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/*
* 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.apache.xerces.impl.xs.models;
import org.apache.xerces.impl.dtd.models.CMNode;
import org.apache.xerces.impl.xs.SchemaSymbols;
import org.apache.xerces.impl.xs.XSComplexTypeDecl;
import org.apache.xerces.impl.xs.XSDeclarationPool;
import org.apache.xerces.impl.xs.XSElementDecl;
import org.apache.xerces.impl.xs.XSModelGroupImpl;
import org.apache.xerces.impl.xs.XSParticleDecl;
/**
* This class constructs content models for a given grammar.
*
* @xerces.internal
*
* @author Elena Litani, IBM
* @author Sandy Gao, IBM
*
* @version $Id: CMBuilder.java 573322 2007-09-06 16:48:47Z peterjm $
*/
public class CMBuilder {
// REVISIT: should update the decl pool to cache XSCM objects too
private XSDeclarationPool fDeclPool = null;
// It never changes, so a static member is good enough
private static final XSEmptyCM fEmptyCM = new XSEmptyCM();
// needed for DFA construction
private int fLeafCount;
// needed for UPA
private int fParticleCount;
//Factory to create Bin, Uni, Leaf nodes
private final CMNodeFactory fNodeFactory;
public CMBuilder(CMNodeFactory nodeFactory) {
fDeclPool = null;
fNodeFactory = nodeFactory ;
}
public void setDeclPool(XSDeclarationPool declPool) {
fDeclPool = declPool;
}
/**
* Get content model for the a given type
*
* @param typeDecl get content model for which complex type
* @return a content model validator
*/
public XSCMValidator getContentModel(XSComplexTypeDecl typeDecl, boolean forUPA) {
// for complex type with empty or simple content,
// there is no content model validator
short contentType = typeDecl.getContentType();
if (contentType == XSComplexTypeDecl.CONTENTTYPE_SIMPLE ||
contentType == XSComplexTypeDecl.CONTENTTYPE_EMPTY) {
return null;
}
XSParticleDecl particle = (XSParticleDecl)typeDecl.getParticle();
// if the content is element only or mixed, but no particle
// is defined, return the empty content model
if (particle == null)
return fEmptyCM;
// if the content model contains "all" model group,
// we create an "all" content model, otherwise a DFA content model
XSCMValidator cmValidator = null;
if (particle.fType == XSParticleDecl.PARTICLE_MODELGROUP &&
((XSModelGroupImpl)particle.fValue).fCompositor == XSModelGroupImpl.MODELGROUP_ALL) {
cmValidator = createAllCM(particle);
}
else {
cmValidator = createDFACM(particle, forUPA);
}
//now we are throught building content model and have passed sucessfully of the nodecount check
//if set by the application
fNodeFactory.resetNodeCount() ;
// if the validator returned is null, it means there is nothing in
// the content model, so we return the empty content model.
if (cmValidator == null)
cmValidator = fEmptyCM;
return cmValidator;
}
XSCMValidator createAllCM(XSParticleDecl particle) {
if (particle.fMaxOccurs == 0)
return null;
// get the model group, and add all children of it to the content model
XSModelGroupImpl group = (XSModelGroupImpl)particle.fValue;
// create an all content model. the parameter indicates whether
// the itself is optional
XSAllCM allContent = new XSAllCM(particle.fMinOccurs == 0, group.fParticleCount);
for (int i = 0; i < group.fParticleCount; i++) {
// add the element decl to the all content model
allContent.addElement((XSElementDecl)group.fParticles[i].fValue,
group.fParticles[i].fMinOccurs == 0);
}
return allContent;
}
XSCMValidator createDFACM(XSParticleDecl particle, boolean forUPA) {
fLeafCount = 0;
fParticleCount = 0;
// convert particle tree to CM tree
CMNode node = useRepeatingLeafNodes(particle) ? buildCompactSyntaxTree(particle) : buildSyntaxTree(particle, forUPA);
if (node == null)
return null;
// build DFA content model from the CM tree
return new XSDFACM(node, fLeafCount);
}
// 1. convert particle tree to CM tree:
// 2. expand all occurrence values: a{n, unbounded} -> a, a, ..., a+
// a{n, m} -> a, a, ..., a?, a?, ...
