sascha@998: package de.intevation.flys.artifacts.datacage.templating;
sascha@998: 
sascha@1023: import java.util.ArrayList;
sascha@998: import java.util.Map;
sascha@998: import java.util.List;
sascha@998: import java.util.HashMap;
sascha@1023: import java.util.HashSet;
sascha@1023: import java.util.Set;
sascha@998: 
sascha@998: import javax.xml.xpath.XPathVariableResolver;
sascha@998: 
sascha@998: import javax.xml.namespace.QName;
sascha@998: 
sascha@998: import org.apache.log4j.Logger;
sascha@998: 
felix@4594: 
felix@4594: /**
felix@4594:  * Maintains stack of 'frames' which are maps from string to object.
felix@4914:  * Used for variables in datacage/meta-data system and acts
felix@4914:  * as a XPathVariablResolver in xpath evaluation, e.g. by own
felix@4914:  * dc: - methods.
felix@4594:  */
sascha@998: public class StackFrames
sascha@998: implements   XPathVariableResolver
sascha@998: {
sascha@998:     private static Logger log = Logger.getLogger(StackFrames.class);
sascha@998: 
felix@4594:     /** The frames (used like a stack). */
sascha@998:     protected List<Map<String, Object>> frames;
sascha@998: 
sascha@998:     public StackFrames() {
sascha@998:         frames = new ArrayList<Map<String, Object>>();
sascha@998:     }
sascha@998: 
sascha@998:     public StackFrames(Map<String, Object> initialFrame) {
sascha@998:         this();
sascha@998:         if (initialFrame != null) {
sascha@998:             frames.add(new HashMap<String, Object>(initialFrame));
sascha@998:         }
sascha@998:     }
sascha@998: 
felix@4594:     /** Push a new String->Object map. */
sascha@998:     public void enter() {
sascha@998:         frames.add(new HashMap<String, Object>());
sascha@998:     }
sascha@998: 
felix@4594:     /** Pop/Remove last String->Object map. */
sascha@998:     public void leave() {
sascha@998:         frames.remove(frames.size()-1);
sascha@998:     }
sascha@998: 
felix@4594:     /** Put Key/Value in last String->Object map. */
sascha@998:     public void put(String key, Object value) {
sascha@998:         int N = frames.size();
sascha@998:         if (N > 0) {
sascha@998:             frames.get(N-1).put(key, value);
sascha@998:         }
sascha@998:     }
sascha@998: 
felix@4594:     /** Put multiple Key/Values in last String->Object map. */
sascha@998:     public void put(String [] keys, Object [] values) {
sascha@998:         Map<String, Object> top = frames.get(frames.size()-1);
sascha@998:         for (int i = 0; i < keys.length; ++i) {
sascha@998:             top.put(keys[i], values[i]);
sascha@998:         }
sascha@998:     }
sascha@998: 
felix@4594:     /** Check last frame (string->object map) for key. */
sascha@998:     public boolean containsKey(String key) {
sascha@1716:         key = key.toUpperCase();
sascha@998:         for (int i = frames.size()-1; i >= 0; --i) {
sascha@998:             if (frames.get(i).containsKey(key)) {
sascha@998:                 return true;
sascha@998:             }
sascha@998:         }
sascha@998:         return false;
sascha@998:     }
sascha@998: 
felix@1930:     /**
felix@1930:      * Get element (variable) key.
felix@1930:      * Returns null if not found.
felix@1930:      * @param key name to resolve
felix@1930:      * @return resolution, null if not found.
felix@1930:      */
sascha@998:     public Object get(String key) {
sascha@998:         return get(key, null);
sascha@998:     }
sascha@998: 
felix@4594:     /** result[0] is modified with value when true returned.
felix@4594:      * @return false if key not found in any frame. */
sascha@1716:     public boolean getStore(String key, Object [] result) {
sascha@1716: 
sascha@1716:         key = key.toUpperCase();
sascha@1716: 
sascha@1716:         for (int i = frames.size()-1; i >= 0; --i) {
sascha@1716:             Map<String, Object> frame = frames.get(i);
sascha@1716:             if (frame.containsKey(key)) {
sascha@1716:                 result[0] = frame.get(key);
sascha@1716:                 return true;
sascha@1716:             }
sascha@1716:         }
sascha@1716: 
sascha@1716:         return false;
sascha@1716:     }
sascha@1716: 
felix@4914:     /**
felix@4914:      * Returns Object stored for as key, parameter def
felix@4914:      * if not found.
felix@4914:      */
felix@4914:     private Object get(String key, Object def) {
sascha@998: 
sascha@1716:         key = key.toUpperCase();
sascha@1716: 
sascha@998:         for (int i = frames.size()-1; i >= 0; --i) {
sascha@998:             Map<String, Object> frame = frames.get(i);
sascha@998:             if (frame.containsKey(key)) {
sascha@998:                 return frame.get(key);
sascha@998:             }
sascha@998:         }
sascha@998: 
sascha@998:         return def;
sascha@998:     }
sascha@998: 
sascha@998:     @Override
sascha@998:     public Object resolveVariable(QName variableName) {
sascha@998:         if (log.isDebugEnabled()) {
sascha@998:             log.debug("resolve var: " + variableName);
sascha@998:         }
sascha@998:         return get(variableName.getLocalPart());
sascha@998:     }
sascha@1023: 
sascha@1023:     public String dump() {
sascha@1023:         StringBuilder sb = new StringBuilder("[");
sascha@1023:         Set<String> already = new HashSet<String>();
sascha@1023: 
sascha@1023:         boolean first = true;
sascha@1023: 
sascha@1023:         for (int i = frames.size()-1; i >= 0; --i) {
sascha@1023:             Map<String, Object> frame = frames.get(i);
sascha@1023:             for (Map.Entry<String, Object> entry: frame.entrySet()) {
sascha@1023:                 if (already.add(entry.getKey())) {
sascha@1023:                     if (first) { first = false;   }
sascha@1023:                     else       { sb.append(", "); }
sascha@1023:                     sb.append('\'').append(entry.getKey())
sascha@1023:                       .append("'='").append(entry.getValue()).append('\'');
sascha@1023:                 }
sascha@1023:             }
sascha@1023:         }
sascha@1023:         return sb.append(']').toString();
sascha@1023:     }
sascha@998: }
sascha@998: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :