template.java

java xml开发指南（初学者推荐）Java Xml 编程指南书籍源码

package MyNa.xml;

import MyNa.utils.*;
import java.io.*;
import java.util.*;
import java.sql.SQLException;


import org.w3c.dom.Node;


public class Template {

// handles an xml template defined according to template.dtd;
// output to a Writer. (This will sometimes be a StringWriter
// in order to use the template to define Env entries.)
// We start with an Env, which may or may not contain a
// DBHandler to connect us with a database. If there is no
// DBHandler, there are no dbOperation attributes. The Env
// may be generated by a RowSeq in which case
// substrow, substerr and substrowlist are legitimate;
// <substrowlist enumerateThrough="StrSeq" name="FieldName">
//  may also be used to generate items from StrSeqs in an Env.

// in general, use this by identifying the top <template>
// node nd, the output out
   Logger lg;
   Writer out;
   Env defs;
   RowSeq rows;

   int[]index;
   int curIndex;
   boolean substFailure;

public Template(){
   lg=new Logger();
   out=new PrintWriter(System.out);
   defs=new Env();   rows=null;
   index=new int[20];curIndex=-1;
   substFailure=false;
   lg.logIt("template default initialization");
}
public void setOut(Writer o){out=o;}
public void setDefs(Env e){defs=e;}
public void setRows(RowSeq re){
  rows=re; 
  defs=re.getRow();
}
public Template(Env e,Writer o){
   lg=new Logger();
  out=o;defs=e; rows=null;
  index=new int[20];curIndex=-1;
  substFailure=false;
   lg.logIt("template Env+Writer initialization");
}
public Template(RowSeq e,Writer o){
   lg=new Logger();
  rows=e;out=o;defs=e.getRow();
  index=new int[20];curIndex=-1;
  substFailure=false;
   lg.logIt("template RowSeq+Writer initialization");
}

// these are the seven tagnames we use

   static String templateN="template"; // only at root
   static String textN="text";
   static String substN="subst";
   static String setdefN="setdef";
   static String substrowN="substrow";
   static String substerrN="substerr";
   static String substrowlistN="substrowlist";

// the four attrs used are name,num,dbOperation, and enumerateThrough;

   static String nameAttr="name";
   static String numAttr="num";
   static String dbOperationAttr="dbOperation";
   static String enumerateThroughAttr="enumerateThrough";

// enumerateThrough has the two possible values ResultSet and StrSeq

   static String resultsetAttrVal="ResultSet";
   static String strseqAttrVal="StrSeq";

// given a node, we can choose what to do based on its name.

public void chooseRule(Node theNode,Writer out) throws TemplateException{
  lg.logIt("choosing rule");
  String tag=theNode.getNodeName();
  lg.logIt("tag="+tag);
  if(textN.equals(tag))doText(theNode,out);
  else if(substN.equals(tag))doSubst(theNode,out);
  else if(setdefN.equals(tag))doSetdef(theNode,out);
  else if(substrowN.equals(tag))doSubstrow(theNode,out);
  else if(substerrN.equals(tag))doSubsterr(theNode,out);
  else if(substrowlistN.equals(tag))doSubstrowlist(theNode,out);
  else if(templateN.equals(tag))doTemplate(theNode,out);
  else throw new TemplateException("invalid tag "+tag+" in template DTD");
}

public void chooseRule(Node theNode)throws TemplateException{
  chooseRule(theNode,out);
}
// after we process a node, we do its children.

public void doChildren(Node theNode,Writer out)
   throws TemplateException{
  lg.logIt("doChildren");
  Node child=theNode.getFirstChild();
  while(child!=null){
    doDBOperation(child);
    chooseRule(child,out);
    child=child.getNextSibling();
    }
}

// we can extract any of the four attributes; "num" is numeric,
// with default 0;
// and "enumerateThrough" has default value "ResultSet".

