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Ultra-high performance non-blocking XML processor (Stax/Stax2, SAX/SAX2)
package com.fasterxml.aalto.dom;
import java.util.*;
import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;
/* !!! 18-Dec-2008, tatu: Copied from Woodstox almost verbatim, should be
* replaced/removed/rewritten soon.
*/
/**
* Helper class that implements "bijective map" (Map that allows use of values
* as keys and vice versa, bidirectional access), and is specifically
* used for storing namespace binding information.
* One thing worth noting is that Strings stored are NOT assumed to have
* been unified (interned) -- if they were, different implementation would
* be more optimal.
*/
public final class BijectiveNsMap
{
/*
///////////////////////////////////////////////
// Constants
///////////////////////////////////////////////
*/
/**
* Let's plan for having up to 14 explicit namespace declarations (2
* defaults, for 'xml' and 'xmlns', are pre-populated)
*/
final static int DEFAULT_ARRAY_SIZE = 2 * 16;
/*
///////////////////////////////////////////////
// Member vars
///////////////////////////////////////////////
*/
final int _scopeStart;
/**
* Array that contains { prefix, ns-uri } pairs, up to (but not including)
* index {@link #_scopeEnd}.
*/
String[] _nsStrings;
int _scopeEnd;
/*
///////////////////////////////////////////////
// Life-cycle
///////////////////////////////////////////////
*/
private BijectiveNsMap(int scopeStart, String[] strs)
{
_scopeStart = _scopeEnd = scopeStart;
_nsStrings = strs;
}
public static BijectiveNsMap createEmpty()
{
String[] strs = new String[DEFAULT_ARRAY_SIZE];
strs[0] = XMLConstants.XML_NS_PREFIX;
strs[1] = XMLConstants.XML_NS_URI;
strs[2] = XMLConstants.XMLNS_ATTRIBUTE;
strs[3] = XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
/* Let's consider pre-defined ones to be 'out of scope', i.e.
* conceptually be part of (missing) parent's mappings.
*/
return new BijectiveNsMap(4, strs);
}
public BijectiveNsMap createChild() {
return new BijectiveNsMap(_scopeEnd, _nsStrings);
}
/*
///////////////////////////////////////////////
// Public API, accessors
///////////////////////////////////////////////
*/
public String findUriByPrefix(String prefix)
{
/* This is quite simple: just need to locate the last mapping
* for the prefix, if any:
*/
String[] strs = _nsStrings;
int phash = prefix.hashCode();
for (int ix = _scopeEnd - 2; ix >= 0; ix -= 2) {
String thisP = strs[ix];
if (thisP == prefix ||
(thisP.hashCode() == phash && thisP.equals(prefix))) {
return strs[ix+1];
}
}
return null;
}
public String findPrefixByUri(String uri)
{
/* Finding a valid binding for the given URI is trickier, since
* mappings can be masked by others... so, we need to first find
* most recent binding, from the freshest one, and then verify
* it's still unmasked; if not, continue with the first loop,
* and so on.
*/
String[] strs = _nsStrings;
int uhash = uri.hashCode();
main_loop:
for (int ix = _scopeEnd - 1; ix > 0; ix -= 2) {
String thisU = strs[ix];
if (thisU == uri ||
(thisU.hashCode() == uhash && thisU.equals(uri))) {
// match, but has it been masked?
String prefix = strs[ix-1];
/* only need to check, if it wasn't within current scope
* (no masking allowed within scopes)
*/
if (ix < _scopeStart) {
int phash = prefix.hashCode();
for (int j = ix-1, end = _scopeEnd; j < end; j += 2) {
String thisP = strs[ix];
if (thisP == prefix ||
(thisP.hashCode() == phash && thisP.equals(prefix))) {
// Masking... got to continue the main loop:
continue main_loop;
}
}
}
// Ok, unmasked one, can return
return prefix;
}
}
return null;
}
public List getPrefixesBoundToUri(String uri, List l)
{
/* Same problems (masking) apply here, as well as with
* findPrefixByUri...
