[lang-482] Added support for substitution in variable names.
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1005974 13f79535-47bb-0310-9956-ffa450edef68
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Oliver Heger
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790140111d
commit
6f6eddbf3a
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@ -86,6 +86,16 @@
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* <pre>
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* The variable $${${name}} must be used.
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* </pre>
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* <p>
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* In some complex scenarios you might even want to perform substitution in the
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* names of variables, for instance
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* <pre>
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* ${jre-${java.specification.version}}
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* </pre>
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* <code>StrSubstitutor</code> supports this recursive substitution in variable
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* names, but it has to be enabled explicitly by setting the
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* {@link #setEnableSubstitutionInVariables(boolean) enableSubstitutionInVariables}
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* property to <b>true</b>.
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*
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* @author Apache Software Foundation
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* @version $Id$
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@ -122,6 +132,10 @@ public class StrSubstitutor {
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* Variable resolution is delegated to an implementor of VariableResolver.
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*/
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private StrLookup<?> variableResolver;
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/**
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* The flag whether substitution in variable names is enabled.
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*/
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private boolean enableSubstitutionInVariables;
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//-----------------------------------------------------------------------
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/**
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@ -571,7 +585,8 @@ private int substitute(StrBuilder buf, int offset, int length, List<String> prio
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int bufEnd = offset + length;
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int pos = offset;
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while (pos < bufEnd) {
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int startMatchLen = prefixMatcher.isMatch(chars, pos, offset, bufEnd);
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int startMatchLen = prefixMatcher.isMatch(chars, pos, offset,
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bufEnd);
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if (startMatchLen == 0) {
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pos++;
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} else {
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@ -579,7 +594,7 @@ private int substitute(StrBuilder buf, int offset, int length, List<String> prio
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if (pos > offset && chars[pos - 1] == escape) {
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// escaped
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buf.deleteCharAt(pos - 1);
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chars = buf.buffer; // in case buffer was altered
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chars = buf.buffer; // in case buffer was altered
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lengthChange--;
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altered = true;
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bufEnd--;
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@ -588,45 +603,73 @@ private int substitute(StrBuilder buf, int offset, int length, List<String> prio
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int startPos = pos;
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pos += startMatchLen;
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int endMatchLen = 0;
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int nestedVarCount = 0;
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while (pos < bufEnd) {
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endMatchLen = suffixMatcher.isMatch(chars, pos, offset, bufEnd);
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if (isEnableSubstitutionInVariables()
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&& (endMatchLen = prefixMatcher.isMatch(chars,
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pos, offset, bufEnd)) != 0) {
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// found a nested variable start
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nestedVarCount++;
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pos += endMatchLen;
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continue;
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}
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endMatchLen = suffixMatcher.isMatch(chars, pos, offset,
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bufEnd);
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if (endMatchLen == 0) {
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pos++;
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} else {
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// found variable end marker
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String varName = new String(chars, startPos + startMatchLen,
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pos - startPos - startMatchLen);
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pos += endMatchLen;
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int endPos = pos;
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if (nestedVarCount == 0) {
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String varName = new String(chars, startPos
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+ startMatchLen, pos - startPos
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- startMatchLen);
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if (isEnableSubstitutionInVariables()) {
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StrBuilder bufName = new StrBuilder(varName);
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substitute(bufName, 0, bufName.length());
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varName = bufName.toString();
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}
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pos += endMatchLen;
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int endPos = pos;
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// on the first call initialize priorVariables
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if (priorVariables == null) {
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priorVariables = new ArrayList<String>();
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priorVariables.add(new String(chars, offset, length));
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// on the first call initialize priorVariables
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if (priorVariables == null) {
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priorVariables = new ArrayList<String>();
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priorVariables.add(new String(chars,
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offset, length));
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}
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// handle cyclic substitution
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checkCyclicSubstitution(varName, priorVariables);
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priorVariables.add(varName);
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// resolve the variable
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String varValue = resolveVariable(varName, buf,
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startPos, endPos);
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if (varValue != null) {
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// recursive replace
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int varLen = varValue.length();
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buf.replace(startPos, endPos, varValue);
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altered = true;
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int change = substitute(buf, startPos,
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varLen, priorVariables);
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change = change
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+ (varLen - (endPos - startPos));
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pos += change;
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bufEnd += change;
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lengthChange += change;
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chars = buf.buffer; // in case buffer was
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// altered
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}
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// remove variable from the cyclic stack
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priorVariables
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.remove(priorVariables.size() - 1);
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break;
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} else {
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nestedVarCount--;
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pos += endMatchLen;
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}
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// handle cyclic substitution
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checkCyclicSubstitution(varName, priorVariables);
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priorVariables.add(varName);
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// resolve the variable
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String varValue = resolveVariable(varName, buf, startPos, endPos);
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if (varValue != null) {
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// recursive replace
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int varLen = varValue.length();
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buf.replace(startPos, endPos, varValue);
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altered = true;
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int change = substitute(buf, startPos, varLen, priorVariables);
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change = change + (varLen - (endPos - startPos));
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pos += change;
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bufEnd += change;
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lengthChange += change;
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chars = buf.buffer; // in case buffer was altered
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}
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// remove variable from the cyclic stack
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priorVariables.remove(priorVariables.size() - 1);
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break;
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}
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}
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}
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@ -740,7 +783,7 @@ public StrSubstitutor setVariablePrefixMatcher(StrMatcher prefixMatcher) {
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/**
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* Sets the variable prefix to use.