public String getNameAttr(Node theNode){
  Node attr=theNode.getAttributes().getNamedItem(nameAttr);
  String R=(attr==null)?null:attr.getNodeValue();
  return R;
}
public String getdbOperationAttr(Node theNode){
  Node attr=theNode.getAttributes().getNamedItem(dbOperationAttr);
  String R=(attr==null)?null:attr.getNodeValue();
  return R;
}
public int getNumAttr(Node theNode){
  Node attr=theNode.getAttributes().getNamedItem(numAttr);
  String R=(attr==null)?null:attr.getNodeValue();
  if(null==R)return 0;
  int n=Integer.parseInt(R);
  if(n<0)return index[curIndex]; // -1 means use current index
  return n;
}
public String getEnumerateThroughAttr(Node theNode){
  Node attr=theNode.getAttributes().getNamedItem(enumerateThroughAttr);
  String R=(attr==null)?null:attr.getNodeValue();
  if(null==R)return resultsetAttrVal;
 return R;
}

public String getTextNodeValue(Node textNode){
  String S=textNode.getNodeValue();
  if(S==null)S="";
  Node C=textNode.getFirstChild();
  while(C!=null){String cV=C.getNodeValue();
    if(cV!=null)S+=cV;
    C=C.getNextSibling();
    }
  return S;
}
public void doText(Node theNode,Writer out)
    throws TemplateException{ // no children
   lg.logIt("doText");
  try{
    String S=getTextNodeValue(theNode);
    lg.logIt("text value=["+S+"]");
    out.write(S);
    }
  catch(IOException e){
    throw new TemplateException("I/O err in text: "+e);
    }
}

public void doSubst(Node theNode,Writer out)
  throws TemplateException{ // no children
   lg.logIt("doSubst");
  String key=getTextNodeValue(theNode); 
  lg.logIt("subst key="+key);
  if(key==null)return;
  int n=getNumAttr(theNode);
  try{String val;
    if(n==0)val=(defs.getStr(key));
    else {
      String[] A=defs.getStrSeq(key);
      if(A==null || A.length==0 || A.length<n) return;
      val=(A[n-1]);
      }
    lg.logIt("subst val="+val);
    if(val!=null)out.write(val);
  }catch(IOException e){
     throw new TemplateException("I/O err in subst: "+e);
  }
}
public void doSetdef(Node theNode,Writer out) // bypass out
   throws TemplateException{
   lg.logIt("doSetdef");
   StringWriter sW=new StringWriter();
   String key=getNameAttr(theNode);
   if(key==null)throw new TemplateException("No Name on setDef node");
   doChildren(theNode,sW);
   int n=getNumAttr(theNode);
   if(n==0)defs.put(key,sW.toString());   
  else {
    String[] A=defs.getStrSeq(key);
    if(A==null || A.length==0 || A.length<n) 
      throw new IndexOutOfBoundsException("invalid index "+n+"on key "+key+
          "with value ["+defs.getStr(key)+"]");
    A[n-1]=sW.toString(); 
    defs.put(key,A); // in case it wasn't really a StrSeq before.
    }
}


public void doSubstrow(Node theNode,Writer out)
   throws TemplateException{
   lg.logIt("doSubstrow");
  if(substFailure || null==rows ||
     !rows.next())
    {substFailure=true; return;}
  defs=rows.getRow();
  doChildren(theNode,out);
}
public void doSubsterr(Node theNode,Writer out)
   throws TemplateException{
   lg.logIt("doSubsterr");
  if(substFailure)doChildren(theNode,out);
}
public void doSubstrowlist(Node theNode,Writer out)
   throws TemplateException{
   lg.logIt("doSubstrowlist");
  String enumType=getEnumerateThroughAttr(theNode);
  if(strseqAttrVal.equals(enumType))
    doEnumThroughStrSeq(theNode,out);
  else if(substFailure || null==rows) return;
  else {
    while(rows.next()){
      defs=rows.getRow();
      doChildren(theNode,out);
    }
   }
}
public void doEnumThroughStrSeq(Node theNode,Writer out)
   throws TemplateException{
   lg.logIt("doEnumThroughStrSeq");
  String ssName=getNameAttr(theNode);
  lg.logIt("got ssname="+ssName);
  if(ssName==null)
    throw new TemplateException("no name for strseq enumthrough");
  String[]ssVal=defs.getStrSeq(ssName);
  if(ssVal==null)
    throw new TemplateException("no val for "+ssName+" in enumthrough");
  lg.logIt("got ssval=["+Misc.stringArrayJoin(ssVal,",")+"]");
  curIndex++;
  lg.logIt("curIndex="+curIndex);
  if(index.length<=curIndex)
    throw new TemplateException("stack overflow in enumthrough at "+ssName);
  for(index[curIndex]=1;index[curIndex]<=ssVal.length;index[curIndex]++)
    doChildren(theNode,out);
}
public void doTemplate(Node theNode,Writer out) // set up root
   throws TemplateException{
   lg.logIt("doTemplate");
   doDBOperation(theNode); 
   lg.logIt("did dboperation");
   doChildren(theNode,out);
}
public void doDBOperation(Node theNode)throws TemplateException{
  String theOp=getdbOperationAttr(theNode);
  lg.logIt("doDBOp "+theOp);
  if(theOp==null)return;
  defs.put(dbOperationAttr,theOp);
  DBHandler theDBHandler=(DBHandler)defs.get("dbHandler");
  if(theDBHandler==null)
    throw new TemplateException("no dbhandler for op "+theOp);
  try{
    setRows(theDBHandler.getQueryRows(defs));
  }catch(SQLException ex){
    throw new TemplateException("dbHandler for op "+theOp+
             "failed with SQLException "+ex);
  }
}

