
}
if (haltComparison) {
messages.append("\n[different]");
} else {
messages.append("\n[not identical]");
}
appendDifference(messages, difference);
return returnValue;
}
public int evaluate(Difference difference) {
int returnValue = RETURN_ACCEPT_DIFFERENCE;
if (differenceListenerDelegate != null) {
returnValue = differenceListenerDelegate.differenceFound(difference);
}
return returnValue;
}
/**
* DifferenceListener implementation.
* If the {@link Diff#overrideDifferenceListener overrideDifferenceListener}
* method has been called then the call will be delegated
* otherwise a message is printed to System.err.
* @param control
* @param test
*/
public void skippedComparison(Node control, Node test) {
if (differenceListenerDelegate != null) {
differenceListenerDelegate.skippedComparison(control, test);
} else {
System.err.println("DifferenceListener.skippedComparison: "
+ "unhandled control node type=" + control
+ ", unhandled test node type=" + test);
}
}
/**
* ComparisonController implementation.
* @param afterDifference
* @return true if the difference is not recoverable and
* the comparison should be halted, or false if the difference
* is recoverable and the comparison can continue
*/
public boolean haltComparison(Difference afterDifference) {
return haltComparison;
}
/**
* Append the message from the result of this Diff instance to a specified
* StringBuffer
* @param toAppendTo
* @return specified StringBuffer with message appended
*/
public StringBuffer appendMessage(StringBuffer toAppendTo) {
compare();
if (messages.length()==0) {
messages.append("[identical]");
}
// fix for JDK1.4 backwards incompatibility
return toAppendTo.append(messages.toString());
}
/**
* Get the result of this Diff instance as a String
*
* Note: This method will perform the comparison and
* cache the result if it hasn't been performed already. Any
* configuration changes made after calling this method will be
* ignored.
*
* @return result of this Diff
*/
public String toString(){
StringBuffer buf = new StringBuffer(getClass().getName());
appendMessage(buf);
return buf.toString();
}
/**
* Override the DifferenceListener used to determine how
* to handle differences that are found.
* @param delegate the DifferenceListener instance to delegate handling to.
*/
public void overrideDifferenceListener(DifferenceListener delegate) {
this.differenceListenerDelegate = delegate;
}
/**
* Override the ElementQualifier used to determine which
* control and test nodes are comparable for this difference comparison.
* @param delegate the ElementQualifier instance to delegate to.
*/
public void overrideElementQualifier(ElementQualifier delegate) {
this.elementQualifierDelegate = delegate;
}
/**
* Override the MatchTracker used to track
* successfully matched nodes.
* @param delegate the MatchTracker instance to delegate handling to.
*/
public void overrideMatchTracker(MatchTracker delegate) {
this.matchTrackerDelegate = delegate;
if (differenceEngine != null) {
differenceEngine.setMatchTracker(delegate);
}
}
/**
* Lazily initializes the difference engine if it hasn't been set
* via a constructor.
*/
private DifferenceEngineContract getDifferenceEngine() {
if (differenceEngine == null) {
if (
XMLUnit.getIgnoreAttributeOrder()
&&
(!usesUnknownElementQualifier()
|| XMLUnit.getCompareUnmatched())
) {
return new NewDifferenceEngine(this, matchTrackerDelegate);
}
return new DifferenceEngine(this, matchTrackerDelegate);
}
return differenceEngine;
}
private boolean usesUnknownElementQualifier() {
return elementQualifierDelegate != null
&& !(elementQualifierDelegate instanceof ElementNameQualifier)
&& !(elementQualifierDelegate instanceof ElementNameAndTextQualifier)
&& !(elementQualifierDelegate instanceof ElementNameAndAttributeQualifier);
}
private static Document toDocument(DOMSource d) {
Node n = d.getNode();
return n instanceof Document ? (Document) n : n.getOwnerDocument();
}
}