001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.jet.utils;
018    
019    import org.jetbrains.annotations.NotNull;
020    
021    import java.io.IOException;
022    import java.util.Collection;
023    import java.util.Iterator;
024    
025    public class Printer {
026        private static final String INDENTATION_UNIT = "    ";
027        private static final String LINE_SEPARATOR = System.getProperty("line.separator");
028    
029        private final Appendable out;
030        private final int maxBlankLines;
031    
032        private String indent = "";
033        private int blankLineCountIncludingCurrent = 0;
034    
035        public Printer(@NotNull Appendable out) {
036            this(out, Integer.MAX_VALUE);
037        }
038    
039        public Printer(@NotNull Appendable out, int maxBlankLines) {
040            this.out = out;
041            this.maxBlankLines = maxBlankLines;
042        }
043    
044        private void append(Object o) {
045            try {
046                out.append(o.toString());
047            }
048            catch (IOException e) {
049                // Do nothing
050            }
051        }
052    
053        @NotNull
054        public Printer println(Object... objects) {
055            print(objects);
056            printLineSeparator();
057    
058            return this;
059        }
060    
061        private void printLineSeparator() {
062            if (blankLineCountIncludingCurrent <= maxBlankLines) {
063                blankLineCountIncludingCurrent++;
064                append(LINE_SEPARATOR);
065            }
066        }
067    
068        @NotNull
069        public Printer print(Object... objects) {
070            append(indent);
071            printWithNoIndent(objects);
072    
073            return this;
074        }
075    
076        @NotNull
077        public Printer printWithNoIndent(Object... objects) {
078            for (Object object : objects) {
079                blankLineCountIncludingCurrent = 0;
080                append(object);
081            }
082    
083            return this;
084        }
085    
086        @NotNull
087        public Printer printlnWithNoIndent(Object... objects) {
088            printWithNoIndent(objects);
089            printLineSeparator();
090    
091            return this;
092        }
093    
094        @NotNull
095        public Printer pushIndent() {
096            indent += INDENTATION_UNIT;
097    
098            return this;
099        }
100    
101        @NotNull
102        public Printer popIndent() {
103            if (indent.length() < INDENTATION_UNIT.length()) {
104                throw new IllegalStateException("No indentation to pop");
105            }
106    
107            indent = indent.substring(INDENTATION_UNIT.length());
108    
109            return this;
110        }
111    
112        @NotNull
113        public Printer separated(Object separator, Object... items) {
114            for (int i = 0; i < items.length; i++) {
115                if (i > 0) {
116                    printlnWithNoIndent(separator);
117                }
118                printlnWithNoIndent(items[i]);
119            }
120            return this;
121        }
122    
123        @NotNull
124        public Printer separated(Object separator, Collection<?> items) {
125            for (Iterator<?> iterator = items.iterator(); iterator.hasNext(); ) {
126                printlnWithNoIndent(iterator.next());
127                if (iterator.hasNext()) {
128                    printlnWithNoIndent(separator);
129                }
130            }
131            return this;
132        }
133    }