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003: * Copyright (c) 2001-2007, JavaPLT group at Rice University (javaplt@rice.edu)
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036:
037: package edu.rice.cs.drjava.model.definitions.indent;
038:
039: import edu.rice.cs.drjava.model.AbstractDJDocument;
040:
041: /**
042: * A question node in the decision tree for the indentation system.
043: * Calls to <code>indentLine</code> on an IndentRuleQuestion will
044: * make a decision based on context and call the same method on
045: * one of its children. The leaves of the tree are represented
046: * by IndentRuleAction objects.
047: * @version $Id: IndentRuleQuestion.java 4255 2007-08-28 19:17:37Z mgricken $
048: */
049: public abstract class IndentRuleQuestion extends IndentRuleWithTrace {
050: /**
051: * Node in decision tree to use if the rule holds in this context.
052: */
053: private final IndentRule _yesRule;
054:
055: /**
056: * Node in decision tree to use if the rule does not hold in this context.
057: */
058: private final IndentRule _noRule;
059:
060: /**
061: * Constructs a new Question indent rule using the two given children.
062: * @param yesRule Rule to use if this rule holds
063: * @param noRule Rule to use if this rule does not hold
064: */
065: public IndentRuleQuestion(final IndentRule yesRule,
066: final IndentRule noRule) {
067: _yesRule = yesRule;
068: _noRule = noRule;
069: }
070:
071: /** Determines if the given rule holds in this context.
072: * @param doc AbstractDJDocument containing the line to be indented.
073: * @param reason The reason that indentation was initiated, specified in Indenter
074: * @return true if this node's rule holds.
075: */
076: abstract boolean applyRule(AbstractDJDocument doc,
077: Indenter.IndentReason reason);
078:
079: /** Determines if the given rule holds in this context.
080: * @param doc AbstractDJDocument containing the line to be indented.
081: * @param pos Position within line to be indented.
082: * @param reason The reason that indentation was initiated, specified in Indenter
083: * @return true if this node's rule holds.
084: */
085: boolean applyRule(AbstractDJDocument doc, int pos,
086: Indenter.IndentReason reason) {
087: int oldPos = doc.getCurrentLocation();
088: doc.setCurrentLocation(pos);
089: boolean result = applyRule(doc, reason);
090: if (oldPos > doc.getLength()) {
091: oldPos = doc.getLength();
092: }
093: doc.setCurrentLocation(oldPos);
094: return result;
095: }
096:
097: /**
098: * Determines if the given rule holds in this context and calls
099: * the same method on one of its child nodes.
100: * @param doc AbstractDJDocument containing the line to be indented.
101: * @param reason The reason that indentation was initiated, specified in Indenter
102: * @return true if the caller should update the current location itself,
103: * false if the indenter has already handled this
104: */
105: public boolean indentLine(AbstractDJDocument doc,
106: Indenter.IndentReason reason) {
107: if (applyRule(doc, reason)) {
108: _addToIndentTrace(getRuleName(), YES, false);
109: return _yesRule.indentLine(doc, reason);
110: } else {
111: _addToIndentTrace(getRuleName(), NO, false);
112: return _noRule.indentLine(doc, reason);
113: }
114: }
115: }
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