/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery.functions.text;
import java.util.ArrayList;
import java.util.List;
import org.exist.dom.Match;
import org.exist.dom.NodeProxy;
import org.exist.dom.QName;
import org.exist.dom.TextImpl;
import org.exist.memtree.DocumentBuilderReceiver;
import org.exist.memtree.MemTreeBuilder;
import org.exist.util.FastQSort;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionCall;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReference;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.IntegerValue;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
import org.xml.sax.SAXException;
public class KWICDisplay extends BasicFunction {
protected static final FunctionParameterSequenceType TEXT_ARG = new FunctionParameterSequenceType("text", Type.TEXT, Cardinality.ZERO_OR_MORE, "The text nodes");
protected static final FunctionParameterSequenceType WIDTH_ARG = new FunctionParameterSequenceType("width", Type.POSITIVE_INTEGER, Cardinality.EXACTLY_ONE, "The width");
protected static final FunctionParameterSequenceType CALLBACK_ARG = new FunctionParameterSequenceType("callback-function", Type.FUNCTION_REFERENCE, Cardinality.EXACTLY_ONE, "The callback function");
protected static final FunctionParameterSequenceType RESULT_CALLBACK_ARG = new FunctionParameterSequenceType("result-callback", Type.FUNCTION_REFERENCE, Cardinality.EXACTLY_ONE, "The result callback function");
protected static final FunctionParameterSequenceType PARAMETERS_ARG = new FunctionParameterSequenceType("parameters", Type.ITEM, Cardinality.ZERO_OR_MORE, "The parameters passed into the last argument of the callback function");
public final static FunctionSignature signatures[] = {
new FunctionSignature(
new QName("kwic-display", TextModule.NAMESPACE_URI, TextModule.PREFIX),
"Deprecated: kwic functionality is now provided by an XQuery module, see " +
"http://exist-org/kwic.html." +
"This function takes a sequence of text nodes in $a, containing matches from a fulltext search. " +
"It highlights matching strings within those text nodes in the same way as the text:highlight-matches " +
"function. However, only a defined portion of the text surrounding the first match (and maybe following matches) " +
"is returned. If the text preceding the first match is larger than the width specified in the second argument $b, " +
"it will be truncated to fill no more than (width - keyword-length) / 2 characters. Likewise, the text following " +
"the match will be truncated in such a way that the whole string sequence fits into width characters. " +
"The third parameter $c is a callback function (defined with util:function). $d may contain an additional sequence of " +
"values that will be passed to the last parameter of the callback function. Any matching character sequence is reported " +
"to the callback function, and the " +
"result of the function call is inserted into the resulting node set where the matching sequence occurred. " +
"For example, you can use this to mark all matching terms with a <span class=\"highlight\">abc</span>. " +
"The callback function should take 3 or 4 arguments: 1) the text sequence corresponding to the match as xs:string, " +
"2) the text node to which this match belongs, 3) the sequence passed as last argument to kwic-display. " +
"If the callback function accepts 4 arguments, the last argument will contain additional " +
"information on the match as a sequence of 4 integers: a) the number of the match if there's more than " +
"one match in a text node - the first match will be numbered 1; b) the offset of the match into the original text node " +
"string; c) the length of the match as reported by the index.",
new SequenceType[]{ TEXT_ARG, WIDTH_ARG, CALLBACK_ARG, PARAMETERS_ARG },
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_MORE, "the results"),
"Improved kwic functionality is now provided by a separate XQuery module, see " +
"http://exist-db.org/kwic.html."),
new FunctionSignature(
new QName("kwic-display", TextModule.NAMESPACE_URI, TextModule.PREFIX),
"This function takes a sequence of text nodes in $a, containing matches from a fulltext search. " +
"It highlights matching strings within those text nodes in the same way as the text:highlight-matches " +
"function. However, only a defined portion of the text surrounding the first match (and maybe following matches) " +
"is returned. If the text preceding the first match is larger than the width specified in the second argument $b, " +
"it will be truncated to fill no more than (width - keyword-length) / 2 characters. Likewise, the text following " +
"the match will be truncated in such a way that the whole string sequence fits into width characters. " +
"The third parameter $c is a callback function (defined with util:function). $d may contain an additional sequence of " +
"values that will be passed to the last parameter of the callback function. Any matching character sequence is reported " +
"to the callback function, and the " +
"result of the function call is inserted into the resulting node set where the matching sequence occurred. " +
"For example, you can use this to mark all matching terms with a <span class=\"highlight\">abc</span>. " +
"The callback function should take 3 or 4 arguments: 1) the text sequence corresponding to the match as xs:string, " +
"2) the text node to which this match belongs, 3) the sequence passed as last argument to kwic-display. " +
"If the callback function accepts 4 arguments, the last argument will contain additional " +
"information on the match as a sequence of 4 integers: a) the number of the match if there's more than " +
"one match in a text node - the first match will be numbered 1; b) the offset of the match into the original text node " +
"string; c) the length of the match as reported by the index.",
new SequenceType[]{ TEXT_ARG, WIDTH_ARG, CALLBACK_ARG, RESULT_CALLBACK_ARG, PARAMETERS_ARG },
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_MORE, "the results"),
"Improved kwic functionality is now provided by a separate XQuery module, see " +
"http://exist-db.org/kwic.html.")
