aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.xml.internal.bind.v2.schemagen;
aoqi@0: 
aoqi@0: import java.util.ArrayList;
aoqi@0: import java.util.Arrays;
aoqi@0: import java.util.List;
aoqi@0: 
aoqi@0: import com.sun.xml.internal.bind.v2.schemagen.xmlschema.ContentModelContainer;
aoqi@0: import com.sun.xml.internal.bind.v2.schemagen.xmlschema.Particle;
aoqi@0: import com.sun.xml.internal.bind.v2.schemagen.xmlschema.TypeDefParticle;
aoqi@0: import com.sun.xml.internal.bind.v2.schemagen.xmlschema.Occurs;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * Normalized representation of the content model.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * This is built from bottom up so that we can eliminate redundant constructs,
aoqi@0:  * and produce the most concise content model definition in XML.
aoqi@0:  *
aoqi@0:  * @author Kohsuke Kawaguchi
aoqi@0:  */
aoqi@0: abstract class Tree {
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns "T?" from "T".
aoqi@0:      *
aoqi@0:      * @param really
aoqi@0:      *      if false this method becomes no-op. This is so that we can write
aoqi@0:      *      the caller fluently.
aoqi@0:      */
aoqi@0:     Tree makeOptional(boolean really) {
aoqi@0:         return really?new Optional(this) :this;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns "T+" from "T".
aoqi@0:      *
aoqi@0:      * @param really
aoqi@0:      *      if false this method becomes no-op. This is so that we can write
aoqi@0:      *      the caller fluently.
aoqi@0:      */
aoqi@0:     Tree makeRepeated(boolean really) {
aoqi@0:         return really?new Repeated(this) :this;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns a group tree.
aoqi@0:      */
aoqi@0:     static Tree makeGroup(GroupKind kind, List<Tree> children ) {
aoqi@0:         // pointless binary operator.
aoqi@0:         if(children.size()==1)
aoqi@0:             return children.get(0);
aoqi@0: 
aoqi@0:         // we neither have epsilon or emptySet, so can't handle children.length==0 nicely
aoqi@0: 
aoqi@0:         // eliminated nesting groups of the same kind.
aoqi@0:         // this is where binary tree would have shined.
aoqi@0:         List<Tree> normalizedChildren = new ArrayList<Tree>(children.size());
aoqi@0:         for (Tree t : children) {
aoqi@0:             if (t instanceof Group) {
aoqi@0:                 Group g = (Group) t;
aoqi@0:                 if(g.kind==kind) {
aoqi@0:                     normalizedChildren.addAll(Arrays.asList(g.children));
aoqi@0:                     continue;
aoqi@0:                 }
aoqi@0:             }
aoqi@0:             normalizedChildren.add(t);
aoqi@0:         }
aoqi@0: 
aoqi@0:         return new Group(kind,normalizedChildren.toArray(new Tree[normalizedChildren.size()]));
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns true if this tree accepts empty sequence.
aoqi@0:      */
aoqi@0:     abstract boolean isNullable();
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns true if the top node of this tree can
aoqi@0:      * appear as a valid top-level content model in XML Schema.
aoqi@0:      *
aoqi@0:      * <p>
aoqi@0:      * Model groups and occurrences that have model group in it can.
aoqi@0:      */
aoqi@0:     boolean canBeTopLevel() { return false; }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Writes out the content model.
aoqi@0:      *
aoqi@0:      * Normall this runs recursively until we write out the whole content model.
aoqi@0:      */
aoqi@0:     protected abstract void write(ContentModelContainer parent, boolean isOptional, boolean repeated);
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Writes inside the given complex type.
aoqi@0:      */
aoqi@0:     protected void write(TypeDefParticle ct) {
aoqi@0:         if(canBeTopLevel())
aoqi@0:             write(ct._cast(ContentModelContainer.class), false, false);
aoqi@0:         else
aoqi@0:             // need a dummy wrapper
aoqi@0:             new Group(GroupKind.SEQUENCE,this).write(ct);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Convenience method to write occurrence constraints.
aoqi@0:      */
aoqi@0:     protected final void writeOccurs(Occurs o, boolean isOptional, boolean repeated) {
aoqi@0:         if(isOptional)
aoqi@0:             o.minOccurs(0);
aoqi@0:         if(repeated)
aoqi@0:             o.maxOccurs("unbounded");
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Represents a terminal tree node, such as element, wildcard, etc.
aoqi@0:      */
aoqi@0:     abstract static class Term extends Tree {
aoqi@0:         boolean isNullable() {
aoqi@0:             return false;
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * "T?"
aoqi@0:      */
aoqi@0:     private static final class Optional extends Tree {
aoqi@0:         private final Tree body;
aoqi@0: 
aoqi@0:         private Optional(Tree body) {
aoqi@0:             this.body = body;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         boolean isNullable() {
aoqi@0:             return true;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         Tree makeOptional(boolean really) {
aoqi@0:             return this;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         protected void write(ContentModelContainer parent, boolean isOptional, boolean repeated) {
aoqi@0:             body.write(parent,true,repeated);
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * "T+"
aoqi@0:      */
aoqi@0:     private static final class Repeated extends Tree {
aoqi@0:         private final Tree body;
aoqi@0: 
aoqi@0:         private Repeated(Tree body) {
aoqi@0:             this.body = body;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         boolean isNullable() {
aoqi@0:             return body.isNullable();
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         Tree makeRepeated(boolean really) {
aoqi@0:             return this;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         protected void write(ContentModelContainer parent, boolean isOptional, boolean repeated) {
aoqi@0:             body.write(parent,isOptional,true);
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * "S|T", "S,T", and "S&amp;T".
aoqi@0:      */
aoqi@0:     private static final class Group extends Tree {
aoqi@0:         private final GroupKind kind;
aoqi@0:         private final Tree[] children;
aoqi@0: 
aoqi@0:         private Group(GroupKind kind, Tree... children) {
aoqi@0:             this.kind = kind;
aoqi@0:             this.children = children;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         boolean canBeTopLevel() {
aoqi@0:             return true;
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         boolean isNullable() {
aoqi@0:             if(kind== GroupKind.CHOICE) {
aoqi@0:                 for (Tree t : children) {
aoqi@0:                     if(t.isNullable())
aoqi@0:                         return true;
aoqi@0:                 }
aoqi@0:                 return false;
aoqi@0:             } else {
aoqi@0:                 for (Tree t : children) {
aoqi@0:                     if(!t.isNullable())
aoqi@0:                         return false;
aoqi@0:                 }
aoqi@0:                 return true;
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         @Override
aoqi@0:         protected void write(ContentModelContainer parent, boolean isOptional, boolean repeated) {
aoqi@0:             Particle c = kind.write(parent);
aoqi@0:             writeOccurs(c,isOptional,repeated);
aoqi@0: 
aoqi@0:             for (Tree child : children) {
aoqi@0:                 child.write(c,false,false);
aoqi@0:             }
aoqi@0:         }
aoqi@0:     }
aoqi@0: }