// 3. convert model groups (a, b, c, ...) or (a | b | c | ...) to
// binary tree: (((a,b),c),...) or (((a|b)|c)|...)
// 4. make sure each leaf node (XSCMLeaf) has a distinct position
private CMNode buildSyntaxTree(XSParticleDecl particle, boolean forUPA) {
int maxOccurs = particle.fMaxOccurs;
int minOccurs = particle.fMinOccurs;
boolean compactedForUPA = false;
if (forUPA) {
// When doing UPA, we reduce the size of the minOccurs/maxOccurs values to make
// processing the DFA faster. For UPA the exact values don't matter.
if (minOccurs > 1) {
if (maxOccurs > minOccurs || particle.getMaxOccursUnbounded()) {
minOccurs = 1;
compactedForUPA = true;
}
else { // maxOccurs == minOccurs
minOccurs = 2;
compactedForUPA = true;
}
}
if (maxOccurs > 1) {
maxOccurs = 2;
compactedForUPA = true;
}
}
short type = particle.fType;
CMNode nodeRet = null;
if ((type == XSParticleDecl.PARTICLE_WILDCARD) ||
(type == XSParticleDecl.PARTICLE_ELEMENT)) {
// (task 1) element and wildcard particles should be converted to
// leaf nodes
// REVISIT: Make a clone of the leaf particle, so that if there
// are two references to the same group, we have two different
// leaf particles for the same element or wildcard decl.
// This is useful for checking UPA.
nodeRet = fNodeFactory.getCMLeafNode(particle.fType, particle.fValue, fParticleCount++, fLeafCount++);
// (task 2) expand occurrence values
nodeRet = expandContentModel(nodeRet, minOccurs, maxOccurs);
if (nodeRet != null) {
nodeRet.setIsCompactUPAModel(compactedForUPA);
}
}
else if (type == XSParticleDecl.PARTICLE_MODELGROUP) {
// (task 1,3) convert model groups to binary trees
XSModelGroupImpl group = (XSModelGroupImpl)particle.fValue;
CMNode temp = null;
// when the model group is a choice of more than one particles, but
// only one of the particle is not empty, (for example
//
//
//
//
// ) we can't not return that one particle ("e"). instead, we should
// treat such particle as optional ("e?").
// the following int variable keeps track of the number of non-empty children
int count = 0;
for (int i = 0; i < group.fParticleCount; i++) {
// first convert each child to a CM tree
temp = buildSyntaxTree(group.fParticles[i], forUPA);
// then combine them using binary operation
if (temp != null) {
compactedForUPA |= temp.isCompactedForUPA();
++count;
if (nodeRet == null) {
nodeRet = temp;
}
else {
nodeRet = fNodeFactory.getCMBinOpNode(group.fCompositor, nodeRet, temp);
}
}
}
// (task 2) expand occurrence values
if (nodeRet != null) {
// when the group is "choice" and the group has one or more empty children,
// we need to create a zero-or-one (optional) node for the non-empty particles.
if (group.fCompositor == XSModelGroupImpl.MODELGROUP_CHOICE && count < group.fParticleCount) {
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_ONE, nodeRet);
}
nodeRet = expandContentModel(nodeRet, minOccurs, maxOccurs);
nodeRet.setIsCompactUPAModel(compactedForUPA);
}
}
return nodeRet;
}
// 2. expand all occurrence values: a{n, unbounded} -> a, a, ..., a+
// a{n, m} -> a, a, ..., a?, a?, ...
// 4. make sure each leaf node (XSCMLeaf) has a distinct position
private CMNode expandContentModel(CMNode node,
int minOccurs, int maxOccurs) {
CMNode nodeRet = null;
if (minOccurs==1 && maxOccurs==1) {
nodeRet = node;
}
else if (minOccurs==0 && maxOccurs==1) {
//zero or one
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_ONE, node);
}
else if (minOccurs == 0 && maxOccurs==SchemaSymbols.OCCURRENCE_UNBOUNDED) {
//zero or more
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_MORE, node);
}
else if (minOccurs == 1 && maxOccurs==SchemaSymbols.OCCURRENCE_UNBOUNDED) {
//one or more
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ONE_OR_MORE, node);
}
else if (maxOccurs == SchemaSymbols.OCCURRENCE_UNBOUNDED) {
// => a,a,..,a+
// create a+ node first, then put minOccurs-1 a's in front of it
// for the first time "node" is used, we don't need to make a copy
// and for other references to node, we make copies
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ONE_OR_MORE, node);
// (task 4) we need to call copyNode here, so that we append
// an entire new copy of the node (a subtree). this is to ensure
// all leaf nodes have distinct position
// we know that minOccurs > 1
nodeRet = fNodeFactory.getCMBinOpNode(XSModelGroupImpl.MODELGROUP_SEQUENCE,
multiNodes(node, minOccurs-1, true), nodeRet);
}
else {
// {n,m} => a,a,a,...(a),(a),...