};
public KWICDisplay(XQueryContext context, FunctionSignature signature) {
super(context, signature);
}
public Sequence eval(Sequence[] args, Sequence contextSequence)
throws XPathException {
if (args[0].isEmpty())
return Sequence.EMPTY_SEQUENCE;
FunctionReference func = (FunctionReference) args[2].itemAt(0);
FunctionCall call = func.getFunctionCall();
FunctionCall resultCallback = null;
if (getArgumentCount() == 5) {
func = (FunctionReference) args[3].itemAt(0);
resultCallback = func.getFunctionCall();
}
int width = ((IntegerValue)args[1].itemAt(0)).getInt();
context.pushDocumentContext();
MemTreeBuilder builder = context.getDocumentBuilder();
Sequence result = processText(builder, args[0], width, call, resultCallback, args[getArgumentCount() - 1]);
context.popDocumentContext();
return result;
}
private final Sequence processText(MemTreeBuilder builder, Sequence nodes, int width,
FunctionCall callback, FunctionCall resultCallback, Sequence extraArgs) throws XPathException {
StringBuilder str = new StringBuilder();
NodeValue node;
List offsets = null;
NodeProxy firstProxy = null;
// First step: scan the passed node sequence and collect the string values of all nodes.
// Translate the relative offsets into absolute offsets.
for (SequenceIterator i = nodes.iterate(); i.hasNext(); ) {
node = (NodeValue) i.nextItem();
if (node.getImplementationType() == NodeValue.IN_MEMORY_NODE)
throw new XPathException(this, "Function kwic-display" +
" can not be invoked on constructed nodes");
NodeProxy proxy = (NodeProxy) node;
// remember the first node, we need it later
if (firstProxy == null)
firstProxy = proxy;
TextImpl text = (TextImpl) proxy.getNode();
Match next = proxy.getMatches();
while (next != null) {
if (next.getNodeId().equals(text.getNodeId())) {
if (offsets == null)
offsets = new ArrayList();
int freq = next.getFrequency();
for (int j = 0; j < freq; j++) {
// translate the relative offset into an absolute offset and add it to the list
Match.Offset offset = next.getOffset(j);
offset.setOffset(str.length() + offset.getOffset());
offsets.add(offset);
}
}
next = next.getNextMatch();
}
// append the string value of the node to the buffer
str.append(text.getData());
}
// Second step: output the text
ValueSequence result = new ValueSequence();
DocumentBuilderReceiver receiver = new DocumentBuilderReceiver(builder);
int nodeNr;
int currentWidth = 0;
if (offsets == null) {
// no matches: just output the entire text
if (width > str.length())
width = str.length();
nodeNr = builder.characters(str.substring(0, width));
result.add(builder.getDocument().getNode(nodeNr));
currentWidth += width;
} else {
// sort the offsets
FastQSort.sort(offsets, 0, offsets.size() - 1);
int nextOffset = 0;
int pos = 0;
int lastNodeNr = -1;
// prepare array for callback function arguments
Sequence params[] = new Sequence[callback.getSignature().getArgumentCount()];
params[1] = firstProxy;
params[2] = extraArgs;
// handle the first match: if the text to the left of the match
// is larger than half of the width, truncate it.
if (str.length() > width) {
Match.Offset firstMatch = (Match.Offset) offsets.get(nextOffset++);
if (firstMatch.getOffset() > 0) {
int leftWidth = (width - firstMatch.getLength()) / 2;
if (firstMatch.getOffset() > leftWidth) {
pos = truncateStart(str, firstMatch.getOffset() - leftWidth, firstMatch.getOffset());
leftWidth = firstMatch.getOffset() - pos;
} else
leftWidth = firstMatch.getOffset();
nodeNr = builder.characters(str.substring(pos, pos + leftWidth));
// adjacent chunks of text will be merged into one text node. we may
// thus get duplicate nodes here. check the nodeNr to avoid adding
// the same node twice.
