Package org.jibx.util
Class StringStack
- java.lang.Object
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- org.jibx.util.StringStack
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public class StringStack extends java.lang.Object
GrowableString
stack with type specific access methods. This implementation is unsynchronized in order to provide the best possible performance for typical usage scenarios, so explicit synchronization must be implemented by a wrapper class or directly by the application in cases where instances are modified in a multithreaded environment.- Author:
- Dennis M. Sosnoski
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Field Summary
Fields Modifier and Type Field Description static int
DEFAULT_SIZE
Default initial array size.private java.lang.String[]
m_baseArray
The underlying array used for storing the data.private int
m_countLimit
Size of the current array.private int
m_countPresent
The number of values currently present in the stack.private int
m_maximumGrowth
Maximum size increment for growing array.
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Constructor Summary
Constructors Constructor Description StringStack()
Default constructor.StringStack(int size)
Constructor with initial size specified.StringStack(int size, int growth)
Constructor with full specification.StringStack(java.lang.String[] strings)
Constructor from array of strings.StringStack(StringStack base)
Copy (clone) constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clear()
Set the stack to the empty state.java.lang.Object
clone()
Duplicates the object with the generic call.private void
discardValues(int from, int to)
Discards values for a range of indices in the array.void
ensureCapacity(int min)
Ensure that the array has the capacity for at least the specified number of values.private int
getAddIndex()
Gets the array offset for appending a value to those in the stack.private void
growArray(int required)
Increase the size of the array to at least a specified size.boolean
isEmpty()
Check if stack is empty.java.lang.String
peek()
Copy top value from the stack.java.lang.String
peek(int depth)
Copy a value from the stack.java.lang.String
pop()
Pop a value from the stack.java.lang.String
pop(int count)
Pop multiple values from the stack.void
push(java.lang.String value)
Push a value on the stack.private void
resizeCopy(java.lang.Object base, java.lang.Object grown)
Copy data after array resize.int
size()
Get the number of values currently present in the stack.java.lang.String[]
toArray()
Constructs and returns a simple array containing the same data as held in this stack.
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Field Detail
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DEFAULT_SIZE
public static final int DEFAULT_SIZE
Default initial array size.- See Also:
- Constant Field Values
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m_countLimit
private int m_countLimit
Size of the current array.
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m_countPresent
private int m_countPresent
The number of values currently present in the stack.
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m_maximumGrowth
private int m_maximumGrowth
Maximum size increment for growing array.
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m_baseArray
private java.lang.String[] m_baseArray
The underlying array used for storing the data.
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Constructor Detail
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StringStack
public StringStack(int size, int growth)
Constructor with full specification.- Parameters:
size
- number ofString
values initially allowed in stackgrowth
- maximum size increment for growing stack
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StringStack
public StringStack(int size)
Constructor with initial size specified.- Parameters:
size
- number ofString
values initially allowed in stack
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StringStack
public StringStack()
Default constructor.
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StringStack
public StringStack(StringStack base)
Copy (clone) constructor.- Parameters:
base
- instance being copied
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StringStack
public StringStack(java.lang.String[] strings)
Constructor from array of strings.- Parameters:
strings
- array of strings for initial contents
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Method Detail
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resizeCopy
private void resizeCopy(java.lang.Object base, java.lang.Object grown)
Copy data after array resize. This just copies the entire contents of the old array to the start of the new array. It should be overridden in cases where data needs to be rearranged in the array after a resize.- Parameters:
base
- original array containing datagrown
- resized array for data
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discardValues
private void discardValues(int from, int to)
Discards values for a range of indices in the array. Checks if the values stored in the array are object references, and if so clears them. If the values are primitives, this method does nothing.- Parameters:
from
- index of first value to be discardedto
- index past last value to be discarded
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growArray
private void growArray(int required)
Increase the size of the array to at least a specified size. The array will normally be at least doubled in size, but if a maximum size increment was specified in the constructor and the value is less than the current size of the array, the maximum increment will be used instead. If the requested size requires more than the default growth, the requested size overrides the normal growth and determines the size of the replacement array.- Parameters:
required
- new minimum size required
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ensureCapacity
public final void ensureCapacity(int min)
Ensure that the array has the capacity for at least the specified number of values.- Parameters:
min
- minimum capacity to be guaranteed
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push
public void push(java.lang.String value)
Push a value on the stack.- Parameters:
value
- value to be added
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pop
public java.lang.String pop()
Pop a value from the stack.- Returns:
- value from top of stack
- Throws:
java.lang.ArrayIndexOutOfBoundsException
- on attempt to pop empty stack
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pop
public java.lang.String pop(int count)
Pop multiple values from the stack. The last value popped is the one returned.- Parameters:
count
- number of values to pop from stack (must be strictly positive)- Returns:
- value from top of stack
- Throws:
java.lang.ArrayIndexOutOfBoundsException
- on attempt to pop past end of stack
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peek
public java.lang.String peek(int depth)
Copy a value from the stack. This returns a value from within the stack without modifying the stack.- Parameters:
depth
- depth of value to be returned- Returns:
- value from stack
- Throws:
java.lang.ArrayIndexOutOfBoundsException
- on attempt to peek past end of stack
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peek
public java.lang.String peek()
Copy top value from the stack. This returns the top value without removing it from the stack.- Returns:
- value at top of stack
- Throws:
java.lang.ArrayIndexOutOfBoundsException
- on attempt to peek empty stack
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toArray
public java.lang.String[] toArray()
Constructs and returns a simple array containing the same data as held in this stack. Note that the items will be in reverse pop order, with the last item to be popped from the stack as the first item in the array.- Returns:
- array containing a copy of the data
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clone
public java.lang.Object clone()
Duplicates the object with the generic call.- Overrides:
clone
in classjava.lang.Object
- Returns:
- a copy of the object
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getAddIndex
private int getAddIndex()
Gets the array offset for appending a value to those in the stack. If the underlying array is full, it is grown by the appropriate size increment so that the index value returned is always valid for the array in use by the time of the return.- Returns:
- index position for added element
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size
public int size()
Get the number of values currently present in the stack.- Returns:
- count of values present
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isEmpty
public boolean isEmpty()
Check if stack is empty.- Returns:
true
if stack empty,false
if not
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clear
public void clear()
Set the stack to the empty state.
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