// first n a's, then m-n a?'s.
// copyNode is called, for the same reason as above
if (minOccurs > 0) {
nodeRet = multiNodes(node, minOccurs, false);
}
if (maxOccurs > minOccurs) {
node = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_ONE, node);
if (nodeRet == null) {
nodeRet = multiNodes(node, maxOccurs-minOccurs, false);
}
else {
nodeRet = fNodeFactory.getCMBinOpNode(XSModelGroupImpl.MODELGROUP_SEQUENCE,
nodeRet, multiNodes(node, maxOccurs-minOccurs, true));
}
}
}
return nodeRet;
}
private CMNode multiNodes(CMNode node, int num, boolean copyFirst) {
if (num == 0) {
return null;
}
if (num == 1) {
return copyFirst ? copyNode(node) : node;
}
int num1 = num/2;
return fNodeFactory.getCMBinOpNode(XSModelGroupImpl.MODELGROUP_SEQUENCE,
multiNodes(node, num1, copyFirst),
multiNodes(node, num-num1, true));
}
// 4. make sure each leaf node (XSCMLeaf) has a distinct position
private CMNode copyNode(CMNode node) {
int type = node.type();
// for choice or sequence, copy the two subtrees, and combine them
if (type == XSModelGroupImpl.MODELGROUP_CHOICE ||
type == XSModelGroupImpl.MODELGROUP_SEQUENCE) {
XSCMBinOp bin = (XSCMBinOp)node;
node = fNodeFactory.getCMBinOpNode(type, copyNode(bin.getLeft()),
copyNode(bin.getRight()));
}
// for ?+*, copy the subtree, and put it in a new ?+* node
else if (type == XSParticleDecl.PARTICLE_ZERO_OR_MORE ||
type == XSParticleDecl.PARTICLE_ONE_OR_MORE ||
type == XSParticleDecl.PARTICLE_ZERO_OR_ONE) {
XSCMUniOp uni = (XSCMUniOp)node;
node = fNodeFactory.getCMUniOpNode(type, copyNode(uni.getChild()));
}
// for element/wildcard (leaf), make a new leaf node,
// with a distinct position
else if (type == XSParticleDecl.PARTICLE_ELEMENT ||
type == XSParticleDecl.PARTICLE_WILDCARD) {
XSCMLeaf leaf = (XSCMLeaf)node;
node = fNodeFactory.getCMLeafNode(leaf.type(), leaf.getLeaf(), leaf.getParticleId(), fLeafCount++);
}
return node;
}
// A special version of buildSyntaxTree() which builds a compact syntax tree
// containing compound leaf nodes which carry occurence information. This method
// for building the syntax tree is chosen over buildSyntaxTree() when
// useRepeatingLeafNodes() returns true.
private CMNode buildCompactSyntaxTree(XSParticleDecl particle) {
int maxOccurs = particle.fMaxOccurs;
int minOccurs = particle.fMinOccurs;
short type = particle.fType;
CMNode nodeRet = null;
if ((type == XSParticleDecl.PARTICLE_WILDCARD) ||
(type == XSParticleDecl.PARTICLE_ELEMENT)) {
return buildCompactSyntaxTree2(particle, minOccurs, maxOccurs);
}
else if (type == XSParticleDecl.PARTICLE_MODELGROUP) {
XSModelGroupImpl group = (XSModelGroupImpl)particle.fValue;
if (group.fParticleCount == 1 && (minOccurs != 1 || maxOccurs != 1)) {
return buildCompactSyntaxTree2(group.fParticles[0], minOccurs, maxOccurs);
}
else {
CMNode temp = null;
// when the model group is a choice of more than one particles, but
// only one of the particle is not empty, (for example
//
//
//
//
// ) we can't not return that one particle ("e"). instead, we should
// treat such particle as optional ("e?").
