org.jibx.schema.elements.SchemaPath Maven / Gradle / Ivy
/*
* Copyright (c) 2007-2009, Dennis M. Sosnoski All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of
* JiBX nor the names of its contributors may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/
package org.jibx.schema.elements;
import java.util.ArrayList;
import java.util.List;
import org.jibx.runtime.QName;
import org.jibx.schema.INamed;
import org.jibx.schema.IReference;
import org.jibx.schema.validation.ValidationContext;
import org.jibx.util.LazyList;
/**
* Path specification within a schema definition. This implements simple XPath-like expressions, consisting of any
* number of path components given as element names or '*' for any element or '**' for any nesting of elements, along
* with optional position number or name attribute predicates in square brackets.
*
* @author Dennis M. Sosnoski
*/
public class SchemaPath
{
/** Single element wildcard step. */
private static final StepBase WILDCARD_ELEMENT_STEP = new StepBase() {
public boolean isRepeating() {
return false;
}
public boolean match(OpenAttrBase elem) {
return true;
}
public int position() {
return -1;
}
};
/** Nesteing element wildcard step. */
private static final StepBase WILDCARD_NESTING_STEP = new StepBase() {
public boolean isRepeating() {
return true;
}
public boolean match(OpenAttrBase elem) {
return true;
}
public int position() {
return -1;
}
};
/** Source object for path expression. */
private final Object m_sourceObject;
/** Validation context used for reporting errors. */
private final ValidationContext m_validationContext;
/** Path steps. */
private StepBase[] m_steps;
/**
* Constructor.
*
* @param obj source object for expression
* @param vctx validation context
*/
private SchemaPath(Object obj, ValidationContext vctx) {
m_sourceObject = obj;
m_validationContext = vctx;
}
/**
* Validate a name attribute value.
*
* @param nameattr name value
* @return true if valid, false if not
*/
private boolean validateName(String nameattr) {
for (int i = 0; i < nameattr.length(); i++) {
char chr = nameattr.charAt(i);
if (!Character.isLetter(chr) && chr != '.' && chr != '_' && chr != '-' &&
(i <= 0 || !Character.isDigit(chr))) {
m_validationContext.addError("Invalid path expression name predicate '" + nameattr + '\'',
m_sourceObject);
return false;
}
}
return true;
}
/**
* Validate and convert a position value.
*
* @param postext position text
* @return position value (strictly positive), or -1 if error
*/
private int convertPosition(String postext) {
// first check that all characters are digits (for better error message)
for (int i = 0; i < postext.length(); i++) {
char chr = postext.charAt(i);
if (chr < '0' || chr > '9') {
if (i == 0) {
m_validationContext.addError("Unknown path expression predicate '" + postext + '\'',
m_sourceObject);
} else {
m_validationContext.addError("Illegal character in path expression position predicate '" + postext +
"' (must be digits only)", m_sourceObject);
}
return -1;
}
}
// convert the actual position value
int position = -1;
try {
position = Integer.parseInt(postext);
if (position <= 0) {
m_validationContext.addError("Path expression position predicate value must be >= 1", m_sourceObject);
}
} catch (NumberFormatException e) {
m_validationContext.addError("Error parsing position predicate in path expression", m_sourceObject);
}
return position;
}
/**
* Build a path step.
*
* @param step expression
* @return constructed step, or null if error
*/
private StepBase buildPathStep(String step) {
if ("*".equals(step)) {
return WILDCARD_ELEMENT_STEP;
} else if ("**".equals(step)) {
return WILDCARD_NESTING_STEP;
} else {
// check if there's a predicate present
boolean valid = true;
String elemname = null;
String nameattr = null;
String postext = null;
int split = step.indexOf('[');
if (split >= 0) {
// split off element name as part before predicate start
elemname = step.substring(0, split);
step = step.substring(split + 1);
// make sure there's a matching predicate end
split = step.indexOf(']');
if (split >= 0) {
// check type of predicate
String clause = step.substring(0, split).trim();
if (clause.startsWith("@name=")) {
nameattr = clause.substring(6);
valid = validateName(nameattr);
} else {
postext = clause;
}
// check for a second predicate
step = step.substring(split + 1);
if (step.length() > 0) {
// second predicate must be position
int end = step.length() - 1;
if (step.charAt(0) == '[' && step.charAt(end) == ']') {
clause = step.substring(1, end).trim();
if (postext == null) {
postext = clause;
} else {
m_validationContext.addError("Multiple predicates only allowed in path expression " +
"with [@name=xxx] as first predicate", m_sourceObject);
valid = false;
}
} else {
m_validationContext.addError("Invalid predicate in path expression", m_sourceObject);
valid = false;
}
}
} else {
m_validationContext.addError("Invalid predicate in path expression", m_sourceObject);
valid = false;
}
} else {
elemname = step;
}
// decode the position predicate
int position = -1;
if (valid && postext != null) {
position = convertPosition(postext);
valid = position > 0;
}
// return constructed step if syntax is valid
if (valid) {
return new PathStep(elemname, position, nameattr);
} else {
return null;
}
}
}
/**
* Find matches for expression starting from a supplied schema element.
*
* @param offset current path step offset
* @param end ending match list offset
* @param base starting element for match
* @param matches elements matching expression
*/
private void match(int offset, int end, OpenAttrBase base, ArrayList matches) {
LazyList childs = base.getChildrenWritable();
StepBase step = m_steps[offset];
int steppos = step.position();
int position = 0;
for (int i = 0; i < childs.size(); i++) {
OpenAttrBase child = (OpenAttrBase)childs.get(i);
if (step.match(child)) {
if (steppos <= 0 || steppos == ++position) {
if (offset == end) {
matches.add(child);
} else {
match(offset + 1, end, child, matches);
}
if (step.isRepeating()) {
match(offset, end, child, matches);
}
if (steppos > 0) {
break;
}
}
}
}
}
/**
* Get length of this path (minimum number of nested elements).