}
/*
<!ELEMENT template (text | subst | substrow | substerr | substrowlist | setdef)*>
<!ELEMENT text (#PCDATA)>
<!ELEMENT subst (#PCDATA)>
<!ATTLIST subst
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
>
<!ELEMENT setdef (#PCDATA)>
<!ATTLIST setdef
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
>

<!ELEMENT subst (#PCDATA)>
<!ATTLIST subst
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
>
<!ELEMENT substrow (text | subst | substrow | substerr | substrowlist)*>
<!ATTLIST substrow
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
>
<!ELEMENT substerr (text | subst | substrow | substerr | substrowlist)*>
<!ATTLIST substerr
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
>
<!ELEMENT substrowlist (text | subst | substrow | substerr | substrowlist)*>
<!ATTLIST substrowlist
    name CDATA #IMPLIED
    num CDATA #IMPLIED
    dbOperation CDATA #IMPLIED
    enumerateThrough CDATA #IMPLIED
>
<?xml version="1.0"?>
<!DOCTYPE template SYSTEM "template.dtd">
<myna:template>

<myna:text>
<?xml version="1.0"?>
<!DOCTYPE dbdata SYSTEM "dbdata.dtd">
<dbdata>
</myna:text>
  <!-- up to here is just echoed, defines 
           <?xml version="1.0"?>
           <!DOCTYPE dbdata SYSTEM "dbdata.dtd">
           <dbdata>
   -->

<myna:text>
<jdbc-info driver="</myna:text>
<myna:subst>theDBDriver</myna:subst>
<myna:text>" db_url="</myna:text>
<myna:subst>theDBURL</myna:subst>
<myna:text>" /></myna:text>

  <!-- we have now sent the jdbc-info tag with substitutions -->

<myna:text>
<user-info>
<uname>
</myna:text>
<myna:subst>theUserName</myna:subst>
<myna:text>
</uname>
  <upass>
</myna:text>
<myna:subst>theUserPassword</myna:subst>
<myna:text>
</upass>
</user-info>
</myna:text>

  <!-- we have now sent the user-info tag with substitutions -->

<myna:text><table name="</myna:text>
<myna:subst num="1">Parameter</myna:subst>

  <!-- that was Parameter[1], the table name, e.g.PresBirthday -->

<myna:text>
  <headers>
</myna:text>
<myna:substrowlist enumerateThrough="StrSeq" StrSeq="FieldName">
  <myna:text><header name="</myna:text>
  <myna:subst num="-1">FieldName</myna:subst>
  <myna:text>"  fieldType="</myna:text>
  <myna:subst num="-1">FieldType</myna:subst>
  <myna:text>" /></myna:text>
</myna:substrowlist>
<myna:text>
  </headers>
</myna:text>
  <!-- and now we have sent the headers block, enumerating through
      the FieldName strseq rather than through a rowenumeration, using
       "-1" as a current-index indicator
   -->
<myna:substrowlist>  <!-- default enumerateThrough="resultSet" -->
  <myna:text>
    <row>
  </myna:text>
    <myna:substrowlist enumerateThrough="StrSeq" name="FieldName">
      <myna:text><field name="</myna:text>
      <myna:subst num="-1">FieldName</myna:subst>
      <myna:text>"></myna:text>
      <myna:subst num="-1">FieldValue</myna:subst>
    </myna:substrowlist>
  <myna:text>
    </row>
  </myna:text>
</myna:substrowlist>
  <!-- we have now sent all the rows of the table -->
<myna:text>
</table>
</dbdata>
</myna:text>
</myna:template>

*/