// the following int variable keeps track of the number of non-empty children
int count = 0;
for (int i = 0; i < group.fParticleCount; i++) {
// first convert each child to a CM tree
temp = buildCompactSyntaxTree(group.fParticles[i]);
// then combine them using binary operation
if (temp != null) {
++count;
if (nodeRet == null) {
nodeRet = temp;
}
else {
nodeRet = fNodeFactory.getCMBinOpNode(group.fCompositor, nodeRet, temp);
}
}
}
if (nodeRet != null) {
// when the group is "choice" and the group has one or more empty children,
// we need to create a zero-or-one (optional) node for the non-empty particles.
if (group.fCompositor == XSModelGroupImpl.MODELGROUP_CHOICE && count < group.fParticleCount) {
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_ONE, nodeRet);
}
}
}
}
return nodeRet;
}
private CMNode buildCompactSyntaxTree2(XSParticleDecl particle, int minOccurs, int maxOccurs) {
// Convert element and wildcard particles to leaf nodes. Wrap repeating particles in a CMUniOpNode.
CMNode nodeRet = null;
if (minOccurs == 1 && maxOccurs == 1) {
nodeRet = fNodeFactory.getCMLeafNode(particle.fType, particle.fValue, fParticleCount++, fLeafCount++);
}
else if (minOccurs == 0 && maxOccurs == 1) {
// zero or one
nodeRet = fNodeFactory.getCMLeafNode(particle.fType, particle.fValue, fParticleCount++, fLeafCount++);
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_ONE, nodeRet);
}
else if (minOccurs == 0 && maxOccurs==SchemaSymbols.OCCURRENCE_UNBOUNDED) {
// zero or more
nodeRet = fNodeFactory.getCMLeafNode(particle.fType, particle.fValue, fParticleCount++, fLeafCount++);
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_MORE, nodeRet);
}
else if (minOccurs == 1 && maxOccurs==SchemaSymbols.OCCURRENCE_UNBOUNDED) {
// one or more
nodeRet = fNodeFactory.getCMLeafNode(particle.fType, particle.fValue, fParticleCount++, fLeafCount++);
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ONE_OR_MORE, nodeRet);
}
else {
// {n,m}: Instead of expanding this out, create a compound leaf node which carries the
// occurence information and wrap it in the appropriate CMUniOpNode.
nodeRet = fNodeFactory.getCMRepeatingLeafNode(particle.fType, particle.fValue, minOccurs, maxOccurs, fParticleCount++, fLeafCount++);
if (minOccurs == 0) {
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ZERO_OR_MORE, nodeRet);
}
else {
nodeRet = fNodeFactory.getCMUniOpNode(XSParticleDecl.PARTICLE_ONE_OR_MORE, nodeRet);
}
}
return nodeRet;
}
// This method checks if this particle can be transformed into a compact syntax
// tree containing compound leaf nodes which carry occurence information. Currently
// it returns true if each model group has minOccurs/maxOccurs == 1 or
// contains only one element/wildcard particle with minOccurs/maxOccurs == 1.
private boolean useRepeatingLeafNodes(XSParticleDecl particle) {
int maxOccurs = particle.fMaxOccurs;
int minOccurs = particle.fMinOccurs;
short type = particle.fType;
if (type == XSParticleDecl.PARTICLE_MODELGROUP) {
XSModelGroupImpl group = (XSModelGroupImpl) particle.fValue;
if (minOccurs != 1 || maxOccurs != 1) {
if (group.fParticleCount == 1) {
XSParticleDecl particle2 = (XSParticleDecl) group.fParticles[0];
short type2 = particle2.fType;
return ((type2 == XSParticleDecl.PARTICLE_ELEMENT ||
type2 == XSParticleDecl.PARTICLE_WILDCARD) &&
particle2.fMinOccurs == 1 &&
particle2.fMaxOccurs == 1);
}
return (group.fParticleCount == 0);
}
for (int i = 0; i < group.fParticleCount; ++i) {
if (!useRepeatingLeafNodes(group.fParticles[i])) {
return false;
}
}
}
return true;
}
}