*
* @return path length
*/
public int getPathLength() {
return m_steps.length;
}
/**
* Check if the first path step is a wildcard.
*
* @return true if wildcard, false if not
*/
public boolean isWildStart() {
return m_steps[0] == WILDCARD_ELEMENT_STEP || m_steps[0] == WILDCARD_NESTING_STEP;
}
/**
* Find any number of matches for subexpression starting from a supplied schema element annotation.
*
* @param first starting path step index
* @param last ending path step index
* @param base starting element for match
* @return matching element, or null if error
*/
public List partialMatchMultiple(int first, int last, OpenAttrBase base) {
ArrayList matches = new ArrayList();
match(first, last, base, matches);
return matches;
}
/**
* Find unique match for subexpression starting from a supplied schema element annotation. An error is reported if
* no match is found, or if multiple matches are found.
*
* @param first starting path step index
* @param last ending path step index
* @param base starting element for match
* @return matching element, or null if error
*/
public OpenAttrBase partialMatchUnique(int first, int last, OpenAttrBase base) {
List matches = partialMatchMultiple(first, last, base);
OpenAttrBase match = null;
if (matches.size() == 0) {
m_validationContext.addError("No match found for path expression", m_sourceObject);
} else if (matches.size() > 1) {
m_validationContext.addError("Multiple matches found for path expression", m_sourceObject);
} else {
match = (OpenAttrBase)matches.get(0);
}
return match;
}
/**
* Find unique match for expression starting from a supplied schema element annotation. An error is reported if no
* match is found, or if multiple matches are found.
*
* @param base starting element for match
* @return matching element, or null if error
*/
public OpenAttrBase matchUnique(OpenAttrBase base) {
return partialMatchUnique(0, m_steps.length-1, base);
}
/**
* Build a path. If a path expression is supplied, the final path step in the expression must either not use an
* element name, or the element name must match the actual element supplied.
*
* @param path expression (null if none)
* @param elemname element name for final step in path
* @param nameattr name attribute (applied to final step in path, null if none)
* @param postext position (applied to final step in path, null if none)
* @param obj object defining the path
* @param vctx validation context
* @return constructed path, or null if error
*/
public static SchemaPath buildPath(String path, String elemname, String nameattr, String postext, Object obj,
ValidationContext vctx) {
// start by handling supplied values for final step predicates
SchemaPath inst = new SchemaPath(obj, vctx);
boolean valid = true;
int position = -1;
if (postext != null) {
position = inst.convertPosition(postext);
if (position < 0) {
valid = false;
}
}
if (nameattr != null && !inst.validateName(nameattr)) {
valid = false;
}
// check for only last step involved
StepBase[] steps;
if (path == null) {
steps = new StepBase[] { new PathStep(elemname, position, nameattr) };
} else {
// path supplied, process each step
ArrayList steplist = new ArrayList();
int base = 0;
int split;
while ((split = path.indexOf('/', base)) >= 0) {
StepBase step = inst.buildPathStep(path.substring(base, split));
base = split + 1;
if (step == null) {
valid = false;
} else {
steplist.add(step);
}
}
// check the final step
String steptext = path.substring(base);
if ("**".equals(steptext)) {
// add wildcard step, then create separate final step from attributes and name
steplist.add(WILDCARD_NESTING_STEP);
} else {
// strip element name from last path step, if present
if (steptext.startsWith(elemname)) {
steptext = steptext.substring(elemname.length());
}
// build the last path step from path
StepBase step = inst.buildPathStep(elemname + steptext);
if (step instanceof PathStep) {
// make sure all components match specified values
PathStep laststep = (PathStep)step;
if (!elemname.equals(laststep.m_elementName)) {
vctx.addError("Last path step must use no element name, or the specified element name", obj);
valid = false;
}
if (position <= 0) {
position = laststep.m_position;
} else if (laststep.m_position > 0 && position != laststep.m_position) {
vctx.addError("Position must not be used in last path step, or must match specified value",
obj);
valid = false;
}
if (nameattr == null) {
nameattr = laststep.m_name;
} else if (laststep.m_name != null && !nameattr.equals(laststep.m_name)) {
vctx.addError("Name atribute must not be used in last path step, or must match specified value",
obj);
valid = false;
}
}
}
// add generated final step combining specified values with those from path
steplist.add(new PathStep(elemname, position, nameattr));
steps = (StepBase[])steplist.toArray(new StepBase[steplist.size()]);
}
// return configured instance if valid
if (valid) {
inst.m_steps = steps;
return inst;
} else {
return null;
}
}
public abstract static class StepBase
{
public abstract boolean match(OpenAttrBase elem);
public abstract boolean isRepeating();
public abstract int position();
}
public static class PathStep extends StepBase
{
private final String m_elementName;
private final int m_position;
private final String m_name;
protected PathStep(String elemname, int position, String name) {
m_elementName = elemname;
m_position = position;
m_name = name;
}
public boolean isRepeating() {
return false;
}
public boolean match(OpenAttrBase elem) {
if (elem.name().equals(m_elementName)) {
if (m_name == null) {
return true;
} else if (elem instanceof INamed && m_name.equals(((INamed)elem).getName())) {
return true;
} else if (elem instanceof IReference) {
QName ref = ((IReference)elem).getRef();
return ref != null && m_name.equals(ref.getName());
} else {
return false;
}
} else {
return false;
}
}
public int position() {
return m_position;
}
}
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