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1
4 package com.tc.text;
5
6 import java.io.PrintWriter  ;
7 import java.util.ArrayList ;
8 import java.util.Collection ;
9 import java.util.IdentityHashMap ;
10 import java.util.Iterator ;
11 import java.util.Map ;
12
13 public class PrettyPrinter {
14
15 private static final String INDENT = "--> ";
16
17 private final StringBuffer prefix;
18 private final PrintWriter out;
19 private final IdentityHashMap visited;
20
21 private final PrintPolicy defaultPolicy = new BasicPrintPolicy();
22 private final Collection policies;
23
24 private boolean autoflush = true;
25
26 public PrettyPrinter(PrintWriter out) {
27 this(INDENT, out, new IdentityHashMap ());
28 }
29
30 private PrettyPrinter(String prefix, PrintWriter out, IdentityHashMap visited) {
31 this.prefix = new StringBuffer (prefix);
32 this.out = out;
33 this.visited = visited;
34 this.policies = initPolicies();
35 }
36
37 public synchronized void autoflush(boolean b) {
38 this.autoflush = b;
39 }
40
41 public synchronized boolean autoflush() {
42 return this.autoflush;
43 }
44
45
49 private boolean accountFor(Object o) {
50 if (o == null) return false;
51 synchronized (visited) {
52 if (visited.containsKey(o)) {
53 return true;
54 } else {
55 visited.put(o, "");
56 return false;
57 }
58 }
59 }
60
61 public PrettyPrinter print(Object o) {
62 this.out.print(o);
63 if (autoflush()) this.out.flush();
64 return this;
65 }
66
67 public PrettyPrinter println(Object o) {
68 this.out.println(o);
69 if (autoflush()) this.out.flush();
70 return this;
71 }
72
73 public PrettyPrinter println() {
74 this.out.println();
75 if (autoflush()) this.out.flush();
76 return this;
77 }
78
79 public PrettyPrinter indent() {
80 return print(prefix);
81 }
82
83 public PrettyPrinter duplicateAndIndent() {
84 PrettyPrinter rv = duplicate();
85 rv.indentPrefix();
86 return rv;
87 }
88
89 private void indentPrefix() {
90 if (prefix.indexOf("+") > -1) prefix.replace(prefix.indexOf("+"), prefix.indexOf("+") + 1, "|");
91 prefix.insert(prefix.indexOf("-->"), " +");
92 }
93
94 private PrettyPrinter duplicate() {
95 return new PrettyPrinter(prefix.toString(), out, this.visited);
96 }
97
98 public PrettyPrinter visit(Object o) {
99 if (accountFor(o)) {
100 print("ALREADY VISITED: " + o);
101 return this;
102 } else {
103 return basicVisit(o);
104 }
105 }
106
107 private PrettyPrinter basicVisit(Object o) {
108 PrintPolicy policy = findPolicyFor(o);
109 return policy.visit(this, o);
110 }
111
112 private PrintPolicy findPolicyFor(Object o) {
113 if (o == null) return defaultPolicy;
114 for (Iterator i = policies.iterator(); i.hasNext();) {
115 PrintPolicy policy = (PrintPolicy) i.next();
116 if (policy.accepts(o)) { return policy; }
117 }
118 return defaultPolicy;
119 }
120
121
124 private Collection initPolicies() {
125 Collection rv = new ArrayList ();
126 rv.add(new PrettyPrintablePrintPolicy());
127 rv.add(new ShallowMapPrintPolicy());
128 rv.add(new ShallowCollectionPrintPolicy());
129 rv.add(defaultPolicy);
130 return rv;
131 }
132
133 private static interface PrintPolicy {
134 public PrettyPrinter visit(PrettyPrinter pp, Object o);
135
136 public boolean accepts(Object o);
137 }
138
139 private static class PrettyPrintablePrintPolicy implements PrintPolicy {
140
141 public PrettyPrinter visit(PrettyPrinter pp, Object o) {
142 return ((PrettyPrintable) o).prettyPrint(pp);
143 }
144
145 public boolean accepts(Object o) {
146 return o != null && o instanceof PrettyPrintable;
147 }
148
149 }
150
151 private static class ShallowMapPrintPolicy implements PrintPolicy {
152
153 public PrettyPrinter visit(PrettyPrinter pp, Object o) {
154 return pp.print(o.getClass().getName()).print(".size()=").print(((Map ) o).size() + "");
155 }
156
157 public boolean accepts(Object o) {
158 return o != null && o instanceof Map ;
159 }
160
161 }
162
163 private static class ShallowCollectionPrintPolicy implements PrintPolicy {
164
165 public PrettyPrinter visit(PrettyPrinter pp, Object o) {
166 return pp.print(o.getClass().getName()).print(".size()=").print(((Collection ) o).size() + "");
167 }
168
169 public boolean accepts(Object o) {
170 return o != null && o instanceof Collection ;
171 }
172
173 }
174
175 private static class BasicPrintPolicy implements PrintPolicy {
176
177 public PrettyPrinter visit(PrettyPrinter pp, Object o) {
178 return pp.print(o);
179 }
180
181 public boolean accepts(Object o) {
182 return true;
183 }
184
185 }
186 }
187 |
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