added parser for such files like the new solr.key.list

it parses text files with the following syntax:
 - all lines beginning with '##' are comments
 - all non-empty lines not beginning with '#' are keyword lines
 - all lines beginning with '#' and where the second character is not '#' are commented-out keyword lines


git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@7808 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/net/yacy/cora/storage/ConfigurationSet.java

@@ -0,0 +1,261 @@
+/**
+ *  ConfigurationSet
+ *  Copyright 2011 by Michael Peter Christen, mc@yacy.net, Frankfurt a. M., Germany
+ *  First released 29.06.2011 at http://yacy.net
+ *
+ *  $LastChangedDate: 2011-05-30 10:53:58 +0200 (Mo, 30 Mai 2011) $
+ *  $LastChangedRevision: 7759 $
+ *  $LastChangedBy: orbiter $
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library 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 GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program in the file lgpl21.txt
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.yacy.cora.storage;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.AbstractSet;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.Set;
+
+/**
+ * this class reads configuration attributes as a list of keywords from a list
+ * the list may contain lines with one keyword, comment lines, empty lines and out-commented keyword lines
+ * when an attribute is changed here, the list is stored again with the original formatting
+ *
+ * @author Michael Christen
+ */
+public class ConfigurationSet extends AbstractSet<String> implements Set<String> {
+
+    private final File file;
+    private String[] lines;
+
+    public ConfigurationSet(final File file) {
+        this.file = file;
+        try {
+            final BufferedReader br = new BufferedReader(new FileReader(this.file));
+            final LinkedList<String> sl = new LinkedList<String>();
+            String s;
+            while ((s = br.readLine()) != null) sl.add(s.trim());
+            this.lines = new String[sl.size()];
+            int c = 0;
+            for (final String s0: sl) this.lines[c++] = s0;
+        } catch (final IOException e) {
+            this.lines = new String[0];
+        }
+    }
+
+    /**
+     * save the configuration back to the file
+     * @throws IOException
+     */
+    private void commit() throws IOException {
+        final BufferedWriter writer = new BufferedWriter(new FileWriter(this.file));
+        for (final String s: this.lines) {
+            writer.write(s);
+            writer.write("\n");
+        }
+        writer.close();
+    }
+
+    @Override
+    public Iterator<String> iterator() {
+        return new LineIterator(true);
+    }
+
+    public Iterator<String> disabledIterator() {
+        return new LineIterator(false);
+    }
+
+    public Iterator<Entry> allIterator() {
+        return new EntryIterator();
+    }
+
+    private boolean isCommentLine(final int line) {
+        return this.lines[line].startsWith("##");
+    }
+
+    private boolean isKeyLine(final int line) {
+        return this.lines[line].length() > 0 && this.lines[line].charAt(0) != '#';
+    }
+
+    private boolean isDisabledLine(final int line) {
+        return this.lines[line].length() > 1 && this.lines[line].charAt(0) == '#' && this.lines[line].charAt(1) != '#';
+    }
+
+    public void enable(final String key) throws IOException {
+        for (int i = 0; i < this.lines.length; i++) {
+            if (isDisabledLine(i) && this.lines[i].substring(1).trim().equals(key)) {
+                this.lines[i] = key;
+                commit();
+                return;
+            }
+        }
+    }
+
+    public void disable(final String key) throws IOException {
+        for (int i = 0; i < this.lines.length; i++) {
+            if (isKeyLine(i) && this.lines[i].equals(key)) {
+                this.lines[i] = "#" + key;
+                commit();
+                return;
+            }
+        }
+    }
+
+    public String commentHeadline(final String key) {
+        for (int i = 1; i < this.lines.length; i++) {
+            if (this.lines[i].equals(key) ||
+                (isDisabledLine(i) && this.lines[i].substring(1).trim().equals(key))
+               ) {
+                return isCommentLine(i - 1) ? this.lines[i - 1].substring(2).trim() : "";
+            }
+        }
+        return "";
+    }
+
+    public class LineIterator implements Iterator<String> {
+
+        EntryIterator i;
+        Entry nextEntry;
+        private final boolean enabled;
+
+        public LineIterator(final boolean enabled) {
+            this.enabled = enabled;
+            this.i = new EntryIterator();
+            findNextValid();
+        }
+
+        public void findNextValid() {
+            while (this.i.hasNext()) {
+                this.nextEntry = this.i.next();
+                if (this.nextEntry.enabled() == this.enabled) return;
+            }
+            this.nextEntry = null;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return this.nextEntry != null;
+        }
+
+        @Override
+        public String next() {
+            if (this.nextEntry == null) return null;
+            final String s = this.nextEntry.key();
+            findNextValid();
+            return s;
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+
+    }
+
+    public class EntryIterator implements Iterator<Entry> {
+
+        private int line;
+
+        public EntryIterator() {
+            this.line = -1;
+            findNextKeywordLine();
+        }
+
+        /**
+         * increase line counter until it points to the next keyword line
+         * @return true if a next line was found, false if EOL
+         */
+        private boolean findNextKeywordLine() {
+            this.line++;
+            if (this.line >= ConfigurationSet.this.lines.length) return false;
+            while (ConfigurationSet.this.lines[this.line].length() == 0 ||
+                   ConfigurationSet.this.lines[this.line].startsWith("##")) {
+                 this.line++;
+                 if (this.line >= ConfigurationSet.this.lines.length) return false;
+             }
+            return true;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return this.line < ConfigurationSet.this.lines.length;
+        }
+
+        @Override
+        public Entry next() {
+            final String s = ConfigurationSet.this.lines[this.line];
+            findNextKeywordLine();
+            if (s.charAt(0) == '#') return new Entry(s.substring(1).trim(), false);
+            return new Entry(s, true);
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+
+    }
+
+    public class Entry {
+        private final String key;
+        private final boolean enabled;
+        public Entry(final String key, final boolean enabled) {
+            this.enabled = enabled;
+            this.key = key;
+        }
+        public String key() {
+            return this.key;
+        }
+        public boolean enabled() {
+            return this.enabled;
+        }
+    }
+
+    @Override
+    public int size() {
+        int c = 0;
+        for (final String s: this.lines) {
+            if (s.length() > 0 && s.charAt(0) != '#') c++;
+        }
+        return c;
+    }
+
+    public static void main(final String[] args) {
+        if (args.length == 0) return;
+        final File f = new File(args[0]);
+        final ConfigurationSet cs = new ConfigurationSet(f);
+        Iterator<String> i = cs.iterator();
+        String k;
+        System.out.println("\nall activated attributes:");
+        while (i.hasNext()) {
+            k = i.next();
+            System.out.println(k + " - " + cs.commentHeadline(k));
+        }
+        i = cs.disabledIterator();
+        System.out.println("\nall deactivated attributes:");
+        while (i.hasNext()) {
+            k = i.next();
+            System.out.println(k + " - " + cs.commentHeadline(k));
+        }
+    }
+
+}