if (lastNodeNr != nodeNr)
result.add(builder.getDocument().getNode(nodeNr));
lastNodeNr = nodeNr;
currentWidth += leftWidth;
pos += leftWidth;
}
// put the matching term into argument 0 of the callback function
params[0] = new StringValue(str.substring(firstMatch.getOffset(), firstMatch.getOffset() + firstMatch.getLength()));
// if the callback function accepts 4 arguments, the last argument should contain additional
// information on the match:
if (callback.getSignature().getArgumentCount() == 4) {
params[3] = new ValueSequence();
params[3].add(new IntegerValue(nextOffset - 1));
params[3].add(new IntegerValue(firstMatch.getOffset()));
params[3].add(new IntegerValue(firstMatch.getLength()));
}
// now execute the callback func.
Sequence callbackResult = callback.evalFunction(null, null, params);
// iterate through the result of the callback
for (SequenceIterator iter = callbackResult.iterate(); iter.hasNext(); ) {
Item next = iter.nextItem();
if (Type.subTypeOf(next.getType(), Type.NODE)) {
nodeNr = builder.getDocument().getLastNode();
try {
next.copyTo(context.getBroker(), receiver);
result.add(builder.getDocument().getNode(++nodeNr));
lastNodeNr = nodeNr;
} catch (SAXException e) {
throw new XPathException(this, "Internal error while copying nodes: " + e.getMessage(), e);
}
}
}
currentWidth += firstMatch.getLength();
pos += firstMatch.getLength();
} else
width = str.length();
// output the rest of the text and matches
Match.Offset offset;
for (int i = nextOffset; i < offsets.size() && currentWidth < width; i++) {
offset = (Match.Offset) offsets.get(i);
if (offset.getOffset() > pos) {
int len = offset.getOffset() - pos;
if (currentWidth + len > width)
len = width - currentWidth;
nodeNr = builder.characters(str.substring(pos, pos + len));
if (lastNodeNr != nodeNr)
result.add(builder.getDocument().getNode(nodeNr));
currentWidth += len;
pos += len;
}
if (currentWidth + offset.getLength() < width) {
// put the matching term into argument 0 of the callback function
params[0] = new StringValue(str.substring(offset.getOffset(), offset.getOffset() + offset.getLength()));
// if the callback function accepts 4 arguments, the last argument should contain additional
// information on the match:
if (callback.getSignature().getArgumentCount() == 4) {
params[3] = new ValueSequence();
params[3].add(new IntegerValue(i));
params[3].add(new IntegerValue(offset.getOffset()));
params[3].add(new IntegerValue(offset.getLength()));
}
// execute the callback function
Sequence callbackResult = callback.evalFunction(null, null, params);
for (SequenceIterator iter = callbackResult.iterate(); iter.hasNext(); ) {
Item next = iter.nextItem();
if (Type.subTypeOf(next.getType(), Type.NODE)) {
nodeNr = builder.getDocument().getLastNode();
try {
next.copyTo(context.getBroker(), receiver);
result.add(builder.getDocument().getNode(++nodeNr));
lastNodeNr = nodeNr;
} catch (SAXException e) {
throw new XPathException(this, "Internal error while copying nodes: " + e.getMessage(), e);
}
}
}
currentWidth += offset.getLength();
pos += offset.getLength();
} else
break;
}
// print the final text chunk if more space is available
if (currentWidth < width && pos < str.length()) {
boolean truncated = false;
int len = str.length() - pos;
if (len > width - currentWidth) {
truncated = true;
len = width - currentWidth;
}
nodeNr = builder.characters(str.substring(pos, pos + len));
if (lastNodeNr != nodeNr)
result.add(builder.getDocument().getNode(nodeNr));
lastNodeNr = nodeNr;
currentWidth += len;
if (truncated) {
nodeNr = builder.characters(" ...");
if (lastNodeNr != nodeNr)
result.add(builder.getDocument().getNode(nodeNr));
lastNodeNr = nodeNr;
}
}
}
// if the user specified a result callback function, call it now
if (resultCallback != null) {
Sequence params[] = new Sequence[3];
params[0] = result;
params[1] = new IntegerValue(currentWidth);
params[2] = extraArgs;
return resultCallback.evalFunction(null, null, params);
} else
return result;
}
private final static int truncateStart(StringBuilder buf, int start, int end) {
if (start > 0 && !Character.isLetterOrDigit(buf.charAt(start - 1)))
return start;
while (start < end && Character.isLetterOrDigit(buf.charAt(start))) {
start++;
}
while (start < end && !Character.isLetterOrDigit(buf.charAt(start))) {
start++;
}
return start;
}
}