*/
String[] strs = _nsStrings;
int uhash = uri.hashCode();
main_loop:
for (int ix = _scopeEnd - 1; ix > 0; ix -= 2) {
String thisU = strs[ix];
if (thisU == uri ||
(thisU.hashCode() == uhash && thisU.equals(uri))) {
// match, but has it been masked?
String prefix = strs[ix-1];
/* only need to check, if it wasn't within current scope
* (no masking allowed within scopes)
*/
if (ix < _scopeStart) {
int phash = prefix.hashCode();
for (int j = ix-1, end = _scopeEnd; j < end; j += 2) {
String thisP = strs[ix];
if (thisP == prefix ||
(thisP.hashCode() == phash && thisP.equals(prefix))) {
// Masking... got to continue the main loop:
continue main_loop;
}
}
}
// Ok, unmasked one, can add
if (l == null) {
l = new ArrayList();
}
l.add(prefix);
}
}
return l;
}
public int size() {
return (_scopeEnd >> 1);
}
public int localSize() {
return ((_scopeEnd - _scopeStart) >> 1);
}
/*
///////////////////////////////////////////////
// Public API, mutators
///////////////////////////////////////////////
*/
/**
* Method to add a new prefix-to-URI mapping for the current scope.
* Note that it should NOT be used for the default namespace
* declaration
*
* @param prefix Prefix to bind
* @param uri URI to bind to the prefix
*
* @return If the prefix was already bound, the URI it was bound to:
* null if it's a new binding for the current scope.
*/
public String addMapping(String prefix, String uri)
{
String[] strs = _nsStrings;
int phash = prefix.hashCode();
for (int ix = _scopeStart, end = _scopeEnd; ix < end; ix += 2) {
String thisP = strs[ix];
if (thisP == prefix ||
(thisP.hashCode() == phash && thisP.equals(prefix))) {
// Overriding an existing mapping
String old = strs[ix+1];
strs[ix+1] = uri;
return old;
}
}
// no previous binding, let's just add it at the end
if (_scopeEnd >= strs.length) {
// let's just double the array sizes...
strs = Arrays.copyOf(strs, (strs.length << 1));
_nsStrings = strs;
}
strs[_scopeEnd++] = prefix;
strs[_scopeEnd++] = uri;
return null;
}
/**
* Method used to add a dynamic binding, and return the prefix
* used to bind the specified namespace URI.
*/
public String addGeneratedMapping(String prefixBase, NamespaceContext ctxt,
String uri, int[] seqArr)
{
String[] strs = _nsStrings;
int seqNr = seqArr[0];
String prefix;
main_loop:
while (true) {
/* We better intern the resulting prefix? Or not?
* TODO: maybe soft cache these for other docs?
*/
prefix = (prefixBase + seqNr).intern();
++seqNr;
/* Ok, let's see if we have a mapping (masked or not) for
* the prefix. If we do, let's just not use it: we could
* of course mask it (unless it's in current scope), but
* it's easier to just get a "virgin" prefix...
*/
int phash = prefix.hashCode();
for (int ix = _scopeEnd - 2; ix >= 0; ix -= 2) {
String thisP = strs[ix];
if (thisP == prefix ||
(thisP.hashCode() == phash && thisP.equals(prefix))) {
continue main_loop;
}
}
/* So far so good... but do we have a root context that might
* have something too?
*/
if (ctxt != null && ctxt.getNamespaceURI(prefix) != null) {
continue;
}
break;
}
seqArr[0] = seqNr;
// Ok, good; then let's just add it in...
if (_scopeEnd >= strs.length) {
// let's just double the array sizes...
strs = Arrays.copyOf(strs, (strs.length << 1));
_nsStrings = strs;
}
strs[_scopeEnd++] = prefix;
strs[_scopeEnd++] = uri;
return prefix;
}
}