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* <p>
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* The variable prefix is the characer or characters that identify the
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* The variable prefix is the character or characters that identify the
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* start of a variable. This method allows a single character prefix to
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* be easily set.
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*
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@ -819,7 +862,7 @@ public StrSubstitutor setVariableSuffix(char suffix) {
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/**
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* Sets the variable suffix to use.
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* <p>
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* The variable suffix is the characer or characters that identify the
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* The variable suffix is the character or characters that identify the
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* end of a variable. This method allows a string suffix to be easily set.
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*
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* @param suffix the suffix for variables, not null
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@ -853,4 +896,29 @@ public void setVariableResolver(StrLookup<?> variableResolver) {
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this.variableResolver = variableResolver;
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}
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// Substitution support in variable names
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//-----------------------------------------------------------------------
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/**
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* Returns a flag whether substitution is done in variable names.
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*
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* @return the substitution in variable names flag
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* @since 3.0
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*/
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public boolean isEnableSubstitutionInVariables() {
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return enableSubstitutionInVariables;
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}
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/**
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* Sets a flag whether substitution is done in variable names. If set to
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* <b>true</b>, the names of variables can contain other variables which are
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* processed first before the original variable is evaluated, e.g.
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* <code>${jre-${java.version}}</code>. The default value is <b>false</b>.
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*
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* @param enableSubstitutionInVariables the new value of the flag
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* @since 3.0
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*/
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public void setEnableSubstitutionInVariables(
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boolean enableSubstitutionInVariables) {
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this.enableSubstitutionInVariables = enableSubstitutionInVariables;
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}
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}
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@ -255,6 +255,57 @@ public void testReplacePartialString_noReplace() {
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assertEquals("${animal} jumps", sub.replace("The ${animal} jumps over the ${target}.", 4, 15));
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}
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/**
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* Tests whether a variable can be replaced in a variable name.
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*/
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public void testReplaceInVariable() {
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values.put("animal.1", "fox");
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values.put("animal.2", "mouse");
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values.put("species", "2");
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StrSubstitutor sub = new StrSubstitutor(values);
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sub.setEnableSubstitutionInVariables(true);
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assertEquals(
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"Wrong result (1)",
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"The mouse jumps over the lazy dog.",
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sub.replace("The ${animal.${species}} jumps over the ${target}."));
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values.put("species", "1");
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assertEquals(
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"Wrong result (2)",
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"The fox jumps over the lazy dog.",
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sub.replace("The ${animal.${species}} jumps over the ${target}."));
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}
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/**
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* Tests whether substitution in variable names is disabled per default.
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*/
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public void testReplaceInVariableDisabled() {
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values.put("animal.1", "fox");
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values.put("animal.2", "mouse");
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values.put("species", "2");
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StrSubstitutor sub = new StrSubstitutor(values);
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assertEquals(
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"Wrong result",
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"The ${animal.${species}} jumps over the lazy dog.",
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sub.replace("The ${animal.${species}} jumps over the ${target}."));
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}
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/**
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* Tests complex and recursive substitution in variable names.
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*/
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public void testReplaceInVariableRecursive() {
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values.put("animal.2", "brown fox");
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values.put("animal.1", "white mouse");
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values.put("color", "white");
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values.put("species.white", "1");
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values.put("species.brown", "2");
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StrSubstitutor sub = new StrSubstitutor(values);
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sub.setEnableSubstitutionInVariables(true);
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assertEquals(
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"Wrong result",
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"The white mouse jumps over the lazy dog.",
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sub.replace("The ${animal.${species.${color}}} jumps over the ${target}."));
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}
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//-----------------------------------------------------------------------
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/**
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* Tests protected.
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