created mirror

Java/storage/ZZCacheContentStore.java

@@ -0,0 +1,122 @@
+/*   
+ZZCacheContentStore.java
+ *    
+ *    Copyright (c) 2000, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Tuomas Lukka
+ */
+package org.gzigzag;
+import java.util.*;
+
+/** A locally cached content storage, which tracks text changes.
+ */
+public class ZZCacheContentStore implements ContentStore,
+		ContentStorer {
+public static final String rcsid = "$Id: ZZCacheContentStore.java,v 1.7 2000/09/19 10:32:01 ajk Exp $";
+    public static boolean dbg = false;
+    final static void p(String s) { if(dbg) System.out.println(s); }
+    final static void pa(String s) { System.out.println(s); }
+
+    UndoList undo;
+    public void setUndoList(UndoList l) { undo = l; }
+
+    ZZCacheDimSpace ds;
+    public void setSpace(ZZCacheDimSpace s) { ds = s; }
+
+    /** The current contents. */
+    Hashtable c = new Hashtable();
+
+    /** The earlier connection on each cell's poswards or negwards
+     * direction at commit time.
+     * This list is created at commit time by reversing all operations
+     * so we can then compare these values and the current values to
+     * see which have changed.
+     * Hmm.. do we really even need comm?
+     */
+    Hashtable com;
+
+    static final Object nolla = new Object();
+
+    synchronized public void startCommit() {
+	com = new Hashtable();
+    }
+
+    synchronized public void endCommit(ContentStorer sto) {
+	for(Enumeration e = com.keys(); 
+	    e.hasMoreElements();) {
+	    String id = (String)e.nextElement();
+	    Object chgfrom = com.get(id);
+	    Object chgto = c.get(id);
+	    if(chgfrom == nolla) chgfrom = null;
+	    if(chgfrom == chgto ||
+		(chgfrom != null && chgfrom.equals(chgto)))
+		    continue;
+	    sto.putContent(id, chgto);
+	}
+	com = null;
+    }
+
+    /** The abstracted operation of connecting two cells.
+     * Parameters: cell1 cell2.
+     * The cells are explicitly assumed to be not connected before
+     * this.
+     */
+    protected class ChangeContent implements UndoList.Op {
+	public void undo(Object[] list, int nth) {
+	    String id = (String)list[nth+1];
+	    Object before = list[nth+2];
+	    Object after = list[nth+3];
+	    if(before == null)
+		c.remove(id);
+	    else
+		c.put(id, before);
+	    ds.invalidateText(id);
+	}
+	public void redo(Object[] list, int nth) {
+	    String id = (String)list[nth+1];
+	    Object before = list[nth+2];
+	    Object after = list[nth+3];
+	    c.put(id, after);
+	    ds.invalidateText(id);
+	}
+	public void commit(Object[] list, int nth) {
+	    String id = (String)list[nth+1];
+	    Object before = list[nth+2];
+	    Object after = list[nth+3];
+	    if(before == null)
+		com.put(id, nolla);
+	    else
+		com.put(id,before);
+	}
+    }
+
+    protected ChangeContent mychange = new ChangeContent();
+
+    public Object get(String id) { 
+	return c.get(id); 
+    }
+    public void put(String id, Object o) { 
+	undo.add(mychange, id, c.get(id), o);
+	p("SetText: "+id+" '"+o+"'");
+	c.put(id, o); 
+    }
+    public void putContent(String id, Object o) {
+	c.put(id, o);
+    }
+
+}